EXPERIMENTAL EVALUATION OF HFC/HFO BINARY MIXTURES IN A SMALL-SCALE WATER-TO-WATER HEAT PUMP SYSTEM: ENERGY, EXERGY AND LCCP ANALYSES

Abstract

In this study, two different hydrochlorofluorocarbon (HFC)/hydrofluoroolefin (HFO) binary blends [R134a/R1234yf (75/25) and R134a/R1234yf (25/75)] are studied experimentally. Energetic, exergetic, and LCCP (life cycle climate performance) evaluations of the heat pump for HFC/HFO binary blends were carried out. Worldwide, there is a need for comprehensive and qualified research for the adoption and use of new generation environmentally friendly refrigerants or refrigerant mixtures in vapor compression refrigeration cycles. In the literature, no studies are available on the use of HFC/HFO in heat pumps or cooling systems at these blend ratios. This study differs from previous studies on HFC/ HFO binary mixtures. Therefore, it will contribute to the literature on binary HFC/HFO blends with lower global warming potential (GWP). HFC/HFO binary blends for different temperature of evaporator (-10°C, -5°C, and 0°C) and fixed temperature of condenser (35°C) were studied. The performance of R134a/R1234yf (75/25) refrigerant blend is superior to that of the R134a/R1234yf (25/75) refrigerant blend based on the first and second laws of thermodynamics. Although the GWP of R134a/R1234yf (75/25) is higher than that of R134a/R1234yf (25/75), R134a/R1234yf (75/25) has a relatively smaller total LCCP than R134a/R1234yf (25/75). Low GWP is not the only criterion for selecting a refrigerant. Energy and exergy are also important, because an important part of the overall system emissions of the heat pump is seen to be caused by the consumption of energy.