DEGREE PROJECT IN DESIGN AND PRODUCT REALISATION, SECOND CYCLE, 30 CREDITS STOCKHOLM, SWEDEN 2021
Next Generation Kettle A Realisation of an Induction Cooktop Kettle with Automatic Deactivation
JENNIFER LI
IDA ÖSTLUND
KTH ROYAL INSTITUTE OF TECHNOLOGY SCHOOL OF INDUSTRIAL ENGINEERING AND MANAGEMENT
Next Generation Kettle A Realisation of an Induction Cooktop Kettle with Automatic Deactivation
Jennifer Li Ida Östlund
Master of Science Thesis TRITA-ITM-EX 2021-378 KTH Industrial Engineering and Management Machine Design SE-100 44 STOCKHOLM
Examensarbete TRITA-ITM-EX 2021:378
Nästa generations vattenkokare Utveckling av en vattenkokare med automatisk avstängning för induktionshäll
Jennifer Li Ida Östlund
Godkänt Examinator Handledare 2021-06-14 Claes Tisell Claes Tisell Uppdragsgivare Kontaktperson Svensk Konstruktionstjänst AB Niklas Svahn
Sammanfattning KTH alumnerna Frida Bylund and Linnea Kåwe undersökte ett alternativt sätt att koka vatten på induktionshällar. Projektet utfördes år 2018 på företaget C3 Scandinavian Lifestyles vägnar. Idén bestod i att utveckla en mekanisk vattenkokare som stänger av sig själv när vattnet kokat upp till 100°C. Produkten skulle även uppfylla Skandinavers drömmar om ett minimalistiskt kök fritt från stökiga köksbänkar.
Detta Masterexamensarbete är en fortsättning på Bylund och Kåwes arbete och utfördes tillsammans med Svensk Konstruktionstjänst AB mot C3 Scandinavian Lifestyle. Målet var att evaluera och utveckla mekanismen i produkten för att hitta en förfinad robust lösning. En funktionsprototyp skulle tas fram - den skulle visa på mekanismens duglighet och repeterbara funktionalitet. Ett designförslag skulle realiseras i form av renderingar och en fysisk uteseendemodell som inkluderade mekanismen.
Projektet delades in i fyra faser: Frame of reference, Development of the mechanism, Evaluation of final prototype, Industrial design Proposal. Den första fasen bestod av att testa och evaluera Bylund och Kåwes mekanismförslag, samt att utföra en litteraturstudie vilken undersökte nyckelkomponenter och material för produkten. I fas två utfördes konceptgenerering och evaluering för konceptet. Metoder som: Crazy Eight´s, Brainstorming/Braindrawing, Structural and Shape variation, Negative brainstorming och Kriterieviktsmetoden användes. Den tredje fasen bestod av att konstruera en robust funktionsprototyp som repeterbart skulle kunna koka vatten. Användartester utfördes med prototypen och viktiga insikter samlades in med hjälp av Think Aloud metoden och Semi strukturerade intervjuer. Prototypen evaluerades även mot en framtagen kravspecifikation. Slutligen konstruerades ett designförslag av den mekaniska vattenkokaren i form av renderingar och en fysisk uteseendemodell, detta utfördes i projektets fjärde fas.
En väl fungerande mekanism-lösning banade vägen för en fungerande prototyp. Prototypen kokade vatten 20 gånger i rad, med testerna löpande under tre dagar, utan problem. En 0,5 liter vatten kokades på 4 minuter och 45 sekunder. Koktiden var längre än önskvärt vilket berodde på att kannan var konvex på insidan, vilket resulterade i ett oönskat avstånd till induktionshällen uppstod. Detta resulterade i en förlorad effekt. Prototypen mätte upp till ca 1000W vid användning. En orsak till att effekten var låg i prototypen var då det ferromagnetiska materialet, som förser kontakten med induktionshällen, hade delvis hade förlorat sin magnetiska förmåga i och med värme som uppstått vid tillverkandet av komponenten. Resultatet hade varit annorlunda om kannan varit planare i botten och den ferromagnetiska komponenten hade varit tillräckligt magnetisk.
Från ett hållbarhetsperspektiv skulle en mekanisk vattenkokare kunna vara mer hållbar än en elektrisk vattenkokare eftersom den inte in består av några elektriska komponenter. En livscykelanalys var utförd för att jämföra designförslaget för den mekaniska vattenkokaren med en elektrisk vattenkokare. En förenklad livscykelanalys visade att en mekanisk vattenkokare hade en bättre end-of-life potential i jämförelse med en elektrisk vattenkokare, däremot visade det sig att de valda materialen för den mekaniska vattenkokaren var listade som kritiska material vilket gjorde att koldioxidavtrycket för den mekaniska vattenkokaren var högre än förväntan. Detta kan sänkas om den mekaniska vattenkokaren inte kräver rena obehandlade material för dess komponenter.
Syftet och målet med projektet uppnåddes, en lösning för en fungerande mekanism hittades och evaluerades - mekanismen visade sig att vara tillräckligt robust för vidare utveckling av produkten. Områden för vidare utveckling var; undersökande av funktionen med plastkomponenter och toleranser för mekanismen. Master of Science Thesis TRITA-ITM-EX 2021:378
Next Generation Kettle A Realisation of an Induction Cooktop Kettle with Automatic Deactivation
Jennifer Li Ida Östlund
Approved Examiner Supervisor 2021-06-14 Claes Tisell Claes Tisell Commissioner Contact person Svensk Konstruktionstjänst AB Niklas Svahn
Abstract In 2018 KTH alumni Frida Bylund and Linnea Kåwe investigated, on behalf of C3 Scandinavian lifestyle, a new way of boiling water on an induction cooktop. The idea was to develop an induction kettle that shuts itself off when the water reaches 100°C. This product would fulfil the user desire to keep their kitchen counter minimalistic and clean from clutter and home appliance products.
This thesis is a continuation of Bylund and Kåwe’s work and carried out together with Svensk konstruktionstjänst AB. The mechanism of the product was to be evaluated and developed, resulting in a refined solution. A repetitive prototype was to be built to present and ensure the functionality of the mechanism. Furthermore, a design concept was to be realised as renderings and a physical model, which included the mechanism.
The project was divided into four phases: Frame of reference, Development of the mechanism, Evaluation of final prototype, Industrial design Proposal. The first phase consisted of testing and evaluating Bylund and Kåwe’s mechanism. Furthermore, a literature study was conducted to examine key components and materials for the product. The second phase consisted of generating concepts for the mechanism using the methods; Crazy eight´s, Brainstorming/Braindrawing, Structural and Shape variation and Negative brainstorming. The concepts were evaluated with the Weight criteria matrix to find the most suitable solution. The third phase consisted of building a robust and repetitive prototype which could be tested with users as well as evaluated against the requirements specification. The user tests were carried out with the Think aloud method and Semi structured interviews. Finally, a design proposal for the product was designed and presented with renderings and a physical model in the fourth phase.
A solution for the mechanism was found and the functional prototype was successful. It could boil water 20 times in a row over the course of three days without failure - half a liter of water boiled in 4 minutes and 45 seconds. However, the prototype was only able to manage about 1000W which resulted in a long boiling time. The power drop was partly because the jug was convex in the bottom which created an unwanted distance to the induction cooktop, hence decreasing the transferred power. The second reason was most likely that the ferrous material, which established contact with the induction cooktop, had lost some of its magnetic properties during manufacturing of the prototype. If a better jug and ferrous material for the induction cooktop could be manufactured, the prototype would perform better. An induction kettle could be more sustainable than an electric kettle since it does not consist of electrical components. An eco-analysis was conducted to compare the design suggestion of the induction kettle with an electric kettle. The simplified life-cycle assessment showed that the induction kettle had better end of life potential than an electric kettle, however the materials selected for the induction kettle proved to be on the critical materials list which made the carbon footprint of the induction kettle higher than expected. This could be lowered if the induction kettle does not require virgin materials for its components.
The purpose and the goal for the project was reached, a solution for the mechanisms was found and evaluated - the mechanism proved to be robust enough to further develop the product. Areas of future work were found; The housing and other plastic components has to be investigated further and the tolerances of the mechanism has to be customised for the solution.
Acknowledgement This project would not have been possible without several helpful people guiding us through the course of this project. The project team would like to take this opportunity to properly acknowledge and thank them. The project would not have been possible without Ulf Bork, CEO at Empire Sweden, thank you for accepting us two students to work with your idea for the product.
Thanks to all the staff at Svensk Konstruktionstjänst AB, SVEKON, for welcoming us to your offices and making us feel a part of your team. Especially thanks to Niklas Svahn and Mårten Andrén, our industrial supervisors from SVEKON. Without you this project would not have succeeded as well as it did, thank you for all the time invested in steering us in the right direction.
A great thank you to our KTH supervisor Claes Tisell for a great supervision session and guidance with our thesis, it has been invaluable for us to have you as our sounding board throughout the project!
And finally, a thank you to Jenny Janhager Stier for orchestrating a great thesis course with constructive seminars and factual information.
Jennifer Li Ida Östlund
Table of contents 1 INTRODUCTION ...... 1
1.1 BACKGROUND ...... 1 1.2 PURPOSE & DELIVERABLES ...... 2 1.3 DELIMITATIONS ...... 2 2 METHOD ...... 5
2.1 PHASE 1 - FRAME OF REFERENCE ...... 5 2.2 PHASE 2 - DEVELOPMENT OF THE MECHANISM ...... 5 2.3 PHASE 3 - EVALUATION OF FINAL PROTOTYPE ...... 6 2.4 PHASE 4 - INDUSTRIAL DESIGN PROPOSAL ...... 6 3 FRAME OF REFERENCE ...... 7
3.1 INDUCTION ...... 7 3.2 THERMOSTATIC BIMETALS ...... 9 3.3 FUNCTIONALITY TESTS OF BYLUND AND KÅWE’S PROTOTYPE ...... 10 3.4 REQUIREMENT SPECIFICATION ...... 12 4 DEVELOPMENT OF THE MECHANISM ...... 15
4.1 MECHANISM CONCEPTS ...... 15 4.2 TESTING THE CONCEPT ...... 22 4.3 CANCELATION SWITCH CONCEPTS ...... 25 4.4 FERROMAGNETIC DISC ...... 28 5 FINAL FUNCTIONAL PROTOTYPE ...... 31
5.1 PERFORMANCE ...... 32 5.2 USER TESTS & RESULTS ...... 33 6 DESIGN PROPOSAL ...... 37
6.1 EXTERIOR DESIGN ...... 38 6.2 DESIGN FOR ASSEMBLY AND MANUFACTURING ...... 40 6.3 SIMPLIFIED LIFE CYCLE ASSESSMENT ...... 44 7 DISCUSSION ...... 47
7.1 VERIFICATION & VALIDATION ...... 47 7.2 THE PROCESS ...... 48 8 FUTURE WORK & CONCLUSION ...... 51 REFERENCES ...... 53
APPENDIX A - USABILITY ENGINEERING SPECIFICATION APPENDIX B - RISK ANALYSIS APPENDIX C - REQUIREMENT SPECIFICATION APPENDIX D - THE PROCESS OF TESTING THE MECHANISM APPENDIX E - DESIGN GUIDELINES APPENDIX F - THE LID´S DESIGN PROCESS APPENDIX G - ECO AUDIT REPORT FOR THE INDUCTION KETTLE APPENDIX H - ECO AUDIT REPORT FOR THE ELECTRIC KETTLE APPENDIX I - UPDATED REQUIREMENT SPECIFICATION
1 Introduction This chapter presents the background, purpose and delimitation of the thesis.
1.1 Background In a modern Scandinavian home, there are essentially two ways to boil water today, with a saucepan/ stovetop kettle or with an electric kettle. KTH alumni Frida Bylund and Linnea Kåwe investigated in their master thesis how the two ways of boiling water can be combined to create a new solution to boil water. The solution would solve the problem of dry boiling that boiling water on a stovetop have. The master thesis was conducted on behalf of the company Empire Sweden, C3 Scandinavian Lifestyle. It was found that it is desired to keep the kitchen and especially the kitchen counter as minimalistic as possible. Induction cooktops are more frequently used in Scandinavian homes today, and boiling water on them has proven to be time and energy efficient. These two facts created an opportunity space for an induction cooktop kettle that can be stored when the product is not in use and automatically switches itself off when the water has reached boiling temperature. [1]
The previous master thesis students designed a concept for the induction kettle which resulted in a simple functional prototype and a rendered design concept. Bylund and Kåwe’s final mechanism is illustrated in Figure 1. When water is to be boiled the user activates the kettle by pushing down a button on the lid (1) from state A to state B. The kettle is activated and interacts with the induction cooktop if the button is in its lowered state, B. [1]
The principle of the mechanism is that a ferromagnetic disc (8) interacts with the induction cooktop and heats up the water inside of the jug (6). When the water reaches boiling temperature, 100°C, a bimetal snap disc (4) reacts to the water vapor and bends. The movement of the bimetal disk forces a snap fitting (5) to bend sideways to the left and thereby releases the spring-loaded rod (2 and 7) which is connected to the ferromagnetic disk (8). Causing the ferromagnetic disk to rise and interrupts the connection to the induction cooktop. [1]
Figure 1. Illustration of Bylund and Kåwe’s final mechanism [1]
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Bylund and Kåwe built a simplified functional prototype of the mechanism, using 3D printed parts, materials and components that were easily accessible. However, the mechanism needed further investigation with a more robust prototype, to ensure that the mechanism functioned as intended.
1.2 Purpose & Deliverables This thesis is a continuation of Bylund and Kåwe’s work and aims to evaluate and develop the mechanism for a more manufacturing ready design. A prototype of the product mechanism was to be developed to repeatedly test the functionality of the mechanism. Furthermore, a suggestion for the exterior design of the kettle lid that fits the mechanism was to be realised.
The project was carried out together with the Engineering firm Svensk konstruktionstjänst and Empire Sweden, specifically C3 Scandinavian Lifestyle, as a client. The deliverables for the project were a prototype that reflects the mechanism’s functionality and a model that represents its appearance, verifications and validations of the prototype, as well as a full report of the work.
1.3 Delimitations The project was limited to use the general form, material and measurements of a jug that the client provided, the C3 jug, see Figure 2. The water jug was made of borosilicate glass and met C3 Scandinavian Lifestyle’s demands concerning manufacturing. The general form of the jug is straight with a bottom diameter of 133 mm and glass thickness of 2.7 mm with a slightly thicker and concave bottom.
Figure 2. The C3 Jug provided for the project
Another delimitation was to use Bylund and Kåwe’s work as a basis, a spring to lift the ferromagnetic disc and a bimetal snap disc of type TP140/80, presented in Figure 3. A bimetal snap disc is generally used in Electric water kettle to switch the kettle off when the water reaches 100°C. It would therefore be beneficial for the product to make use of the very same component and therefore it was chosen to be at the center of the mechanism early in the project.
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Figure 3. The Bimetal snap disc
The prototype was only tested on an induction hob from Menuett 004271 [2] and an induction cooktop from Bosch PVS775FC5E [3] Figure 4 presents the induction hob and cooktop.
Figure 4. The Menuett induction hob to the left [2] and the Bosch Induction cooktop to the right [3]
The lifespan of the product was considered to be investigated after the finalisation of this master thesis, this includes long term tests of the mechanism and calculations for solid mechanics and is not a part of this thesis.
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4 2 Method The project was divided into four phases: ● Phase 1 - Frame of Reference ● Phase 2 - Development of the Mechanism ● Phase 3 - Functional Prototype ● Phase 4 - Final design proposal
These phases and corresponding contents such as the used methods are presented in this chapter.
2.1 Phase 1 - Frame of Reference Phase 1 was initiated with an investigation concerning the previous design proposal and the existing functional prototype to identify possible problem areas. To get a better understanding of the products usage and risks that could occur during the usage process, a usability engineering specification and risk analysis was made with consideration to different scenarios. The fundamental principle of the mechanism, such as ferromagnetic material and the functionality of bimetals was tested and backed up with literature studies to get a deeper knowledge.
Usability engineering specification - The Usability engineering specification contains an analysis of use specification, operating principles, user interface characteristics, use scenarios, user interface specification and hazard-related situations and scenarios. Where the hazard-related situation and scenarios in the usage study laid the basis for the risk analysis.
Risk analysis - The risk analysis is a method to analyse the potential cause, severity, probability, risk and risk control measure, making sure possible risk will be taken into consideration during the development of the product. Together making sure that the requirement specification is established with respect to the target group and how the product will be used in the end to minimise risks. The requirement specification was discussed and agreed with the client early on to ensure the goal of the product.
2.2 Phase 2 - Development of the Mechanism The second phase focused on developing functional prototypes, this phase follows a highly iterative process with continuous ideation, concept development, building and testing the prototypes for evaluation. Ideation methods used were: Crazy eight´s, Brainstorming/Braindrawing, Structural and Shape variation and Negative brainstorming.
Crazy eight´s - A method where all participants spend one minute to sketch and describe each of their ideas. With a goal to quickly generate ideas. [4]
Brainstorming & Braindrawing - With the focus on generating a large number of ideas by writing and drawing ideas without criticizing others or yourself. The goal is quantity rather than quality in these methods. [5]
Structural & Shape variation - Structural variation is a method where the structure of the idea varies in location (in relation to other), dimension (of a specific part) and amount (parts) while working in a matrix. Shape variation varies the shape of parts of the idea in a matrix. [6]
5 Negative brainstorming - A brainstorming method to generate solutions by thinking of bad solutions to the problem and transform them into solutions that solve these problems. [7]
Weight criteria matrix - Concepts were evaluated using a weighted criteria matrix. Including criteria that have an impact on the decision with a weight to assess the importance and impact the criteria has on the decision form insignificant to great impact (1-3). The concepts were evaluated against the criteria which could score 1,3 or 5 in each criterion. [8]
2.3 Phase 3 - Evaluation of Final Prototype Phase 3 involved an evaluation of the final prototype, which consisted of a verification and validation process. Verifying the prototype through evaluation of the requirement and function specification and validating with user tests to estimate the prototypes performance and how it meets user needs.
Thinking aloud - Or user narration is a method where the users are asked to use the product while continuously thinking out loud, verbalizing their thought throughout the process. The method is generally used with the goal to discover what the users really think of the design and usage process as well as learning the why to how they are using the product in a specific way. [9]
Semi-structured Interview - Interview method where the user is asked questions simultaneously while the user is using the product and after the usage phase to get an understanding of how the product is used, why and how the product is perceived in general. The method reveals information in the usage moment that the user might not be aware of and general insights about the process. [9]
2.4 Phase 4 - Industrial Design Proposal The final stage was phase 4 it involved: identifying design guidelines, with a designer mixerboard and an is/is not analysis, and a simplified life cycle assessment. A final design proposal was developed in this phase.
Designer Mixerboard - The design mixerboard act as guiding rules to obtain a coherency between different designers and generally consider three different categories: application, semantics and tweaks. Key words connected to what the product should express through the design will be determined and described. The application part of the design mixerboard was used to describe what the product expresses and in what way it is communicated in the volume, surface, detail, material/texture, graphics or colour. [10]
Is/is not – Is a method that explains what a product or brand is and what it is not. The method was used to clarify the design mixerboard and get a coherent vision of the design of the product a comparison between some different products were made with the descriptions from the design mixerboard as a basis. The comparison was done on two products that are not too different to enhance the vision and expression for the desired goal. [11]
Simplified life cycle assessment - A method to help estimate the carbon footprint, energy consumption and cost of a product. The analysis was in this project made with Ansys Granta Edupack feature Eco audit tool. Input data is product usage routines, material weights and choices as well as transportation logistics such as packaging sizes or transportation vehicle and distance. [12]
6 3 Frame of Reference This chapter presents the project's frame of reference. It is a summary of the online literature study of the fundamental principles of induction and thermostatic bimetals and Kåwe and Bylund’s project and results. The induction analysis included an investigation to a saucepan’s connection to an induction cooktop. The analysis aided the design and optimization of the connection between the developed product and the induction cooktop. This pre study was critical to proceed with the project in the right direction.
3.1 Induction Induction cooking generates heat directly from the induction cooktop to the cookware with minimal heat losses between heating element and cookware. According to Tom Williams, a researcher at National Renewable Energy Lab, induction stoves have an efficiency of 85% which is comparable with an electric kettle that has an efficiency of 80%. The efficiency of induction cooktops and electric kettles are quite similar but varies depending on the quality of the product [13]. The overall energy efficiency of boiling water is however much dependent on the user's boiling habits. Where an immense amount of energy is wasted through overfilling and reboiling [14].
The technology behind induction cooktops relies on the principle of magnetic induction, see Figure 5. The induction cooktop contains a planar coil of wire where alternating current passes through resulting in an oscillating magnetic field which couples to a cookware with a ferromagnetic bottom. The oscillating magnetic field induces a magnetic flux producing an alternating current, eddy current, that generates heat directly in the cookware. [15]
Figure 5. Section view of a cooking vessel on an induction cooktop
The obtained magnetic field, B, from the planar coils alternating current, I, drops rapidly with distance, r, and number of coil wire turns, N. The magnetic field at a distance r is calculated through
NI B = (1) 2r
The permeability, μ, of a material is the measure of magnetization that the material obtains when exposed to a magnetic field. The permeability is calculated as
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= r 0 (2)
where μr is the relative permeability and μ0 is the permeability of free space which is equal to 1.257×10-6 m kg s-2 A-2.
The current flow depends on the resistance of the metal [15]. The electric power is given by
P= RI 2 (3) where I is the current that flows in the cookware and R is the resistance of the cookware’s ferromagnetic bottom calculated as
R = (4) where ρ is the resistivity and δ is the skin depth. The resistivity measures how strongly a material resists electric currents. The skin depth of a material represents the depth in a material where an electric current will flow and is calculated as = 3160 (5) r f where f is the frequency of excitation, ρ is the resistivity and μ is the permeability. The resistivity, permeability and skin depth of Carbon steel 1010, stainless steel 432, stainless steel 304, aluminium and copper are presented in Table 1. [16]
Table 1. Resistivity, relative permeability and skin depth of Carbon steel 1010, stainless steel 432, stainless steel 304, aluminium and copper [16]
Resistivity (ρ) Relative permeability (μr) Skin depth at 24 kHz (δ) Material [10-6 ohm-inches] [ohm-inches] [inches]
Carbon steel 1010 9 200 0.004
Stainless steel 304 20 1 0.112
Aluminium 3004 1.12 1 0.022
Copper 0.68 1 0.017
Aluminium and copper are excellent conductors for both heat and electricity, however cooktops made of aluminium or copper alone do not work on induction cooktops because of the material's deep skin depth and low resistivity. Conventional magnetic materials such as carbon steel 1010 that have a high permeability, a low skin depth and high resistivity which provide the material with good magnetic properties and allows for good contact with an induction cooktop. The material's high permeability induces larger voltages to drive the induced eddy currents which produces heat. Cookware for induction cooking is therefore developed of laminated utensils for efficient heating and high electric power for example with five layers. The laminated utensil, shown in Figure 6, is made of stainless steel 304 for the bottom, middle and top layer, cold rolled steel in layer two and aluminium in the fourth layer.
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Figure 6. The five layers of the laminated utensil in cookware for induction cooking [16]
The stainless steel on the top and bottom layer acts as a corrosion protection and provides the utensil with a high resistivity skin. The middle layer of stainless steel acts as a bond between the cold rolled carbon steel and aluminium. The cold rolled steel offers the necessary magnetic properties to induce the eddy currents. The aluminium layer provides the cookware with its high thermal conductivity and makes sure that the cooking temperature is uniform throughout the cookware. [16]
A utensil that elaborate with five layers is however not a necessity for induction cooking. A sandwich principle using three layers of material is more commonly used in saucepans. The saucepan bottoms are often impact bonded stainless steel, where a layer of aluminium is bonded through high pressure between two thin layers of stainless steel, one magnetic and one non-magnetic [17].
Stainless steel 304 is the most common type used in saucepans but cannot solely be used for induction saucepans since it is not magnetic enough. The material needs additional magnetic properties for the utensil to work properly on induction cooktops. A material that has been used instead is Stainless steel 430. Stainless steel 430 is food safe and has a high electric resistivity resulting in a superior performance on an induction cooktop. 430 is less expensive compared to stainless steel 304 since it does not contain nickel, which makes 304 more corrosion resistant than 430. However, 430 has been used for components that must withstand corrosive environments, which is enough since the induction kettle in this project is not intended to be used in these kinds of environments [18] [19].
3.2 Thermostatic Bimetals Thermostatic bimetal is a composite material made of at least two layers that are permanently bonded together, each layer having a different coefficient of thermal expansion. When the material is subjected to changes in temperature it will result in a change in curvature. There are several different thermostatic bimetal shapes, for example spiral coils, cantilever strips, U-shapes and discs.
A thermostatic bimetal material is made of two metal strips of identical length which have different coefficients of thermal expansion at a given temperature, one high and the other low. When the temperature rises the strips' relative lengths change. The low expansion strip will be under tension and the high expansion strip will be under compression. A moment is the result of these combined forces, which causes the material to bend in a uniformed arc. Figure 7 presents this phenomenon. Thermostatic bimetal bending is directly proportional to the metal strips temperature changes as well as to the difference in coefficients of expansion. The bending is inversely proportional to the total thickness of the merged strips. [20]
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Figure 7. How bimetal strips expand and bends with temperature changes
3.3 Functionality Tests of Bylund and Kåwe’s Prototype Bylund and Kåwe built a prototype that reflected the function of their proposal, see Figure 8. It was critical to further investigate the prototype with functionality tests and efficiency calculations to analyse the functionality of the mechanism and problem areas that need further work.
Figure 8. The functional prototype assembled to the left and disassembled to the right. Picture borrowed from Bylund and Kåwe [1]
Functionality Tests The received prototype from Bylund and Kåwe was built around a tapered glass jug with 149 mm as the bottom diameter and 2.3 mm glass thickness, a 3D-printed snap fitting, lathed rod and a water-cut ferromagnetic disc. However, the 3D-printed parts of the prototype in PLA had to be replaced at the very start since they had shrunk and deformed in the previous prototype tests. Therefore, a new snap fitting for the prototype was modelled and printed.
Tests with the prototype were made on a 2000W induction hob from Menuett [2]. The tests included activating the prototype to boil water by pressing down the spring-loaded rod and analysing the release of the snap fitting as well as the elevation of the ferromagnetic disc when the water reached boiling temperature.
A critical insight was gathered from these tests - the functional prototype did turn off when the water reached boiling temperature, but not because of the bimetal snap disc’s reaction as was the intention. The prototype turned off because the PLA material in the 3D-printed snap fitting melted and became
10 soft and flexible which released the loaded rod. The melting of the PLA was only visible during a short period of time, when the temperature was at its highest. After the test, the PLA quickly cools down and the snap fitting reforms back to its initial shape but slightly deformed making the hook unreliable for repeated use. These results suggest that additional research and investigation into the mechanism had to occur.
The functional prototype had to be updated to properly reflect the functionality of the design proposal, therefore the components were modelled and ordered to be 3D - printed in PA with infused glass beads, which withstands a temperature of 100°C without being deformed. Figure 9 shows the updated prototype.
Figure 9. The functional prototype assembled to the left and disassembled to the right.
This prototype could test the reaction of the bimetal snap disc in combination with the snap fit mechanism. It could also test the effects of directing the water vapor towards the bimetal snap disc via pipes. The test was carried out on a 2000W induction hob and with the updated prototype.
The tests indicated that the mechanism was quite unstable, the hook often released prematurely due to vibrations from the water, and the hook seldom released because of the reaction of the bimetal snap disc. This suggested that the mechanism was not a reliable solution and had to be redesigned. Insights gathered from these tests were that:
● The mechanism must be able to withstand vibrations, since the water bubbles heavily before it stabilizes at 100°C. ● The mechanism should be self-locking when the rod is pushed down. ● The solution should minimize the wear on the mechanism, it should not tear with use.
It was also found from the tests that directioning the water vapor towards the bimetal snap disc was an effective way to faster activate the bimetal snap disc when the water had reached the boiling temperature of 100°C.
11 Efficiency The efficiency, η, of the prototype was analysed and calculated through
mcTT−() = n 21 (6) tP
where P is the electric power, m is the mass of heated water, Cn is the specific heat capacity, ΔT is the temperature difference and t is the boiling time.
The efficiency of boiling 0.5 L water with an initial water temperature of 11°C (cold water from the tap) to 100°C on the induction hob with the prototype and a saucepan was timed and calculated, see Table 2. Where the measured power on an induction hob that claimed to provide a power of 2000W was measured with a plug-in energy monitor. The measured power with the ferromagnetic disc directly in contact with the induction hob was measured to 1480 W for comparison.
Table 2. Measured power and efficiency for boiling water with the prototype and a saucepan
Diameter Time Efficiency Measured power [W] [mm] [s] (eq 6)
Bylund & Kåwes Prototype 125 1140 243 0.67
Saucepan 125 1800 132 0,78
The low efficiency is first and foremost due to the distance between the ferromagnetic disc and induction hob which is a result of having a jug in glass. The concave shape of the bottom of the jug is another reason that adds to the distance. The distance that the glass jug gives decreases measured power with around 300 W.
3.4 Requirement Specification In order to identify problem areas and risks, a usability engineering specification and risk analysis was conducted, see Appendix A & B. Critical findings from the usability specification, risk analysis and important insights from the tests of Bylund and Kåwe’s prototype was the foundation for the requirement specification. The specification was a critical document in the project which the results of the project would be evaluated and verified against. The specification was divided into four headlines: Active use, Cleaning, Safety and Function & Performance. The full requirement specification, including measurements and reference values is presented in Appendix C.
Active use The product is only intended to be used indoors, on an induction cooktop and only for boiling water. These demands describe the fundamental usage areas for the product and were critical to determine, for a common understanding of the fundamental principle of the product.
Furthermore, to ensure that the product is intuitive to use it should indicate when it is or is not activated. It shall also indicate minimum and maximum allowed water level. The product needs to be easily refilled with water and therefore the refilling opening cannot be smaller than a standardized water tap.
12 An important finding from the usability specification was that the process of boiling water with the product should be able to be cancelled by the user. This was considered a critical function to enhance the user experience of the product and therefore stated in the requirement specification. C3 Scandinavian Lifestyle suggested that the product's water capacity should be at least 1,2 liter but not more than 1,7 liters. These sizes have been proven to be popular amongst C3 Scandinavian Lifestyle’s customers and were therefore decided.
Cleaning Users will need to clean the product from limestone and other substances, which adds several demands on the product. The jug should be able to be cleaned in the dishwasher and allow the user to clean it by hand.
Safety There are several risks connected to the usage of a product that manage hot content. Therefore, it was critical to place several demands concerning leakage of hot water and the fitting of the lid against the jug. User injuries due to malfunction of the product cannot be tolerated. It was stated that the jugs material had to be able to withstand high temperature and not burst if the jug would be placed empty in its activated state on an induction cooktop. The pressure inside of the jug must be taken into consideration, overpressure inside the product should not be able to occur, due to safety reasons. Another safety demand was that the user should be able to get a grip of the jug even with moist hands. The temperature of the jug handle should not exceed 50°C to prevent burns. Lastly all materials in the product must be food safe and to the highest extent, recyclable.
Function & Performance A few function and performance requirements were further stated. The first one concerning the time it would require to boil 1 liter of water with the power of 3000W, since a risk with the product was that it might lose too much of its efficiency because of the ferromagnetic material that is not in direct contact with the induction cooktop, and might lead to unsatisfied users. The boiling time was therefore determined to a maximum of 3 minutes, close to the time it takes to boil water in an electric kettle.
The product's material must be protected against corrosion, high cooking temperature and humidity - to reach full functionality. Water is not to be allowed to accumulate in other places than the jug, it must be drained from the mechanism and the lid. Further, pure functionality demands were stated such as the product shall be deactivated when the bimetal component reaches 100 °C, and the product shall have connection to the induction cooktop when in activated state and lose connection when it deactivates. The minimum lifespan was stated to be three years or to manage at least 10 000 boils. The aim was to prolong the lifespan.
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14 4 Development of the Mechanism The most critical phase of the project was to find a reliable solution for the mechanism of the product and this chapter describes the process of designing the mechanism.
Several ideation methods were used to generate ideas. The ideation session started with the Crazy eight´s, to cleanse all top-of-mind ideas in the beginning phase of the ideation. The method resulted in six different quick ideas. Several ideas were further ideated through brainstorming and brain drawing sessions to generate more ideas. The focus was to ensure that there is a stable fitting between the locking of the rod that would withstand vibrations. Also, it was critical to reduce friction, since the bimetal snap disc reacts with a limited force.
To test out different ideas quick prototypes were built with ice cream sticks, easily bendable metal, parts and components from other products and 3D printing. Building quick prototypes helped to understand the functionality and movement of the ideas. This resulted in 3 more refined concepts based on different principles. A structural variation was used to generate and test out different ways of positioning and dimensioning the components in relation to each other for each of the concepts. This method helped to bring out the best possible combination for the mechanism. The concepts were then evaluated with a weighted evaluation matrix.
To test the concept and realise the functionality, some more refined functional prototypes were built for the chosen concept. The prototypes were evaluated through repeated testing to get a sense of the mechanism's stability and longevity.
4.1 Mechanism Concepts Iterations of ideating and building quick prototypes resulted in three more defined concepts. The main function in all concepts was to make use of the bimetal snap disc in combination with a spring-loaded rod. All concepts use a compression spring; however, the same effect could be achieved with a tension spring.
Concept 1 The first concept is based on the Bic M10 Pen, shown in Figure 10. The idea came from the fact that a Bic pen requires a small force to generate a large movement while its locking mechanism is reliable, which is the same principles that the induction kettle should adhere to.
Figure 10. A Bic M10 Pen
15 Figure 11 presents the principle implemented in concept 1 with all its components.
Figure 11. Schematic figure over Concept 1, based on a Bic pen
The basis of the concept is a form dependent locking component. The spring-loaded rod is kept in place with the locking part (8) which is wedged in between the housing walls (4) due to the spring force from the compression spring (7). The spring force pushes on the piston (9) and thereby locks the locking part (8). Figure 12 presents the concepts movement in sequence when the bimetal reacts and releases the mechanism.
When the bimetal snap disc (3) reacts from the hot water vapor it will push the foot of the locking part (8), which turns sideways. The foot will push down on the piston (9) and overcome the force from the compression spring (7) for a short while before letting go and sliding up inside the housing (4), raising the rod (5) and ferromagnetic disc (6).
Figure 12. Schematic sequence of Concept 1. Rod and disc locked to the left and released to the right
16 Concept 2 Concept 2 was designed with inspiration from the induction design of the electric kettle’s temperature controller switch that is used to switch of an electric kettle when the water has reached 100°C. The temperature controller switch is designed in a way that the force from the bimetal disc pushes on a plate spring, see Figure 13, which breaks the circuit and thereby switches the kettle off.
Figure 13. The temperature controller switch, thermostat and coupler part from an electric kettle
A plate spring is a component that help increase the stroke length of the bimetallic motion, see Figure 14. The spring plate has three static states, two unloaded states where the spring plate is resting (State 1 and 3) and one loaded state in the middle (State 2). The plate spring in the middle state is loaded and balanced in a sensitive position, a small force would make it strive towards one of the resting states. In Figure 14 the plate spring is striving towards the unloaded state 3, but it is stopped by the fixed housing. A small push from the bimetal snap disc pushes the spring plate over the sensitive middle state 2 and make it strive towards the other side, the unloaded state 1. Figure 15 presents the principle implemented in concept 2 with all its components.
Figure 14. Description of the spring plates function in the concept
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Figure 15. A Schematic figure of Concept 2, based on a temperature controller switch
The general functionality of this mechanism is based on the movement of the bimetal disc (3), plate spring (9) and a rotating snap hook (10). A schematic sequence figure of the mechanism is presented in Figure 16. The plate spring (9) in this concept is placed between a snap hook (10) and a fixed wall where the bimetal disc (3) is fastened. The snap hook (10) is at the same time connected to the fixed wall with a rotational joint giving the design a lever. When the bimetal disc (3) is activated, the bent disc will push one end of the snap hook (10) and the plate spring (9) away from the rod waist (5). The rotation of the snap hook frees the way for the rod to move upward with the compression spring (7), lifting the ferromagnetic disc (6) up and disconnecting the magnetic field, thus cancels the induction.
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Figure 16. Schematic sequence of concept 2. Rod and disc locked to the left and released to the right
Concept 3 The last concept was inspired by the function of a solder sucker, see Figure 17, a product used when soldering. When the button is pressed a loaded spring releases creating a vacuum inside of the Solder sucker which sucks up the solder.
Figure 17. A solder sucker
19 Figure 18 presents the principle implemented in concept 3 with all its components.
Figure 18. Schematic figure over Concept 3, based on a solder sucker
The piston with pin (10) hinders the spring-loaded rod (5) from moving upwards in the locked position, since the pin (11) locks against the waist of the rod (5) with the help of the small compression spring (9). When the bimetal snap disc (3) reacts, it overcomes the force from the small compression spring (9), resulting in the piston (10) moving sideways to the right in the housing (3) which releases the rod (5). The rod and ferromagnetic disc (6) rise with the compression spring (7) and disconnects from the induction cooktop. Figure 19 presents the mechanism's movement from a locked to a released position.
Figure 19. Schematic figure of concept 3. Rod and disc locked to the left and released to the right
20 Mechanism - Concept Evaluation The concepts were evaluated and weighted against each other using a Weight criteria matrix, see Table 3. The criteria that evaluated the concepts were stated through discussions based on the gathered insights from the previous prototype and design for assembly guidelines. The criteria and its weights, 1-3, are explained and motivated below.
Table 3. Evaluation matrix for mechanism concepts
Criteria Weight (1-3)
Concept 1 Concept 2 Concept 3 Withstands 3 5 5 5 vibrations
Size 2 5 4 5
Few components 2 5 3 5
Friction surfaces 2 2 5 4
Assembly 1 5 3 4 sequence
SUM 22 20 23
SUM WITH 44 42 47 WEIGHT
Withstand vibrations - The mechanism had to be able to withstand vibrations caused by the boiling water in the jug, this was discovered when analysing Bylund and Kåwe’s prototype. It was important that such vibrations did not disturb the functionality of the mechanism to ensure the reliability of the mechanism, hence it was weighted the highest, a 3.
Size - The mechanism should be as small as possible. This was a conclusion from the requirement specification since the mechanism cannot be allowed to occupy too much of the space inside the jug. This would also cause the product to look bulky. Due to these requirements this criterion was weighted a 2.
Few components - Simplicity was strived for with fewer components. Fewer components often suggest a lower price point for the product, since it reduces the assembly time and requires less manufacturing tools. This was estimated to be equally important to the size of the mechanism and was weighted a 2.
Friction surfaces - The Bimetal snap disc reacts with a limited amount of force that must be large enough to ensure the reliability of the mechanism. The number of friction surfaces in the mechanism should therefore be as low as possible, making it easier for the bimetal snap disc to overcome the
21 required force. Depending on the friction surface placement and component design the surfaces can be more or less critical. This criterion was weighted a 2.
Assembly sequence - The assembly sequence is of importance to minimise the assembly time and cost. This criterion was an estimation of how complex the concept might become in an assembly perspective. It was weighted a 1.
The evaluation matrix suggested that Concept 3 would be the best for further investigation. Concept 3 was found to be a simple and neat mechanism with few components, which would allow for a discreet design of the product. It also withstands vibrations well, which was established when a solder sucker was investigated. The functionality of this solution is already confirmed in an actual product, the solder sucker, which was a major advantage to consider. However, the winning concept was tightly followed by Concept 1, which in comparison fell on the finish line because of the friction that the concept will encounter. The concept needs to compress the spring a little further when releasing the rod which lowers the reliability of the mechanism resulting in a score of 2 for the criteria friction surfaces. Concept 2 and 3 will also encounter friction but the surfaces for these concepts were not considered as critical.
Furthermore, it was found that Concept 2 was the worst out of the three concepts mainly due to the design for assembly guidelines where the concept scored low. The concept scored a 3 on Number of components and assembly sequence, since the concept required additional joints and fastening solutions resulting in a high assembly complexity which was not the case for Concepts 1 and 3.
4.2 Testing the Concept The functionality of the mechanism for the chosen concept, Concept 3, was further analysed, tested and evaluated. The process was iterative, and a more detailed description is presented in Appendix D.
Firstly, since the general mechanism of the chosen concept was built on an existing product, a solder sucker, it was of interest to analyse the design of this product and investigate different solder suckers to identify the best design for the application. A solder sucker was disassembled, see Figure 20. The solder sucker is built of a tip, housing, washers, collet, shaft, compression springs and a piston with a pin.
Figure 20. Components in a solder sucker
It was found that solder suckers are designed a bit different from each other, the positioning of the spring, shape of the button and shape of the piston are different. The solder suckers that were analysed are presented in Figure 21.
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Figure 21. Some solder suckers on the market that were analysed.
Components from different solder suckers were used and tested for the prototype. Both springs were replaced with more suitable springs, a spring that will lift for the weight of the rod and ferromagnetic disc and a spring that was strong enough to lock the rod in place and that the bimetal disc can overcome. The constant factor characteristic of the springs, k, was calculated with Hooke's law by
F k= x (7) where F is the spring force estimated by the needed weight to compress the spring and x is the offset distance from the equilibrium position.
Tests with the first functional prototypes showed that the tolerances between the housing and the overall case are of importance for a stable control of the total movement. It was further realized that a metal piston, which locks the rod in place, would increase the life length of the product and be more reliable since it will not tear as much as a form-dependent plastic.
The movement and force that the bimetal disc generates when it reacts was analysed by heating up the bimetal disc and fastening the disc in different ways. The fastening method affects the movement of the bimetal disc which was considered. A fastening that is completely fixed resulted in a slow bending of the bimetal, which is not desired in order to overcome the spring force and move the piston enough to release the rod. On the other hand, a bimetallic disc that is fastened loosely will allow the bimetal to move itself rather than pushing the piston. The maximum force of the bimetallic snap disc is approximately 2.1 N from the resting state to the bent state, based on tests. The shape and states of the bimetal is presented in Figure 22. The bimetal disc has a circular cut out on top and a corresponding cylindrical shape can lock the rotation of the disc.
Figure 22. Bimetal disc from the front(left), the side resting state (middle) and side bent state (right)
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Furthermore, the shape of the bimetal disc affects the shape of the piston. Since the flap of the bimetal disc bends out and deviates to the otherwise flat surface the piston it should be shaped to focus on the flap. This ensures that the bimetal disc reaches and pushes the piston, creating the largest possible movement when it snaps, see Figure 23.
Figure 23. Focused piston VS unfocused piston
To test out the overall functionality of the mechanism, a functional prototype was built by using on hand products of materials that can withstand high temperatures (~120°C). The rod was attached to the ferromagnetic disc and placed inside the solder sucker case. A bimetal snap disc housing, from an electric water kettle, was fastened against the solder sucker with cable ties and the water vapor was directed through a pipe. Figure 24 presents the prototype. The mechanism was then tested by boiling water on an induction hob.
Figure 24. Prototype 1 built with a solder sucker as the locking mechanism to test the function
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The prototype was successful and showed that the mechanism worked for the application. The reaction of the bimetal disc at 100 °C pushed on the piston which released the locking of the ferromagnetic disc. The prototype was however not built well enough to be used repeatedly since the cable ties became weaker with use and made the fastening of the bimetal disc unstable resulting in an inconsistent distance between the bimetal and piston. A more robust prototype that ensures a repetitive usage was of interest for prototype 2.
4.3 Cancelation Switch Concepts An important insight stated in the beginning of the project was the fact that the product would benefit from having a cancelation switch which would minimise unnecessary annoyance. The cancelation switch would allow the user to cancel their usage of the product and lift the ferromagnetic plate manually when the bimetal has not reacted.
The ideation began with the method Negative brainstorming, where the characteristics of what makes a switch poorly designed were stated. The goal was to find solutions that avoided the negative characteristics. The main findings were that the characteristics of a poorly designed switch is a switch that: ● Does not provide the user with feedback ● Is often pressed accidently ● Is not intuitive ● Ruin the aesthetic design
The movement of the bimetal disc is small, and a corresponding movement in a switch would be perceived as unsatisfying to a user. A well-designed switch should therefore require a larger movement to activate the cancelation than the bimetal snap disc requires. The placement and sensitivity of the switch should be carefully designed to prevent the switch from being pressed accidentally.
The product does not require a large colourful switch that could be perceived as an emergency switch. The functionality of the switch should instead be an option to disconnect the product from the induction stove top. Hence the cancellation switch should be neutral to colour and size. Furthermore, it is important that the product’s aesthetic design is appealing to most users, and a cancelation switch should therefore follow the design guidelines of the product.
The general idea for the manual deactivation mechanism was to take advantage of the existing way the mechanism is releasing the lock - by putting force on the bimetal disk and let it snap and push on the piston or push directly on the piston. This would require the least number of components and it would be the most space efficient way to solve the problem. Three different deactivation concepts were generated and evaluated: Slide switch, Toggle switch and Button switch.
Slide Switch The first concept was the slide switch, see Figure 25. The idea was to spring load a slide switch which should be placed on top of the product’s lid. The switch can then be slid horizontally by a user and thereby push on the bimetal snap disk. This would result in releasing the rod and ferromagnetic disc and cancel the connection with the induction cooktop. When the user lets go of the slide switch it would return to its initial position with the help of a compression spring.
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Figure 25. Schematic overview of the Slide switch concept. The Slide switch is illustrated in dark blue
Toggle Switch Figure 26 presents the second concept, the Toggle switch. This concept uses a torsion spring to relocate a lever arm to its initial state after a user has pushed it towards the bimetal snap disk. The lever arm travels in an arc of a circle to reach the bimetal component.
Figure 26. Schematic overview of the Toggle switch concept. The Toggle switch is illustrated in dark blue
Button Switch The Button switch concept, which is presented in Figure 27, is quite similar to the slide switch. It travels horizontally and uses a compression spring to relocate to its initial position.
Figure 27. Schematic overview of the Button switch concept. The Button switch is illustrated in dark blue
26 Cancelation Switch - Concept Evaluation The concepts were weighted and evaluated against each other via a Weight criteria matrix, see Table 4. The criteria and its weights, 1-3, are explained and motivated below. The concepts could score 1, 3 or 5 for each criterion. . Table 4. Evaluation Matrix for manual deactivation mechanisms
Criteria Weight (1-3) Button switch Toggle switch Slide switch
Few components 3 5 1 5
Intuitive 3 5 3 1
Discreet 2 3 1 5
Size 1 5 3 3
Accessibility 2 3 5 1
SUM 21 13 15
SUM AFTER WEIGHT 42 24 30
Few Components - A low number of components indicates a simple solution which is cost efficient, it also implies that the complexity of the solution is low. This was considered important and was weighted a 3.
Intuitive - Equally as important was the expected experience of using the manual deactivation switch which was also weighted a 3. This criterion evaluated how well the concepts might communicate “cancel” or “stop” to the user.
Discreet - Keeping the solution sleek and not disturbing the overall design of the product was weighted a 2.
Size - The solution should aim to be as small as possible, this criterion was weighted a 1.
Accessibility - The cancelation switch must be accessible to the user. The size, stiffness and position of the interface should be taken into consideration. The importance of this criterion was rated to a 2.
The Button switch scored the highest both with and without the weights and these results suggests that this concept would be the most beneficial to integrate in the product. It has the least number of components and would result in the smallest solution. The concept was considered the most intuitive concept since a button switch is most commonly used for cancellation.
The Buttons switch was however not considered the most discreet solution since a sliding switch could be perceived as sleeker. Nor was it considered to be as accessible as the Toggle switch, because of its inability to be placed on top of the lid and rather on the side of the lid.
27 4.4 Ferromagnetic Disc To make the product more efficient the ferromagnetic disc needed to be analysed. The efficiency was analysed by testing a few saucepans while using the same induction hob with the highest power setting (2000W), the results are presented in Table 5.
Table 5. Measured power of different cookware and sizes
Diameter Measured Power Cookware [mm] [W]
Ikea Snitsig 125 1800
Ikea Annons 140 1870
Ikea Oumbärlig 145 1960
Wmf 150 1834
Menuett 155 1830
Ikea Snitsig 160 1965
Ikea Oumbärlig 180 1907
Wmf 190 1800
The tests showed that there is not a significant difference in measured power while comparing the diameters of the cookware, with the positioning of the saucepan on the induction hob as a source of error, since the positioning is of importance for the power. The tests presented the IKEA cookware Snitsig and Oumbärlig to be the best compatible with the induction hob with a power of 2000W and was chosen to be used for further development.
The IKEA cookware’s are made of three layers: stainless steel as the bottom and top layer and an aluminium layer in the middle [21]. Containing materials that elevates the heating efficiency and high power. Stainless steel as a corrosion protection that performs well together with the induction hob because of their high permeability and a quite low skin depth, which correlates to Equation 2-5 in chapter 3.1 Induction. Aluminium that has a high thermal conductivity to provide a uniform cooking temperature [16].
Three Snitsig IKEA saucepans were cut out to a 125 mm diameter to fit the water jug and further treated in different ways: one flat non treated, one concave and one with drilled holes, see Figure 28. The concave ferromagnetic disc was bent to follow the concave bottom shape of the C3 jug to decrease the distance. The disc with drilled holes was an attempt to minimise vibrations in the prototype caused by bubbles. The holes would allow the bubbles to seep through the ferromagnetic disc.
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Figure 28. Cut out ferromagnetic discs
The tests included boiling water and measuring the electric power of the three ferromagnetic discs. A comparison between the measured power when the ferromagnetic discs were placed in the C3 jug, IKEA jug and in direct contact with the induction hob is presented in Table 6.
Table 6. Measured power of the ferromagnetic discs in the C3 jug, IKEA jug & with no jug
C3 Jug IKEA Jug No Jug
Flat disc Concave disc Flat disc with holes Flat disc Flat disc
Measured Power [W] 996 No contact 933 1164 1490
Maximum power is obtained when the ferromagnetic disc is as big and close to the glass jug bottom and induction hob as possible, since the magnetic field decreases with distance – which Equation 1 in chapter 3.1 Induction shows. It is important for the jug to have a flat bottom to minimize the distance and to get a more secure contact with the induction hob. Two jugs were tested: the C3 jug which had a concave bottom and a jug from IKEA with a flatter bottom. The IKEA jug proved to be superior to the C3 jug when compared, a difference of about 130W was discovered between the two.
The test with the concave disc failed which could be due to the bending of the disc that was not perfectly made to fit and follow the shape of the water jug, which instead resulted in a larger distance between ferromagnetic plate and induction hob. However, a flat disc proved to be a must, since a concave disc would make it harder to connect to the induction hob even with a good magnetic material [22]. An assumption is that the bent ferromagnetic disc might receive an uneven magnetic flux and therefore did not connect with the induction hob, since the flux is distance dependent.
The test with the flat disc with holes showed that a few bubbles went through the holes but did not stabilise the vibrations enough to compensate for the power losses which was a result of the holes. Better steering of the rod would presumably stabilize the plate and would be a better option to solve the issue.
The measured power of the cut-out discs when placed directly on the induction hob resulted in a measured power of 1490 W, this could be compared to the measured power of a saucepan with the same diameter. A saucepan with a diameter of 125 mm resulted in a measured power of 1800 W, resulting in a power loss of about 300 W with the cut-out disc. This may be due to several reasons. The processed disc can cause the properties of the metal to change, weakening the magnetic connection to the induction
29 hob. Cutting out the disc from a saucepan results in a disc without any magnetic stainless steel in the edges which affect the flow of eddy currents through the disc.
To ensure that, when the mechanism rises the rod and ferromagnetic plate, the connection to the induction hob is lost; a test of the disconnecting distance was made. The distance it takes to interrupt the connection was measured by placing the ferromagnetic disc directly on the induction hob and to slowly lift the disc until it loses contact. This resulted in a maximum distance of 27 mm. The electric power decreases with distance between the ferromagnetic disc and induction hob. The diminishing power which is generated when the ferromagnetic disc makes contact was tested by stacking and adjusting 1 mm of paper on top of each other. The electric power for the new ferromagnetic disc was measured between each millimetre. The result is presented in Table 7.
Table 7. Measured power of the ferromagnetic disc Ø125 mm
Distance [mm] 1 2 3 4 5
Measured power [W] 1123 1040 935 888 -
The measured power decreases with about 100 W per millimetre which is the same as the result that Bylund and Kåwe’s tests proved [1]. The relation in Equation 1 in chapter 3.1 Induction shows that magnetic field decreases with the distance which suggests that the results are reliable. Furthermore, the test confirmed that the ferromagnetic disc does not connect to the induction hob at 5 mm distance where a distance of 4 mm is the limit for the used induction hob. It was noticed that the maximum distance to connect is smaller (4 mm) compared to the required minimum distance to disconnect an already connected ferromagnetic disc (27mm).
To analyse the correlation between cookware size and transferred electric power tests were executed. The time it takes to boil water with the same saucepan (Ø15 mm) on different induction hob sizes and their corresponding power on boost is shown in Table 8. The water jug should match well with the size of the hob. A small cookware on a large induction cooktop, which generally provides a higher power setting, will not necessarily result in faster boiling since the size of the cookware limits the power. The result could be that a lower power setting is activated instead.
Table 8. Time it takes to boil water with the same saucepan (Ø15 mm) on different induction hob sizes
Induction hob size Power on Boost Time [mm] [W] [s]
Ø14.5 2200 240
Ø18 3100 176
Ø21 3700 (2200 on 9*) 240 *The Ø21 mm induction hob generates a power of 2200W on the second highest setting, which was number 9.
In summary, a ferromagnetic disc that strive to achieve the following attributes is desired to obtain a sufficient power supply: ● Made of 3 layers of materials that are impact bonded. ● Minimize distance between the ferromagnetic disc and induction cooktop ● A flat disc that fits well with the water jug ● Match well with the Ø18 mm induction hob
30 5 Final Functional Prototype This chapter presents the final prototype, its performance and functionality alongside user tests conducted to investigate the solution during the usage phase.
A final prototype, more robust than the previous, was built to enable repetitive tests of the mechanism in order to evaluate its stability. The prototype is presented in Figure 29. The lid and jug were provided by C3 Scandinavian Lifestyle and the ferromagnetic plate is a cut out bottom of an IKEA saucepan (Snitsig) [21]. The block on top of the lid was designed to act as the housing for the mechanism. The block was modelled in CAD and manufactured in aluminium. Aluminium was used since it could be easily milled and did not require a special manufacturing tool and was therefore more accessible for a prototype. The rod and piston were borrowed from a solder sucker. The rod is extended with a spacer nut and screwed together with the ferromagnetic disc. The borrowed piston is in plastic.
Figure 29. Second prototype, activated to the left, deactivated to the right
A lid made from a sheet of aluminium is screwed in place on the aluminium block. The aluminium lid has a black cancelation button attached to it and ventilation holes for the water vapor. The fastening of the bimetal disc was done with screws to enable adjustment of the level of fixation, see Figure 30. It was important to make sure that the bimetal disc was kept in place but not be fastened too tightly - or it will not react. There are ventilation holes placed directly under the bimetal snap disc in the black plastic lid. The water vapor will stream up and pass by the bimetal snap disc heating it up - the vapor then escapes through the holes on the aluminium lid.
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Figure 30. Fastening of bimetal snap disc and location of ventilation holes
5.1 Performance The prototype was successful, it boiled water and shut off about 10 seconds after the water temperature reached 100°C. The 10 seconds was similar to the shut off time with an electric kettle according to tests. The time it took, the calculated efficiency and measured power for boiling water with the prototype and a saucepan with the same diameter is presented in, Table 9. Half a liter of water was heated from 11 to 100°C in 4 minutes and 45 seconds with the prototype and the efficiency was calculated to be 0.66The test was executed on the Menuett induction hob [2]. A similar result was achieved when testing the prototype on the Bosch induction cooktop [3], however it was not possible to measure the electric power during the tests with the Bosch induction cooktop.
Table 9. Data from boiling water in the prototype and saucepan on the Menuett induction hob
Measured Volume of Initial Water Efficiency Diameter Time Power Water Temp. [-] [mm] [s] [W] [L] [°C] (eq 6)
Prototype 125 996 0.5 11 285 0.66
Saucepan 125 1800 0.5 11 132 0.78
The prototype was more robust and ensured a repetitive usage for about 20 times in a row without failure. The piston from the solder sucker proved to be the prototype's weak link. After the first 20 boiling tests it deformed and was unusable. The position was replaced and worked for another 20 boils. This suggests that the piston should be more heat resistant in the final product, aluminium or a plastic like Polyamide would presumably be a good choice of material. The 20 first boiling tests were spread over three days - this suggested that the concept is stable enough to develop further.
The prototype needed additional seal between lid and jug to be fully functional, the water vapor leaked too much all around the jug resulting in that it would not pass by the bimetal snap disc. When testing the prototype, the additional seal was added with tape that covered the jug’s spout, forcing the water vapor in the right direction.
Another insight the prototype provided was that the mechanism housing should be made in plastic. Aluminium is a good conductor of heat and it contributed to cooling the bimetal snap disc until all of the aluminium block reached 100°C. When the bimetal snap disc had reacted 100°C, the snap disc was kept warm by the aluminium instead of quickly cooling down and retracting back to its initial position.
32 The result was that the prototype had to be cooled down before it could be loaded and be ready for the next test. Therefore, a more isolating material like Polyamide, which can withstand the temperature and is a good insulator, would be preferable in the product.
5.2 User Tests & Results Tests were conducted with 6 test persons. The test persons were staff from SVEKON who were unfamiliar with the project solution and prototype. They differentiated in age and gender and half of the test persons had previous experience of induction cooking.
Method and Execution The purpose of the tests was to investigate the user's experience of the mechanism; how a user might use the mechanism and when during the process the prototype is activated. Other topics were how a cancelation of the boiling process would work and what is the user's experience of the actual water boiling. The tests would also show how a user would fill the jug with water and how they wish to serve the water. The method used for the user tests was the Think aloud method, to allow for more substantial information to surface during the tests.
The tests began with showing the test persons how the induction hob worked, since its function was not a part of the test. They received instructions to boil about one teacup of water. When they had filled the prototype and activated it, the test persons were presented with a scenario where they no longer wanted to boil the water and needed to interrupt the heating. The scenario ended and the test persons resumed the heating of the water and waited until the prototype had boiled the water and raised the ferromagnetic disc. The test ended with asking the test persons to pour the boiled water in a cup and answer some follow up questions.
Results and Key Insights Results and key insights gathered from the user tests are stated below. Firstly, it became clear that users who are not accustomed to using induction cooktops had more uncertainty concerning if the prototype was activated. If the user had an induction cooktop at home or frequently used one, they knew right away when the prototype was active.
“Yes, the induction cooktop is on - that is a receipt that the prototype is active.” “I hear that it is active.”
Some users thought that the water was ready at the wrong temperature, since the water starts to bubble a little at about 75°C, and when it reaches 85-90°C it looks like it is truly boiling. They expressed that they might want to turn the prototype off prematurely. This is a phenomenon which occurs in the prototype because of the space between the ferromagnetic plate and jug bottom. The water underneath the ferromagnetic plate reaches 100°C and starts to bubble up from the sides of the plate. However, the rest of the water above has not reached boiling temperature. This phenomenon could perhaps be reduced by manufacturing a jug with a flatter bottom and decreasing the spacing between plate and jug, or alternatively make the jug in a non-see-through material so that the user does not see the first bubbles. A better circulation of the water would also reduce these premature bubbles.
Two test persons expressed that the time it takes to boil the water is unimportant for them, since they would do other things whilst the product boils the water and just wait for it to react by itself.
33 Another insight which was confirmed in two of the user tests was that the user gets anxious if the plate vibrates too much that the ferromagnetic disc rattles against the jug when the prototype is active. This can be solved with improved stability of the rod or added cushioning to the ferromagnetic disc.
Before the tests, a concern was that users might find it hard, disturbing or clumsy to lift the lid with the mechanism and ferromagnetic plate when filling the jug with water. However, this did not appear to be problematic for any of the test persons. They all lifted the lid and did not try to find alternative solutions. Figure 31 shows a user lifting the lid including the mechanism.
Figure 31. A test person puts back the lid, mechanism and ferromagnetic plate in the jug
The tests confirmed that the knob should not be reachable when the prototype is active. Since the knob in the prototype was easy to grip even at activated state, several of the test persons tried to raise the plate by grabbing the knob. This behaviour could potentially damage the mechanism and the knob should therefore be unreachable when the prototype is in active mode and the cancelation button should be used instead.
When serving the water, it was noticed that some of the test persons were worried that the lid was not placed secure enough. Almost every test person placed their other hand on top of the lid as support when pouring the heated water in a teacup, see Figure 32. They did not trust that the lid would stay in place - even if they expressed a wish that it would.
“I feel like I need to hold the lid in place, but I think it should be able to make it without my support”
Figure 32. A test person pouring water with one hand and supporting the lid with the other hand
34 Some test persons worried about the movement of the rod and ferromagnetic disc while serving water and needed to catch and hold on to the knob, see Figure 33. This behaviour was especially noticed when serving the water at the bottom when the jug was at a 90 degree angle when the rod and disc started to slide upwards more. Stopping the rod from sliding would make sure that the ferromagnetic disc does move when the user is serving the water in the kettle and reassure the user about the stability of the product. A sleek solution for this would therefore be desired.
“It feel like everything is going to tip out”
Figure 33. Catching the knob with the other hand
35
36 6 Design Proposal The C3 Induction Kettle AutoOff is a kettle that works together with an induction cooktop and automatically turns itself off when the water has reached boiling temperature. The kettle can be used for both boiling and serving the water in a presentable way while at the same time keeping the kitchen counter free from clutter when it is not in use. This chapter presents the design proposal of the kettle’s final solution, a rendering of the exterior design that follows the design guidelines and fits the mechanism, see Figure 35. This chapter also presents design for assembly and the executed simplified life cycle assessment for the design proposal. A section view presented in Figure 36 shows the positioning of the mechanism and the locking of the rod at lowered and raised position.
Figure 34. Rendering of the C3 Induction Kettle AutoOff
Figure 35. Section view of the lid at lowered and raised position
37 A physical model was built to represent the appearance and weight of the design proposal, the model is presented in Figure 36. The model also includes components of the mechanism which can be disassembled to show the functionality but is not intended for boiling water since the model is 3D- printed.
Figure 36. Model of the Induction Kettle AutoOff
6.1 Exterior design The exterior of the kettle lid was designed to fit the mechanism and follow the design guidelines with the core expressions; minimalistic, modern and industrial. The guidelines are presented in Appendix E. The exterior design was developed through iterations of sketching, 3D-modelling in solid works and quick prototypes, the thought process is presented in Appendix F.
The overall shape of the lid is simple with clean straight lines and smooth surfaces, but with sharp transitions while embracing the exposed metallic elements. The logo is placed on top of the lid, coated with a shiny varnish - designed to keep a minimalistic design with a modern and industrial touch. The lid design is presented in Figure 37.
Figure 37. The design of the lid
38 The lid will be offered in matte black polyamide, PA, with details in stainless steel. Few colours but mixing materials and finishes to express modern with interesting details that catches the eye. PA was chosen since it is a common material used in kitchen utensils due to the high durability, strength and stiffness at high temperatures. The maximum service temperature of PA is 130°C [23].
The compression spring in stainless steel, which raises the ferromagnetic plate, was decided to be placed exposed on top of the lid. The placement minimises the number of materials that will be in the water as well as it gives an industrial feel to the product.
A stainless steel filter is placed all the way around the lid and filters the boiled water while the water is poured, regardless of the placement of the lid. The lid is sealed with a silicone ring on the top and bottom edge of the filter. The silicone ensures that the lid stays in place when water is poured and makes sure that most of the water vapor goes through the mechanism. The two silicone seals provide a satisfying experience for the user when the lid is placed on the jug.
A discrete and integrated cancelation button was designed. The button is 10 mm in diameter and made of the same material and colour as the rest of the lid but with a small metallic ring to slightly highlight the otherwise discreet button and tie together the user interaction buttons. The placement and size of the button will ensure that the button will not be pressed accidently.
The knob was designed to keep the simplicity with straight lines that fit perfectly when it is pressed down and locked in place, making it intuitive and minimising the tendency of pulling the knob when it is locked, see Figure 38. The knob is highlighted on the edge with a small metallic ring expressing modernism with the change of material and finish.
Figure 38. The knob in the lowered position
Small ventilation holes for the water vaport were decided to be positioned on the top part of the knob. The placement was based on the tests that verified that holes are perceived as a function which warns the user. The holes are positioned on one side of the knob making it possible for users to lift the lid even when the water is hot.
39 The water level is printed on the glass jug and positioned on an open surface to ensure visibility, see Figure 39. The maximum and minimum amount of water that can be boiled in the kettle was limited to 1 L and 0.25 L. The minimum level 0.25 L was chosen as it is a standard cup of tea and will ensure that the user does not dry boil. The water level increases with 0.25 L to clarify the amount of water and minimize the tendency to overfill the kettle.
Figure 39. Water level printed on the jug
6.2 Design for Assembly and Manufacturing The design of the mechanism was based on Design for Assembly guidelines, by minimising the number of components, designing features that are easy to understand and making the assembly in one main direction, all to reduce the assembly time and cost. The rod and ferromagnetic disc are placed in the jug followed by putting on the lid, the locking mechanism, the protection filter and finally the compression spring for the rod which is stopped by the knob. The housing and protection filter is fastened to the lid with countersunk M2.5 screws. An exploded view is presented in Figure 40.
40 Figure 40. The exploded view of all components
Rod & Ferromagnetic disc The rod is extruded and lathed to form a waist and a sharp edge. The ferromagnetic disc is manufactured by deep drawing a stainless steel sheet for the bottom and sides followed by using an induction brazing machine to encapsulate the impact-bonded stainless steel bottom [24]. The rod is welded together with the ferromagnetic disc.
41 Lid The lid, filter and cancel button is assembled as a subassembly, see Figure 41.
Figure 41. Close up of the exploded view of the lid
The lid consists of two separate parts, the top half in PA coated with a matte finish and the filter as a second part in stainless steel with silicone seals. The top part in PA will be injection molded using two molds. The filter is made of a stainless steel sheet metal with punched holes, the sheet metal is then bent as a cylinder and covered with a silicone seal on the top and bottom edge. The filter is assembled on the top lid though snap fittings placed on the bottom of the lid.
The cancel button will be injection molded in PA and assembled with a compression spring that makes sure that the button will bounce back to its initial state after it has been pressed. The button is inserted with the compression spring through a hole on the lid and fastened with two circlips on each of the pins. The circlips are mounted from the top of the lid.
Locking mechanism & Knob The locking mechanism consists of a housing, a compression spring, a piston and the bimetal snap disc and is assembled as a subassembly, see Figure 42. The housing should be injection molded in PA with two molds and the help of shutoffs for the fastenings of the bimetal snap disc. The housing might need additional finishing processes to obtain required tolerances between the housing and the rod and the housing and the piston. The housing is fastened with countersunk M2.5 on the through the bottom of the lid.
Figure 42. Close up of the exploded view of the locking mechanism
42 A compression spring and piston will be inserted inside the housing though the hole on the side and the fastening of the bimetal snap disc was decided to be designed with hooks as they are today in an electric water kettle. The compression spring inside the piston is recommended to 1132 from Lesjöfors which have a maximum spring force of 0.91 N and a constant factor characteristic for the spring of 0.25 N/mm, properties for the spring is presented in Table 10. The spring keeps the piston in place and should be enough for the bimetal disc to overcome, since the bimetal disc force is estimated to be 2.1 N. The piston was decided to be made in stainless steel. The decision was made since no injection molds would be needed, which reduces the cost. Furthermore, the contact between aluminium and plastic surfaces results in less friction than plastic to plastic contacts. A downside with a metallic piston could be the added weight to the piston making it harder to move with the force of the bimetal disc but might be balanced out with the reduced friction. The subassembly of the locking mechanism is placed inside the lid housing and covered with a protection filter that is screwed on top of the lid. The stainless steel protection filter is soldered together with a punched ring in stainless steel. The knob will be injection molded in polyamide, PA and screwed on to the rod.
The compression spring 2813 from Lesjöfors is recommended to be used to lift the ferromagnetic plate, the spring properties is shown in Table 10. The compression spring has an unloaded length of 44 mm and has a spring force of 3.2 N which is enough to lift the ferromagnetic plate that weighs 0.2 kg and lifts a minimum of 27 mm that will automatically disconnect the plate from the induction cooktop.
The recommended materials for the components are summarised in Table 11. Components not presented in the figure are standard component and should be corrosion resistant.
Table 10. Properties for compression spring 1132 and 2813
Maximum Unloaded Spring Wire Loaded length spring force length Diameter Diameter [mm] [N] [mm] [mm] [mm] Compression 0.91 5 1.4 2.9 0.20 spring 1132 Compression 3.2 44 8.6 4 0.32 spring 2813
Table 11. Summary of the recommended materials for the components
Component Material Jug Borosilicate - 7740 Rod Stainless steel, ferritic, AISI 430, annealed Ferromagnetic disc top and bottom layer Stainless steel, ferritic, AISI 430, annealed Ferromagnetic disc middle layer Aluminum, 3004, O Pouring filter Stainless steel, austenitic, AISI 304, annealed Protection filter Stainless steel, austenitic, AISI 304, annealed Housing PA6 Knob PA6 Cancel button PA6 Piston Aluminum, A332.0, cast, T6 Silicone (VMQ, heat cured, 10-30% fumed Silicone seal silica)
43 6.3 Simplified Life Cycle Assessment A Simplified Life Cycle Assessment was made for the end product of the induction kettle with the Eco Audit tool in Ansys Granta Edupack. The goal of the analysis was first and foremost to investigate emissions and energy consumption related to the material choices of the induction kettle and the assessment was conducted with reference to an electric kettle. The recommendations for the induction kettle and an electric kettle with all of their components were listed, including the material choices and weights. The Eco Audit reports are presented in Appendix G & Appendix H. The transportation distance and transport vehicle for the two products was an estimation. The electric kettle was considered to be transported from China where most electric kettle are manufactured. Whilst, the induction kettle is considered to be transported from Europe since it was a goal of C3 Scandinavian Life Style to have manufactures in Europe and had a manufacturer in mind from the Czech Republic. Both products were considered to use 2000W for 4 minutes per day, since this would be the goal for the induction kettle as well.
The results show that the usage of a kettle, induction or electric, is the most energy consuming and costly part of the product. It is also the usage which contributes mostly to the products CO2-footprint. Helping the user to not overfill the jug and boil several times in a row would decrease these three factors and help save money, energy and reduce the CO2-footprint. C3 preferred if the product is to be manufactured in Europe rather than China, like most electric kettles are [14]. The transport for the induction kettle is better in all three aspects: it will be cheaper, more energy efficient and produce less carbon dioxide emissions. These results are presented in Figure 43-45.
The energy consumption, usage excluded, for the induction kettle showed to be slightly better than for an electric kettle, see Figure 43. This could be a result of more components in an electric kettle compared to the induction kettle. These components require additional manufacturing and materials.
Figure 43. The energy usage for the two compared products
44 . The total carbon footprint result is presented in Figure 44. The results showed that the total Carbon footprint for the material is higher for the induction kettle, this is because the stainless steel and aluminium used in the product are on either the EU or US Critical Elements List [18] [19]. A solution to decrease the footprint would be to use recycled materials in the induction kettle instead of virgin materials.
The end-of-life potential seemed more promising for the induction kettle than it is for the electric kettle. This is because all materials in the induction kettle, except for the silicone seal and ferromagnetic plate can be fully recycled. This would mean that the induction kettle would decrease its total carbon footprint at its end of life. This is not the case for the electric kettle since it is hard to recycle the heating element and electrical components inside of the electric kettle.
Figure 44. The carbon footprint of the two compared products
The cost of the kettles is quite similar, but the induction kettle includes a more expensive manufacturing process, one aspect of why the manufacturing could be higher is the manufacturing country. Producing a product in Europe compared to China would increase manufacturing costs. The costs are presented in Figure 45.
45 Figure 45. The cost of the two compared products
The eco audit tool has not taken into consideration the disposal and circular economy of the products. Repair services and spare parts can easily be sold separately to the C3 Induction Kettle Auto Off - resulting in less waste. This was possible due to the design for assembly and disassembly of the product, no parts are glued in place or fastened with irreversible snap fittings, but rather with screws. If an electrical kettle stops working, the whole product will most likely be thrown away and replaced with a brand new product.
Another topic that the eco audit tool does not recognize is the environmental and social risks and hazards that automatically come with electronic products. The European Parliament states that the risks with electronic waste are large and therefore they have created an action plan in March 2020 concerning circular economy. One of the most critical topics is that electronic waste must be decreased. Tangible goals are the customers' right to repair products and improvements to reuse products etc. [25]
46 7 Discussion Verification and validation of the design proposal and prototype were discussed in this chapter together with the delimitation and methods validity.
7.1 Verification & Validation This chapter discusses how well the requirements and demands of the design proposal and prototype have been fulfilled, via a validation and verification of the requirements specification, the updated version of the requirement specification is presented in Appendix I. Improvements are suggested and additional requirements are listed.
Active use The product indicates when it is activated: both visually, the ferromagnetic plate and knob is lowered, and audibly, a buzzing sound when the ferromagnetic plate is in contact with the induction cooktop. This is however more intuitive for a user who is accustomed to induction stove tops. The user tests noted that the user interfaces in the product are intuitive. A manual cancelation button has been added to the prototype and design proposal. However, the button could be developed further since it is difficult to assemble it as it is designed.
The prototype and design proposal shows minimum and maximum water level in black on an open surface of the jug to ensure visibility to the users. The water filling of the jug is easily executed and the opening is larger than a standardized water tap. The prototype's capacity as of now is 1 liter, due to the jug delimitation in this project. This can and should be improved in the future by making the jug larger to be able to boil at least 1.2 liters, since it is a common volume for kettles by C3.
Cleaning The jug can be washed in a dishwasher. The rest of the materials in the design proposal allows for hand wash. The mechanism is concealed to prevent dirt from accumulating in the mechanism through filters but would need further development to ensure that limestone will not be accumulated in the mechanism or enable easier access for hand wash close to the bimetal disc.
Safety The lid in the prototype does not meet the safety requirements concerning leakage of hot water. However, this has been considered in the design proposal, the lid should be sealed with silicone that should keep the lid in place and prevent leakage. This must be tested with a future prototype and tolerances have to be set.
The jug is made of borosilicate which withstands high and rapid temperature changes, is resistant to chemical corrosion and thermal shock. The risk of it bursting and shattering when placed empty on an induction stove is low since it is commonly used for household ovens and cookware. There are also ventilation solutions in both prototype and design proposal to ensure that there is no overpressure inside the jug. The handle of the jug does not get above 50°C and the glass material is not dangerously slippery with moist hands, based on tests. The choices of material in the design concept is food safe and to the greatest extent possible recyclable.
47 Function & Performance The prototype managed to boil 1 liter of water in about 8 minutes with a power of 1000W. The prototype was not able to transfer enough energy to boil the water quicker. The reason was most likely due to the ferromagnetic discs' properties being affected by the generated heat when it was cut out from the saucepan. To fully investigate how fast the product could boil water a new ferromagnetic disc should be manufactured which can manage at least 3000W. The boiling time is perceived to be slow and should be improved. Another factor to help the prototype gain power would be to optimize the distance between induction cooktop and ferromagnetic disc. This could be done by optimizing the thickness and surface of the jugs bottom. The diameter of the ferromagnetic disc and jug could also be increased to fit a larger induction hob; the larger hobs typically manage higher wattage than the small ones. The product could therefore be designed to match the 180mm induction hob instead of the current design which matches the145mm induction hob the best.
The pure functionality demands such as; when the bimetal snap disc should react, that the product should deactivate when the water reaches 100°C and that contact with the induction cooktop is established when the product is activated are all fulfilled.
A goal lifespan of the product was listed in the requirement specification, this was however not tested to estimate fulfilment. This will have to be calculated or tested when a product closer to production is to be manufactured.
Additional Requirements Additional requirements that were found during the thesis work which need to be considered when the project is developed further are listed below:
The friction between the piston and housing must be minimal and it is critical to make sure that the spring force of the compression spring, that lifts the ferromagnetic disc, does not cause too much friction. The bimetal snap disc force is limited enough and too much friction might result in poor mechanism. The fastening of the bimetal disc should have the same tolerances as in an electric kettle but should be analysed further for a reliable mechanism. Where the fastening should allow a flap movement of 2mm at a minimum. The piston which is pressed by the bimetal snap disc should be placed directly behind the snap disc, where it does not apply force on the snap disc. The bimetal snap disc must be locked in rotation. The end of the piston should focus on the bimetal snap discs flap for a reliable mechanism.
To improve the functionality and performance of the future product the distance between ferromagnetic plate and induction stove top should be minimized and not exceed a larger distance than 3mm. This implies that the jug should have as flat and thin a bottom as possible without being perceived as fragile. This should be combined with the ferromagnetic plate being placed as tightly towards the bottom as possible at the lowered state. The distance the ferromagnetic plate must be lifted to lose connection with the induction hob has to be at least 27mm. However, tests with other induction stovetops need to be executed to ensure the required distance.
7.2 The process The chosen delimitations and methods proved to be valid to fulfil the goal. Delimitations, methods used and alternative approaches are discussed below.
48 Delimitations The delimitations made for the thesis: to use the provided jug, use Bylund and Kåwe’s work as a basis, test on one induction hob and one induction cooktop and exclude tests and calculations concerning the lifespan were required due to the thesis time limitation. The delimitations made it possible to focus on the goals to develop a robust mechanism, making the analysis detailed and nuanced and ensuring a reliable result.
Limiting the project to use the provided jug made it easier to move forward in the project and focus on the functionality of the mechanism, however it resulted in a limitation of the prototype performance, especially because of the size and shape of the jugs bottom. To adjust the jug and enable possibilities to enlarge the ferromagnetic disc, for a better performance, would affect the functionality of the mechanism because of the added mass. The additional mass would require a larger spring force, for lifting the ferromagnetic disc, which would cause more friction between the piston and the housing this is critical. Recommendations for future developments and possibilities for the jug has despite the limitations been made based on tests of two jugs with different bottoms.
Testing and investigating the sensitivity to connect/disconnect the ferromagnetic disc with other induction cooktops on the market should be done for future work. However, having the limitation of testing the prototype on an induction hob and cooktop was considered reasonable. This to make sure that the prototype worked on the two applications that the product is intended for, with minor differences of performance between induction models.
Methods It was important to not try and reinvent the wheel when developing the mechanism, a focus on investigating existing products to find a suitable solution for the mechanism was therefore a priority. This was a good course of action which enabled high potential concepts. Because of this the method structural variation was suitable to identify the best variant for the application with the existing mechanism. With hindsight, it could have been beneficial to implement the found solutions in a function and means tree. That could have improved, structured and or aided the concept generation phase.
The use of the methods Designer mixerboard and is/is not was considered successful that made the final design proposal a cohesive design expression throughout the product that would fit well in a Scandinavian kitchen. To further expand the design guidelines to cover additional areas in more detail; moodboards for the texture, surface, colour and logo placement could be developed.
The Weight criteria matrix was chosen as an evaluation method since it was important to be able to compare the different criteria against each other. The importance of each criteria varied, and when properly weighted a fair decision was obtained. However, it was difficult to: determine the criteria subjectively, weigh the criteria properly and at the same time avoid redundancy. The discussion leading up to the determined criteria could have been performed as its own method and more iterative, thereby providing a more reliable result.
The LCA was an estimation of the carbon footprint and energy consumption related to the material in the product. It can be argued that the LCA as a method was a too specific method in this stage of the development process, and is somewhat true. Especially since the largest impact on environmental sustainability was related to the usage phase which in this case was based on an estimation or hypothesis. It is important to state that a life cycle assessment and sustainability of a product is a complex matter
49 and drawing strong conclusions from this analysis would not be appropriate - the analysis should be seen as an indication of what could be. Another more extensive investigation of the product could generate different results and are therefore recommended to be executed in the future.
Furthermore, prototyping was considered the right course of action to find a suitable and robust mechanism. The prototyping enabled problem discoveries early in the development phase, which minimized the risk of proceeding too far with a poor design. If the time schedule would have allowed for extended investigation calculations concerning solid mechanics and life length would have been beneficial. Perhaps even a friction simulation analysis could have aided the project. As of now the minimal life length was set to 3 years or 10 000 boils, which is too short of a life length both according to the project team and C3 Scandinavian lifestyle. The aim would definitely be to increase the life length as much as possible to increase product value and to ensure a more sustainable product.
50 8 Future work & Conclusion The goal of the thesis: to evaluate previous work, further develop the mechanism, suggest an exterior design of the kettle lid and verify the mechanism with a functional prototype are all considered fulfilled. The functional prototype showed that the mechanism is robust enough for a reliable product that will shut off automatically when the water has reached 100°C. The lid is designed to fit the mechanism and presented as renderings and a physical model. The C3 Induction Kettle AutoOff, minimises clutter on the kitchen counter and works excellently for boiling and serving water in a clean, cordless and appealing way, to fulfil the users’ needs and desires. The design should now be ready for optimisation and a second round of verification and validation. The most important step is to design a more manufacturing ready prototype in materials recommended for the product, such as Polyamide for the housing and lid, aluminium for the piston and an impact bounded ferromagnetic disc. The suggested future developments for the product are summarized in the following bullet points:
• The cancelation button should be developed further to be designed for assembly. • Test the functionality of a silicone sealed lid and tolerances between the lid and jug. • Manufacturing a new jug. o Optimising the bottom to be as flat as possible. o Optimizing the thickness of the bottom. o Bigger, to enable boiling of at least 1.2 l of water. o Preferably bigger in diameter to match well with the Ø18 mm induction hob. • Solution to prevent accumulation of limestone in the mechanism or enable hand wash close to the bimetal disc. • Manufacturing a new ferromagnetic disc. o Made through impact bonding. o Flat disc that fits well in the water jug. • Determine a new compression springs to lift the new ferromagnetic disc while considering the friction between the housing and piston. • Consider general tolerances for the housing and eventual finishing processes. • Test tolerances for the fastening of the bimetal snap disc. • Developing a sleek solution to stop the rod and ferromagnetic disc from sliding up too much, based on user test insights. • Improved the stability of the rod to minimise rattles against the jug, based on user test insights. • Tests to ensure the lifespan of the product. • Additional tests should be carried out with users to get an understanding of how the product is perceived as a whole when a prototype close to the finalised product has been manufactured. • Investigate the sensitivity to connect/disconnect the ferromagnetic disc with induction stovetops on the market.
51 52 References
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53 [22] J. Dart, “Are My Saucepans Suitable For Induction Hobs?,” 2 Feb. 2016. [Online]. Available: www.hartsofstur.com. [Accessed 18 May 2021]. [23] Ansys Granta Edupack, “Polyamides (Nylons, PA),” Ansys Granta Edupack, Canonsburg, PA., 2020. [24] Sales Export Tecno Induzione, “Induction Brazing Machinery,” 20 July 2018. [Online]. Available: www.youtube.com. [Accessed 18 May 2021]. [25] The European Parliament, “Elavfall i EU: Fakta och siffror,” 23 Dec. 2020. [Online]. Available: www.europarl.europa.eu. [Accessed 18 May 2021].
54 Appendix A
Usability Engineering Specification UES
Jennifer Li & Ida Östlund
Svensk Konstruktionstjänst AB
Appendix A: 1(10) Revision history
Date Rev Author(s) Comments 2021-05-06 C Jennifer Li Ida Östlund
CONTENTS
1 Use specification ...... 5 1.1 Intended needs the product should fulfil ...... 5 1.2 Possible needs the product should not fulfil ...... 5 1.3 Intended target group ...... 5 1.4 Intended items the products should work together with ...... 5 1.5 Intended user profile...... 5 1.6 Use environment ...... 5 1.6.1 Intended user environment ...... 5 1.6.2 Environment requirements ...... 5 1.6.3 Frequency of use ...... 6 1.6.4 Mobility ...... 6 2 Operating principles ...... 6 3 User interface characteristics ...... 6 4 Use scenarios ...... 6 4.1 Unpacking and arrival inspection ...... 6 4.2 Installation ...... 6 4.3 Preparing ...... 6 4.4 Starting device ...... 7 4.5 During operation ...... 7 4.6 End of operation ...... 7 4.7 Other ...... 7 5 User interface specification ...... 7 5.1 Purchase ...... 7 5.2 Production ...... 7 5.3 Storage ...... 7 5.4 Transport ...... 7
Appendix A: (10) 5.5 Sales method ...... 7 5.6 Unpacking ...... 7 5.7 Installation ...... 7 5.8 Usage ...... 8 5.8.1 The mechanism should be adapted to the size of the current water container. ... 8 5.8.2 Grip-friendly/ergonomic shape ...... 8 5.8.3 Minimise spills and splashes ...... 8 5.8.4 The product should be adapted to rapid temperature changes ...... 8 5.8.5 The product is intended for boiling water only ...... 8 5.8.6 Safe to use together with an induction stovetop/hub ...... 8 5.8.7 The product is intended for indoor use only ...... 8 5.8.8 Indications when activating the product ...... 8 5.8.9 Easy to fill the water container ...... 8 5.8.10 The water container should have a capacity of boiling 1.2 liter of water ...... 8 5.8.11 Maximum and minimum water level should be obvious for the user ...... 8 5.8.12 Easy to clean ...... 8 5.8.13 Fixated lid when angeling the product (during serving) ...... 8 5.8.14 No toxic substances should be able to transfer to the water ...... 8 5.8.15 Boiling water with the product should be quick ...... 8 5.8.16 Recyclable according to standards ...... 8 5.8.17 Deactivates by itself when the water has reached 100°C ...... 8 5.8.18 The material shall endure high temperatures (water vapor) ...... 8 6 Hazard-related situations and scenarios ...... 8 6.1 Transport ...... 8 6.1.1 The product generates unnecessary transportation costs ...... 8 6.2 Storage ...... 8 6.3 Unpacking and arrival inspection ...... 8 6.4 Installation ...... 8 6.5 Usage ...... 8 6.5.1 The time required to boil water is too long...... 8 6.5.2 The product is non ergonomic ...... 8 6.5.3 The product might be dropped or overturned ...... 9 6.5.4 It is difficult to fill the product with water ...... 9 6.5.5 Water is accumulated in inconvenient spaces ...... 9 6.5.6 Toxic substances are found in the boiled water ...... 9 6.5.7 The water boils over in the product ...... 9 6.5.8 Risk of over/underfilling the container with water ...... 9 6.5.9 Thermal burn injuries caused by poor design ...... 9
Appendix A: (10) 6.5.10 The product might damage other material (i.e furniture etc) ...... 9 6.5.11 The products lifespan is unsatisfactory ...... 9 6.5.12 Fire ...... 9 6.5.13 Incorrect usage might lead to injuries ...... 9 6.5.14 Overpressure in product could occur ...... 9 6.6 Cleaning ...... 9 6.6.1 The product becomes difficult to clean ...... 9 6.7 Maintenance and repair ...... 10 6.8 Disposal ...... 10 6.8.1 The product is not recyclable or incorrectly recycled ...... 10
Appendix A: (10) 1 Use specification
1.1 Intended needs the product should fulfil The product should have a capacity to boil at least 1.2 liters of water.
The product will be used together with an induction stovetop and automatically turn off when the water is boiled.
It should be easy to clean the product and the water container should be able to be cleaned in the dishwasher.
The product shall be easy to operate and move, the user shall have the ability to the move and pour water with the product with minimal to no leakage.
The user experience of the product should be satisfying and smooth, i.e. good fits and no unexpected/unwanted sounds or sudden movements. The product’s design, shape and material must satisfy the user.
1.2 Possible needs the product should not fulfil The product is only intended for boiling water and not any other substances. The product is only intended for indoor use only.
1.3 Intended target group People who lives in Scandinavia (especially Sweden) and have an induction stovetop or induction hob in their home. The target group has a desirer to be more effective in their everyday routines (want it to be quick and easy to boil water), minimise the occupied space on the kitchen counter and be able to serve boiling water in an aesthetically pleasing way.
1.4 Intended items the products should work together with Induction stovetops or induction hobs that has a minimum diameter of 145mm.
1.5 Intended user profile No education is needed. Everyone that owns an inductions stovetop/induction hob and boils water.
1.6 Use environment
1.6.1 Intended user environment
At home, the product will be used for boiling water in the kitchen and used for serving water (most often) in the kitchen, dining room and/or living room. Hot surfaces and substances will be present during the use of the product for boiling water.
1.6.2 Environment requirements
The product should endure humid environment.
Appendix A: (10) The products bottom material, that will be in contact with the induction stovetop/induction hob, must be a ferromagnetic material. The product must endure temperatures of water vapor and rapid temperature changes. The water container should endure the dishwasher. Materials used should be “Livsmedelgodkända”.
1.6.3 Frequency of use
Once per day for 3 years.
1.6.4 Mobility
Grip-friendly for moving with one hand (even wet hands).
2 Operating principles
The product is filled with water and placed on an induction stovetop or induction hob, where the water will be boiled, and the product deactivates by itself. The product will also be used as a serving vessel for serving the boiled water. 3 User interface characteristics
Button to lower and lift the ferromagnetic disk. Markings that indicates the amount of water. 4 Use scenarios
4.1 Unpacking and arrival inspection The product should be unpacked fully assembled from the delivery package. The experience during the unpacking is less important. An instruction and safety manual should be included in the packaging.
The product should be ready to use at arrival.
4.2 Installation No installation should be necessary.
4.3 Preparing Rinse the product before first use.
• Remove the lid • Fill the water container with decried amount of water • Put the lid on • Place the product on the induction stovetop/hob • Turn on the induction stovetop/hob
Appendix A: 6(10) 4.4 Starting device • Start the product by pushing down a button to lowers the induction plate.
4.5 During operation • The user does not need have to keep track of the product when it is in active use • The product will be automatically deactivated when the water has reached 100°C • The water is boiled and ready to be served. • The product will be placed on a serving area. • Water will be poured from the product.
4.6 End of operation • The product will be cleaned occasionally, the water container can be placed in the dishwasher and other parts cleaned by hand.
4.7 Other
Materials used for the product should be recyclable.
5 User interface specification
5.1 Purchase N/A
5.2 Production N/A
5.3 Storage N/A
5.4 Transport The transportation will be in the sales packaging, cardboard and shock-absorbing materials for the water container.
5.5 Sales method Online or in stores.
5.6 Unpacking N/A
5.7 Installation N/A
Appendix A: (10) 5.8 Usage 5.8.1 The mechanism should be adapted to the size of the current water container. 5.8.2 Grip-friendly/ergonomic shape 5.8.3 Minimise spills and splashes 5.8.4 The product should be adapted to rapid temperature changes 5.8.5 The product is intended for boiling water only 5.8.6 Safe to use together with an induction stovetop/hub 5.8.7 The product is intended for indoor use only 5.8.8 Indications when activating the product 5.8.9 Easy to fill the water container 5.8.10 The water container should have a capacity of boiling 1.2 liter of water 5.8.11 Maximum and minimum water level should be obvious for the user 5.8.12 Easy to clean 5.8.13 Fixated lid when angeling the product (during serving) 5.8.14 No toxic substances should be able to transfer to the water 5.8.15 Boiling water with the product should be quick 5.8.16 Recyclable according to standards 5.8.17 Deactivates by itself when the water has reached 100°C 5.8.18 The material shall endure high temperatures (water vapor)
6 Hazard-related situations and scenarios
6.1Transport 6.1.1 The product generates unnecessary transportation costs The product might be fully assembled in transport which leads to a lot of transported air.
6.2 Storage N/A
6.3 Unpacking and arrival inspection N/A
6.4 Installation N/A
6.5 Usage 6.5.1 The time required to boil water is too long. It can depend on poor connection to the induction cooktop, or that the container has poor thermal conductivity or that the deactivation mechanism doesn’t react.
6.5.2 The product is non ergonomic The product might become heavy and is therefore difficult for the user to use. The handle of the container might be poorly shaped and does not meet user needs in terms of size and shape. The handle might also be slippery, especially if the user has wet hands.
Appendix A: (10) 6.5.3 The product might be dropped or overturned The product might become hot and the user doesn’t anticipate it, the product is heavier than expected or the grip on the handle is poor.
6.5.4 It is difficult to fill the product with water The spacing for filling up the container is small, or it is difficult or inconvenient to remove the internal parts when filling the product.
6.5.5 Water is accumulated in inconvenient spaces The drainage might be unsatisfactory or water vapor unable to evaporate.
6.5.6 Toxic substances are found in the boiled water Precipitation from product materials
6.5.7 The water boils over in the product The container is filled over the maximum volume level and that combined with the power on the induction cooktop being high.
6.5.8 Risk of over/underfilling the container with water It might be hard to interpret the markings on the product, or the level of water is somehow difficult to see.
6.5.9 Thermal burn injuries caused by poor design Incorrect choices of material, water leakage or other bad design might cause thermal burns on the user, which is not acceptable.
6.5.10 The product might damage other material (i.e furniture etc) The product might be placed unprotected directly on sensitive surfaces.
6.5.11 The products lifespan is unsatisfactory Components are too weak or incorrect joints or fastening methods have been used in the product.
6.5.12 Fire Poor material choices could cause fire at high temperatures, this would occur during incorrect usage of the product - i.e. if a user activates the product and places it on the induction cooktop.
6.5.13 Incorrect usage might lead to injuries If the product is poorly constructed or includes materials that take damage during incorrect usage this could potentially be harmful for the user. I.e. the product might break and harm the user if large and rapid temperature changes occur.
6.5.14 Overpressure in product could occur If the product is poorly constructed the pressure inside of the container could be too high and eventually cause damage to the product which could lead to unnecessary risks for the user.
6.6 Cleaning 6.6.1 The product becomes difficult to clean Areas are troublesome to reach or are hidden from the user.
Appendix A: (10) 6.7 Maintenance and repair N/A
6.8 Disposal 6.8.1 The product is not recyclable or incorrectly recycled There might be information missing, materials that aren't recyclable are used in the product or components in the products require disassembly before recycling.
Appendix A: 10(10) Appendix B Risk Analysis
This appendix presents the risk analysis of a mechanical kettle that works together with an induction hob. The risk analysis including the hazard, potential cause, harm, severity, probability, risk and risk control measure or rational are presented in Table 1 below.
Table 1. The risk analysis
Hazard (Top-down) Potential cause (Top-down) R.id. Harm Severity Probability Risk Risk control measure (mitigation) or rational RCM.id. Failure mode (Bottom-up) Potential hazard (Bottom-up)
1.1 Usability hazards 1.1.1 Transport Alot of air in the package, since the Lagre transport volyme generates 1.1.1.1 product is pre-assembled when costly marginal likely unnecessary costs transported
1.1.2 Storage
1.1.3 Unpacking and arrival inspection
1.1.4 Installation
1.1.5 Usage The timme required to boil water is too The distance between the induction hob 1.1.5.1 irritation minor injury likely Prototype tests, try different distances 1.1.5.1.M1 long and the ferromagnetic plate is too large Prototype test with different bimetal components, The bimetal snap disc doesn't react to the irritaiton minor injury likely placement of the component and directioning of 1.1.5.1.M2 water vapor. And does not shut itself of. the water vapor The contianer's material has poor thermal irritation marginal likely 1.1.5.1.M3 conductivity (glass)
The product is manufactured in material 1.1.5.2 The product is non ergonomic with high density and becomes heavy to irritation marginal likely 1.1.5.2.M1 hanled The handle is not ergonomicly designed irritation marginal likely 1.1.5.2.M2 (shape and size) Poor grip on the container's handle irritation marginal likely
1.1.5.3 Drops or overturns the container The product becomes hot Health hazard major injury likely Prototype tests or trigger material tests with users 1.1.5.3.M1 The product is heavy Health hazard major injury likely Prototype tests or trigger material tests with users 1.1.5.3.M2 Poor grip on the contianer's handle Health hazard major injury likely Prototype tests or trigger material tests with users 1.1.5.3.M3
1.1.5.4 Difficult to fill the container with water The refill space is too small irritation marginal very unlikely 1.1.5.4.M1 Difficult to remove the ferromagnetic plate irritation marginal occasional Prototype tests or trigger material tests with users 1.1.5.4.M2 and lid when filling the container
Water accumulates in other spaces than damage to other Prototype tests, different angles on eventual 1.1.5.5 the drainage is not satisfactory major injury likely 1.1.5.5.M1 the container material housing surfaces damage to other Prototype tests, fill too much water and let it boil water or watervapor cannot evaporate major injury unlikely 1.1.5.5.M2 material over
1.1.5.6 Precipitation of toxic substances The products materials are not foodsafe Health hazard major injury unlikely make sure the material in the product is foodsafe 1.1.5.6.M1
Too much water is filled in the contianer 1.1.5.7 Water boils over combined with to high power [W] on the irritation neglectable frequent 1.1.5.7.M1 induction cooktop
Difficult for the user to fill the correct damage to other 1.1.5.8 amount of water in the container (too Poorly marked on the product minor injury unlikely 1.1.5.8.M1 material, irritation much or to little)
Incorrect choice of material on the 1.1.5.9 Thermal burn injuries Health hazard minor injury extremely unlikely 1.1.5.9.M1 contianer Incorrect choice of material on the handle Health hazard minor injury occasional thermal analysis of the handle's material 1.1.5.9.M2 prototpye tests or shall we make do with the Poor design of the spout Health hazard major injury likely 1.1.5.9.M3 existing container? Water leakage between lid and contianer Health hazard major injury likely prototype tests 1.1.5.9.M4 Hot steam Health hazard major injury likely 1.1.5.9.M5
Damage to furniture (heat from the The product is placed unprotected on damage to other 1.1.5.10 minor injury likely include an underlay with product? 1.1.5.10.M1 product or the boiled water) furniture material
irritation, damage to 1.1.5.11 Product has a short lifespan The products components are too weak major injury likely FEM/calculations 1.1.5.11.M1 other material Incorrect choices of joints and irritation, damage to major injury unlikely FEM/calculations 1.1.5.11.M2 attachements other material
damage to other 1.1.5.12 Fire Incorrect material choices material, Health major injury unlikely material analisys 1.1.5.12.M1 hazard The product is empty, activated and damage to other include warnings in instructions, is it the users placed on the induction cooktop. material, Health major injury unlikely 1.1.5.12.M1 responsibility to not use the product incorrectly? (torrkokning) hazard
Rapid temperature changes causes the The current container (borosilicate glass) is ok in 1.1.5.13 Incorrect usage Health hazard major injury unlikely container to crack/break this regard? 1.1.5.14 Overpressure in the container Incorrectly constructed Health hazard major injury unlikely prototpye tests 1.1.6 Cleaning The container is not completely clean irritation, unpleasant 1.1.6.1 Certain areas are difficult to reach major injury likely prototype tests 1.1.6.1 M1 after washing odor, bacteria irritation, unpleasant Narrow spaces major injury likely prototype tests 1.1.6.1 M2 odor, bacteria
1.1.7 Maintenance and repair
1.1.8 Disposal toxic/non lacks instructions or has insufficient degradable 1.1.8.1 Incorrect recycling major injury likely outside of the scope of the master thesis 1.1.8.1 M1 instruction substances in nature toxic/non degradable material cannot be recycled major injury unlikely material analisys 1.1.8.1 M2 substances in nature toxic/non degradable components require disassembly major injury likely material analisys 1.1.8.1 M3 substances in nature
Appendix B: 1(1)
Appendix C Requirements Specification
This appenix presents the Requirement specification created from UES and Risk analisys in the beginning of the project. It is divided into five categories: Water continer, Active use, Cleaning and Function and performance. The specification is presented in Table 1 below.
Table 1. Requirements specification.
Req source Req source Req Id Req text Category Test method Comment Usability Risk
Requirement Check Requirement from Usability Category of the implementation from Risk Requirement Engineering intended component or testing is analysis Specification required
1. Depending on the water container Check TR 1.1 UES. 5.9.1 Measurements of the water container: Ø130mm, Height 136mm Mech implementation TR 1.2 UES. 5.9.3 1.1.5.9 M3 The shape of the spout shall result in drip-free pouring of water UI Testing required The material choice on the water container is adapted to rapid Check TR 1.3 UES. 5.9.4 1.1.5.13 Mech temperature changes. implementation 2. Active use Check TR 2.1 UES. 5.9.5 1.1.6.1 The product is intended for boiling water only Mech implementation Check TR 2.2 UES. 5.9.6 The product is intended for use on induction hobs only Mech implementation Check TR 2.3 UES. 5.9.7 The product is intended for indoor use only Mech implementation TR 2.4 UES. 5.9.8 The product shall indicate when it is activated for boiling UI Testing required 1.1.5.4 M1 Check The approximate diameter of a water beam from TR 2.5 UES. 5.9.9 Minimum dimension for the water refill opening is 15mm in diameter Mech 1.1.6.1 implementation a kitchen tap 1.1.5.2 M1 TR 2.6 UES. 5.9.10 The product should have a capacity of boiling 1.2 liter of water Mech Testing required 1.1.5.3 M1 TR 2.7 1.1.5.12 M2 A minimum of 0.25 liter of water should be used when boiling Mech Testing required 1.1.5.12 M2 TR 2.8 UES. 5.9.11 1.1.5.7 The product visibly indicates max and min water level UI Testing required 1.1.5.8 3. Cleaning
TR 3.1 UES. 5.9.12 1.1.6.1 Water container are accessible for hand wash Mech Testing required Check TR 3.2 UES. 5.9.12 1.1.6.1 The water container can be cleaned in the dishwasher Mech implementation 4. Safety No leakage of water between lid and water container when water is TR 4.1 UES. 5.9.3 1.1.5.9 M3, M4 Mech Testing required poured No leakage of water between lid and water container when the TR 4.2 UES. 5.9.3 1.1.5.9 M3, M4 Mech Testing required product is moved
Ability to angle the product 100° vertically in the direction of the TR 4.3 UES. 5.9.13 sprout without the lid coming off. The angle is measured from the Mech Testing required products centerline when in upright position, see figure in comment.
Check TR 4.4 UES. 5.9.14 1.1.5.6 The products materials should be "Livsmedelsgodkänt" Labelling implementation Ensure that the water container does not cause the user injuries, if TR 4.5 1.1.5.13 the product is placed empty on the induction hub.
https://www-sciencedirect-com.focus.lib.kth. TR 4.6 UES. 5.9.2 1.1.5.9 M2 The handle should not be able to get hotter than 50°C. Mech Testing required se/science/article/pii/B9780128000342002202
1.1.5.2 M2, M3 The surface of the handle should be grippable with wet hands, TR 4.7 UES. 5.9.2 UI Testing required 1.1.5.3 M3 without slipping Water vapor must be able to seep out of the water container during TR 4.8 1.1.5.14 Mech Testing required boiling to prevent overpressure in the water container. 5. Function and performance Boiling 1 liter of water in room temperature on a power of 3000 W TR 5.1 UES. 5.9.15 1.1.5.1 Mech Testing required should take a maximum 3 minutes on a 145mm induction plate. Check TR 5.2 UES. 5.9.16 1.1.8.1 Recyclable material. Mech implementation Check TR 5.3 UES. 5.9.17 Bimetal deactivates the boiling at 100°C. Mech implementation 1.1.5.9 M1, M2 Materials that are in direct contact with the induction hob shall endure Check TR 5.4 UES. 5.9.6 Mech 1.1.5.12 200°C at a minimum implementation Materials that are not in direct contact with the induction hob shall Check TR 5.5 UES. 5.9.6 1.1.5.11 Mech endure 120°C at a minimum implementation Check TR 5.6 UES. 5.9.14 1.1.5.6 Material protected against corrosion Mech implementation Check TR 5.7 UES 5.9.18 1.1.5.11 M1 The product can withstand water vapor without affecting the function Mech implementation The product shall manage a power of maximum 3300W (booster Check TR 5.8 UES. 5.9.6 Mech mode on induction hobs) implementation No liquid shall be accumulated in the product other than the water TR 5.9 1.1.5.5 Mech Testing required container Longer with replaceable parts or components. 3 The product has a minimum lifespan of 3 years or 1000 numbers of Check TR 5.12 1.1.5.11 Mech years is an absolout minimum, with an aim for a boils implementation longer lifespan. The product should start boiling the water when the ferromagnetic TR 5.13 UES. 5.9.6 Mech Testing required disc is in contact with the induction hob The product should stop boiling the water when the ferromagnetic TR 5.14 UES. 5.9.6 1.1.5.11 M2 Mech Testing required disc has lost its contact with the induction hob
Appendix : 1(1)
Appendix D The Process of Testing the Mechanism
This appendix presents the process of designing, building and testing the small intermediate prototypes of the thesis project, Next Generation Kettle, written by Jennifer Li and Ida Östlund. The prototypes were made to test and find a mechanism for a mechanical water kettle used on induction stove tops. The purpose of the mechanism was to release and lift a ferromagnetic plate when the water in the kettle has reached 100°C. A schematic over the mechanism concept is shown in Figure 1.
In the activated position the pin (11) hinders the spring loaded rod (5) from moving upwards, since the pin (11) locks against the waist of the rod (5). When the bimetallic snap disc (3) reacts it overcomes the force from the piston spring (9) and the result is that the piston (10) slides sideways to the right in the housing (3) and therefore releases the rod (5). The rod and ferromagnetic disc (6) rises with the compression spring (7) and disconnects from the induction stove top.
Figure 1. The mechanism concept in sequence.
1. The Bimetal snap disc; movement and force A first Cad model was created to see if the bimetal disks force and movement would be large enough to overcome required spring forces. The model was 3D-printed and the bimetal snap disc was heated with a lighter, Figure 2 shows the setup. The compression springs on top press the model down along the rod when the bimetal snap disc reacts and releases the small compression spring.
D Figure 2. First tests: 3D-printed housing and test of spring next to the piston. Testing with a lighter for quick tests.
A critical insight was found during these tests, the area where the bimetal snap disc pushes on the piston cannot be too large, because of the shape of the bimetal. The flap of the bimetal, which snaps when activated, bends out and deviates to the otherwise flat surface. The bimetal snap disc reaction will therefore have a more reliable effect if it presses on a small area, making the force focused and more adapted to the shape of the bimetal. The shape and position of the focused and unfocused piston is shown in Figure 3.
Figure 3. Focused piston VS unfocused piston
D The movement of the piston with different springs were tested and analysed by comparing the position of the piston when the bimetal is at its original state and at activated state (snapped). The tests showed that the bimetal snap disc generated a large enough movement, about 2mm, and that its force could overcome light springs. Figure 4 shows the movement of the piston and compression of spring when the bimetal snap disc has reacted.
Figure 4. Bimetal snap disc has not reacted in figure to the left, and it has reacted in figure to the right.
2. Lifting Ferromagnetic Plate It was also important to test the springs required force to be able to lift the ferromagnetic plate. Therefore tests were made where different springs were used to lift the plate. In Figure 5 a tension spring with a force of about 4.4 N was able to lift the ferromagnetic plate with a satisfying movement. The tension spring lifted the ferromagnetic about 30mm from the bottom of the jug.
Figure 5. Testing tension springs that can lift the rod and ferromagnetic disc ~3cm
D 3. Testing the bimetal snap disc together with a correct tension spring When both springs were dimensioned and the motion of the bimetal snap disc was established testing them together was the next step. The material used was a two parted 3d printed model that was the holder of bimetal snap disc, two screws, a bimetal snapdisc and a soldersucker. The spring in the solder sucker had been replaced with the new tension spring. Figure 6 presents the setup. The test was again tested with a lighter that heated up the bimetal snap disc since water vapor would melt the PLA in the 3D-printed part, and a lighter could direct the heat to only the bimetal snap disc.
Figure 6. Testing the movement that the bimetallic disc generates with a solder sucker
The prototype worked and it was time to build a prototype that should be able to withstand water vapor, to truly test the function of the mechanism, including how the bimetallic disc should be fastened. Figure 7 presents two prototypes that could handle the heat from the water vapor enough to test the fastening of the bimetallic disc.
Figure 7. Testing different ways of fastening the bimetallic disc with onhand parts that can withstand 100°C.
The material that was used was; two solder suckers and bimetallic snap disc fasteners from an electric water kettle. The black plastic bimetal fastener in Figure 7 is a part of the mechanism inside of an
D electric water kettle that shuts the electric kettle off when the water reaches 100°C. The metallic bimetal fastener keeps the overheating protection bimetal snap disc in place in an electric water kettle.
These two prototypes were then tested by holding them over water vapor and seeing if the bimetal snap disc would react and trigger the mechanism. A realisation from these tests was that it was easier to heat up the bimetal snap disc when it was less covered up by the holder. Therefore it was decided to create the first functional prototype with the construction seen in Figure 7 to the left.
Figure 8 shows the construction from the side, both when it is loaded and when the mechanism has been triggered and released the spring loaded rod. The bimetallic flap has been focused on the piston with a black plastic piece which is glued to the red button on the solder sucker. When the bimetal reacts it presses on the black piece which moves the red button and releases the rod.
Figure 8. Solder sucker with bimetallic disc housing from a kettle tied together with cable ties with an added plastic piece to focus on the bimetallic flap.
A solution to manually trigger the mechanism was added, here in the form of a transparent plastic part which can be pressed horizontally and then releasing the rod. Figure 9 presents the sequence, starting with the rod in loaded position and ending with the rod fully released.
Figure 9. Testing the manual cancelation solution. Loaded rod to in the left picture, pressing the trigger in the middle picture and the rod fully released to the right.
D The ferromagnetic plate was added to the construction to try the mechanism with the actual weight it has to lift. A test was conducted and water vapor was directed towards the bimetal snap disc via a tube. The bimetallic snap disc reacted and lifted the spring loaded rod and ferromagnetic plate 30mm. The testing setup is shown in Figure 10.
Figure 10. Focusing the water vapor onto the bimetallic snap disc via a tube.
The last step was to place the construction in a jug and test it when the prototype produced its own water vapor. This would initially show if the concept had enough potential to produce a more stable prototype of. Figure 11 presents the setup for the test, an aluminum sheet was used as a lid for the jug. The prototype worked and lifted the ferromagnetic plate, disconnecting from the induction stove top, when the bimetallic snap disc reacted and triggered the mechanism. However this prototype was quite unstable and needed adjustments after every test, since parts were not fully fixed etc.
Figure 11. Putting it all together for Prototype 1 and testing to boil water.
D The test implied that a second more repetitive prototype, prototype 2, should be built to fully evaluate the function of the concept. The first step towards a second prototype was to find an alternative way to fasten the bimetallic snap disc. It was important that the prototype allowed for some adjustments of the fastening of the component, since the tolerances were quite sensible.
The idea was to fasten the bimetallic snap disc with screws, these screws could then be adjustable to keep the component in place without applying too little or too much pressure on it. The idea was tested with screws, and an aluminum sheet with drilled holes. The sheet and snap disc was then placed over water vapor and the component reacted well, see Figure 12.
Figure 12. Testing out the tightness of the bimetallic disc fastening with screws
D
Appendix E Design Guidelines
The industrial design phase was initiated with defining core expressions for the product, since C3 Scandinavian Lifestyle does not have a cohesive design expression to their products today. The core expressions for the product was based on the client's request to enhance a scanfincavian design which was boiled down to minimalistic, modern and industrial. The application part of the design Mixerboard was used as a tool to specify the expression of the product, see Figure 1.
Figure 1. Mixerboard
The product should express minimalistic by removing and editing down information and details that are not needed. Making sure that a minimalistic design will enhance the important features avoiding an overwhelming feeling by keeping a simplistic surface. Furthermore, the product should be perceived as modern by mixing soft curves with sharp edges to get suspense in the product and keeping the lines clean. The surfaces should be smooth with no unnecessary embellishments. Industrial should be expressed with clean straight lines and embracing exposed elements. The colors should be kept natural monochromatic such as gray, white and black.
Appendix : ( ) To define the mixerboard further the method Is/Is not was used to get a visualisation of how the expressions can work together and define what it is and is not by comparing two similar products, see Figure 2.
Figure 2. Is/Is not comparison of a lamp
Both lamps are similar but the first one is more inline with the expression of the kettle. Clean straight lines with no to minimal embellishments and smooth surfaces.
Appendix : ( ) Appendix F The Lid’s Design Process
The lid was designed to follow the design guidelines. The overall shape of the lid should follow the straight lines of the jug and focus to minimise the amount of materials touching the water when it is activated inconsideration to the sensitive user. It was further important to design the product in a way that feels familiar to the user since the product will present a new way of boiling water. This was done by taking inspiration from a coffee press to enhance familiarity and making it easy for the user to understand the product. Sketches based on the design expressions and descriptions were made with consideration to the size of the mechanism and the received jug, see Figure 1.
Figure 1. Sketches of the lid based on these design expressions and descriptions
Iterations of sketches, modeling in Solidworks and quick prototypes in cardboard were made to test and get a feeling for the size and the placement of the mechanism see Figure 2.
Figure 2. CAD models and quick prototypes to test out placements of the housing for the mechanism.
Appendix : ( ) The housing for the mechanism should be placed in a way that will not touch the water when it is boiling. The housing should at the same time be perceived as a part of the design of the lid and not extruded upwards too much. An extruded top would increase the tendency of the user to grab onto it to remove the lid and should be big enough to offer a pleasant grip.
It was further important to design the knob to be intuitive for the user to know when it has been pressed down and locked in place and when the ferromagnetic disc is elevated. This was experimented with quick models using clay, see Figure 3.
Figure 3. Testing different types of knobs using clay models.
The models clarified that a protruding knob encourages the user to grab onto it and confuses the user to know if they have pressed the button far enough. A knob that is in level with the rest of the lid, when it is pressed, will clarify that the knob is pressed enough at the same time as it shows that it can not be used for pulling which ensures the longevity of the product and gives a submerged feeling to the rest of the lid.
The cancel button was designed around the fact that it is not and should not be perceived as an emergency button but an intentional action button that is used to lift the ferromagnetic plate without the reaction of the bimetal disc. The button should therefore not be highlighted too much. The size of the button should be smaller and more discreetly placed than the knob to make sure that it is prevacid as a side function. Different types of cancel buttons were tested using clay, see Figure 4.
Figure 4. Different cancel buttons modeled with clay.
Appendix : ( ) Another design challenge concerned the steam flow and how the steam that leaks out after flowing through the mechanism can be designed to warn the user and minimise the risk for burn hazard when using the product. Since the steam needs to flow through the mechanism and especially the bimetall, the steam will have to seep out on the side of the housing or on top. Where a steam flow on the side of the housing would be more harmful for the user since large parts of the area will most feasibly be touched when removing the lid. Sketches of different ideas to highlight the feature but still be discreet were made, for example with multiple holes, a material transition or through the shape of the overall knob.
The most promising ideas were 3D-printed and tested with users. The purpose of the tests were to identify how the lid and knob will be handled, how different designs affect the usage and how clear the warning is perceived.
The tests showed that all test persons lifted the lid in the same way regardless of the details on the knob. The height at which the jug was placed had an impact on the grip. In general, the hand often covered parts of the knob. Many people lifted the lid with the index finger on top of the knob and grabbed round the housing with the thumb and middle finger on each side of the housing where some only grabbed around the housing either from the side or upwards, covering half the knob. Figure 5 presents the different ways that the lid was lifted.
Figure 5. Different ways the lid is lifted
Multiple round holes on the knob were identified as a function where steam could flow which was not as clear with only a gap between the knob and housing. The user was generally aware of the holes and aimed to grab the lid on the opposite side. Furthermore, the test also confirmed that a protruding knob signals that the knob is movable making it important to make sure that the knob is leveled with the rest of the lid when it is pressed down to ensure the longevity of the product.
Appendix : ( )
Appendix G co udit o t o Induction tt
Product name Induction Kettle
Country of manufacture Sweden
Country of use Sweden
Product life (years) 8
Summary:
Energy details CO2 footprint details Cost details
Energy Energy CO2 footprint CO2 footprint Cost Cost Phase (MJ) (%) (kg) (%) (SEK) (%) Material 48,9 4,5 3,05 15,1 25,6 4,85 Manufacture 6,08 0,6 0,474 2,3 26 4,91 Transport 1,89 0,2 0,136 0,7 4,49 0,849 Use 1,04e+03 94,8 16,6 81,8 473 89,4 Disposal 0,47 0,0 0,0329 0,2 0,0432 0,00817 Total (for first life) 1,09e+03 100 20,3 100 529 100 End of life potential -23 -1,37
inductionkettle.prd NOTE: Differences of less than 20% are not usually significant. Page 1 / 16 See notes on precision and data sources. den 28 maj 2021 Eco Audit Report
Energy Analysis Summary
Energy (MJ/year) Equivalent annual environmental burden (averaged over 8 year product life): 137
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 2 / 16 Ltd. den 28 maj 2021 Detailed breakdown of individual life phases
Material: Summary
Recycled Part Total mass Energy Component Material content* mass Qty. processed** % (MJ) (%) (kg) (kg) Jug Borosilicate - 7740 70,0% 0,4 1 0,4 7,9 16,1 Stainless steel, austenitic, Rod Virgin (0%) 0,024 1 0,024 1,6 3,3 AISI 304, annealed Housing PA6 (molding and extrusion) Virgin (0%) 0,013 1 0,013 1,8 3,6 Copper-tellurium alloy, Bimetal snap disc Virgin (0%) 0,0013 1 0,0013 0,077 0,2 C14500, soft (h.c. copper) Lid PA6 (molding and extrusion) Virgin (0%) 0,07 1 0,07 9,5 19,4 Knob + cancel button PA6 (molding and extrusion) Virgin (0%) 0,016 1 0,016 2,2 4,4 Stainless steel, austenitic, Springs Virgin (0%) 0,001 1 0,001 0,062 0,1 AISI 301, annealed Stainless steel, austenitic, Protection filter Virgin (0%) 0,007 1 0,007 0,54 1,1 AISI 316, annealed Stainless steel, austenitic, Circlips Virgin (0%) 0,0001 1 0,0001 0,0062 0,0 AISI 301, annealed Stainless steel, austenitic, Pouring filter Virgin (0%) 0,03 1 0,03 2 4,1 AISI 304, annealed Silicone (VMQ, heat cured, 10 Silicone Virgin (0%) 0,002 1 0,002 0,25 0,5 -30% fumed silica) Stainless steel, ferritic, AISI Ferromagnetic disc Virgin (0%) 0,04 1 0,04 1,8 3,8 430, annealed Ferromagnetic disc Aluminum, 3004, O Virgin (0%) 0,1 1 0,1 20 40,5 Carbon steel, AISI 1030, Screws Virgin (0%) 0,002 1 0,002 0,065 0,1 annealed Pistion Aluminum, A332.0, cast, T6 Virgin (0%) 0,007 1 0,007 1,3 2,7 Total 15 0,71 49 100
*Typical: Includes 'recycle fraction in current supply' **Where applicable, includes material mass removed by secondary processes
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 3 / 16 Ltd. den 28 maj 2021 Manufacture: Summary
Energy Component Process % Removed Amount processed % (MJ) Jug Glass molding - 0,4 kg 3,5 56,8 Rod Extrusion, foil rolling - 0,024 kg 0,11 1,8 Rod Fine machining - 0 kg 0 0,0 Housing Polymer molding - 0,013 kg 0,28 4,7 Bimetal snap disc Roll forming - 0,0013 kg 0,00097 0,0 Lid Polymer molding - 0,07 kg 1,5 25,1 Knob + cancel button Polymer molding - 0,016 kg 0,35 5,7 Springs Wire drawing - 0,001 kg 0,012 0,2 Protection filter Roll forming - 0,007 kg 0,017 0,3 Protection filter Cutting and trimming - 0 kg 0 0,0 Circlips Roll forming - 0,0001 kg 0,00018 0,0 Circlips Cutting and trimming - 0 kg 0 0,0 Pouring filter Roll forming - 0,03 kg 0,072 1,2 Pouring filter Cutting and trimming - 0 kg 0 0,0 Ferromagnetic disc Coarse machining - 0 kg 0 0,0 Ferromagnetic disc Roll forming - 0,1 kg 0,18 3,0 Pistion Casting - 0,007 kg 0,076 1,3 Total 6,1 100
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 4 / 16 Ltd. den 28 maj 2021 Transport: Summary
Breakdown by transport stage Distance Energy Stage name Transport type (km) (MJ) % Kettle 14 tonne (2 axle) truck 1,8e+03 1,9 100,0 Total 1,8e+03 1,9 100
Breakdown by components Mass Energy Component (kg) (MJ) % Jug 0,4 1,1 56,1 Rod 0,024 0,064 3,4 Housing 0,013 0,034 1,8 Bimetal snap disc 0,0013 0,0034 0,2 Lid 0,07 0,19 9,8 Knob + cancel button 0,016 0,042 2,2 Springs 0,001 0,0026 0,1 Protection filter 0,007 0,019 1,0 Circlips 0,0001 0,00026 0,0 Pouring filter 0,03 0,079 4,2 Silicone 0,002 0,0053 0,3 Ferromagnetic disc 0,04 0,11 5,6 Ferromagnetic disc 0,1 0,26 14,0 Screws 0,002 0,0053 0,3 Pistion 0,007 0,019 1,0 Total 0,71 1,9 100
Use: Summary
Static mode
Energy input and output type Electric to thermal Country of use Sweden Power rating 2e+03 (W) Usage (hours per day) 0,039 Usage (days per year) 3,7e+02 Product life (years) 8
Relative contribution of static and mobile modes
Energy Mode % (MJ) Static 1e+03 100,0 Mobile 0 Total 1e+03 100
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 5 / 16 Ltd. den 28 maj 2021 Disposal: Summary
End of life Energy Component % recovered % option (MJ) Jug Recycle 100,0 0,28 59,6 Rod Recycle 100,0 0,017 3,6 Housing Recycle 100,0 0,0091 1,9 Bimetal snap disc Recycle 100,0 0,00091 0,2 Lid Recycle 100,0 0,049 10,4 Knob + cancel button Recycle 100,0 0,011 2,4 Springs Recycle 100,0 0,0007 0,1 Protection filter Recycle 100,0 0,0049 1,0 Circlips Recycle 100,0 7e-05 0,0 Pouring filter Recycle 100,0 0,021 4,5 Silicone Downcycle 100,0 0,001 0,2 Ferromagnetic disc Downcycle 100,0 0,02 4,3 Ferromagnetic disc Downcycle 100,0 0,05 10,6 Screws Landfill 100,0 0,0004 0,1 Pistion Recycle 100,0 0,0049 1,0 Total 0,47 100
EoL potential:
End of life Energy Component % recovered % option (MJ) Jug Recycle 100,0 -0,49 2,1 Rod Recycle 100,0 -1,2 5,4 Housing Recycle 100,0 -1,2 5,2 Bimetal snap disc Recycle 100,0 -0,06 0,3 Lid Recycle 100,0 -6,5 28,1 Knob + cancel button Recycle 100,0 -1,5 6,4 Springs Recycle 100,0 -0,048 0,2 Protection filter Recycle 100,0 -0,42 1,8 Circlips Recycle 100,0 -0,0048 0,0 Pouring filter Recycle 100,0 -1,6 6,8 Silicone Downcycle 100,0 -0,0002 0,0 Ferromagnetic disc Downcycle 100,0 -0,7 3,0 Ferromagnetic disc Downcycle 100,0 -8,2 35,7 Screws Landfill 100,0 0 0,0 Pistion Recycle 100,0 -1,1 4,8 Total -23 100
Notes: Summary
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 6 / 16 Ltd. den 28 maj 2021 Eco Audit Report
CO2 Footprint Analysis Summary
CO2 (kg/year) Equivalent annual environmental burden (averaged over 8 year product life): 2,53
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 7 / 16 Ltd. den 28 maj 2021 Detailed breakdown of individual life phases
Material: Summary
Recycled Part Total mass CO2 Component Material content* mass Qty. processed** footprint % (%) (kg) (kg) (kg) Jug Borosilicate - 7740 70,0% 0,4 1 0,4 0,44 14,5 Stainless steel, austenitic, Rod Virgin (0%) 0,024 1 0,024 0,11 3,6 AISI 304, annealed Housing PA6 (molding and extrusion) Virgin (0%) 0,013 1 0,013 0,099 3,2 Copper-tellurium alloy, Bimetal snap disc Virgin (0%) 0,0013 1 0,0013 0,0047 0,2 C14500, soft (h.c. copper) Lid PA6 (molding and extrusion) Virgin (0%) 0,07 1 0,07 0,53 17,5 Knob + cancel button PA6 (molding and extrusion) Virgin (0%) 0,016 1 0,016 0,12 4,0 Stainless steel, austenitic, Springs Virgin (0%) 0,001 1 0,001 0,0046 0,2 AISI 301, annealed Stainless steel, austenitic, Protection filter Virgin (0%) 0,007 1 0,007 0,039 1,3 AISI 316, annealed Stainless steel, austenitic, Circlips Virgin (0%) 0,0001 1 0,0001 0,00046 0,0 AISI 301, annealed Stainless steel, austenitic, Pouring filter Virgin (0%) 0,03 1 0,03 0,14 4,5 AISI 304, annealed Silicone (VMQ, heat cured, 10 Silicone Virgin (0%) 0,002 1 0,002 0,013 0,4 -30% fumed silica) Stainless steel, ferritic, AISI Ferromagnetic disc Virgin (0%) 0,04 1 0,04 0,14 4,7 430, annealed Ferromagnetic disc Aluminum, 3004, O Virgin (0%) 0,1 1 0,1 1,3 43,1 Carbon steel, AISI 1030, Screws Virgin (0%) 0,002 1 0,002 0,0047 0,2 annealed Pistion Aluminum, A332.0, cast, T6 Virgin (0%) 0,007 1 0,007 0,085 2,8 Total 15 0,71 3 100
*Typical: Includes 'recycle fraction in current supply' **Where applicable, includes material mass removed by secondary processes
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 8 / 16 Ltd. den 28 maj 2021 Manufacture: Summary
CO2 Component Process % Removed Amount processed footprint % (kg) Jug Glass molding - 0,4 kg 0,28 58,4 Rod Extrusion, foil rolling - 0,024 kg 0,0081 1,7 Rod Fine machining - 0 kg 0 0,0 Housing Polymer molding - 0,013 kg 0,021 4,5 Bimetal snap disc Roll forming - 0,0013 kg 7,3e-05 0,0 Lid Polymer molding - 0,07 kg 0,11 24,1 Knob + cancel button Polymer molding - 0,016 kg 0,026 5,5 Springs Wire drawing - 0,001 kg 0,00087 0,2 Protection filter Roll forming - 0,007 kg 0,0013 0,3 Protection filter Cutting and trimming - 0 kg 0 0,0 Circlips Roll forming - 0,0001 kg 1,3e-05 0,0 Circlips Cutting and trimming - 0 kg 0 0,0 Pouring filter Roll forming - 0,03 kg 0,0054 1,1 Pouring filter Cutting and trimming - 0 kg 0 0,0 Ferromagnetic disc Coarse machining - 0 kg 0 0,0 Ferromagnetic disc Roll forming - 0,1 kg 0,014 2,9 Pistion Casting - 0,007 kg 0,0057 1,2 Total 0,47 100
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 9 / 16 Ltd. den 28 maj 2021 Transport: Summary
Breakdown by transport stage Distance CO2 footprint Stage name Transport type (km) (kg) % Kettle 14 tonne (2 axle) truck 1,8e+03 0,14 100,0 Total 1,8e+03 0,14 100
Breakdown by components Mass CO2 footprint Component (kg) (kg) % Jug 0,4 0,076 56,1 Rod 0,024 0,0046 3,4 Housing 0,013 0,0025 1,8 Bimetal snap disc 0,0013 0,00025 0,2 Lid 0,07 0,013 9,8 Knob + cancel button 0,016 0,003 2,2 Springs 0,001 0,00019 0,1 Protection filter 0,007 0,0013 1,0 Circlips 0,0001 1,9e-05 0,0 Pouring filter 0,03 0,0057 4,2 Silicone 0,002 0,00038 0,3 Ferromagnetic disc 0,04 0,0076 5,6 Ferromagnetic disc 0,1 0,019 14,0 Screws 0,002 0,00038 0,3 Pistion 0,007 0,0013 1,0 Total 0,71 0,14 100
Use: Summary
Static mode
Energy input and output type Electric to thermal Country of use Sweden Power rating 2e+03 (W) Usage (hours per day) 0,039 Usage (days per year) 3,7e+02 Product life (years) 8
Relative contribution of static and mobile modes
CO2 footprint Mode % (kg) Static 17 100,0 Mobile 0 Total 17 100
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 10 / Ltd. 16 den 28 maj 2021 Disposal: Summary
CO2 End of life Component % recovered footprint % option (kg) Jug Recycle 100,0 0,02 59,6 Rod Recycle 100,0 0,0012 3,6 Housing Recycle 100,0 0,00064 1,9 Bimetal snap disc Recycle 100,0 6,4e-05 0,2 Lid Recycle 100,0 0,0034 10,4 Knob + cancel button Recycle 100,0 0,00078 2,4 Springs Recycle 100,0 4,9e-05 0,1 Protection filter Recycle 100,0 0,00034 1,0 Circlips Recycle 100,0 4,9e-06 0,0 Pouring filter Recycle 100,0 0,0015 4,5 Silicone Downcycle 100,0 7e-05 0,2 Ferromagnetic disc Downcycle 100,0 0,0014 4,3 Ferromagnetic disc Downcycle 100,0 0,0035 10,6 Screws Landfill 100,0 2,8e-05 0,1 Pistion Recycle 100,0 0,00034 1,0 Total 0,033 100
EoL potential:
CO2 End of life Component % recovered footprint % option (kg) Jug Recycle 100,0 -0,05 3,7 Rod Recycle 100,0 -0,081 5,9 Housing Recycle 100,0 -0,06 4,4 Bimetal snap disc Recycle 100,0 -0,0033 0,2 Lid Recycle 100,0 -0,32 23,5 Knob + cancel button Recycle 100,0 -0,073 5,4 Springs Recycle 100,0 -0,0035 0,3 Protection filter Recycle 100,0 -0,03 2,2 Circlips Recycle 100,0 -0,00035 0,0 Pouring filter Recycle 100,0 -0,1 7,4 Silicone Downcycle 100,0 -1,4e-05 0,0 Ferromagnetic disc Downcycle 100,0 -0,054 4,0 Ferromagnetic disc Downcycle 100,0 -0,52 38,3 Screws Landfill 100,0 0 0,0 Pistion Recycle 100,0 -0,066 4,9 Total -1,4 100
Notes: Summary
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 11 / Ltd. 16 den 28 maj 2021 Eco Audit Report
Cost Analysis Summary
Cost (SEK/year) Equivalent annual environmental burden (averaged over 8 year product life): 66,1
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 12 / Ltd. 16 den 28 maj 2021 Detailed breakdown of individual life phases
Material: Summary
Recycled Part Total mass Cost Component Material content* mass Qty. processed** % (SEK) (%) (kg) (kg) Jug Borosilicate - 7740 70,0% 0,4 1 0,4 18 68,5 Stainless steel, austenitic, Rod Virgin (0%) 0,024 1 0,024 0,74 2,9 AISI 304, annealed Housing PA6 (molding and extrusion) Virgin (0%) 0,013 1 0,013 0,31 1,2 Copper-tellurium alloy, Bimetal snap disc Virgin (0%) 0,0013 1 0,0013 0,1 0,4 C14500, soft (h.c. copper) Lid PA6 (molding and extrusion) Virgin (0%) 0,07 1 0,07 1,6 6,4 Knob + cancel button PA6 (molding and extrusion) Virgin (0%) 0,016 1 0,016 0,38 1,5 Stainless steel, austenitic, Springs Virgin (0%) 0,001 1 0,001 0,027 0,1 AISI 301, annealed Stainless steel, austenitic, Protection filter Virgin (0%) 0,007 1 0,007 0,27 1,1 AISI 316, annealed Stainless steel, austenitic, Circlips Virgin (0%) 0,0001 1 0,0001 0,0026 0,0 AISI 301, annealed Stainless steel, austenitic, Pouring filter Virgin (0%) 0,03 1 0,03 0,91 3,6 AISI 304, annealed Silicone (VMQ, heat cured, 10 Silicone Virgin (0%) 0,002 1 0,002 0,087 0,3 -30% fumed silica) Stainless steel, ferritic, AISI Ferromagnetic disc Virgin (0%) 0,04 1 0,04 0,59 2,3 430, annealed Ferromagnetic disc Aluminum, 3004, O Virgin (0%) 0,1 1 0,1 2,7 10,7 Carbon steel, AISI 1030, Screws Virgin (0%) 0,002 1 0,002 0,017 0,1 annealed Pistion Aluminum, A332.0, cast, T6 Virgin (0%) 0,007 1 0,007 0,23 0,9 Total 15 0,71 26 100
*Typical: Includes 'recycle fraction in current supply' **Where applicable, includes material mass removed by secondary processes
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 13 / Ltd. 16 den 28 maj 2021 Manufacture: Summary
Country of manufacture Sweden
Cost Component Process Length (m) % Removed Amount processed % (SEK) Jug Glass molding - - 0,4 kg 0,078 0,3 Extrusion, foil Rod - - 0,024 kg 0 0,0 rolling Rod Fine machining - - 0 kg 0 0,0 Housing Polymer molding - - 0,013 kg 2,1 7,9 Bimetal snap disc Roll forming - - 0,0013 kg 0 0,0 Lid Polymer molding - - 0,07 kg 3,4 13,2 Knob + cancel button Polymer molding - - 0,016 kg 2,2 8,4 Springs Wire drawing - - 0,001 kg 0 0,0 Protection filter Roll forming - - 0,007 kg 0 0,0 Cutting and Protection filter - - 0 kg 0 0,0 trimming Circlips Roll forming - - 0,0001 kg 0 0,0 Cutting and Circlips - - 0 kg 0 0,0 trimming Pouring filter Roll forming - - 0,03 kg 0 0,0 Cutting and Pouring filter - - 0 kg 0 0,0 trimming Coarse Ferromagnetic disc - - 0 kg 0 0,0 machining Ferromagnetic disc Roll forming - - 0,1 kg 0 0,0 Pistion Casting - - 0,007 kg 18 70,1 Total 26 100
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 14 / Ltd. 16 den 28 maj 2021 Transport: Summary
Package dimensions Height (m) Width (m) Depth (m) 0,2 0,25 0,17
Breakdown by transport stage Distance Cost Stage name Transport type (km) (SEK) % Kettle 14 tonne (2 axle) truck 1,8e+03 4,5 100,0 Total 1,8e+03 4,5 100
Breakdown by components Mass Cost Component (kg) (SEK) % Jug 0,4 2,5 56,1 Rod 0,024 0,15 3,4 Housing 0,013 0,082 1,8 Bimetal snap disc 0,0013 0,0082 0,2 Lid 0,07 0,44 9,8 Knob + cancel button 0,016 0,1 2,2 Springs 0,001 0,0063 0,1 Protection filter 0,007 0,044 1,0 Circlips 0,0001 0,00063 0,0 Pouring filter 0,03 0,19 4,2 Silicone 0,002 0,013 0,3 Ferromagnetic disc 0,04 0,25 5,6 Ferromagnetic disc 0,1 0,63 14,0 Screws 0,002 0,013 0,3 Pistion 0,007 0,044 1,0 Total 0,71 4,5 100
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 15 / Ltd. 16 den 28 maj 2021 Use: Summary
Static mode
Energy input and output type Electric to thermal Country of use Sweden Fuel rate Domestic Power rating 2e+03 (W) Usage (hours per day) 0,039 Usage (days per year) 3,7e+02 Product life (years) 8
Relative contribution of static and mobile modes
Cost Mode % (SEK) Static 4,7e+02 100,0 Mobile 0 Total 4,7e+02 100
Disposal: Summary
End of life Cost Component % recovered % option (SEK) Jug Recycle 100,0 0,024 56,1 Rod Recycle 100,0 0,0015 3,4 Housing Recycle 100,0 0,00079 1,8 Bimetal snap disc Recycle 100,0 7,9e-05 0,2 Lid Recycle 100,0 0,0042 9,8 Knob + cancel button Recycle 100,0 0,00097 2,2 Springs Recycle 100,0 6,1e-05 0,1 Protection filter Recycle 100,0 0,00042 1,0 Circlips Recycle 100,0 6,1e-06 0,0 Pouring filter Recycle 100,0 0,0018 4,2 Silicone Downcycle 100,0 0,00012 0,3 Ferromagnetic disc Downcycle 100,0 0,0024 5,6 Ferromagnetic disc Downcycle 100,0 0,0061 14,0 Screws Landfill 100,0 0,00012 0,3 Pistion Recycle 100,0 0,00042 1,0 Total 0,043 100
Notes: Summary
inductionkettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 16 / Ltd. 16 den 28 maj 2021 Appendix Eco Audit Report For The Electric Kettle
Product name Electric kettle
Country of manufacture China
Country of use Sweden
Product life (years) 8
Summary:
Energy details CO2 footprint details Cost details
Energy Energy CO2 footprint CO2 footprint Cost Cost Phase (MJ) (%) (kg) (%) (SEK) (%) Material 53 4,8 1,95 9,9 23,4 4,52 Manufacture 8,08 0,7 0,606 3,1 15,5 3 Transport 7,93 0,7 0,571 2,9 6,63 1,28 Use 1,04e+03 93,7 16,6 84,0 473 91,2 Disposal 0,636 0,1 0,0445 0,2 0,0656 0,0127 Total (for first life) 1,11e+03 100 19,7 100 518 100 End of life potential -11,4 -0,606
electrickettle.prd NOTE: Differences of less than 20% are not usually significant. Page 1 / 21 See notes on precision and data sources. den 28 maj 2021 Eco Audit Report
Energy Analysis Summary
Energy (MJ/year) Equivalent annual environmental burden (averaged over 8 year product life): 138
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 2 / 21 Ltd. den 28 maj 2021 Detailed breakdown of individual life phases
Material: Summary
Recycled Part Total mass Energy Component Material content* mass Qty. processed** % (MJ) (%) (kg) (kg) Stainless steel, austenitic, Boiler - main part (9) 60,0% 0,4 1 0,4 11 20,2 AISI 205, annealed Stainless steel, austenitic, Lid - metal part (11) Virgin (0%) 0,028 1 0,028 1,4 2,6 AISI 205, annealed PA1010 (molding and Electric cable blobb (1) Virgin (0%) 0,01 1 0,01 2,3 4,4 extrusion) PA1010 (molding and Big black beetle (19) Virgin (0%) 0,015 1 0,015 3,5 6,5 extrusion) PA1010 (molding and Beetle head (17) Virgin (0%) 0,003 1 0,003 0,69 1,3 extrusion) Tube (26) + Silicone plugs Silicone (VMQ, heat cured, 10 Virgin (0%) 0,002 1 0,002 0,25 0,5 (22) -30% fumed silica) PP (homopolymer, Boiler plate, top (5) Virgin (0%) 0,046 1 0,046 3,2 6,1 clarified/nucleated) PP (homopolymer, Boiler plate, bottom (3) Virgin (0%) 0,029 1 0,029 2 3,8 clarified/nucleated) PP (homopolymer, Bottom plate (8) Virgin (0%) 0,05 1 0,05 3,5 6,6 clarified/nucleated) PP (homopolymer, Lid (plastic part) (10) Virgin (0%) 0,012 1 0,012 0,84 1,6 clarified/nucleated) PP (homopolymer, Handle (13) Virgin (0%) 0,046 1 0,046 3,2 6,1 clarified/nucleated) PP (homopolymer, Handle attachment (12) Virgin (0%) 0,007 1 0,007 0,49 0,9 clarified/nucleated) PP (homopolymer, Button (25) Virgin (0%) 0,005 1 0,005 0,35 0,7 clarified/nucleated) Black rectangular with hole PP (homopolymer, Virgin (0%) 0,002 1 0,002 0,14 0,3 (18) clarified/nucleated) Carbon steel, AISI 1030, Metal plate (gray) (16) Virgin (0%) 0,019 1 0,019 0,61 1,2 annealed Carbon steel, AISI 1030, Screws big (7) Virgin (0%) 0,004 1 0,004 0,13 0,2 annealed Carbon steel, AISI 1030, Screws small (21) Virgin (0%) 0,002 1 0,002 0,065 0,1 annealed Carbon steel, AISI 1030, Screws (4) Virgin (0%) 0,002 1 0,002 0,065 0,1 annealed Carbon steel, AISI 1030, Screws big hat (6) Virgin (0%) 0,002 1 0,002 0,065 0,1 annealed Copper-tellurium alloy, Thin metal plates (15) Virgin (0%) 0,001 1 0,0013 0,063 0,1 C14500, soft (h.c. copper) Copper-tellurium alloy, Bent copper plates (20) Virgin (0%) 0,002 1 0,0025 0,13 0,2 C14500, soft (h.c. copper) Copper-tellurium alloy, bent metal tube Virgin (0%) 0,002 1 0,0025 0,13 0,2 C14500, soft (h.c. copper) Power cord (2) PVC (flexible, Shore A60) Virgin (0%) 0,086 1 0,086 5,1 9,7 Brass, CuZn28Sn1, C44300, Bent brass plates (28) Virgin (0%) 0,001 1 0,001 0,057 0,1 half hard (admiralty brass) Brass, CuZn28Sn1, C44300, Crown (30) Virgin (0%) 0,003 1 0,003 0,17 0,3 half hard (admiralty brass) Cardboard Cardboard Virgin (0%) 0,3 1 0,3 14 26,1 Total 26 1,1 53 100
*Typical: Includes 'recycle fraction in current supply' **Where applicable, includes material mass removed by secondary processes
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 3 / 21 Ltd. den 28 maj 2021 Manufacture: Summary
Energy Component Process % Removed Amount processed % (MJ) Boiler - main part (9) Roll forming - 0,4 kg 1,8 21,7 Lid - metal part (11) Forging - 0,028 kg 0,12 1,5 Electric cable blobb (1) Polymer molding - 0,01 kg 0,22 2,7 Big black beetle (19) Polymer molding - 0,015 kg 0,33 4,0 Beetle head (17) Polymer molding - 0,003 kg 0,065 0,8 Tube (26) + Silicone plugs (22) Polymer molding - 0,002 kg 0,03 0,4 Boiler plate, top (5) Polymer molding - 0,046 kg 1,1 13,4 Boiler plate, bottom (3) Polymer molding - 0,029 kg 0,68 8,4 Bottom plate (8) Polymer molding - 0,05 kg 1,2 14,5 Lid (plastic part) (10) Polymer molding - 0,012 kg 0,28 3,5 Handle (13) Polymer molding - 0,046 kg 1,1 13,4 Handle attachment (12) Polymer molding - 0,007 kg 0,16 2,0 Button (25) Polymer molding - 0,005 kg 0,12 1,5 Black rectangular with hole Polymer molding - 0,002 kg 0,047 0,6 (18) Metal plate (gray) (16) Casting - 0,019 kg 0,22 2,7 Screws big (7) Wire drawing - 0,004 kg 0,087 1,1 Screws small (21) Wire drawing - 0,002 kg 0,044 0,5 Screws big hat (6) Wire drawing - 0,002 kg 0,044 0,5 Thin metal plates (15) Roll forming - 0,0013 kg 0,00093 0,0 Thin metal plates (15) Cutting and trimming 20 0,00025 kg 7,5e-05 0,0 Bent copper plates (20) Roll forming - 0,0025 kg 0,0019 0,0 Bent copper plates (20) Cutting and trimming 20 0,0005 kg 0,00015 0,0 bent metal tube Roll forming - 0,0025 kg 0,0019 0,0 bent metal tube Cutting and trimming 20 0,0005 kg 0,00015 0,0 Power cord (2) Polymer extrusion - 0,086 kg 0,52 6,5 Bent brass plates (28) Extrusion, foil rolling - 0,001 kg 0,0067 0,1 Crown (30) Extrusion, foil rolling - 0,003 kg 0,02 0,2 Total 8,1 100
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 4 / 21 Ltd. den 28 maj 2021 Transport: Summary
Breakdown by transport stage Distance Energy Stage name Transport type (km) (MJ) % Ocean freight 2,4e+04 4,7 59,0 14 tonne (2 axle) truck 2e+03 3,2 41,0 Total 2,6e+04 7,9 100
Breakdown by components Mass Energy Component (kg) (MJ) % Boiler - main part (9) 0,4 3 37,3 Lid - metal part (11) 0,028 0,2 2,6 Electric cable blobb (1) 0,01 0,073 0,9 Big black beetle (19) 0,015 0,11 1,4 Beetle head (17) 0,003 0,022 0,3 Tube (26) + Silicone plugs (22) 0,002 0,015 0,2 Boiler plate, top (5) 0,046 0,34 4,2 Boiler plate, bottom (3) 0,029 0,21 2,7 Bottom plate (8) 0,05 0,37 4,6 Lid (plastic part) (10) 0,012 0,088 1,1 Handle (13) 0,046 0,34 4,2 Handle attachment (12) 0,007 0,051 0,6 Button (25) 0,005 0,037 0,5 Black rectangular with hole (18) 0,002 0,015 0,2 Metal plate (gray) (16) 0,019 0,14 1,8 Screws big (7) 0,004 0,029 0,4 Screws small (21) 0,002 0,015 0,2 Screws (4) 0,002 0,015 0,2 Screws big hat (6) 0,002 0,015 0,2 Thin metal plates (15) 0,001 0,0073 0,1 Bent copper plates (20) 0,002 0,015 0,2 bent metal tube 0,002 0,015 0,2 Power cord (2) 0,086 0,63 7,9 Bent brass plates (28) 0,001 0,0073 0,1 Crown (30) 0,003 0,022 0,3 Cardboard 0,3 2,2 27,7 Total 1,1 7,9 100
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 5 / 21 Ltd. den 28 maj 2021 Use: Summary
Static mode
Energy input and output type Electric to thermal Country of use Sweden Power rating 2e+03 (W) Usage (hours per day) 0,039 Usage (days per year) 3,7e+02 Product life (years) 8
Relative contribution of static and mobile modes
Energy Mode % (MJ) Static 1e+03 100,0 Mobile 0 Total 1e+03 100
Disposal: Summary
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 6 / 21 Ltd. den 28 maj 2021 End of life Energy Component % recovered % option (MJ) Boiler - main part (9) Recycle 100,0 0,28 44,5 Lid - metal part (11) Recycle 100,0 0,02 3,1 Electric cable blobb (1) Downcycle 100,0 0,005 0,8 Big black beetle (19) Downcycle 100,0 0,0075 1,2 Beetle head (17) Downcycle 100,0 0,0015 0,2 Tube (26) + Silicone plugs (22) Combust 100,0 0,001 0,2 Boiler plate, top (5) Downcycle 100,0 0,023 3,6 Boiler plate, bottom (3) Downcycle 100,0 0,015 2,3 Bottom plate (8) Downcycle 100,0 0,025 3,9 Lid (plastic part) (10) Downcycle 100,0 0,006 0,9 Handle (13) Downcycle 100,0 0,023 3,6 Handle attachment (12) Downcycle 100,0 0,0035 0,6 Button (25) Downcycle 100,0 0,0025 0,4 Black rectangular with hole (18) Downcycle 100,0 0,001 0,2 Metal plate (gray) (16) Recycle 100,0 0,013 2,1 Screws big (7) Recycle 100,0 0,0028 0,4 Screws small (21) Recycle 100,0 0,0014 0,2 Screws (4) Recycle 100,0 0,0014 0,2 Screws big hat (6) Recycle 100,0 0,0014 0,2 Thin metal plates (15) Recycle 100,0 0,0007 0,1 Bent copper plates (20) Recycle 100,0 0,0014 0,2 bent metal tube Recycle 100,0 0,0014 0,2 Power cord (2) Downcycle 100,0 0,043 6,8 Bent brass plates (28) Recycle 100,0 0,0007 0,1 Crown (30) Recycle 100,0 0,0021 0,3 Cardboard Downcycle 100,0 0,15 23,6 Total 0,64 100
EoL potential:
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 7 / 21 Ltd. den 28 maj 2021 End of life Energy Component % recovered % option (MJ) Boiler - main part (9) Recycle 100,0 -6 52,4 Lid - metal part (11) Recycle 100,0 -1 9,1 Electric cable blobb (1) Downcycle 100,0 -0,31 2,7 Big black beetle (19) Downcycle 100,0 -0,46 4,0 Beetle head (17) Downcycle 100,0 -0,092 0,8 Tube (26) + Silicone plugs (22) Combust 100,0 -0,0068 0,1 Boiler plate, top (5) Downcycle 100,0 -0,41 3,5 Boiler plate, bottom (3) Downcycle 100,0 -0,26 2,2 Bottom plate (8) Downcycle 100,0 -0,44 3,9 Lid (plastic part) (10) Downcycle 100,0 -0,11 0,9 Handle (13) Downcycle 100,0 -0,41 3,5 Handle attachment (12) Downcycle 100,0 -0,062 0,5 Button (25) Downcycle 100,0 -0,044 0,4 Black rectangular with hole (18) Downcycle 100,0 -0,018 0,2 Metal plate (gray) (16) Recycle 100,0 -0,45 4,0 Screws big (7) Recycle 100,0 -0,095 0,8 Screws small (21) Recycle 100,0 -0,048 0,4 Screws (4) Recycle 100,0 -0,048 0,4 Screws big hat (6) Recycle 100,0 -0,048 0,4 Thin metal plates (15) Recycle 100,0 -0,046 0,4 Bent copper plates (20) Recycle 100,0 -0,092 0,8 bent metal tube Recycle 100,0 -0,092 0,8 Power cord (2) Downcycle 100,0 -0,68 6,0 Bent brass plates (28) Recycle 100,0 -0,044 0,4 Crown (30) Recycle 100,0 -0,13 1,1 Cardboard Downcycle 100,0 -0,03 0,3 Total -11 100
Notes: Summary
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 8 / 21 Ltd. den 28 maj 2021 Eco Audit Report
CO2 Footprint Analysis Summary
CO2 (kg/year) Equivalent annual environmental burden (averaged over 8 year product life): 2,47
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 9 / 21 Ltd. den 28 maj 2021 Detailed breakdown of individual life phases
Material: Summary
Recycled Part Total mass CO2 Component Material content* mass Qty. processed** footprint % (%) (kg) (kg) (kg) Stainless steel, austenitic, Boiler - main part (9) 60,0% 0,4 1 0,4 0,76 39,3 AISI 205, annealed Stainless steel, austenitic, Lid - metal part (11) Virgin (0%) 0,028 1 0,028 0,094 4,8 AISI 205, annealed PA1010 (molding and Electric cable blobb (1) Virgin (0%) 0,01 1 0,01 0,04 2,1 extrusion) PA1010 (molding and Big black beetle (19) Virgin (0%) 0,015 1 0,015 0,06 3,1 extrusion) PA1010 (molding and Beetle head (17) Virgin (0%) 0,003 1 0,003 0,012 0,6 extrusion) Tube (26) + Silicone plugs Silicone (VMQ, heat cured, 10 Virgin (0%) 0,002 1 0,002 0,013 0,7 (22) -30% fumed silica) PP (homopolymer, Boiler plate, top (5) Virgin (0%) 0,046 1 0,046 0,083 4,2 clarified/nucleated) PP (homopolymer, Boiler plate, bottom (3) Virgin (0%) 0,029 1 0,029 0,052 2,7 clarified/nucleated) PP (homopolymer, Bottom plate (8) Virgin (0%) 0,05 1 0,05 0,09 4,6 clarified/nucleated) PP (homopolymer, Lid (plastic part) (10) Virgin (0%) 0,012 1 0,012 0,022 1,1 clarified/nucleated) PP (homopolymer, Handle (13) Virgin (0%) 0,046 1 0,046 0,083 4,2 clarified/nucleated) PP (homopolymer, Handle attachment (12) Virgin (0%) 0,007 1 0,007 0,013 0,6 clarified/nucleated) PP (homopolymer, Button (25) Virgin (0%) 0,005 1 0,005 0,009 0,5 clarified/nucleated) Black rectangular with hole PP (homopolymer, Virgin (0%) 0,002 1 0,002 0,0036 0,2 (18) clarified/nucleated) Carbon steel, AISI 1030, Metal plate (gray) (16) Virgin (0%) 0,019 1 0,019 0,045 2,3 annealed Carbon steel, AISI 1030, Screws big (7) Virgin (0%) 0,004 1 0,004 0,0095 0,5 annealed Carbon steel, AISI 1030, Screws small (21) Virgin (0%) 0,002 1 0,002 0,0047 0,2 annealed Carbon steel, AISI 1030, Screws (4) Virgin (0%) 0,002 1 0,002 0,0047 0,2 annealed Carbon steel, AISI 1030, Screws big hat (6) Virgin (0%) 0,002 1 0,002 0,0047 0,2 annealed Copper-tellurium alloy, Thin metal plates (15) Virgin (0%) 0,001 1 0,0013 0,0039 0,2 C14500, soft (h.c. copper) Copper-tellurium alloy, Bent copper plates (20) Virgin (0%) 0,002 1 0,0025 0,0078 0,4 C14500, soft (h.c. copper) Copper-tellurium alloy, bent metal tube Virgin (0%) 0,002 1 0,0025 0,0078 0,4 C14500, soft (h.c. copper) Power cord (2) PVC (flexible, Shore A60) Virgin (0%) 0,086 1 0,086 0,2 10,4 Brass, CuZn28Sn1, C44300, Bent brass plates (28) Virgin (0%) 0,001 1 0,001 0,0037 0,2 half hard (admiralty brass) Brass, CuZn28Sn1, C44300, Crown (30) Virgin (0%) 0,003 1 0,003 0,011 0,6 half hard (admiralty brass) Cardboard Cardboard Virgin (0%) 0,3 1 0,3 0,3 15,6 Total 26 1,1 1,9 100
*Typical: Includes 'recycle fraction in current supply' **Where applicable, includes material mass removed by secondary processes
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 10 / Ltd. 21 den 28 maj 2021 Manufacture: Summary
CO2 Component Process % Removed Amount processed footprint % (kg) Boiler - main part (9) Roll forming - 0,4 kg 0,13 21,7 Lid - metal part (11) Forging - 0,028 kg 0,0091 1,5 Electric cable blobb (1) Polymer molding - 0,01 kg 0,016 2,7 Big black beetle (19) Polymer molding - 0,015 kg 0,024 4,0 Beetle head (17) Polymer molding - 0,003 kg 0,0049 0,8 Tube (26) + Silicone plugs (22) Polymer molding - 0,002 kg 0,0024 0,4 Boiler plate, top (5) Polymer molding - 0,046 kg 0,081 13,4 Boiler plate, bottom (3) Polymer molding - 0,029 kg 0,051 8,4 Bottom plate (8) Polymer molding - 0,05 kg 0,088 14,5 Lid (plastic part) (10) Polymer molding - 0,012 kg 0,021 3,5 Handle (13) Polymer molding - 0,046 kg 0,081 13,4 Handle attachment (12) Polymer molding - 0,007 kg 0,012 2,0 Button (25) Polymer molding - 0,005 kg 0,0088 1,5 Black rectangular with hole Polymer molding - 0,002 kg 0,0035 0,6 (18) Metal plate (gray) (16) Casting - 0,019 kg 0,016 2,7 Screws big (7) Wire drawing - 0,004 kg 0,0065 1,1 Screws small (21) Wire drawing - 0,002 kg 0,0033 0,5 Screws big hat (6) Wire drawing - 0,002 kg 0,0033 0,5 Thin metal plates (15) Roll forming - 0,0013 kg 7e-05 0,0 Thin metal plates (15) Cutting and trimming 20 0,00025 kg 5,8e-06 0,0 Bent copper plates (20) Roll forming - 0,0025 kg 0,00014 0,0 Bent copper plates (20) Cutting and trimming 20 0,0005 kg 1,2e-05 0,0 bent metal tube Roll forming - 0,0025 kg 0,00014 0,0 bent metal tube Cutting and trimming 20 0,0005 kg 1,2e-05 0,0 Power cord (2) Polymer extrusion - 0,086 kg 0,039 6,5 Bent brass plates (28) Extrusion, foil rolling - 0,001 kg 0,0005 0,1 Crown (30) Extrusion, foil rolling - 0,003 kg 0,0015 0,2 Total 0,61 100
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 11 / Ltd. 21 den 28 maj 2021 Transport: Summary
Breakdown by transport stage Distance CO2 footprint Stage name Transport type (km) (kg) % Ocean freight 2,4e+04 0,34 59,0 14 tonne (2 axle) truck 2e+03 0,23 41,0 Total 2,6e+04 0,57 100
Breakdown by components Mass CO2 footprint Component (kg) (kg) % Boiler - main part (9) 0,4 0,21 37,3 Lid - metal part (11) 0,028 0,015 2,6 Electric cable blobb (1) 0,01 0,0053 0,9 Big black beetle (19) 0,015 0,0079 1,4 Beetle head (17) 0,003 0,0016 0,3 Tube (26) + Silicone plugs (22) 0,002 0,0011 0,2 Boiler plate, top (5) 0,046 0,024 4,2 Boiler plate, bottom (3) 0,029 0,015 2,7 Bottom plate (8) 0,05 0,026 4,6 Lid (plastic part) (10) 0,012 0,0063 1,1 Handle (13) 0,046 0,024 4,2 Handle attachment (12) 0,007 0,0037 0,6 Button (25) 0,005 0,0026 0,5 Black rectangular with hole (18) 0,002 0,0011 0,2 Metal plate (gray) (16) 0,019 0,01 1,8 Screws big (7) 0,004 0,0021 0,4 Screws small (21) 0,002 0,0011 0,2 Screws (4) 0,002 0,0011 0,2 Screws big hat (6) 0,002 0,0011 0,2 Thin metal plates (15) 0,001 0,00053 0,1 Bent copper plates (20) 0,002 0,0011 0,2 bent metal tube 0,002 0,0011 0,2 Power cord (2) 0,086 0,045 7,9 Bent brass plates (28) 0,001 0,00053 0,1 Crown (30) 0,003 0,0016 0,3 Cardboard 0,3 0,16 27,7 Total 1,1 0,57 100
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 12 / Ltd. 21 den 28 maj 2021 Use: Summary
Static mode
Energy input and output type Electric to thermal Country of use Sweden Power rating 2e+03 (W) Usage (hours per day) 0,039 Usage (days per year) 3,7e+02 Product life (years) 8
Relative contribution of static and mobile modes
CO2 footprint Mode % (kg) Static 17 100,0 Mobile 0 Total 17 100
Disposal: Summary
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 13 / Ltd. 21 den 28 maj 2021 CO2 End of life Component % recovered footprint % option (kg) Boiler - main part (9) Recycle 100,0 0,02 44,5 Lid - metal part (11) Recycle 100,0 0,0014 3,1 Electric cable blobb (1) Downcycle 100,0 0,00035 0,8 Big black beetle (19) Downcycle 100,0 0,00053 1,2 Beetle head (17) Downcycle 100,0 0,00011 0,2 Tube (26) + Silicone plugs (22) Combust 100,0 7e-05 0,2 Boiler plate, top (5) Downcycle 100,0 0,0016 3,6 Boiler plate, bottom (3) Downcycle 100,0 0,001 2,3 Bottom plate (8) Downcycle 100,0 0,0018 3,9 Lid (plastic part) (10) Downcycle 100,0 0,00042 0,9 Handle (13) Downcycle 100,0 0,0016 3,6 Handle attachment (12) Downcycle 100,0 0,00025 0,6 Button (25) Downcycle 100,0 0,00018 0,4 Black rectangular with hole (18) Downcycle 100,0 7e-05 0,2 Metal plate (gray) (16) Recycle 100,0 0,00093 2,1 Screws big (7) Recycle 100,0 0,0002 0,4 Screws small (21) Recycle 100,0 9,8e-05 0,2 Screws (4) Recycle 100,0 9,8e-05 0,2 Screws big hat (6) Recycle 100,0 9,8e-05 0,2 Thin metal plates (15) Recycle 100,0 4,9e-05 0,1 Bent copper plates (20) Recycle 100,0 9,8e-05 0,2 bent metal tube Recycle 100,0 9,8e-05 0,2 Power cord (2) Downcycle 100,0 0,003 6,8 Bent brass plates (28) Recycle 100,0 4,9e-05 0,1 Crown (30) Recycle 100,0 0,00015 0,3 Cardboard Downcycle 100,0 0,011 23,6 Total 0,044 100
EoL potential:
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 14 / Ltd. 21 den 28 maj 2021 CO2 End of life Component % recovered footprint % option (kg) Boiler - main part (9) Recycle 100,0 -0,4 65,3 Lid - metal part (11) Recycle 100,0 -0,069 11,3 Electric cable blobb (1) Downcycle 100,0 -0,0053 0,9 Big black beetle (19) Downcycle 100,0 -0,0079 1,3 Beetle head (17) Downcycle 100,0 -0,0016 0,3 Tube (26) + Silicone plugs (22) Combust 100,0 0,0022 -0,4 Boiler plate, top (5) Downcycle 100,0 -0,0063 1,0 Boiler plate, bottom (3) Downcycle 100,0 -0,004 0,7 Bottom plate (8) Downcycle 100,0 -0,0068 1,1 Lid (plastic part) (10) Downcycle 100,0 -0,0016 0,3 Handle (13) Downcycle 100,0 -0,0063 1,0 Handle attachment (12) Downcycle 100,0 -0,00096 0,2 Button (25) Downcycle 100,0 -0,00068 0,1 Black rectangular with hole (18) Downcycle 100,0 -0,00027 0,0 Metal plate (gray) (16) Recycle 100,0 -0,032 5,3 Screws big (7) Recycle 100,0 -0,0068 1,1 Screws small (21) Recycle 100,0 -0,0034 0,6 Screws (4) Recycle 100,0 -0,0034 0,6 Screws big hat (6) Recycle 100,0 -0,0034 0,6 Thin metal plates (15) Recycle 100,0 -0,0026 0,4 Bent copper plates (20) Recycle 100,0 -0,0051 0,8 bent metal tube Recycle 100,0 -0,0051 0,8 Power cord (2) Downcycle 100,0 -0,027 4,4 Bent brass plates (28) Recycle 100,0 -0,0027 0,4 Crown (30) Recycle 100,0 -0,0081 1,3 Cardboard Downcycle 100,0 -0,0021 0,3 Total -0,61 100
Notes: Summary
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 15 / Ltd. 21 den 28 maj 2021 Eco Audit Report
Cost Analysis Summary
Cost (SEK/year) Equivalent annual environmental burden (averaged over 8 year product life): 64,8
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 16 / Ltd. 21 den 28 maj 2021 Detailed breakdown of individual life phases
Material: Summary
Recycled Part Total mass Cost Component Material content* mass Qty. processed** % (SEK) (%) (kg) (kg) Stainless steel, austenitic, Boiler - main part (9) 60,0% 0,4 1 0,4 7,3 31,3 AISI 205, annealed Stainless steel, austenitic, Lid - metal part (11) Virgin (0%) 0,028 1 0,028 0,71 3,0 AISI 205, annealed PA1010 (molding and Electric cable blobb (1) Virgin (0%) 0,01 1 0,01 1,6 6,7 extrusion) PA1010 (molding and Big black beetle (19) Virgin (0%) 0,015 1 0,015 2,4 10,1 extrusion) PA1010 (molding and Beetle head (17) Virgin (0%) 0,003 1 0,003 0,47 2,0 extrusion) Tube (26) + Silicone plugs Silicone (VMQ, heat cured, 10 Virgin (0%) 0,002 1 0,002 0,096 0,4 (22) -30% fumed silica) PP (homopolymer, Boiler plate, top (5) Virgin (0%) 0,046 1 0,046 1,1 4,9 clarified/nucleated) PP (homopolymer, Boiler plate, bottom (3) Virgin (0%) 0,029 1 0,029 0,72 3,1 clarified/nucleated) PP (homopolymer, Bottom plate (8) Virgin (0%) 0,05 1 0,05 1,2 5,3 clarified/nucleated) PP (homopolymer, Lid (plastic part) (10) Virgin (0%) 0,012 1 0,012 0,3 1,3 clarified/nucleated) PP (homopolymer, Handle (13) Virgin (0%) 0,046 1 0,046 1,1 4,9 clarified/nucleated) PP (homopolymer, Handle attachment (12) Virgin (0%) 0,007 1 0,007 0,17 0,7 clarified/nucleated) PP (homopolymer, Button (25) Virgin (0%) 0,005 1 0,005 0,12 0,5 clarified/nucleated) Black rectangular with hole PP (homopolymer, Virgin (0%) 0,002 1 0,002 0,05 0,2 (18) clarified/nucleated) Carbon steel, AISI 1030, Metal plate (gray) (16) Virgin (0%) 0,019 1 0,019 0,17 0,7 annealed Carbon steel, AISI 1030, Screws big (7) Virgin (0%) 0,004 1 0,004 0,035 0,1 annealed Carbon steel, AISI 1030, Screws small (21) Virgin (0%) 0,002 1 0,002 0,017 0,1 annealed Carbon steel, AISI 1030, Screws (4) Virgin (0%) 0,002 1 0,002 0,017 0,1 annealed Carbon steel, AISI 1030, Screws big hat (6) Virgin (0%) 0,002 1 0,002 0,017 0,1 annealed Copper-tellurium alloy, Thin metal plates (15) Virgin (0%) 0,001 1 0,0013 0,095 0,4 C14500, soft (h.c. copper) Copper-tellurium alloy, Bent copper plates (20) Virgin (0%) 0,002 1 0,0025 0,19 0,8 C14500, soft (h.c. copper) Copper-tellurium alloy, bent metal tube Virgin (0%) 0,002 1 0,0025 0,19 0,8 C14500, soft (h.c. copper) Power cord (2) PVC (flexible, Shore A60) Virgin (0%) 0,086 1 0,086 2 8,4 Brass, CuZn28Sn1, C44300, Bent brass plates (28) Virgin (0%) 0,001 1 0,001 0,07 0,3 half hard (admiralty brass) Brass, CuZn28Sn1, C44300, Crown (30) Virgin (0%) 0,003 1 0,003 0,21 0,9 half hard (admiralty brass) Cardboard Cardboard Virgin (0%) 0,3 1 0,3 3 12,8 Total 26 1,1 23 100
*Typical: Includes 'recycle fraction in current supply' **Where applicable, includes material mass removed by secondary processes
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 17 / Ltd. 21 den 28 maj 2021 Manufacture: Summary
Country of manufacture China
Cost Component Process Length (m) % Removed Amount processed % (SEK) Boiler - main part (9) Roll forming 0,47 - 0,4 kg 0,003 0,0 Lid - metal part (11) Forging - - 0,028 kg 5,7 36,7 Electric cable blobb (1) Polymer molding - - 0,01 kg 0,38 2,5 Big black beetle (19) Polymer molding - - 0,015 kg 0,43 2,8 Beetle head (17) Polymer molding - - 0,003 kg 0,27 1,7 Tube (26) + Silicone plugs Polymer molding - - 0,002 kg 0,24 1,5 (22) Boiler plate, top (5) Polymer molding - - 0,046 kg 0,62 4,0 Boiler plate, bottom (3) Polymer molding - - 0,029 kg 0,53 3,4 Bottom plate (8) Polymer molding - - 0,05 kg 0,64 4,1 Lid (plastic part) (10) Polymer molding - - 0,012 kg 0,41 2,6 Handle (13) Polymer molding - - 0,046 kg 0,62 4,0 Handle attachment (12) Polymer molding - - 0,007 kg 0,34 2,2 Button (25) Polymer molding - - 0,005 kg 0,31 2,0 Black rectangular with hole Polymer molding - - 0,002 kg 0,24 1,5 (18) Metal plate (gray) (16) Casting - - 0,019 kg 4,8 30,8 Screws big (7) Wire drawing - - 0,004 kg 0 0,0 Screws small (21) Wire drawing 0,005 - 0,002 kg 5,6e-06 0,0 Screws big hat (6) Wire drawing 0,005 - 0,002 kg 5,6e-06 0,0 Thin metal plates (15) Roll forming - - 0,0013 kg 0 0,0 Cutting and Thin metal plates (15) - 20 0,00025 kg 2,9e-06 0,0 trimming Bent copper plates (20) Roll forming - - 0,0025 kg 0 0,0 Cutting and Bent copper plates (20) - 20 0,0005 kg 5,9e-06 0,0 trimming bent metal tube Roll forming - - 0,0025 kg 0 0,0 Cutting and bent metal tube - 20 0,0005 kg 5,9e-06 0,0 trimming Polymer Power cord (2) 0,4 - 0,086 kg 0,0054 0,0 extrusion Extrusion, foil Bent brass plates (28) 0,01 - 0,001 kg 4,6e-05 0,0 rolling Extrusion, foil Crown (30) 0,01 - 0,003 kg 8,7e-05 0,0 rolling Total 16 100
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 18 / Ltd. 21 den 28 maj 2021 Transport: Summary
Package dimensions Height (m) Width (m) Depth (m) 0,2 0,2 0,2
Breakdown by transport stage Distance Cost Stage name Transport type (km) (SEK) % Ocean freight 2,4e+04 1,9 29,2 14 tonne (2 axle) truck 2e+03 4,7 70,8 Total 2,6e+04 6,6 100
Breakdown by components Mass Cost Component (kg) (SEK) % Boiler - main part (9) 0,4 2,5 37,3 Lid - metal part (11) 0,028 0,17 2,6 Electric cable blobb (1) 0,01 0,061 0,9 Big black beetle (19) 0,015 0,092 1,4 Beetle head (17) 0,003 0,018 0,3 Tube (26) + Silicone plugs (22) 0,002 0,012 0,2 Boiler plate, top (5) 0,046 0,28 4,2 Boiler plate, bottom (3) 0,029 0,18 2,7 Bottom plate (8) 0,05 0,31 4,6 Lid (plastic part) (10) 0,012 0,073 1,1 Handle (13) 0,046 0,28 4,2 Handle attachment (12) 0,007 0,043 0,6 Button (25) 0,005 0,031 0,5 Black rectangular with hole (18) 0,002 0,012 0,2 Metal plate (gray) (16) 0,019 0,12 1,8 Screws big (7) 0,004 0,024 0,4 Screws small (21) 0,002 0,012 0,2 Screws (4) 0,002 0,012 0,2 Screws big hat (6) 0,002 0,012 0,2 Thin metal plates (15) 0,001 0,0061 0,1 Bent copper plates (20) 0,002 0,012 0,2 bent metal tube 0,002 0,012 0,2 Power cord (2) 0,086 0,53 7,9 Bent brass plates (28) 0,001 0,0061 0,1 Crown (30) 0,003 0,018 0,3 Cardboard 0,3 1,8 27,7 Total 1,1 6,6 100
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 19 / Ltd. 21 den 28 maj 2021 Use: Summary
Static mode
Energy input and output type Electric to thermal Country of use Sweden Fuel rate Domestic Power rating 2e+03 (W) Usage (hours per day) 0,039 Usage (days per year) 3,7e+02 Product life (years) 8
Relative contribution of static and mobile modes
Cost Mode % (SEK) Static 4,7e+02 100,0 Mobile 0 Total 4,7e+02 100
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 20 / Ltd. 21 den 28 maj 2021 Disposal: Summary
End of life Cost Component % recovered % option (SEK) Boiler - main part (9) Recycle 100,0 0,024 37,3 Lid - metal part (11) Recycle 100,0 0,0017 2,6 Electric cable blobb (1) Downcycle 100,0 0,00061 0,9 Big black beetle (19) Downcycle 100,0 0,00091 1,4 Beetle head (17) Downcycle 100,0 0,00018 0,3 Tube (26) + Silicone plugs (22) Combust 100,0 0,00012 0,2 Boiler plate, top (5) Downcycle 100,0 0,0028 4,2 Boiler plate, bottom (3) Downcycle 100,0 0,0018 2,7 Bottom plate (8) Downcycle 100,0 0,003 4,6 Lid (plastic part) (10) Downcycle 100,0 0,00073 1,1 Handle (13) Downcycle 100,0 0,0028 4,2 Handle attachment (12) Downcycle 100,0 0,00042 0,6 Button (25) Downcycle 100,0 0,0003 0,5 Black rectangular with hole (18) Downcycle 100,0 0,00012 0,2 Metal plate (gray) (16) Recycle 100,0 0,0012 1,8 Screws big (7) Recycle 100,0 0,00024 0,4 Screws small (21) Recycle 100,0 0,00012 0,2 Screws (4) Recycle 100,0 0,00012 0,2 Screws big hat (6) Recycle 100,0 0,00012 0,2 Thin metal plates (15) Recycle 100,0 6,1e-05 0,1 Bent copper plates (20) Recycle 100,0 0,00012 0,2 bent metal tube Recycle 100,0 0,00012 0,2 Power cord (2) Downcycle 100,0 0,0052 7,9 Bent brass plates (28) Recycle 100,0 6,1e-05 0,1 Crown (30) Recycle 100,0 0,00018 0,3 Cardboard Downcycle 100,0 0,018 27,7 Total 0,066 100
Notes: Summary
electrickettle.prd Report generated by GRANTA EduPack 2020 (C) Granta Design Page 21 / Ltd. 21 den 28 maj 2021
Appendix Updated Requirements Specification This appendix presents the updated requirement specification for a mechanical kettle. A new column has been added "Thesis work results", the column describes if the requirements ha e been fulfilled or needs further investigation. New requirements found during the project has also been added under a new category: "New requirements, found during the thesis work".The specification is presented in Table 1 below.
Table 1. Requirements specification.
Req source Req source Req Id Req text Category Test method Thesis work results Usability Risk
Requirement Check Requirement from Usability Category of the implementation from Risk Requirement Engineering intended component or testing is analysis Specification required
1. Depending on the water container Check Fullfilled. The watercontainer was provided by Empire Sweden and the TR 1.1 UES. 5.9.1 Measurements of the water container: Ø130mm, Height 136mm Mech implementation thesis did not focus on changing it. Fullfilled. The watercontainer was provided by Empire Sweden and the TR 1.2 UES. 5.9.3 1.1.5.9 M3 The shape of the spout shall result in drip-free pouring of water UI Testing required thesis did not focus on changing it. The material choice on the water container is adapted to rapid Check TR 1.3 UES. 5.9.4 1.1.5.13 Mech Fulfilled temperature changes. implementation 2. Active use Check TR 2.1 UES. 5.9.5 1.1.6.1 The product is intended for boiling water only Mech Fulfilled implementation Check TR 2.2 UES. 5.9.6 The product is intended for use on induction hobs only Mech Fulfilled implementation Check TR 2.3 UES. 5.9.7 The product is intended for indoor use only Mech Fulfilled implementation TR 2.4 UES. 5.9.8 The product shall indicate when it is activated for boiling UI Testing required Fulfilled 1.1.5.4 M1 Check TR 2.5 UES. 5.9.9 Minimum dimension for the water refill opening is 15mm in diameter Mech Fulfilled 1.1.6.1 implementation This requirement has not been fulfilled, the water container used for the 1.1.5.2 M1 TR 2.6 UES. 5.9.10 The product should have a capacity of boiling 1.2 liter of water Mech Testing required prototype was to small to allow for boiling 1.2 liters. Changes to the water 1.1.5.3 M1 containers dimentions is required. TR 2.7 1.1.5.12 M2 A minimum of 0.25 liter of water should be used when boiling Mech Testing required Fulfilled 1.1.5.12 M2 TR 2.8 UES. 5.9.11 1.1.5.7 The product visibly indicates max and min water level UI Testing required Fulfilled 1.1.5.8 3. Cleaning
TR 3.1 UES. 5.9.12 1.1.6.1 Water container are accessible for hand wash Mech Testing required Fulfilled Check TR 3.2 UES. 5.9.12 1.1.6.1 The water container can be cleaned in the dishwasher Mech Fulfilled implementation 4. Safety This requirement was not the focus in the functional prototype and needs No leakage of water between lid and water container when water is TR 4.1 UES. 5.9.3 1.1.5.9 M3, M4 Mech Testing required to be tested in the next prototype. The deisign proposal suggest that the poured lid will be kept in place with a seal made of silicone. No leakage of water between lid and water container when the TR 4.2 UES. 5.9.3 1.1.5.9 M3, M4 Mech Testing required Fulfilled product is moved
Ability to angle the product 100° vertically in the direction of the This requirement was not the focus in the functional prototype and needs TR 4.3 UES. 5.9.13 sprout without the lid coming off. The angle is measured from the Mech Testing required to be tested in the next prototype. The deisign proposal suggest that the products centerline when in upright position, see figure in comment. lid will be kept in place with a seal made of silicone.
The design proposal suggests that the product would b food safe. Check TR 4.4 UES. 5.9.14 1.1.5.6 The products materials should be "Livsmedelsgodkänt" Labelling However this requirement needs to checked again before the product implementation would be manufactured. Ensure that the water container does not cause the user injuries, if TR 4.5 1.1.5.13 A safety test must be conducted. the product is placed empty on the induction hub.
TR 4.6 UES. 5.9.2 1.1.5.9 M2 The handle should not be able to get hotter than 50°C. Mech Testing required Fulfilled
1.1.5.2 M2, M3 The surface of the handle should be grippable with wet hands, TR 4.7 UES. 5.9.2 UI Testing required Fulfilled 1.1.5.3 M3 without slipping Water vapor must be able to seep out of the water container during TR 4.8 1.1.5.14 Mech Testing required Fulfilled boiling to prevent overpressure in the water container. 5. Function and performance Due to the low power administered by the prototype this requirement has Boiling 1 liter of water in room temperature on a power of 3000 W TR 5.1 UES. 5.9.15 1.1.5.1 Mech Testing required not beed fulfilled. The time it takes to boil 1 liter with 1000W on 145mm should take a maximum 3 minutes on a 145mm induction plate. induction stove top is 8 minuites. Check TR 5.2 UES. 5.9.16 1.1.8.1 Recyclable material. Mech implementation Check TR 5.3 UES. 5.9.17 Bimetal deactivates the boiling at 100°C. Mech Fulfilled, it react about 10 sekonds after the water reaches 100°C. implementation 1.1.5.9 M1, M2 Materials that are in direct contact with the induction hob shall endure Check TR 5.4 UES. 5.9.6 Mech 1.1.5.12 200°C at a minimum implementation Materials that are not in direct contact with the induction hob shall Check TR 5.5 UES. 5.9.6 1.1.5.11 Mech endure 120°C at a minimum implementation Check TR 5.6 UES. 5.9.14 1.1.5.6 Material protected against corrosion Mech Fulfilled implementation Check TR 5.7 UES 5.9.18 1.1.5.11 M1 The product must withstand water vapor without affecting the function Mech Fulfilled, if the soldersucker button is made out of aluminum. implementation This requirement is not met as of today. The ferromagnetic disc in the The product shall manage a power of maximum 3300W (booster Check TR 5.8 UES. 5.9.6 Mech prototype was not able to manage 3000W, it reached a maximum of mode on induction hobs) implementation 1000W. To fulfill this requirement additinal work and iterations is needed. No liquid shall be accumulated in the product other than the water TR 5.9 1.1.5.5 Mech Testing required Fulfilled container The product has a minimum lifespan of 3 years or 1000 numbers of Check TR 5.12 1.1.5.11 Mech This needs further investigation. boils implementation The product should start boiling the water when the ferromagnetic TR 5.13 UES. 5.9.6 Mech Testing required Fullfilled disc is in contact with the induction hob The product should stop boiling the water when the ferromagnetic TR 5.14 UES. 5.9.6 1.1.5.11 M2 Mech Testing required Fullfilled disc has lost its contact with the induction hob
New requirements, found during the thesis work
Minimize friction between the piston and housing. TR 6.1 -- Mech Testing required Future work The fastening of the bimetal snap disc should allow a flap TR 6.2 -- movement of 2mm. Mech Testing required Future work TR 6.3 --The bimetal snap disc must be fixed in rotation around its own axes. Mech Testing required Future work The distance between induction stove top and ferromagnetic disc TR 6.4 --when the disc is in lowered position should not be larger than 3mm. Mech Testing required Future work Distance between induction stove top and ferromagnetic disc in Check Mech Future work TR 6.5 --the lifted position must be 27mm to ensure lost connection. implementation Check TR 6.6 --The piston should be positioned directly against the flap of the Mech Future work bimetal snap disc. implementation
Appendix : ( ) TRITA -ITM-EX 2021:378
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