Appliance Power Consumption
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APPLIANCE POWER CONSUMPTION
PROJECT PLAN
May 02-04 October 9, 2001
Client: Herb Harmison
Advisors: John Lamont Ralph Patterson
Team: Stephen Woerdehoff Paul Jonak Yohan Blount Jason Muehlmeier Table of Contents
1. Abstract……………………………………………………………….1 2. Acknowledgement…………………………………………………… 1 3. Definition of Terms……………………………………………..……. 1 4. Introduction………………………………………………………..….1-3 4.1 General Background…………………….……………….………. 1 4.2 Technical Problem…………………………….…………………. 1 4.3 Operating Environment……………………….…………………. 2 4.4 Intended Users and Uses……………………….…………………2 4.5 Assumptions…………………………………..…………………. 2 4.6 Limitations…………………………………….…………………. 3 5. Design Requirements…………………………………………….……3-5 5.1 Design Objectives………………………………..………………. 3 5.2 Functional Requirements………………………..…………….…. 4 5.3 Design Constraints…………………………………..……………4 5.4 Measurable Milestones………………………………..…………. 4 6. End-Product Description………………………………………….…. 5 7. Approach and Design…………………………………………………5-8 7.1 Technical Approaches………………………………..………….. 5 7.2 Technical Design……………………………………..……….…. 7 7.3 Testing Description…………………………………….…………8 7.4 Risks and Risk Management…………………………..………….8 8. Financial Budget………………………………………………………8 9. Personal Effort Budget………………………………………………..9 10. Project Schedule……………………………………………………… 10 11. Project Team Information……………………………………………..11 12. Summary………………………………………………………………11 13. References……………………………………………………………..12
- i - List of Figures Figure 7.1: Data Collector Design.…………………………………………. 6 Figure 7.2: X-10 Protocol Illustration……………………………………….. 7 Figure 10.1: Project Schedule……………………………………………….. 12
- ii - List of Tables Table 8.1: Financial Budget…………………………………………………..9 Table 9.1: Personal Effort Budget…………………………………………….9
- iii - 1. Abstract
Many homeowners and small business owners pay their monthly electric bills not knowing how their individual appliances and devices contribute to that cost. Reviewing power readings and operating costs of a specific appliance may influence the users future use of it to save them money. The decision to keep, service, or replace an older appliance may also be aided by reviewing operating costs. This project intends to produce a system that will provide users with an accurate collection of data that will show readings of power consumption, operation cycles, and operating costs.
2. Acknowledgement
We would like to thank Herb Harmison for his input with the project plan and development.
3. Definition of Terms X-10 – A communication protocol for automation devices using a digital signal superimposed on 120 V, 60 Hz electrical systems.
4. Introduction
4.1 General Background
The purpose of this project is to catalog the power consumption of a household. The system will record the usage of major appliances, lights, and devices and possibly 220V loads. This data will then be available so the users can monitor their power usage. A PC will be used to record the on-off cycles of a load and calculate the power used.
4.2 Technical Problem
There are several different technologies that can be used to implement these systems. These are the technologies that are being reviewed now. One will be selected and implemented:
Cycle Counting The X-10 modules will be used to remotely turn on and off lights and appliances. A central computer could then
- 1 - be used to record the duration of time that a load is on. With this information and knowing the average power rating of each load, the computer can calculate how much power is used in each device on a daily basis. The data can then be manipulated and analyzed any way the user sees fit.
Hard Wiring A small current transformer can be placed on each device’s hot wire so that the current being used is known. This information will then be transformed into digital data that a computer can analyze and manipulate at the users discretion.
Communication Using the X-10 communication protocol a module can be constructed that determines how much current the device is using. This information will then be sent over the household wiring to a computer that will interpret the data that was transmitted and use this along with cycle times that are also recorded to generate data that can be manipulated and analyzed at the users discretion.
4.3 Operating Environment
This system will be located in a residential household, this environment is not very demanding however the system should be able to function despite the following. Possibly a fairly dirty environment with dust and other contaminants such as pet hair may be present. The system should be resistant to any electrical interference caused by operating appliances and other devices. Some resistance to both high and low temperatures would be needed, with an operating range between 30 and 110 degrees Fahrenheit. The individual devices should be somewhat robust and able to survive a drop in shipping or around the house.
4.4 Intended Users and Uses
The home application will be the primary use due to development time, budget constraints, and system complexity. Home residents conscientious about their utility costs can track power usage and learn what is costing them the most and how to save money. The system could be used to monitor larger appliances to determine if they need servicing or replacement.
4.5 Assumptions
The following are a preliminary list of assumptions that are being made under the current plan involving X-10 communication. This may not be the final plan but the assumptions will change accordingly.
- 2 - The user will be familiar with operating a computer. The user will know basic spreadsheet operations. The user will have a basic knowledge of electricity and the concept of power. The house will be compatible with X-10 communications. The house will comply with the operating environment described above. The user will have access to average power consumption rates of appliances. The user will know the current utility rate for their location. The user will be able to operate a simple GUI.
4.6 Limitations
The following limitations are being made under the current plan of X-10 communication. If the plan changes, new limitations will arise.
If a home is greater than 3000 ft2 an X-10 signal booster must be used regardless of home geometry. Transmitted information is small since X-10 communications are very slow. The house will have a modern grounded electrical wiring system.
5. Design Requirements
5.1 Design Objectives
These design objectives are intended to help the user learn more about their electric usage. This is to be done in a simple manner so that the general public could benefit from this project.
Accuracy- Measure power consumption more accurately than pencil estimations. The measurements would be taken at intervals small enough to ensure adequate accuracy, possibly at minute intervals. Power can be measured in different ways, for example measuring voltage and current and calculating power or using a wattmeter to obtain consumption directly. Device communications- Measure amperage of an individual load and have it "wirelessly" reported back to a central computer in one of several ways: RF communication or communication using house wiring (X-10). This could also be achieved using a standalone-metering device, possibly implemented with microcontroller technology. Monitoring capabilities- Central system complete with necessary software capable of simultaneously monitoring multiple power usages. Microcontrollers, each responsible for logging a specific appliance’s usage, could also be used. Reporting- Automated report of consumption details concerning any or all appliances being monitored.
- 3 - 5.2 Functional requirements
These functional requirements should make the end product useful and reliable in the intended operating environment.
Interchanging appliances- System's measurement of consumption at any given wall outlet should allow appliances to be removed to and from outlets and still maintain accuracy as long as the load remains within a limit. Stable communications- Measurement accuracy should be resistant to noise in household wiring and in the system's communications Outlet fluctuations- Measurement accuracy should not be compromised by fluctuations in potential at household outlets Continuous visual data- A homeowner/resident should be able inquire on the system about outlet voltage, total household power usage, power usage per load, cost of operation of a load.
5.3 Design Constraints
These design constraints are intended to minimize interference in normal household activities such as causing static in television reception.
Household life- The system and/or any of its components should not gravely disturb the aesthetic qualities of surroundings or normalcy of life in a household Safety- The system's installation and operation will not pose any unreasonable risk to the safety of non-professionals (eg, typical home automation enthusiasts), children, and pets. Communications- The system’s communication’s scheme, whether it be RF or power line communication, will not aversely effect the operation of any other device.
5.4 Measurable Milestones
These milestones will be deadlines to ensure the project is completed on schedule and will be used to gauge the project’s progress. These are also listed on the Gantt chart on page .
Project Plan- The project plan to outline the project’s functionality and implementation will be completed by September 25. Revised Project Plan- A revised version of the project plan will be completed by October 9. Poster- A poster outlining the project’s design and functions will be completed by October 30. Design Report- A report detailing the project’s proposed design will be completed by December 4.
- 4 - Revised Design Report- A final design plan will be completed by December 18. First Implementation- A design based on the final design plan will be implemented in January 2002. Initial Testing Begins- Individual parts of the product will be tested beginning in February 2002. Design Finalized- After initial testing is complete, a final design will be decided on in March 2002. First Implementation- A final debugged product is implemented and will be ready for final testing in March 2002. Final Testing- A finished product will enter the final testing stage in March 2002. Final Implementation- A finished product will be completed in April 2002. Final Report- A final report that summarizes our project’s design and resulting end product will be completed in April 2002. Presentation- A presentation reporting the project’s final product will be given in April 2002.
6. End-Product Description The end product will be a system of devices that will record the individual power consumptions and operation cycles of up to 20 120V (and possibly 240V) appliances. The devices will each transmit their readings through an interface to a database in a PC. Data will be displayed in a graphical, user-friendly manner.
7. Approach and Design
7.1 Technical Approaches
The design phase of the project can be divided into three separate categories that will be interconnected to for the appliance power consumption monitoring system. The first category is data collectors. In order to measure on/off cycles, current use, or power consumed, a device will be needed to collect data from the appliance or other electrical device. A couple of alternatives are possible for collecting electrical usage and consumption data. The first would be a simple current transformer that could be used to monitor current to the device. The current transformer would be connected to most likely a digital meter and then the data could be outputted from the meter. This approach is the probably the most complicated, but would yield the most information. A second, simpler alternative could entail a device that simply detects whether the device is on or off. This would greater simplify data collection, but would limit the information collected to only on/off cycles. Current use and power consumed would not be available. For either case, the most practical design for the data collector is a device that plugs into the outlet, and then the appliance or light bulb or whatever is being monitored will plug into that. This proposed design is shown in figure 7.1 below.
- 5 - Figure 7.1: Pass through design for the data collection devices for both 110 V and 220 V.
The most important criteria to consider for data collection is the amount of information desired. The outputted information—what the user sees—is dependent upon the data collected and will dictate which method to use in the final project.
Once the data is collected by the device, a method must be in place to transmit the data to a central computer or processor. Again, there are a couple of possibilities. The most straightforward way to transmit data to a central computer would be through hard wiring. However, this would entail extra cost; and with several monitoring devices, the number of wires could be extensive. Another possible option would be infrared communication. However, this has serious limitations. Infrared is limited by “line of sight” functionality. Monitoring devices in other rooms or on other floors away from the central computer would not be able to communicate. Another possibility for communication is radio. This approach would eliminate the need for wires and it would penetrate walls and floors, however if several devices are monitored, each device would require a separate frequency. Otherwise interference would occur between the devices. A final possible approach would be X-10 type devices. The X-10 protocol allows devices to communicate using pre-existing house wiring. It works by sending short 120 kHz bursts at the zero- crossing of a 60 Hz power signal to transmit data in binary form as seen in figure 7.2. This approach is probably the most complicated, but is most advantageous. Using the X- 10 protocol, many devices can communicate using pre-existing home wiring all at once. A major disadvantage to using X-10 protocol is its slow rate of data transmission. There are only 120 zero crossings per second; and as can be seen below, a single command uses 22 of the cycles. Only one X-10 communication can be on the houses wiring at any given time.
- 6 - Figure 7.2: A visual of the zero crossings and bit layout of the X-10 protocol.
The third category for the monitoring system is data collection and processing. Once the data is transmitted by one of the approaches described above, the data must be processed and displayed in an easy-to-read format. Possible approaches are microprocessors, PCs, or perhaps “obsolete” computers. The most important criteria in selecting a central computer is cost. The data collection can most likely be done with minimal computing power, so that is not a determining factor.
7.2 Technical design
Again, as mentioned above the project design is broken down in three main categories that are interconnected to produce a working system. The categories are data collection (monitoring), data transmission, and data processing.
1. Data Collection a. Discuss components of each data-collecting device. For example the current transformer of digital meter. b. Discuss logistics of how device actually connects to appliance or other electrical device. For example is it a pass through plug in, a light switch, or a device that connects directly to the household wiring.
2. Data Transmission a. Discuss how the transmission of data works. b. Discuss necessary hardware (wire, antennas, receivers) that are used for data transmission
3. Data Processing a. Discuss how data is processed. For example, is a microprocessor or an older PC used to gather and process data? b. Discuss how data is presented to the user. For example is the data in visual form (graphs or charts) or the data textual (spreadsheet).
For each of these three categories there are two or more alternatives. Reasons for choosing a certain approach versus another include cost, reliability, and complexity.
- 7 - Other factors include complexity of integration into household settings and ease of use for the targeted user.
7.3 Testing Description
The first step in the testing process of the monitoring system is the data collection system. This is the most important device of the whole system. It is crucial to test that the device in fact works and that the data that is collected is accurate. Once the data collecting device is tested and the results are deemed to be acceptable, the method of transmitting the data must be tested. Criteria to test for transmission are range, accuracy, and reliability. Once it is determined that the method of transmission meets the criteria, the final stage, data processing, can be tested. In this step, it is important that whatever approach is used to process the data, it does it correctly.
Once each stage of the monitoring system is tested and working, it will be necessary to test the system as one complete functioning unit. Initially, a single device connected to the main computer should be tested. By testing only one device, many of the difficulties involved with multiple devices can be eliminated. Instead the testing can focus on the accuracy of the results from one device. Assuming that everything tests out okay, multiple devices will then be connected and tested.
7.4 Risks and Risk Management
This project, like any other engineering project contains, some risk. First, the selected method for transmitting data may fail. The most feasible and logical approaches could fail to deliver accurate data. Also, the project may use older components such as an obsolete computer, which could fail at any time. Completing an implementation early enough so that testing will show a problem in time to formulate a solution will minimize these risks. There is also the possibility of losing a team member throughout the course of the project. Keeping the team informed of individual members’ progress could minimize the impact of this risk.
8. Financial Budget The current proposed design is comprised of three main devices. The interfaced device and software will cost approximately $50. Measuring components for voltage, amperage, etc as well as miscellaneous parts are estimated at $50. Modulation/demodulation equipment for communications is estimated at $50. Based on price inquiries, the poster will cost $50.
- 8 - Table 8.1: Estimated financial budget for the project Item Cost Equipment and parts $150.00 Poster $50.00 Personal computer $0.00 Labor $0.00 Total $200.00
9. Personal Effort Budget Team members will distribute their effort to different tasks depending on their particular expertise. These are estimated hours and will be updated during the course of the project.
Table 9.1: Estimated personal effort budget by team member and by task. t t t t r e n g g r r t u m e n g n n i t o o e e i p i i s s t t t p p s n s b o s m u e e e o e y e r r P p o i d
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I l c D i a r u b d a i Original Estimated v F i d
Team Members n Effort I Yohan Blount 10 20 10 30 8 20 8 5 3 15 129 hours Paul Jonak 10 20 15 40 8 20 7 5 1 15 141 hours Jason Muehlmeier 15 20 15 20 8 20 10 5 5 15 133 hours Stephen Woerdehoff 10 50 15 20 6 15 10 5 1 15 147 hours Total Estimated 45 110 55 110 30 75 35 20 10 60 550 hours Effort
- 9 - 10. Project Schedule The schedule includes several milestones to be completed by the shown dates.
Figure 10.1: Gantt chart
- 10 - 11. Project Team Information
Team Members
Yohan Blount Jason Muehlmeier 211A Westgate Cook 4300 Westbrook Dr, #24 Ames, IA 50012 Ames, IA 50014 (515) 572-6037 (515) 268-9814 [email protected] [email protected] EE EE
Paul Jonak Stephen Woerdehoff 4625 Steinbeck St, #2 1320 Gateway Hills, #501 Ames, IA 50014 Ames, IA 50014 (515) 292-4666 (515) 292-6183 [email protected] [email protected] EE EE
Advisors
John Lamont Ralph Patterson III 1005 Idaho Ave 1807 24th St Ames, IA 50014-3018 Ames, IA 50010-4403 (515) 292-5541 (515) 232-9933 [email protected] [email protected]
Client
Herbert Harmison 2692 Meadow Glen Rd Ames, IA 50014 (515) 292-7059 [email protected]
12. Summary The end product will provide an accurate, reliable tool so consumers can analyze their power usage. They can monitor the operating costs of individual loads and make budgeting decisions based on this information. With this information they can also monitor the health of the loads and possibly predict a malfunction or replace a load based on its inefficiency. This will be implemented using various technologies integrated into a system. A data collection device will be used on the loads to monitor their power usage. A communications device will be used to get the data to the user in a convenient form.
- 11 - 13. References 1. Home Toys. Digital X-10. (1999, February). [On-line]. Available: http://www.hometoys.com/htinews/feb99/articles/kingery/kingery13.htm#Digital
- 12 -