Performance Analysis of CO2 Heat Pump Water Heater with an Ejector

CO2 trans-critical cycle has a large loss of expansion work, based on this, use an ejector in the system to recover expansion work. This paper focused on the CO2 heat pump water heater with an ejector, established a model for it on the basis of equal pressure mixture theory, and analyzed operating parameters and the ejector's influence on system performance. It is found that: Coefficient Of Performance (COP) of the CO2 trans-critical cycle system with an ejector is increased 16% than non-ejector system and the CO2 transcritical system with an ejector has big application value; entropy of ejector accounts 22% of the total entropy change, and appropriate design of ejector is very important to optimize overall system performance.