| dc.description.abstract | Refrigerants HFC-134a and HFC-245fa are common refrigerants on the market at present. Both belong to the third generation refrigerants without chloride ions, which will not destroy the ozone layer. The difference between the two is the difference in working pressure. HFC-134a is a high-pressure refrigerant, so it is used in low-temperature places, such as freezers, car air conditioners, dehumidifiers or ice water machines and other refrigeration equipment. HFC-245fa is a lower pressure refrigerant, so it is used in higher temperature places, and is most commonly used in organic Rankine cycle（ORC）systems to recover industrial waste heat and improve energy efficiency.
In this study, the flow boiling performance of two refrigerants in a chevron plate heat exchanger was compared. The two refrigerants were used as working fluids to test a plate heat exchanger with a mountain-shaped pattern angle of 65°. The experiment condition was temperature at 30°C, and the refrigerant flow rates were respectively For G=10, 20, 30 to 40 (kg/m2s), a total of four flow rates were divided into flow boiling experiments, and the heat transfer coefficients and pressure drops were compared.
In general, HFC-134a has better heat transfer performance than HFC-245fa, so the former can be used in a wider range, but due to its high working pressure, if it is to be used, it must be ensured that the system can withstand his high work pressure. | en_US |