Experimental Research On Mutual Solubility Between R32 And New Oil And Effect On The Performance Of Air Conditioning System

Along with the environmental problem has caused people’s widespread attention, the refrigeration industry has also accelerated the pace of refrigerant replacement. In recent years, a variety of environmentally friendly green refrigerant was introduced in turn, the purpose is to protect the ozone layer and reduce the greenhouse effect. Among them as a R410 A alternative refrigerant R32, with excellent thermal performance and environmental protection has become one of the industry’s promising alternative refrigerants. However, due to the requirement of mutual solubility of refrigerant and re frigeration oil, the development of R32 oil has always been one of the obstacles to hinder its use.This paper has set up the refrigerant oil solubility test experiment platform and the air conditioning performance test experiment platform, the numerical calculation of thermal resistance is used, the new development of special refrigeration oil for R32: The practicality of PVE type refrigeration oil was tested. In PVE oil and R32 mutual solubility test, based on the existing experimental standards of the state, the experimental equipment is improved, and a set of test bench is set up, the two phase separation temperatures of R22/3GS, R410A/POE, R32/POE and R32/PVE were tested in sequence. By comparing with the traditional POE oil, the experimental results show that the new PVE oil and the R32 mutual solubility are improved. Air conditioning performance testing: a E09 EL.NSH LG heat pump split air conditioning was used, through the arrangement of the data acquisition equipment, the performance parameters of R41 0A/POE, R32/POE and R32/PVE were obtained, the effect of oil content on the performance parameters of PVE is studied, the improvement of mutual solubility between R32 and the new PVE oil is obtained, and the effect of the increase of oil content on the performance of the system is obtained. The theoretical calculation of side heat transfer thermal resistance of the heat exchanger was carried out, and the effect of heat transfer on the air conditioning was discussed.The research shows that the traditional P OE oil and R32 are less soluble and can’t meet the requirements of R32 special oil. In the range of experimental test oil content, the two phase separation temperatures are significantly higher than the R410A/POE combination, the maximum temperature difference appears oil rate of about 20%, about 8.4 °C. Poor mutual solubility can lead to thicker oil film in the inner surface of the heat exchanger, the heat resistance is increased, the heat transfer effect is decreased, and the compressor oil return i s difficult, and the lubricating effect is decreased. And with the new PVE oil, the mutual solubility of R32 and PVE oil was obviously improved, the two phase separation temperature of the mixture is lower than that of R410A/POE and R32/POE in the range of test oil ratio, the maximum temperature difference is about 20%, reaching 25.9 °C. The actual use of the new PVE oil in the air conditioning system has also been improved, the R32/PVE combination of compressor exhaust temperature compared to the R32/POE combination has decreased by about 2.6 °C, this is because PVE oil return is easy to the compressor, resulting in the better compressor lubrication effect, friction heat reduction, power consumption compared R32/POE combination was essentially flat. And because the PVE oil is not easy to form the oil film in the heat exchanger, the heat resistance is reduced, and the heat transfer effect is improved, air conditioning cooling capacity and COP value compared to the R410A/POE and R32/POE combination has to upgr ade: R32/POE’s cooling capacity is about 17.9% higher than that of R32/PVE, and R410A/POE is about 24.6% higher. R32/POE’s COP is about 7.74% higher than that of R32/PVE, and R410A/POE is about 12.79% higher. After theoretical calculation, with the increase of PVE oil quantity, the thermal resistance of evaporator decreases and then increases, the minimum value is below R410A/POE about 33.3%, less than R32/POE about 11.1%. The side thermal resistance of the condenser has been increasing, the change of heat transfer effect also affects the COP of the system, first increases and then decreases, the maximum value appears in the charge of PVE oil achieving about 270 cc.Therefore, as R32 special oil, the mutual solubility of PVE oil and R32 is better than that of traditional POE oil, reducing the exhaust temperature of the compressor, improving the heat transfer effect, meeting the requirements of the use of R32 special oil. And taking into account the variation trend of the thermal resistance of the evaporator with the increase of oil content, when filling 270 cc PVE oil, best results are achieved.