Experimental Study On Capillary Throttling Characteristics Of Frequency Conversion Refrigeration System Of Refrigerator

Capillary as a throttling mechanism is widely used in small and medium-sized refrigeration devices,it generally has the advantages of simple structure,low cost,no moving parts,automatic adjustment of flow rate,etc.The capillary can use throttling to reduce the high temperature and high pressure refrigerant from the condenser into low temperature and low pressure liquid refrigerant,and then send the refrigerant to evaporator.The refrigerator refrigeration system with inverter compressor has the advantages of low energy consumption,small starting impact,stable operating conditions,etc.In the frequency conversion refrigerator,the compressor adjusts the cooling capacity of circulation system in time by continuously changing the rotation speed in order to achieve a good match with the heat load.This paper designed a refrigerator refrigeration cycle system based on the inverter compressor to explore throttling characteristics of the capillary in the refrigeration cycle system of inverter refrigerator.The author has conducted meaningful research from the following aspects:(1)A homogeneous flow model was established,the flow of refrigerant in the throttling capillary tubes was analyzed using the model.The equivalent substitution of multiple capillary tubes in parallel was explored.(2)The test bench was built,experimental protocols for different conditions was developed,the throttling performance of different capillary component was analyzed according to the change of parameters such as pressure,dryness,temperature drop,and COP.(3)The experimental results show:when the electrical frequency inputted compressor is 90Hz,single capillary throttling can obtain a low refrigerant dryness at the capillary and high system COP,which is 0.214 and 1.74 respectively;the throttling effect of double capillary in parallel is best when the electrical frequency inputted compressor is 110Hz,and its COP is 1.67.After the input electrical frequency rises to 100 Hz,double capillary in parallel instead of single capillary to throttle,it can the refrigerant dryness reduce by 23.2%and the COP of refrigeration system increase by 21.4%,and which effectively improve the system performance.