Numerical [study] and simulation on nozzle parameters for heat pump system using thermobank and two-phase ejector.

The CFD simulation and numerical study on R404A heat pump system with two-phase ejector and thermobank are presented in this paper. An adjustable ejector based on a two-phase flow simulation model was designed by Solidworks sorfware and Ansys sorftware. Both throat diameter (Dnt) and position (Dnm) of nozzle were studied under the given conditions. The CFD simulation results showed that Dnt of 1mm and Dnm of 15mm yielded the best ejector efficiency and energy efficiency ratio. Nozzle with different Dnt and the adjustable ejector were also studied under different conditions. It also showed that the ejector with adjustable nozzle can meet the requirements of different operation conditions. The special feature of the system is the heat storage equipment and ejector is installed in the heat pump system. Water is used as the heat storage material. During the refrigeration cycle operation, the heat storage equipment acts as a pre-condenser and stores a portion of refrigerant heat rejection in the thermobank. As the experiment results, its COP is increased about 38% when using thermobank and ejector in this heat pump system. It was very useful for the future application of ejector and thermobank in the system.