Simulation And Experimental Research Of Air-source Heat Pump With The Refrigerant R410A

At present, R22 is still used in many kinds of air-source heat pumps, and it's harmful to ozonosphere. According to the Case of the Montreal Protocol, R22 used in air conditions should be prohibited and phased out. R407C and R410A are two main substitutes which be seen as promising refrigerants. R410A is a kind of two elements near-azeotrope refrigerant which is composed of HFC32 and HFC125 by the proportion of 50 to 50, its gliding temperature is no more than 0.1°C and has superiority in the replacement of R22. R410A has effective heat transfer properties and low pressure drop compared with R407C and R22, which is good for the promotion of the system's coefficient performance. So R410A is worth to research deeply.The author has designed an air-source heat pump chiller with the power capacity of 5 HP on the base of theory calculation and analysis of existing units. Moreover, the operating properties of this unit under different conditions have been tested by using environment simulation laboratory and data acquisition system of high accuracy.The steady state simulation model of chiller under refrigerating mode has been established, including compressor, air side heat exchanger, plate heat exchanger and thermal expansion valve. Properties database of R410A has also been established by utilizing NIST REFPROP refrigerant properties data and other refrigerants materials. Simulation software of the system is established by Visual Basic. It is proved that the calculating result is in accordance with experimental data well.The chiller operating properties under refrigerating and heating mode are analyzed according to the experimental result. The changing law of some parameters such as refrigerating (heating) capacity, power input, suction (discharge) pressure, cop, superheat temperature, discharge temperature, pressure ratio, etc has been obtained. It indicates that the COP of R410A air source heat pump chiller can achieve the four-grade at nominal refrigerating condition according to the standard GB 19577-2004 of the minimum allowable value of energy efficiency and energy efficiency grade for water chillers, if each component matches well. The COP of the sample unit at nominal refrigerating condition reaches 2.64.The product standard should meet with International direction, since the entrance to the WTO for China. In accordance with the Standard GB/T18430.1 of water chilling (heat pump) packages using the vapor compression cycle along with household and similar water chilling (heat pump) packages (draft), the experiment of air source heat pump under part load condition has also been carried out. The IPLV of R410A unit which will be a reference to the experiment with new standard is available.