Thermodynamic Analysis and Experimental Investigation of Internal Heat Exchanger Influence on CO2 Trans-Critical Cycle Performance

This work present the experimental evaluation of the energy performance of trans-critical CO2refrigeration and heat pump systems. The optimal gas cooler pressure and the optimal COP have been analysed from a thermodynamic point of view. The experimental evaluation covers five evaporating levels (-10 to 10°C) and in a wide range of gas cooler outlet pressures (75 to 120bar). It is concluded that: With the the internal heat exchanger (IHX) system compressor power is relatively low, when the high side pressure is over 100bar, and the evaporation temperature is below 0°C. The COP of the system without IHX is slightly higher than the system with the IHX, it is increase about 3% to 5%, when the evaporation temperature is over 5°C.