Design and commissioning of an experimental facility for performance evaluation of pure and mixed refrigerants

The recent regulations about fluorinated greenhouse gases introduce a rapid phase-down of traditional, environmentally harmful refrigerants. Consequently, new working fluids are continuously appearing on the market, leading to the need for testing them to analyse their performance before making an ultimate choice. In the present paper, a test rig built to carry out experimental studies on different refrigerant in a drop-in application is described and first results for the set-up commissioning are commented. The experimental campaign was carried out in typical water-to-water heat pump operating conditions, varying the cold water temperature at evaporator inlet from 10 °C to 20 °C, with a step of 2.5 °C, and hot water temperature at condenser inlet from 30 °C to 50 °C, with a step of 10 °C, and the compressor shaft rotational frequency from 30 Hz to 80 Hz, with a step of 10 Hz. The first findings demonstrate that the experimental results of some key performance parameters, namely heating capacity, COP and compressor volumetric efficiency, agree well with open literature trends, allowing to state that the experimental facility was correctly designed and can be used to deepen the analysis on performance assessment of new refrigerants in a drop-in application.