Experimental Research On The Performance Of The Refrigeration System For Light-duty Electric Logistics Vehicle

Since my country entered the 21 st century,its economy has developed rapidly,The people’s requirements for the timeliness and quality of food supply have also increased,People in inland areas can’t get fresh aquatic products and meat from coastal cities without logistics vehicles.Some medical drugs also need logistics vehicles for transportation and preservation.Logistics car has become an important link in the cold chain process.There are still some technical problems in the cold chain logistics in our country,logistics car in frozen condition,the car has been in the cryogenic environment conditions,system run for a long time,there will be a high exhaust temperature,poor performance,causing the refrigerating capacity of the system is insufficient,can’t meet the set temperature,failure can lead to bad food and medicines.To solve the above problems,based on the principle of quasi two-stage compression,a refrigeration system of light pure electric logistics vehicle with intermediate heat exchanger is designed and developed.The theoretical analysis and experimental research of the system are carried out.The results are as follows(1)When the interior ambient temperature is-10℃,-15℃,-18℃ and-23℃,the exhaust temperature of the compressor with medium pressure air replenishment technology decreases by 18.98% ~ 20.40% compared with that of the compressor without air replenishment mode,and the decrease is obvious.(2)After medium pressure air replenish technology is adopted in the system,the compressor speed is in the range of 3000r/min ~ 4800r/min,and the interior ambient temperature is-10℃,-15℃ and-18℃,respectively.The cooling capacity of the system increases by 11.55%,18.44% and 23.24%,respectively.When the interior environment is low and the cooling capacity is insufficient,the cooling capacity of the system can be increased by increasing the compressor speed.(3)The interior fan air volume is within the range of 55% ~ 100%,which has little influence on the performance parameters of the system.When the cooling capacity meets the design requirements,the fan air volume can be appropriately reduced to reduce the fan power and achieve the effect of energy saving.(4)When the ambient temperature outside the vehicle is in the range of 15℃ ~ 43℃,the exhaust temperature of the system is reduced by 8.4℃ ~ 21.6℃ and by 15.04% ~ 22.61%,relative to the mode without air replenishment.(5)When the ambient temperature inside the vehicle increases from-18℃ to-10℃,and the ambient temperature outside the vehicle ranges from 15℃ to 43℃,the cooling capacity of the system increases by 71.56% ~ 100.04%.(6)When the superheat of the main circuit electronic expansion valve was 7 K,the maximum cooling capacity,COP and EER of the system appeared,which were 1.41 kW,1.57 and 1.04,respectively.(7)The exhaust temperature of the system is decreasing with the opening of the supplementary electronic expansion valve increasing,and the refrigeration capacity,cop and EER of the system are all attenuated.