4E Analysis of a new cogeneration system coupling heat pumps and PEMFC in summer and winter modes

In response to the ongoing optimization of energy systems and the promotion of clean energy, this paper introduces a new high-efficiency cogeneration system based on proton exchange membrane fuel cells (PEMFC). Named the Transcritical Combined Cooling Heating and Power with Subcooling Coupled ORC (CPTSO) system, it undergoes energy, exergy, economic, and environmental (4E) assessments to evaluate its performance in both summer and winter modes. This paper also analyzes the effects of key factors on the new system's performance. The results indicate that the new system performs more effectively overall and achieves faster cost recovery during winter operations. With varying degrees of subcooling (ΔT_subcooling), the system's average energy efficiency, fuel energy saving ratio (FESR), exergy efficiency, and pollutant reduction in winter are 60.97 %, 4.51 %, 17.16 %, and 33.35 % higher, respectively, than in summer. Changes in the main evaporation temperature (T_e) result in winter improvements of 74.37 % in energy efficiency, 16.86 % in FESR, 17.6 % in exergy efficiency, and 45.5 % in pollutant reduction compared to summer. Similarly, adjustments to the outlet temperature of the gas cooler (T_g) lead to winter increases of 56.75 % in energy efficiency, 0.49 % in FESR, 17.1 % in exergy efficiency, and 29.3 % in pollutant reduction over summer values.