Performance Simulation and Experimental Testing of Moderately High Temperature Heat Pump Using Non-azeotropic Mixture for Geothermal District Heating

A water-to-water geothermal heat pump is a suitable technology to exploit heat from low-temperature geothermal sources for high-temperature district heating. A distributed parameter model simulation analysis was conducted for the system using non-azeotropic mixture of R245fa and R152a (0.63/0.37) under the condition that the input temperature and the flow rate of the heat transfer fluids were provided. The model was built by interconnecting different sub-models: the heat exchanger models, a compressor model and a thermostatic expansion valve model. Measured performance of the heat pump was presented and used to validate the cycle model. This model was proved to be accurate enough to serve as an optimization tool for further study.