Feasibility study on ammonia heat pump system using electrochemical compressor.

This study examines the feasibility of an ammonia heat pump system using an electrochemical compressor to achieve isothermal compression and enhance the coefficient of performance (COP). An electrochemical ammonia compressor was developed, utilizing a thick polymer membrane to transfer and compress ammonia gas. The compressor was integrated into a vapor compression heat pump system using a mixture of ammonia, hydrogen, and vapor as the working fluid with a pressure ratio of 1.8. A parametric study revealed that increasing the ammonia-to-hydrogen ratio from 1:1 to 2:1 improved the heating capacity from 0.19 W to 0.77 W and raised the COP from 0.02 to 0.14. However, the hydrogen in the mixture reduced the heat transfer efficiency and hindered expansion. Additionally, maintaining a high-pressure ratio was challenging due to back diffusion through the membrane. Further research is needed to separate hydrogen from ammonia and reduce back diffusion to increase the system performance.