Design And Performance Experimental Study Of A New Efficient Dehumidifier

Dehumidification is a comprehensive technology involving multiple disciplines.It has been widely used in instruments,biological engineering,energy conservation and environmental protection and other fields,and plays a huge role in industry and agriculture,national defense,medical treatment,commerce and daily life.At present,the penetration rate of dehumidifier in China is only 2.4%,and at the same time,there are 256 cities with more than 130 days of annual rainfall.Therefore,the demand for dehumidifier is large,and dehumidification technology has broad development prospects in China.However,the proportion of energy consumed by dehumidification increases year by year.Taking air conditioning as an example,condensation dehumidification occupies 30%of the total energy consumption of air conditioning.Dehumidification is limited by high energy consumption.Therefore,it is important to develop a new efficient dehumidifier in this paper.First of all,the design of dehumidification device.Including the determination of the structural parameters of the evaporator and condenser of the dehumidification device and the selection of the compressor and capillary,so that the dehumidification device can meet the requirements of dehumidification under different working conditions.Parameters of each component of dehumidification device are obtained according to the design,which lays a foundation for simulation and performance experiment below.Secondly,Evap-Cond software is used to simulate the heat transfer of evaporator in dehumidifier.According to different sizes of evaporator and inlet air parameters,166 groups of heat transfer were simulated.The influence rule of fin tube diameter,fin spacing,fin tube row number,flow path layout,refrigerant flow rate,inlet air temperature and humidity on total heat transfer and latent heat transfer was obtained,and the change curve of heat transfer with the above parameters was drawn.Thirdly,30 groups of fin center air and fin surface air were simulated by Fluent.The variation of temperature field,velocity field,volume fraction field and relative humidity field with inlet air parameters were obtained.It is found that the outlet temperature and water vapor volume fraction decrease with the increase of inlet wind speed,and the relative humidity increases first and then decreases with the increase of inlet wind speed.After that,the performance experiment of the dehumidifier was carried out.By controlling the inlet air state parameters,Including inlet air dry bulb temperature（24℃,26℃,28℃,30℃,32℃,34℃）,relative humidity（55%,60%,65%,70%,75%,80%,85%,90%）and air inlet wind speed（0.5m/s,lm/s,1.5m/s,2m/s,2.5m/s,3m/s）A total of 96 groups of experimental studies were conducted to systematically analyze the influence of the above parameters on the dehumidification performance of the dehumidification device,and draw the curve of dehumidification and dehumidification per unit power with inlet air temperature,humidity and speed.At the same time,the experiment and design are compared with simulation to explore the reliability of design and simulation.Determine the optimal inlet wind speed under standard working conditions of dehumidifier.Finally,the dehumidification device is improved and optimized.A set of U-shaped heat pipe heat exchanger is designed and customized.The u-shaped heat pipe heat exchanger is used to precool and reheat the air,so as to reduce the dry bulb temperature before the air enters the evaporator and increase the outlet air temperature of the dehumidifier,reduce the cooling capacity and reheat of the system,and improve the operation efficiency of the unit.The performance experiment of the optimized unit was carried out.By comparing the dehumidification device without u-heat pipe heat exchanger,it was found that the dehumidification capacity and dehumidification capacity per unit power of the unit with u-heat pipe heat exchanger were significantly improved compared with the original unit when the air temperature was higher than 26℃.The results of this paper provide a new design scheme for the engineering application and improvement of dehumidification device.