Investigation on the Performance of the Pump-Free Double Heat Source Ejector Refrigeration System with R1234yf

A pump is needed in an ejector refrigeration system, which makes the system high cost and complicated and hinders its application. A pump-free double heat source ejector refrigeration system using R1234yf as working fluid is proposed in which an injector driven by another heat source replaces the liquid circulating pump, making the system more affordable, simpler and more stable. The effect of different operation conditions on entrainment ratios and the influence of different factors on system performance are analyzed on the basis of mass, momentum and energy conservation equations. The influence degree of each factor on system performance is investigated by the orthogonal test method. The condenser temperature has the largest effect on system performance. The pressure drop in the suction chamber of gas-liquid injector has the least impact on system performance. The COP can reach about 0.35 under a certain working condition. The system can be driven by two different temperature heat sources with no electricity needed, and it is a good choice for places with abundant heat resources or lack of electricity.