Energetic, economic, environmental investigation of carbon dioxide as the refrigeration alternative in new energy bus/railway vehicles' air conditioning systems. (1st January 2022)

• Record Type: Journal Article
• Authors: Song, Yulong; Wang, Haidan; Ma, Yuan; Yin, Xiang; Cao, Feng
• Is Part Of: Applied energy. Volume 305(2022)
• Publication Date: 2022-01-01
• Subjects: New energy vehicle -- Transcritical CO2 technology -- Refrigerant substitution -- Energy saving -- Environmental friendliness; Power (Mechanics) -- Periodicals; Energy conservation -- Periodicals; Energy conversion -- Periodicals; 621.042
• DOI: 10.1016/j.apenergy.2021.117830
• Languages: English
• ISSNs: 0306-2619

Abstract

Highlights: The CO2 equators in energetic, environmental and economical perspective is creatively proposed and clearly illustrated. The overall performances of CO2 and R407C air-conditioning systems are comprehensively compared in detail. The operational strategies of both CO2 and R407C systems are developed for new energy bus/railway vehicles. Abstract: New energy transportation is an important link for the future development of global energy industry, while higher and more precise requirements for the new energy vehicles' air conditioning systems are also needed with its rapid development. Because of the stringent environmental and energy problems, the natural refrigerant CO2 (carbon dioxide) is investigated in this paper as an ideal alternative of the conventional HFC (Hydrofluorocarbon, R407C) used in bus/railway vehicle air conditioning systems. First, after constructing the thermodynamic simulation models and developing the operational strategies under the one-dimensional simulation of thermodynamic cycle, the thermodynamic performances of both CO2 and R407C systems are comprehensively compared under all the annual heating/cooling conditions, which showed that CO2 system performs absolutely better in heating but not good enough in cooling mode. Then, based on the annual climate data of 116 cities/regions, the daily heating/cooling loads and corresponding power consumptions, COPs of both CO2 and R407C systems are clearly summarized, thereafter the life cycle climate performances (LCCP) and total costs are obtained. As results, the annual comprehensive ratios of CO2 performances over R407C are 0.949, 1.047, 0.915 from energetic, environmental and economic aspects. By drawing the contour maps, an innovative concept of CO2 equators are proposed and described in detail from energetic, environmental and economic perspectives. By formulating the annual operation strategy of the CO2 system on the vehicle, obtaining its annual comprehensive performance, and comprehensively considering the energy consumption index, environmental protection index and economic index of the CO2 system from the global application perspective, this study has filled the research gap mentioned above, which would also be a significant reference for researchers, manufacturers, component suppliers and policy makers.