Research On The Performance Of The Transfer Process Of Dehumidification Rotary Wheel Of The New Absorption Material

The solid rotary dehumidification air conditioning system based on absorption principle can be driven by low-grade heat sources such as solar energy,industrial waste heat and so on.The desiccant of the rotary dehumidifier needs to achieve its regeneration with the help of heat sources with higher temperature,so the coupled heat and humidity transfer process of the absorption dehumidification material directly affects the dehumidification performance of the solid rotary dehumidification air-conditioning system and the regeneration energy consumption.In light of the situation,the research on the dynamic coupled heat and humidity transfer process of silica gel and new absorption material dehumidification wheel is carried out.On the basis of the analysis of heat and mass transfer mathematical models of gas-sided resistance model and gas and solid sided resistance model,the porous media model of gas-solid side is established,which takes the momentum equations of air on the gas side and water vapor on the solid side and the seepage of the water liquid on the solid side into consideration based on the gas-solid model.The thermal conductivity of the absorption material---silica gel for dehumidification wheel,size of channel,specific heat,porosity,density and other parameters are tested and analyzed with scanning electron microscope,differential scanning calorimeter,thermal conductivity meter.The heat and mass transfer mathematical model of silica gel dehumidification wheel is established by using the porous media mathematical model of gas and solid side.The research on the dehumidification and regeneration performance of silica gel absorption wheel is performed with the COMSOL Multiphysics software.The results suggest that:with the increase in time,the outlet air temperature of the dehumidification side is constantly on the decrease,the moisture content of the outlet air on the dehumidification side decreases at first and increases later.With the increase in time,the outlet air temperature on the regeneration side constantly increases,and the concentration of the outlet air increases at first and then decreases.The numerical simulation results of the dehumidification wheel on the condition of different regeneration temperature are verified through the experiment of silica gel dehumidification wheel.The outlet air temperature and outlet humidity content on the dehumidification side are in good agreement.The absorption material--silica gel is modified by MgCl2 solution,and through secondary intensification with the CaCl2 solution,the new absorption material is obtained.The research on the dehumidification wheel is carried out through the COMSOL Multiphysics simulation software with porosity,velocity of treated air,moisture content of treated air,regeneration air temperature,regeneration air velocity included.The results suggest that:(1)when the porosity is 0.4,the dehumidification performance of the new absorption material is best;and the energy efficiency ratio of dehumidification is 0.74.(2)When the inlet air velocity on the dehumidification side is larger,the dehumidification efficiency obviously increases,the dehumidification capacity and dehumidification COP are constantly on the decrease.Better dehumidification effect and energy-saving effect at low air speed can be achieved,which is 1.91 times higher than the dehumidification capacity compared with traditional silica gel,and the decrease in the dehumidification rate reduced by 0.06%.(3)When the inlet air velocity on the regeneration side increases,the quantity of relosution is constantly on the increase.When the air velocity is more than 0.35m/s,the rate of resolution decreases,but it increases on the whole.Thus for the regeneration side,increasing the wind velocity when increasing regeneration temperature is conducive to desorption regeneration.(4)for the dehumidification side,when the inlet moisture content increases,the dehumidification capacity and dehumidification COP apparently increase,and the dehumidification rate increases at first and then decreases,but the fluctuation value of dehumidification rate is smaller,thus increasing the inlet moisture content is good for dehumidification.Compared with traditional silica gel,the dehumidification capacity can increase by 0.7g/s when the inlet moisture content is increased.(5)When the regeneration temperature increases from 60? to 100?,the dehumidification capacity increased by 0.4g/s,the dehumidification rate increased by 0.09%.In comparison with the traditional absorption material--silica gel,the dehumidification capacity of the new absorption material is larger under low regeneration temperature,which is conducive to the utilization of renewable energy.