Thermodynamic Cycle Concepts for High-Efficiency Power Plants. Part B

sustainability

Article Thermodynamic Cycle Concepts for High-Eﬃciency Power Plants. Part B: Prosumer and Distributed Power Industry

Krzysztof Kosowski 1, Karol Tucki 2,* , Marian Piwowarski 1 , Robert St˛epie´n 1, Olga Orynycz 3,* and Wojciech Włodarski 1

1 Faculty of Mechanical Engineering, Gdansk University of Technology, Gabriela Narutowicza Street 11/12, 80-233 Gdansk, Poland; [email protected] (K.K.); [email protected] (M.P.); [email protected] (R.S.); [email protected] (W.W.) 2 Department of Organization and Production Engineering, Warsaw University of Life Sciences, Nowoursynowska Street 164, 02-787 Warsaw, Poland 3 Department of Production Management, Bialystok University of Technology, Wiejska Street 45A, 15-351 Bialystok, Poland * Correspondence: [email protected] (K.T.); [email protected] (O.O.)

Received: 9 March 2019; Accepted: 5 May 2019; Published: 9 May 2019

Abstract: An analysis was carried out for different thermodynamic cycles of power plants with air turbines. A new modification of a gas turbine cycle with the combustion chamber at the turbine outlet has been described in the paper. A special air by-pass system of the combustor was applied, and in this way, the efficiency of the turbine cycle was increased by a few points. The proposed cycle equipped with an effective heat exchanger could have an efficiency higher than a classical gas turbine cycle with a regenerator. Appropriate cycle and turbine calculations were performed for micro power plants with turbine output in the range of 10–50 kW. The best arrangements achieved very high values of overall cycle efficiency, 35%–39%. Such turbines could also work in cogeneration and trigeneration arrangements, using various fuels such as liquids, gaseous fuels, wastes, coal, or biogas. Innovative technology in connection with ecology and the failure-free operation of the power plant strongly suggests the application of such devices at relatively small generating units (e.g., “prosumers” such as home farms and individual enterprises), assuring their independence from the main energy providers. Such solutions are in agreement with the politics of sustainable development.

Keywords: thermodynamic cycle concepts; eﬃciency; decentralized energy; sustainability; fuels

1. Introduction Values related to respect for the natural environment are becoming a common phenomenon in many countries. Contemporary fears result from limited access to natural resources, degradation of the environment, and continuous energy demand. This results in the main threat to the socio-economic development of current and future generations. Transformations taking place in the market economy and environmental protection should account for the search for new technological solutions in the field of energy. Only a balanced and cautious approach to such actions can effect an increase in energy efficiency. The energetics play an extremely important role among other areas of sustainability. In addition to energy security, sustainable energy is extremely important, and should be perceived as a durable and environmentally friendly access to heat and electricity.

Sustainability 2019, 11, 2647; doi:10.3390/su11092647 www.mdpi.com/journal/sustainability Sustainability 2019, 11, 2647 2 of 13

Striving for methods of energy production and distribution that are least invasive for the natural environment should be a focus in the economic management of this good, and as a consequence, should promote an increase in efficiency and a reduction of pressure on the environment [1]. Considering the concept of sustainable development, it seems necessary to strive to create an entire energy system that is able to meet the requirements of this concept. Such actions can contribute to the implementation of the principle of sustainable development, and at the same time, bring tangible benefits to the environment and to prosumers as well. Dispersed energy, including the energy generated by prosumers, shows that the idea of sustainable development has an impact on the functioning of the economy. It is seen as one of the elements of improving the local security of energy supply to complement the centralized energy supply system [2]. It is the consumer/prosumer that will have an impact on the changes in the energy sector, which will be based on the correlation of various types of fuels that are often available under local systems [3]. The excessive turnover of natural raw materials creates a number of regional conflicts, leading to a lack of energy stabilization and an increase of ecological threats. The constant pursuit of increased energy efficiency, including the development of competitive fuel and energy markets, must take into account the reduction of the aggressive and devastating development pace of these rational changes. Currently, many countries are trying to develop a new concept of energy development which can evaluate their energy systems in terms of compliance with sustainable development policy [4]. Such observations may lead to the search for improved energy management systems [5]. Research on the potential inherent in such systems may prove to be a chance for the further development of a given region. This is one of the challenges for the domestic energy sector. The aim of this research is to indicate the possibility of implementing high-efficiency turbine systems for prosumer’s energetics within the concept of sustainable development and energy security. The Polish system is characterized by a relatively low energy production efficiency. A drawback of the national power generation sector is the relatively low efficiency of energy production from coal [6–8]. For distributed power generation, the efficiencies of small electric power plants are even lower [9–11], and the organic Rankine cycle (ORC)-based thermal power plants reach an efficiency only slightly exceeding ten percent [12–14]. Within the framework of the prosumer power industry, there are no solutions that can help generate energy 24 h a day [15–17]. As part of the development of the microelectric plant, it is possible to use micro power turbines [18–21] and bladeless adhesion turbines [22,23]. Solar collectors are currently very popular, but can only operate during daylight hours [24–26]. Other solutions which do not make use of solar energy have relatively low efficiencies, which makes their installation and operation rather unprofitable.

2. Materials and Methods Part A in [27] presents the results of an efficiency analysis of modified air turbine cycles intended to work in large electric power plants. The analysis of small electric power plants (from several to several tens of kilowatts) presented here was based on the assumption that the maximal turbine inlet temperature is between 850 and 900 ◦C. Moreover, much lower efficiency values were assumed for cycle components [28,29]. For instance, the assumed efficiency of the turbine was 82%, compressor—80%, electric current generator—90%, and combustion chamber—95%. Assumptions adopted for the analysis are presented in Table1. Sustainability 2019, 11, 2647 3 of 13

Table 1. Assumptions adopted for the design analysis of turbine set variants.

Parameter Unit Value Description

ηcompressor [-] 0.800

ηturbine [-] 0.820

ηmech [-] 0.980

ηleakage [-] 0.980

ηgenerator [-] 0.900

ηcomb.cham [-] 0.950

pi/pi-1 [-] 0.995 ﬁlter

pi/pi-1 [-] 0.995 exhaust gases duct/ﬁlter/silencer

pi/pi-1 [-] 0.99 combustion chamber

pi/pi-1 [-] 0.99 regenerator

The pressure drop in gas turbine combustion chambers is usually about 2%, or even 5%. However, in our analysis we considered the possibilities of building high-efficiency gas turbines with small output. Thus, our investigations were carried out on experimental stands with specially designed combustion chambers and regenerators, where pressure losses for some variants were even lower than 1% [15,17]. Like for large power plants, highly efficient heat exchangers were used [30–32]. Five different variants of gas turbine set configuration were analyzed (Figure1): in each variant, the heat exchanger (called the regenerator) played a key role. Taking into account a micro-scale of the considered power plant, only the compact heat exchangers with passive techniques of heat transfer augmentation were suitable. Heat exchangers with cylindrical mini-channels [33,34] and plate heat exchangers [35,36] were preferable. Moreover, heat exchangers with micro-jet technology are very promising [37], which besides the high thermal performance, are characterized by low flow resistance. The selected plate heaters with minichannels were characterized by a very high effectiveness (higher than 95%, final temperature difference lower than 20 ◦C), low pressure losses (lower than 1%), while leakages were significantly reduced by applying 3D printing technology. Sustainability 2019, 11, 2647 4 of 13 Sustainability 2019, 11, x FOR PEER REVIEW 4 of 13

Figure 1.Figure Turbine 1. Turbine set arrangements set arrangements being being analyzed. analyzed. VariantVariant 1: 1: Turbine Turbine set operatingset operating according according to the to the simple opensimple cycle; open cycle; Variant Variant 2: Turbine 2: Turbine set set operating operating accordingaccording to to the the open open cycle cycle with awith regenerator; a regenerator; Variant 3: Turbine set operating according to the open cycle with a combustion chamber at the turbine Variant 3: Turbine set operating according to the open cycle with a combustion chamber at the turbine exit. The air introduced to the combustion chamber had a temperature equal to the temperature just exit. Thebehind air introduced the turbine and to the it could combustion be compared chamber to the situation had a whentemperature the effectiveness equal to of thethe regenerator temperature just behind equaledthe turbine 1. Therefore, and it could the effi beciency compared of variant to 3the could situation be higher when than the the effectiveness efficiency of other of the variants. regenerator equaledThis 1. Therefore, solution has the been efficiency well known of for variant years [ 383 ],could but it be was higher not used than in practice the efficiency due to the of properties other variants. This solutionof the materials has been for well regenerators known/ combustorsfor years [38], which but did it not was allow not the used application in practice of high due temperature to the properties before the turbines. Nowadays, due to technological progress we can overcome these problems, and of the materials for regenerators/combustors which did not allow the application of high temperature propose variant 3 as a realistic solution. Variant 4: Turbine set operating according to the open cycle before thewith turbines. an external Nowadays, combustion due chamber to technological at the turbine progress exit and awe high-temperature can overcome heat these exchanger; problems, and proposeVariant variant 5: 3 Turbine as a realistic set operating solution. according Variant to the 4: openTurbine cycle set with operating partial bypassing according of the to externalthe open cycle with ancombustion external combustion chamber at the chamber turbine exit at and the with turbine a high-temperature exit and a heathigh exchanger.‐temperature heat exchanger; Variant 5: Turbine set operating according to the open cycle with partial bypassing of the external combustion chamber at the turbine exit and with a high‐temperature heat exchanger.

3. Results and Discussion The assumptions adopted in the Introduction formed the basis for the thermodynamic analysis of the above power plant variants. The relative efficiency values obtained for these variants after assuming the turbine inlet temperature T3 = 900 °C are shown in Figure 2, with variant 1 as the reference, while Figure 3 shows optimal compression values for individual variants. Sustainability 2019, 11, 2647 5 of 13

3. Results and Discussion The assumptions adopted in the Introduction formed the basis for the thermodynamic analysis of the above power plant variants. The relative eﬃciency values obtained for these variants after assuming the turbine inlet temperature T3 = 900 ◦C are shown in Figure2, with variant 1 as the Sustainabilityreference, while 2019, 11 Figure, x FOR3 PEER shows REVIEW optimal compression values for individual variants. 5 of 13

1.8 1.7 1.67 1.6 1.5 1.4 1.28 1.3 1.17 1.2 1.15 1.1 1.00 1.0 W1 

/ 0.9  0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 W1 W2 W3 W4 W5

Sustainability 2019, 11, x FOR PEERFigure REVIEW 2. Relative efficiency eﬃciency of the analyzed turbine sets. 6 of 13

Compared 16to the analysis performed for large power plants (Part A), decreasing the efficiency of cycle components (for 14.00very small power values) resulted, to some extent, in the decrease of relative efficiency differences14 between variants [39–41], and in the reduction of optimal compression values [42]. On the other hand, the effect of the efficiencies of heat exchangers were more noticeable. For instance, decreasing12 the final temperature difference T5 – T2 from 50 to 10 °C in variant 3 increased the efficiency by about 11.5% (compared to 9.5% for large power plants, Part A). From a practical point of view, the10 solutions corresponding to thermodynamic cycles of variant 3 and variant 5 seem to be most attractive (Figure 1). In this latter case, the air flow bypassing the combustion chamber opt could be directed to the high‐temperature exchanger or used for cogeneration purposes [43]. The  8 combustion chamber in variant 3 was rather strange for the gas turbine community, but the way of heating the working6 medium from a small temperature to a high temperature by an external burner is well known in various other power plants. This idea is applied, for example, in steam boilers for electric power plants4 or small water heaters for home applications. In variant 5, the working fluid was2.80 bled, and in this way the2.65 heat delivered 2.65 to the combustion chamber was reduced and the outlet temperature T1.756 was decreased, and the cycle efficiency was 2 increased. The amount of the bled stream depended on the final temperature difference in the heat exchanger and on the compressor pressure ratio. In the analyzed variants, the bled stream varied 0 from 3% to 16% of the main stream. For the optimum pressure ratio (Π = 2.65), the final temperature W1 W2 W3 W4 W5 difference in the heat exchanger was 10 °C, and the bled stream amounted to 9.1%. Figure 3. Optimal pressure ratio of the analyzed turbine sets.

It should be emphasized that the use of a high‐efficiency generator (small final temperature difference) led to a reduction of the optimal compression value as compared to the basic system without a regenerator. The effect of compression on the efficiency of individual variants of turbine sets is shown in Figure 4. Such comparatively low pressures led to an increase of the specific volume of the working medium, and to an increase of the volumetric flow rate, which facilitated the design and operation of the flow parts of the compressors and turbines.

1.02

1.00

0.98

0.96

0.94 [‐]

max 0.92  /

 0.90

0.88

0.86

0.84

0.82 6 8 10 12 14 16 18 20 22 24 26

[‐] variant 1 Sustainability 2019, 11, x FOR PEER REVIEW 6 of 13 Sustainability 2019, 11, 2647 6 of 13 16

14.00 Compared to14 the analysis performed for large power plants (Part A), decreasing the efficiency of cycle components (for very small power values) resulted, to some extent, in the decrease of relative efficiency differences between variants [39–41], and in the reduction of optimal compression values [42]. 12 On the other hand, the effect of the efficiencies of heat exchangers were more noticeable. For instance, decreasing the final temperature difference T5 –T2 from 50 to 10 ◦C in variant 3 increased the efficiency 10 by about 11.5% (compared to 9.5% for large power plants, Part A). From a practical point of view, the solutions correspondingopt to thermodynamic cycles of variant 3 and variant 5 seem to be most attractive

(Figure1). In this8 latter case, the air flow bypassing the combustion chamber could be directed to the high-temperature exchanger or used for cogeneration purposes [43]. The combustion chamber in variant 3 was6 rather strange for the gas turbine community, but the way of heating the working medium from a small temperature to a high temperature by an external burner is well known in various other power4 plants. This idea is applied, for example, in steam boilers for electric power plants 2.80 2.65 2.65 or small water heaters for home applications. 1.75 In variant 5,2 the working fluid was bled, and in this way the heat delivered to the combustion chamber was reduced and the outlet temperature T6 was decreased, and the cycle efficiency was increased. The amount0 of the bled stream depended on the final temperature difference in the heat exchanger and on the compressorW1 pressure W2 ratio. In W3 the analyzed W4 variants, the W5 bled stream varied from 3% to 16% of the main stream. For the optimum pressure ratio (Π = 2.65), the final temperature Figure 3. Optimal pressure ratio of the analyzed turbine sets. difference in the heat exchanger was 10 ◦C, and the bled stream amounted to 9.1%. It should be emphasized that the use of a high-ehigh‐efficiencyfficiency generator (small final final temperature difference)difference) ledled to to a reductiona reduction of theof the optimal optimal compression compression value value as compared as compared to the basicto the system basic withoutsystem withouta regenerator. a regenerator. The effect The of compression effect of compression on the efficiency on the of efficiency individual of variants individual of turbine variants sets of is turbine shown setsin Figure is shown4. Such in Figure comparatively 4. Such comparatively low pressures ledlow to pressures an increase led of to the an specificincrease volume of the specific of the working volume ofmedium, the working and to medium, an increase and of to the an volumetric increase of flow the volumetric rate, which flow facilitated rate, which the design facilitated and operation the design of andthe flow operation parts of thethe compressorsflow parts of andthe compressors turbines. and turbines.

1.02

1.00

0.98

0.96

0.94 [‐]

max 0.92  /

 0.90

0.88

0.86

0.84

0.82 6 8 10 12 14 16 18 20 22 24 26

[‐] variant 1

Figure 4. Cont. Sustainability 2019, 11, 2647 7 of 13 Sustainability 2019, 11, x FOR PEER REVIEW 7 of 13

1.01

1.00

0.99 [‐]

max 0.98  /  0.97

0.96

0.95 2.22.42.62.83.03.23.43.63.84.0 [‐]

variant 2 1.01

1.00

0.99

[‐] 0.98 max 

/ 0.97 

0.96

0.95

0.94 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5  [‐]

variant 3

Figure 4. Cont. Sustainability 2019, 11, 2647 8 of 13 Sustainability 2019, 11, x FOR PEER REVIEW 8 of 13

1.01

1.00

0.99

[‐] 0.98 max 

/ 0.97 

0.96

0.95

0.94 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8  [‐] variant 4 1.010

1.000

0.990

[‐] 0.980 max 

/ 0.970 

0.960

0.950

0.940 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0  [‐]

variant 5

Figure 4. TheThe influence inﬂuence of of pressure pressure ratio on the efficiency eﬃciency of the analyzed variants of turbine sets.

Relatively high turbine set efficiency eﬃciency was obtained in variant 3, which could reach as much as 39% at the turbine inlet temperature equal to 900 °C.◦C. For variant 5, the efficiency eﬃciency was on the order of 35%, but this variant allows the hot air air bypassing bypassing the combustion combustion chamber to be used used for for cogeneration cogeneration purposes, forfor instance. instance. Moreover, Moreover, this this variant variant was adjusted was adjusted for cooperation for cooperation with an external with an combustion external combustionchamber fed chamber with practically fed with arbitrary practically fuel. arbitrary Based onfuel. this Based variant, on this preliminary variant, designpreliminary calculations design werecalculations performed were for performed a series of for turbine a series sets, of withturbine powers sets, with ranging powers from ranging 10 to 50 from kW. Designs10 to 50 werekW. workedDesigns outwere for worked compressors, out for turbines, compressors, heat exchangers, turbines, and heat selected exchangers, combustion and chamberselected variantscombustion (for chamber variants (for different chemical compositions of burned biogas). The main parameters of the designed turbine units are shown in Table 2. Sustainability 2019, 11, 2647 9 of 13

Sustainabilitydiﬀerent chemical 2019, 11, x compositions FOR PEER REVIEW of burned biogas). The main parameters of the designed turbine9 units of 13 areSustainability shown 2019 in Table, 11, x2 FOR. PEER REVIEW 9 of 13 Table 2. Parameters of the designed turbine units. Table 2.2. Parameters of the designed turbine units. Parameter 10 kW Turbine 35 kW Turbine 50 kW Turbine ParameterpressureParameter ratio 10 kW10 kW Turbine2.3 Turbine 3535 kW kW Turbine2.3 Turbine 50 50 kW kW2.3 Turbine Turbine temperaturepressurepressure in front ratio ratio of the turbine 2.38502.3 °C 850 2.32.3 °C 8502.3 2.3 °C temperaturetemperature inrotor front in front ofspeed the of turbine the turbine 850120,000◦850C °C rpm 65,000 850850◦C °Crpm 55,000850 850 °Crpm◦C rotor speed 120,000 rpm 65,000 rpm 55,000 rpm compressorrotor speed 1 120,000stage, radial rpm 1 stage,65,000 radial rpm 1 stage,55,000 radial rpm compressor 1 stage, radial 1 stage, radial 1 stage, radial compressor 1 stage, radial 1 stage, radial 1 stage, radial turbineturbine 1 stage,1 stage, axial axial 11 stage, stage, axial axial 1 1stage, stage, axial axial turbine 1 stage, axial 1 stage, axial 1 stage, axial Figure 5 shows a turbine set with visible compressor and turbine flow parts, while Figure 6 Figure5 shows a turbine set with visible compressor and turbine ﬂow parts, while Figure6 presentsFigure selected 5 shows microturbine a turbine set variants,with visible including compressor the variant and turbine adjusted flow for parts,cooperation while Figurewith an 6 presents selected microturbine set variants, including the variant adjusted for cooperation with an arbitrarypresents combustionselected microturbine chamber, andset variants, the variant including with the the boiler variant which adjusted can burn for practicallycooperation arbitrary with an arbitrary combustion chamber, and the variant with the boiler which can burn practically arbitrary fuelarbitrary (with combustionan additional chamber, chamber and for thepartial variant pyrolysis). with the boiler which can burn practically arbitrary fuel (with an additional chamberchamber forfor partialpartial pyrolysis).pyrolysis).

FigureFigure 5. 5. TheThe 35 35-kW‐kW air air turbine turbine set set (compressor (compressor and and turbine). turbine). Figure 5. The 35‐kW air turbine set (compressor and turbine).

Figure 6. Power plant for distributed/prosumer power industry: (a) with external combustion Figure 6. Power plant for distributed/prosumer power industry: (a) with external combustion chamber; (b) adjusted for cooperation with arbitrary combustion chamber; (c) with boiler for practically chamber;Figure 6. (Powerb) adjusted plant forfor cooperationdistributed/prosumer with arbitrary power combustion industry: (chamber;a) with external(c) with combustion boiler for arbitrary fuel. practicallychamber; (arbitraryb) adjusted fuel. for cooperation with arbitrary combustion chamber; (c) with boiler for 4. Conclusionspractically arbitrary fuel. 4. Conclusions 4. ConclusionsThe article proposes and analyzes a unique small power plant that can burn arbitrary fuel. The uniquenessThe article of this proposes solution and is testiﬁedanalyzes by: a unique small power plant that can burn arbitrary fuel. The uniquenessThe article of this proposes solution and is testified analyzes by: a unique small power plant that can burn arbitrary fuel. The uniqueness of this solution is testified by:  The unique design and technological solution;  TheThe lowunique parameters design and of working technological medium solution; (pressure and temperature);  The low parameters of working medium (pressure and temperature); Sustainability 2019, 11, 2647 10 of 13

The unique design and technological solution; • The low parameters of working medium (pressure and temperature); • The working medium is clean air, which has numerous advantages compared to poisonous, • combustible, physically unstable, expensive, and environmentally hazardous working media used in ORC power plants. This property of the working medium increases the time of power plant failure-free operation (in contrast to gas turbines and piston engines currently in operation); A high eﬃciency of power generation—higher by several or even more than ten percentage points • than the eﬃciencies of other competing solutions.

This high efficiency of the device producing electric energy (also heat and cold, if necessary), along with its reliability of operation, ensures long lasting profitability for its users (i.e., prosumers and small energy producers). Entry to the market with this product fills the gap in the supply of such devices. With its further use for own purposes or sale, the possibility of profitable energy production from different types of fuels makes the prosumers (households, small businesses, etc.) independent from the thermal and electric power plant and/or electric network. Part B of the article gives the description of the proposed thermal cycle and its sample execution, complemented with preliminary designs of a series of turbine sets with powers ranging from 5 to 50 kW (Figure1). The results of the design analyses confirm that good conditions can be created for the production, distribution, and service of power plants for the distributed and prosumer power industry:

Turbine sets with powers from 3 to 10 kW for cooperation with gas boilers for the prosumer • power industry; Turbine sets with powers from 20 to 100 kW for small production plants and agro-power engineering; • Turbine sets with powers from 100 to 500 kW (1000 kW) for small power plants, small production • plants, sewage treatment plants, and landﬁll sites.

The proposed turbine sets can be adjusted for operation in cogeneration systems (simultaneous production of heat and electrical energy) and trigeneration systems (simultaneous production of electrical energy, heat, and cold). They can also be adapted for burning various fuels (liquid and gas fuels, coal, wood, biogas, pellets, garbage, waste, etc.), and their advantage is that the turbine and compressor flow parts remain clean during the entire useful life of the power plant, without exhaust pollution. Consequently, they do not need frequent repairs and cleaning. This is a particular advantage, compared, for instance, to biogas-fed piston engines working on landfill sites and in cleaning plants. The proposed modifications of turbine sets with combustion chambers at turbine exit can be successfully used in compressed air energy storage (CAES) systems. In these systems, the combustion chamber works permanently at a constant pressure that is close to the atmospheric pressure. This is a great advantage, because in typical applications, the combustion chamber works at the very high and changing pressure of the air flowing out of the compressed air storage tank. Examples of high-efficiency turbine systems for public and prosumer power industries which were presented in Part A and Part B of the article can be modified and expanded in order to reach even higher efficiencies. Higher efficiency can be reached by:

Optimizing cycle parameters; • Using multi-pressure waste heat boilers; • Increasing the gas turbine inlet temperature; • Expanding the gas cycle (inter-stage coolers, sequential combustion chambers). • It seems that the efficiency of turbine sets for micro-energetics will clearly increase after the introduction of new high-efficiency thermodynamic cycles. For example, intensive work is currently underway on the technical implementation of a turbine set working according to the so-called Ericsson’s Sustainability 2019, 11, x FOR PEER REVIEW 11 of 13 experimental variant of a gas turbine working according to the Ericsson cycle with a design efficiency above 45%. Summarizing the above considerations, it should be noted that, after their implementation as the prosumer’s type of energy system, the examples of high‐efficiency turbine systems that can be supplied with various types of fuels can be considered as integrated activities at particular levels that contribute to the development of a sustainable market. The local energy sector needs to be Sustainabilitymodernized2019 to, 11introduce, 2647 low‐carbon and innovative models. Solutions increasing the efficiency11 of 13of energy consumption give the possibility of diversification, and enable a reduction of energy consumption, as well as the primary consumption. Such effective technological changes and layout circuitimprovements (with effi canciency be one equal of the to Carnot’sstages of ecombatingfficiency). the Figure energy7 shows crisis, an in example addition of to anbeing experimental an element variantof strategic of a development gas turbine working in shaping according the national to the energy Ericsson generation cycle with sector. a design efficiency above 45%.

FigureFigure 7. Example of an experimental variant of a gas turbine working according to the Ericsson cycle.

AuthorSummarizing Contributions: the Conceptualization, above considerations, K.K., M.P., it should R.S., beand noted W.W.; that, Methodology, after their K.T. implementation and O.O.; Validation, as the prosumer’sK.K. and M.P.; type Investigation, of energy system, R.S. and the W.W.; examples Writing—original of high-efficiency draft turbine preparation, systems K.T. that and can O.O.; be supplied Funding withacquisition, various K.K. types of fuels can be considered as integrated activities at particular levels that contribute toFunding: the development This research of areceived sustainable no external market. funding. The local energy sector needs to be modernized to introduce low-carbonAcknowledgments: and innovative The authors models. wish to Solutions express increasingtheir deep gratitude the efficiency to Gdansk of energy University consumption of Technology give the for possibilitythe financial of support diversification, given to the and present enable publication a reduction (Krzysztof of energy Kosowski). consumption, The research as wellwas carried as the out primary under consumption.the financial support Such eobtainedffective from technological the research changes subsidy and of layoutthe Faculty improvements of Engineering can Management be one of the (WIZ) stages of ofBialystok combating University the energy of technology crisis, in (Olga addition Orynycz). to being an element of strategic development in shaping the national energy generation sector. Conflicts of Interest: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to Author Contributions: Conceptualization, K.K., M.P., R.S., and W.W.; Methodology, K.T. and O.O.; Validation, K.K. andpublish M.P.; the Investigation, results. R.S. and W.W.; Writing—original draft preparation, K.T. and O.O.; Funding acquisition, K.K. Funding: This research received no external funding. References Acknowledgments: The authors wish to express their deep gratitude to Gdansk University of Technology for the1. financialOrynycz, support O.; Świ givenć, A. to The the presentEffects publicationof Material’s (Krzysztof Transport Kosowski). on Various The Steps research of Production was carried System out under on the financialEnergetic support Efficiency obtained of Biodiesel from the Production. research subsidy Sustinability of the 2018 Faculty, 10, 2736. of Engineering Management (WIZ) of Bialystok University of technology (Olga Orynycz). 2. Oberst, C.A.; Schmitz, H.; Medlener, R. Are Prosumer Households That Much Different? Evidence from ConflictsStated of Residential Interest: The Energy authors Consumption declare no conflictin Germany. of interest. Ecol. Econ. The 2019 funders, 158 had, 101–115. no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to 3. Kubli, M.; Loock, M.; Wüstenhagen, R. The flexible prosumer: Measuring the willingness to co‐create publish the results. distributed flexibility. Energy Policy 2018, 114, 540–548. References

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