Efficient design and experimental research of large temperature drop ejector heat pump heating system

To solve the problem of heating network expansion in the field of central heating, an ejector heat pump system which can use medium and low grade heat sources to realize large temperature drop heating is proposed. A modified constant rate of momentum change mixing model (CRMC) was proposed for efficient design of the ejector structural profile. Considering the structural parameters and flow characteristics of the diffuser, the adiabatic efficiency of the diffuser is solved iteratively. A 180 kW large temperature drop ejector heat pump heating system prototype was designed and manufactured, and the performance of the ejector and the system were experimentally studied. The results indicate that the modified CRMC ejector can reduce the negative impact of shock wave effect on the entrainment ratio ( ER ). Compared with the constant pressure mixing model ejector, the ER of the modified CRMC ejector increased by 32.07 %. Moreover, the maximum relative error of the experimental results is less than 10.34 %. The experimental prototype can realize the heating process with large temperature drop, and its heating capacity is relatively increased by 15.54 %. The innovation of the ejector heat pump technology provides a new technical scheme for the low-carbon of urban central heating.