Development and performance evaluation of an R718 heat pump system using an electrochemical compressor
This study investigates the thermodynamic performance of an R718/hydrogen heat pump system integrating an electrochemical compressor (EC) as an alternative to conventional mechanical vapor compression, specifically targeting low-pressure and low-temperature cooling applications where conventional compressors exhibit limited efficiency. A comprehensive system-level model was developed using MATLAB and REFPROP to evaluate the effects of key operating parameters, including condenser pressure and evaporator pressure, on the coefficient of performance (COP) and cooling capacity. Increasing the condenser pressure to 60 kPa enhanced R718 condensation and maximized the COP at 4.2, beyond which the COP declined due to increased reversible electrochemical power. The evaporator pressure showed a linear positive effect on COP, reaching 4.6 at 7 kPa, primarily due to a reduced pressure ratio and lower electrochemical work. The results demonstrate the feasibility of electrochemical compression for R718-based heat pump systems and indicate its suitability for high-efficiency, low-GWP heat pump applications operating under low-pressure conditions.