Theoretical Research And Application Of Rotary Dew-point Indirect Evaporative Cooler Based On M Cycle

Evaporative cooling is a low-energy energy-saving technology that can make full use of fresh air.Based on M-cycle indirect evaporative cooling(MIEC),the air can be treated to a temperature close to the dew point of the inlet air.Existing dew point indirect evaporative coolers are mainly plate and tube type.The air flow path of the plate heat exchanger is narrow and easy to block.The air flow path of the tube heat exchanger is large,but the heat exchange efficiency is low and the space is large.A rotary dew point indirect evaporative cooler,RDIEC for short,is now proposed.Aiming at the dew point indirect evaporative cooler of this structure,this paper does the following work:First,the principle of the rotary heat exchanger under dry conditions,wet conditions,and regenerative conditions is analyzed,and the mathematical model of heat and mass transfer is established.Four evaluation indexes of evaporative cooling heat exchanger are given.Then,the thermal calculation model of the rotary heat exchanger under three working conditions is established,and the detailed design calculation steps are given.Under the same cooling capacity,the thermal parameters of the three types of rotary heat exchangers were designed and compared.It was found that the regenerative air supply temperature is lower and the heat exchange area is smaller,that is,the device size is smaller,and the performance And the structure has a greater advantage.Then,in order to compare and verify the reliability of the mathematical model of the rotary dew point indirect evaporative cooler(RDIEC),the simulated dry bulb temperature To at the outlet of the device was compared with the test data in the literature.The maximum absolute error was 1℃and the maximum relative The error is 4.83%,and the fitting is good,indicating that the RDIEC mathematical model has certain reliability.On this basis,the RDIEC structural parameters and operating parameters were optimized.The optimized plate width L is 250 mm,the height H is 0.5m,the specific volume is 360 m~2/m~3,and the dry and wet channel share x_d/x_w is 0.6/0.4;The secondary primary air volume ratio m/M is 0.5;when the air volume is below14350 m~3/h,the wet bulb efficiency can reach more than 100%;the device has better applicability in areas with higher temperatures and lower humidity;when the storage The performance is better when the core speed is low.Finally,the rotary dew point indirect evaporative cooler was applied to an experimental building in Urumqi for system design calculation,and compared with the traditional mechanical refrigeration system in terms of energy saving and economy,it was found that the RDIEC+DEC compound The system can save 50508 k Wh of electricity,the annual economic benefit is 5073.6 yuan,and the static and dynamic methods of equipment recovery period are 3.76 years and 4.39 years respectively.In addition,a comprehensive comparative analysis of the rotary dew point indirect evaporative cooler and the traditional mechanical refrigeration and plate dew point indirect evaporative cooler is carried out.It is found that the rotary dew point indirect evaporative cooling has a compact structure and the device has a Cleansing effect,not easy to block.