For the spiral tube gas cooler in a CO2 heat pump system

a simulation model was established in MATLAB. The effects of the inlet water temperature

CO2 pressure

and mass flow rate of the gas cooler heat transfer

entransy dissipation

exergy loss

exergy efficiency

and outlet water temperature were studied using a single factor analysis method. Compared to the experimental data

the overall error of the model was within ±10% when the inlet temperature was 24.5-35.0 ℃

the CO2 pressure was 8.4-10.7 MPa

and CO2 mass flow rate was 0.0326-0.0476 kg/s. Compared to the inlet water temperature and CO2 mass flow rate

CO2 pressure had considerable effects on the performance of the gas cooler

thereby causing the optimal pressure. At inlet water temperature of 20 ℃ and inlet refrigerant temperature of 90 ℃

the exergy efficiency of the gas cooler reached the peak when CO2 pressure was 10 MPa

and the heat transfer rate of the gas cooler was the highest when CO2 pressure was 11 MPa. When the inlet temperature was lower than 20 ℃ and the CO2 pressure was 10.5 MPa

the outlet water temperature was the highest.