Experimental Study On Affecting Factors Of The Performance Of Ejector And Compression/Ejection Refrigeration System

With the increasing problem of environmental pollution and energy shortage,the energy saving and environmental protection technology have become the consensus of various industries.In the refrigeration industry,due to the large energy loss of the throttle valve,the performance of the traditional refrigeration system is low,and replacing the throttle valve with an ejector has become an effective way to recover the throttle loss.Therefore,in order to improve the performance of the traditional refrigeration system,the research on the performance of the ejector and the new compression/ejection refrigeration system based on the ejector becomes the key,and it is also a research hotspot in the refrigeration industry.The effects of ejector's structural parameters and system operating parameters on performance of the ejector are studied.Furthermore,the influences of structural parameters and operating parameters on performance of the refrigeration system is analyzed.Moreover,the performance of compression/ejection refrigeration system is compared with the performance of traditional refrigeration system.The main contents and results are as follows:?1?Based on the experimental platform of compression/ejection refrigeration system?refrigeration capacity 15 k W?,the influence of the ejector structure parameters on the performance of the ejector and refrigeration system is studied.Results show that the ejector pressure lift ratio,system cooling capacity and COP first increase and then decrease with the increase of the nozzle throat diameter.When the nozzle throat diameter is 1.9 mm,the ejector pressure lift ratio,system cooling capacity and COP are the largest.The optimal nozzle throat diameter does not change with the parameters of the working conditions.Each nozzle throat diameter has an optimal nozzle exit position that matches it.Among them,the nozzle throat diameter and exit position that maximize the pressure lift ratio are 1.9 mm and 9 mm,and the nozzle throat diameter is directly proportional to the exit position,and the relationship is:y=-x/15+2.5.Under different operating conditions,there is a corresponding effective pressure lift range?the pressure lift ratio is greater than 1?with the change of the nozzle outlet position.?2?The effects of operating parameters on the performance of the ejector and refrigeration system are experimentally studied.Results show that the ejector entrainment ratio decreases with the increase of the condenser inlet water temperature and cooling capacity and high-temperature evaporator inlet water temperature and cooling capacity.With the increase of the low-temperature evaporator inlet water temperature,the ejector entrainment ratio increases.The variation of the ejector pressure lift ratio with the operating parameters is opposite to the entrainment ratio.However,the ejector pressure lift ratio decreases with the increase of the low-temperature evaporator inlet water temperature.The cooling capacity?Q?and COP of the system increase with the increase of the condenser water inlet cooling capacity,the high-temperature evaporator inlet water temperature and cold capacity and the low-temperature evaporator inlet water temperature.After considering the power consumption of the pump,the system has an optimal condenser inlet cooling capacity and high-temperature evaporator inlet cooling capacity.The optimal values are 14.66k W and 10.52 k W,respectively.The corresponding condenser inlet water flow and high-temperature evaporator inlet water flow are 2.8 m³·h^-1 and 2.7 m³·h^-1,respectively.?3?The performance of compression/ejection refrigeration system and traditional refrigeration system are compared.Results show that under the same working conditions,the COP of the compression/ejection refrigeration system is better than that of the traditional refrigeration system.The COP increased by about 10.2% to 27.8%.