Performance Study Of Electrolyte Membrane Dehumidification Device

Dehumidification based on electrolyte membrane is a promising new type of technology,which has the advantages of flexible application,compact structure,high accuracy,and could meet the requirements of small space and high-precision humidity control..Dehumidification performance,durability and performance influencing factors of the dehumidifier in various practical application scenarios(low temperature environment in refrigerator,normal temperature environment in daily office)are still not clear.Therefore,this paper studied the operation performance and durability and analyzing the influencing factors in different environments,and theoretically analyzes the performance prediction and energy loss.In view of this,the main research work of this paper is summarized as follows:(1)Experiment results showed that under influence of electrolysis,electric drag and reverse diffusion,performance of the dehumidifier increased with increase of applied voltage,air flow,air humidity and air temperature.The greatest influence on performance of the dehumidifier was air temperature.(2)Experimental results showed that under low temperature and low humidity conditions,the water content,catalyst activity and proton conductivity of the membrane module were at a low level,and performance of the dehumidifier was poor.The dehumidification rate at-8.5? was only 1/6 of that at 25?.However,the dehumidifier operated stably and dehumidification energy efficiency was still competitive compared to other electrochemical dehumidification technologies.Increasing the air flow and humidity to increase water content inside membrane module could effectively improve the dehumidification performance.The effect of increasing the applied voltage to improve the dehumidification performance of the device was not obvious.(3)Under low temperature conditions,the starting voltage of the dehumidifier would increase.When the air temperature dropped from 3.6? to-3.69?,the starting voltage would increase from 1.8V to 2.3V.The main reason for the increase in starting voltage was that the decrease in temperature or water content inside membrane module increased the concentration potential,ohmic potential,and activation overpotential.In addition,under subzero temperatures,the dehumidifier might fail to start.(4)The result of 250 hours' long-term operation showed that the performance of the dehumidification device was seriously attenuated.Under the condition of 4V applied voltage and 90%RH air humidity,dehumidification rate reduced by 45% and current density reduced by 65%.During operation,part of the performance attenuation was due to the reversible attenuation caused by the reduced water content inside membrane module.Experiment results showed that after 50 hours of operation,dehumidification rate decayed by 7%,of which 6% was due to the reversible decay caused by the reduction of water content.(5)Finally,a quick prediction model was established,and the average deviation of the model for the dehumidification rate was within 20%.And through exergy analysis found that the energy utilization rate of the dehumidification component was low,only 1.4?4.1%.Through characterization of the membrane module after the sub-zero temperature test,it was found that volume expansion caused by water phase transition did not cause great damage to the physical structure of PEM,which showed that the dehumidification technology had potential in the field of refrigerator low temperature dehumidification.