Study On Energy Saving And Air Curtain Optimization Of Food Refrigerated Display Cabinet With Natural Cold Source

This work focused on the prominent problem of high energy consumption of refrigerated display cabinet;a food refrigerated display system with natural cold source with energy storage function was developed.The operating performance of the system under five operating modes was studied experimentally.In order to solve the problem of low efficiency of air curtain of open refrigerated display cabinet,aerofoil structure was put forward to be installed on the flow channel of air curtain.The performance of food refrigerated display cabinet with aerofoil structure was studied.The specific research contents and main conclusions are as follows:First,the performance tests were carried out on five operating modes of the refrigerated display cabinet system with natural cold source.The test results showed that the five modes of the natural cold source refrigerated food display cabinet system could maintained the temperature of the test package in the cabinet at-1?7?,which met the requirements of the refrigerated food.When running the separate cooling mode of natural cooling source,the outdoor temperature should be less than-4.5?.When the outdoor temperature is less than-8?,the natural cold source could store the cold in the storage tank.Compared with the refrigeration unit mode,the system energy consumption could be reduced by 68.45% and 46.92%respectively in the cold storage tank release mode and the natural cold source mode.In the actual operation process,according to the outdoor environment temperature change and peakvalley electricity price advantage of each time period,the cold storage tank cooling release and natural cold source cooling mode should be fully utilized.Second,based on the premise that the food temperature in the cabinet could meet the refrigeration requirements,the influences on air curtain performance,food refrigeration performance and refrigeration system performance of vertical open refrigerated food display with or without aerofoil structure were experimentally studied.Compared with the display cabinet without aerofoil structure,after the installation of aerofoil structure,the thermal entrainment coefficient of the air curtain decreased by 48.5%,and the temperature difference between the top and bottom of the cabinet decreased by 31%,and the temperature difference between the inside and outside of the cabinet decreased by 46.2%,and the total energy consumption of the system decreased by about 22.7%.It was indicated that the installation of aerofoil structure has significant significance for energy saving operation of refrigerated display cabinet.Third,the numerical simulation method was used to optimize the installation position of aerofoil structure.In the case that the five shelves of the refrigerated display cabinet were all installed with aerofoil structure,when the aerofoil structure was 90 mm away from the shelf,the flow distribution of the air curtain was more uniform and stable,the cold quantity outside the overflow cabinet was less,and the thermal entrainment coefficient of the air curtain reached the lowest value,0.3.When the aerofoil structure was installed in 3 layers,the thermal entrainment coefficient of the air curtain dropped to the lowest value,which was 0.23,indicating that it was more reasonable to install the 3-layer aerofoil structure at 90 mm away from the shelf,and the air curtain had the best performance at this time.