Simulation And Experimental Study Of Evaporative Cooling And Ejector Refrigeration Air Conditioning Systems

In order to respond to the national energy conservation and emission reduction and low-carbon development strategy of the important measures,in the field of HVAC,dry air energy driven evaporative cooling technology and low grade heat energy driven refrigeration technology（such as jet refrigeration）has gradually attracted attention.Among them,the advantage of evaporative cooling technology is energy saving and environmental protection,but its cooling effect is easily restricted by climatic conditions.The spray refrigeration system is simple in structure,small in size and low in cost.In this context,the research group proposed an air conditioning system that coupled evaporative cooling with jet cooling.The system fully combines the advantages of the two refrigeration technologies,so that the composite system can realize dew-point air supply under low energy consumption.The main research work is as follows:（1）The working principle of the indirect evaporative cooling-jet refrigeration air conditioning system is explained in detail,and the operating mechanism of the system is analyzed.The flow processes of the air side and the refrigerant side are explained in detail respectively from the indirect evaporative cooling subsystem and the jet refrigeration subsystem.（2）Set up the test device of the composite system,and experimentally tested and analyzed the energy consumption and COP of the composite system.It is found that with the increase of the outdoor dry bulb temperature,the cooling effect of the indirect evaporative cooler will also increase,the outdoor dry bulb temperature from 32.22℃ to 36.21℃,the degree of temperature reduction from 2.47℃ to 5.85℃,that is,the pre-cooling capacity of evaporative cooling can be improved,the cooling capacity of the coupled air conditioning system,COPACS also increased.By comparison,it can be seen that COPACS of coupled air conditioning system is generally higher than COPERS of jet refrigeration system,that is,jet refrigeration coupled with evaporative cooling technology improves the performance of single-stage jet refrigeration system.（3）The software TRNSYS and EES were used to build the composite system model,and the simulation system was verified after the model was established.By comparing the experimental value of each parameter with the calculated value of simulation,it can be seen that,except for some parameters,the difference of each parameter was within 15%.（4）The composite system was simulated under different working conditions with R245 fa as refrigerating medium.The cooling of single open evaporative cooling subsystem is limited.The coupling system has good applicability in the middle humidity Xi ’an area and the high humidity Guangzhou area.Compared with the operation status of the coupling system in the two regions,the cooling capacity provided by evaporative cooling in xi ’an area is relatively large,up to 15.3%,and the cooling capacity in Guangzhou is about 3%.The secondary side air of the indirect evaporative cooler can also take away different condensation heat,up to about 14% in Xi ’an and about 4.1% in Guangzhou.At the same time,the total power consumption of the whole cooling season in the two regions is simulated and calculated.It can be seen that the total power consumption of the coupling system in the cooling season in xi ’an region is 590.68 k Wh.If it is a mechanical compression refrigeration air conditioning system,the power consumption is about 968.71 k Wh,saving 40% of the electric energy.The total power consumption of the whole cooling season in Guangzhou is999.14 k Wh,and the total power consumption of the fully mechanical compression refrigeration system is about 2627.155 k Wh,that is,the coupling system can save 60% of the electric energy.（5）In order to improve the utilization degree of evaporative cooling subsystem and lower the energy consumption of the complex system,puts forward three kinds of operation mode,through the analysis of three kinds of mode cooling effects and energy consumption,find mode three（indirect evaporative cooling subsystem intermittent operation,spray cooling subsystem variable flow operation）supply air temperature is uniform,the system has the lowest energy consumption,compared with the mode 1 and mode 2 and mode 3 total energy consumption reduced 12.8% and 14.4%,respectively.There are 53 figures,18 tables and 65 references.