Theoretical And Experimental Research On Indirect Evaporative Cooling Heat Recovery Fan In Dry Areas

To cope with the development of the times and improve energy efficiency,we proposed a combination of plate-fin heat recovery devices and evaporative cooling to effectively recover the cold(heat)contained in the indoor return air,provide fresh air and effectively reduce the air conditioning system energy consumption.It is an energy-efficient fresh air system.This paper first analyzes the advantages and disadvantages of different heat recovery technologies,chooses a compact,small footprint,suitable for indoor heat recovery plate-fin heat exchangers,and analyzes the spray characteristics of the spray-type and packing type evaporative cooling and cooling effect.The two structures are organically combined into a new type of plate-fin indirect evaporative cooling waste heat fan,and the structural characteristics of the unit and the annual operating mode were analyzed.Based on the meteorological parameters of Urumqi,Xinjiang,the design of plate-fin heat recovery section,fan section and direct evaporative cooling section and equipment selection were carried out,and a prototype was developed in cooperation with the production,research and research institutes.In order to further analyze the performance of the experimental prototypes,in the national double enthalpy difference laboratory,under summer dry humidity conditions,compare and analyze the traditional heat recovery new fan(mode 1),the prototype(mode2),wet film heat recovery new Fans(mode 3)heat recovery efficiency and cooling rate in these three ways.The heat recovery performance and frosting conditions of the prototype under winter conditions were tested.conclusion as below:(1)Simulate the outdoor summer conditions in the dry area,conduct an experimental test and draw conclusions:a)In the dry and hot regions of Xinjiang,the prototype has the highest heat recovery efficiency of 145%,which is 2.2 times that of the traditional plate-fin heat exchanger.It is recommended that the ratio of supply and exhaust be 0.7.b)The fresh air cooling rate of this unit is 10.2?> Mode 3 is 6.2?> Mode 1 is 3.5?;The faster the intake air speed,the lower the cooling rate.(2)Under the winter conditions,the unit was subjected to experimental testing and concluded:When the air ratio of the plate-fin indirect evaporative cooling waste heat recovery fresh air unit is 1.0,the indoor return air temperature is 26?.The outdoor air temperature is 8.0? and 5.0?.When the temperature is 5.0?,the frosting rate is fastest.When the outdoor temperature is lower than the indoor return air dew point temperature,the indoor return air vapor will condense and radiate so that the panel temperature will increase and the temperature of the outdoor exhaust port will increase;Condensate on the panel surface will continue to cool and accumulate to generate frost.(3)Apply the unit to Xinjiang villas,and calculate the budget results and DeST energy consumption simulation analysis software knows:a)The sensible cooling capacity of the conventional plate-fin heat exchanger(mode 1)is only 44.8% of the plate-fin indirect evaporative cooling heat exchanger(mode 2)and60.3% of the plate-fin heat recovery fan with wet film(mode 3).b)Use DeST energy simulation software to calculate the mode 1 air-conditioning system to withstand the maximum indoor cooling and heating load,the fresh air system to withstand the minimum cooling load;mode 2 air-conditioning system to withstand the coldest heat load,the fresh air system to bear the largest heat load;Compared to the three methods,Mode 2 bears the summer air-conditioning cooling load of 82.4% for Mode 1 and91.7% for Mode 3.