Experimental assessment of the retrofit of an internal heat exchanger in refrigeration systems: The effect on energy performance and system operation

The aim of this experimental study is to retrofit a refrigeration system with an internal heat exchanger (IHX) and to assess its effect on the energy performance of the system. The separate IHX cases in the investigation are tube-in-tube type and plate type and these are also compared with the system without any IHX. R404A and R442A refrigerants are tested in a single stage vapour compression refrigeration system. In the experimental work evaporation temperatures of -5 degrees C and 0 degrees C are considered while the condenser temperatures are 30 degrees C and 50 degrees C. The results indicated that both utilised types of IHX elements improved the energy performance of the system while the benefit with the tested plate type IHX case was better. Also, the alternative refrigerant R442A can be preferred as a substitute for R404A due to the enhanced energy performance of the system. The thermal effectiveness of IHX devices and the volumetric efficiency of the compressor are considered as well for the evaporation and condenser temperatures covered.