Internal heat exchangers (IHX) are commonly used to improve the energy performance of vapour compression refrigeration cycles. However, the magnitude of the improvement depends on the refrigerant and operational conditions. This paper experimentally investigates the influence of a high IHX on vapour compression systems. The new low global warming potential refrigerant R516A is assessed as a drop-in replacement to R134a at different medium temperature refrigeration conditions. In the case of a 40% effectiveness IHX, R516A shows the highest cooling capacity (4.8% to 9.1%), and COP (4.9% to 11.6%) increases compared to the situation without this element. It can be concluded that the IHX always benefits the energy performance of the refrigeration system at acceptable compressor discharge temperatures.
Keywords IHX, cooling, vapour compression system, low global warming potential (GWP), R516A