Theoretical study on a novel CO_2 Two-stage compression refrigeration system with parallel compression and solar absorption partial cascade refrigeration system

摘要

To discuss the application feasibility of CO2 two-stage compression refrigeration system with parallel compression and solar absorption partial cascade refrigeration system (CTRS + PC + PCRS), a CO2 two-stage compression refrigeration system was proposed for the purpose of commercial supermarket application. Some important parameters, including coefficient of performance (COP), energy saving share (ESS), and partial seasonal energy efficiency ratio (PSEER) are taken as the objective functions to make comparisions among basic CO2 two-stage compression refrigeration system (BCTRS), CO2 two-stage compression refrigeration system with parallel compression (CTRS + PC) and CTRS + PC + PCRS. China's five typical climate representative cities (Beijing, Harbin, Wuhan, Guangzhou, Chengdu) are considered in this study. The results indicated that the COP of CTRS + PC + PCRS increased by 47.28% and 14.28% in Harbin area, compared with BCTRS and CTRS + PC, respectively. When operating under subcritical and transcritical conditions, the maximum COP of CTRS + PC + PCRS increased by 31.71% (Wuhan) and 47.28% (Harbin) respectively compared with the BCTRS, and increased by 12.27% (Harbin) and 7.78% (Wuhan) respectively compared with the CTRS + PC. The ESS and PSEER were introduced to evaluate the energy-saving effect of the solar partial cascade system (PCRS) and the performance of the composite system, and the maximum ESS is 0.19 (Beijing). Compared with the BCTRS and the CTRS + PC, the PSEER is increased by 22.54% and 2.81%, respectively. The research results in this paper provide a theoretical basis for the application of CO2 two-stage compression refrigeration system in the application of commercial supermarket.