Case Studies in Thermal Engineering (Feb 2023)
Comparative analysis on the life cycle climate performance of ground source heat pump using alternative refrigerants
Abstract
The ground source heat pump (GSHP) system is receiving increasing interest because of its potential to increase energy efficiency and thus reduce greenhouse gas emissions. Using low-GWP refrigerants is another effective approach to reducing emissions. However, alternative refrigerants also affect the energy performance of GSHP systems, so the life cycle climate performance (LCCP) is evaluated to facilitate reasonable refrigerant selection. The GSHP systems using five refrigerants (R134a, R152a, R1234yf, R1234ze(E), and R290) are simulated under the fixed and individual design methods, considering different climate zones. The results reveal that (1) R152a and R1234ze(E) are the optimum low-GWP refrigerants in four different climate zones under fixed and individual design methods, respectively. However, R290 and R1234yf are not good alternative refrigerants for their highest total emissions, though their GWP is low. (2) Changchun has the largest direct emissions (0.04–67.92 tCO2eq) and indirect emissions (2628.27–3065.76 tCO2eq) for its severe cold climate. (3) The refrigerant leakage rate (RLR) has a great impact on the total emissions of GSHPs with a high-GWP refrigerant, while the refrigerant charge has the least impact. The carbon emission factor (CEF) also has a rising influence on the LCCP. This research aims to provide suggestions for the selection of GSHP refrigerants towards carbon neutrality.
