Energy efficiency indicators for combined cooling, heating and power systems

• Published in: Energy conversion and management 2021-07, Vol.239, p.114187, Article 114187
• Main Authors: Ma, Weiwu, Fan, Jiaqian, Fang, Song, Hassan, N.M.S., Zhang, Yucong, Wu, Xiaotian, Li, Yi, Hu, Rong, Liu, Gang
• Format: Article
• Language: English
• Subjects: Average comprehensive energy utilization efficiency; Carbon dioxide; Carbon dioxide emissions; Combined cooling; Comparative analysis; Configurations; Cooling; Cooling rate; Cooling systems; Design optimization; Economic analysis; Electric power systems; Electrical loads; Electricity; Energy conservation; Energy consumption; Energy efficiency; Energy utilization; Environmental protection; Genetic algorithms; Heating; Heating and power system; Heating load; Indicators; Office buildings; Optimization; Primary energy rate; Primary energy saving rate; Reference systems; System effectiveness; Thermal analysis
• ISSN: 0196-8904; 1879-2227
• DOI: 10.1016/j.enconman.2021.114187

[Display omitted] •This study conducts an innovative comparative analysis of energy indicators.•Primary energy rate and primary energy saving rate have same optimization effect.•Annual average comprehensive energy utilization efficiency cannot be lonely used.•Larger value of primary energy rate means reduction of carbon dioxide emissions. Combined cooling, heating and power system is an effective technology for energy conservation and environmental protection, especially for buildings with multiple demands on electricity, cooling and heating load. Various energy indicators have been proposed for evaluating and optimizing the energy efficiency of combined cooling, heating and power systems, but previous studies have not yet clarified how to use them in a reasonable way that takes their specific merits into account. This paper aims to identify the underlying effects of three common energy indicators, including the primary energy rate, primary energy saving rate, and annual average comprehensive energy utilization efficiency, based on the optimized performance of combined cooling, heating and power systems with different typical configurations. This paper proposes three combined cooling, heating and power system configurations for an office building in Kunming to conduct a comparative analysis of three energy indicators. Two common operation strategy (the following thermal load and following electricity load) and the genetic algorithm are selected to performed single-objective optimization with energy indicator as target. The economic and environmental analysis is also carried out to show the impact of energy indicators on other indicators. The results show that, the indicators primary energy rate and primary energy saving rate have the same optimization effect of energy consumption when the system configuration and operation strategy are identical, as the difference between the primary energy rate values is not more than 1%, and the difference between the primary energy saving rate values is not more than 0.5%. The advantage of primary energy rate is that the difference between the primary energy rate values of combined cooling, heating and power systems and reference system could show whether carbon dioxide emissions are reduced, and the advantage of primary energy saving rate is that its value directly indicates whether the system achieves energy-saving or not. Furthermore, the annual average comprehensive energy utilization rate is not suitable for the si