A combined heat and power (CHP) system generates electricity from thermal energy and generates heat by utilizing the remaining thermal energy. The system efficiency of the cogeneration system is 75–85 %, which is very high compared to existing only power generation facilities, so it is very useful for energy conservation and environmental protection. For this reason, interest in the cogeneration system is increasing worldwide. Generally, a cogeneration plant consists of a steam turbine alone or the combined power generation of a gas turbine and a steam turbine depending on the scale. The steam turbine is divided into a back-pressure type turbine and a condensing type turbine depending on the operational methodology of the steam turbine. In both cases, the shift in the return temperature of the district heating users influences the performance of the cogeneration plant, thus affecting the power generation costs of the power plant. It is possible to accurately estimate the change in the unit cost of the power generation caused by these changes, and to inflict it on the user, thereby changing the usage pattern of the user and reducing the energy consumption accordingly. In this study, the commercial combined cycle cogeneration system using back - pressure type turbine was simulated, and the change of performance of the combined heat and power plant was analyzed while changing the user facility’s total return temperature. Based on the results of this analysis, a possible loss in the plant according to the change of return temperature was predicted. Also the effect of each user’s return temperature on the plant loss was analyzed using an actual user’s return temperature data. The economic-mechanical approach, such as this study, can alleviate dissatisfaction with the user’s charge and to consume energy in a more rational way. It eventually can play a role in reducing carbon emissions.
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This work was supported by the Energy Demand side Management Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No.20172010000190).
Recommended by Editor Yong Tae Kang
Jongjun Lee is a Principal Researcher of Frontier Research and Training Institute on Korea District Heating Corporation, Gyeonggi, Republic of Korea. He received his Ph.D. in Mechanical Engineering from Inha University. His research interests include cogeneration system, distributed generation, combined cycle performance and performance monitoring.
Kyoung Min Kim is a Principal Researcher of Frontier Research and Training Institute on Korea District Heating Corporation, Gyeonggi, Republic of Korea. His Ph.D. in Mechanical Engineering is from Yonsei University. His research interests include combined heat and power system, district heating and cooling system.
Shinyoung Im is a Department Manager of Global Business Department on Korea District Heating Corporation, Gyeonggi, Republic of Korea. His Ph.D. in Energy Engineering is from Ajou University. His research interests include district heating and cooling system, distributed generation, user’s facilities of district heating and CHP performance.
Won Seok Jang is a Head Researcher of Korea District Heating Corporation Frontier Research and Training Institute, Gyeonggi, Republic of Korea. His Ph.D. in Environmental Engineering is from Inha University. His research interests include CCUS, water treatment-plant technologies, and renewable energy sources such as biogas and SRF.
Mun Sei Oh is a Department Manager of Korea District Heating Corporation Frontier Research and Training Institute, Gyeonggi, Republic of Korea. He received his M.S. in Mechanical Engineering from Chungnam National University. His research interests include regeneration system, distributed generation, zero energy building, smart farm and CCUS technologies.
Sang Ho Shin is a Team Manager of Plant Division on Korea District Heating Corporation, Gyeonggi, Republic of Korea. He received his M.S. in Mechanical Engineering from Inha University. His research interests include OTEC (Ocean Thermal Energy Conversion), water footprint of CHP, cogeneration system and gas turbine cycle innovation.
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Lee, J., Kim, K.M., Im, S. et al. A study on the variation of the performance and the cost of power generation in a combined heat and power plant with the change of the user facility’s return temperature. J Mech Sci Technol 34, 905–915 (2020). https://doi.org/10.1007/s12206-020-0140-5
- District heating
- Combined heat and power
- Back pressure turbine
- Return temperature