Experimental analysis of the R744 vapour compression rack equipped with the multi-ejector expansion work recovery module

A test facility for experimental investigation of the R744 vapour compression rack equipped with the multi-ejector expansion work recovery module was designed and manufactured. Comparison of the R744 multi-ejector refrigeration system with the R744 parallel compression system on the same test facility was carried out based on energy performance characteristics: refrigeration capacity, power consumption, COP, and exergy efficiency. Apart from the system performance comparison, influence of the pressure level in the flash tank on the system performance for both alternatives was analysed. The experimental results indicated COP and exergy efficiency improvement of the multi-ejector refrigeration system up to 7% and 13.7%, respectively. The highest values of COP and the exergy efficiency were obtained by the multi-ejector refrigeration system for the tanks pressure lift value close to the limit value. The values of the overall compressor efficiencies were significantly differentiated, dependent on the operation module (cooling load and heat rejection conditions), which strongly influenced the values of COP, and the exergy efficiency.