Theoretical and experimental research of pre-cooling air-cooled air conditioning units

Develops the air conditioning unit. Performs the experiments on the natural hydrocarbon refrigerants R1270 to analyse its replacing feasibility for R22 in air-cooled air conditioning units. The result shows that the COP of the unit is improved and the exhaust gas temperature of the unit is reduced. On the same condition, the refrigerant charge rate of R1270 system is 47.1% of that of R22 system. On the rated condition, the cooling capacity of R1270 system is higher than that of R22 system, with the increase of outdoor air temperature, the cooling capacity of R1270 system is slightly smaller than that of R22 system. The COP value of the two systems are approximately equal, but the exhaust temperature of R1270 is significantly lower than that of R22. Therefore, from the point of cooling capacity, R1270 is a better choice to replace R22. In particular, when the conventional air conditioning unit adopts evaporative cooling system, the COP value of R1270 is higher than R22 at higher outdoor temperature.