| Since energy saving and consumption reduction have attracted attention with the rapid development of social economy,liquid desiccant air conditioning system is more widely used because of its advantages of flexible temperature and humidity control,reduced energy consumption and optimized urban energy structure.This paper studies the operation characteristics of liquid dehumidifier and heat pump liquid dehumidifier by numerical simulation and experimental analysis.The main research contents are as follows:Firstly,according to the theoretical basis of heat and mass transfer,it establishes the mathematical model of the cross-flow liquid dehumidifier,then creates the GUI visual interface of the cross-flow liquid dehumidifier by using MATLAB software.It uses this interface to analyze the distribution of air and liquid parameters in the liquid dehumidifier under a single working condition.The results show that the driving force of the total heat exchange and mass transfer process of liquid dehumidifier gradually decreases with the heat and mass exchange process.It analyzes the influence of air and liquid inlet parameters on dehumidification performance under variable working conditions.The results show that the decrease of liquid inlet temperature and the increase of concentration and flow rate are beneficial to the liquid dehumidification process,while the increase of air inlet flow rate,moisture content and temperature are unfavorable to the liquid desiccant process.On the other hand,it uses the orthogonal test to analyze the influence degree of liquid and air inlet parameters on dehumidification.The results show that the influence degree of dehumidification is as follows:Air inlet moisture content>liquid inlet concentration>liquid inlet temperature>liquid air ratio>air inlet temperature.In addition,liquid-gas ratio× air inlet temperature,liquid-gas ratio X air inlet moisture content,air inlet temperature ×air inlet moisture content and liquid inlet concentration X liquid inlet temperature have interaction effects on liquid desiccant capacity.Secondly,it conducts experimental research on the operation characteristics of the heat pump pre-cooling liquid desiccant air conditioning and the heat pump heat recovery liquid dehumidification air conditioning in a museum in Yangzhou.The results show that:1)When the heat pump precooling liquid desiccant air conditioning is running in summer,the outdoor air needs to be pretreated by the surface cooler to make the supply air reach the set value.2)COP of liquid desiccant air conditioning increases with the expansion of air supply temperature,moisture content and air volume.When the indoor wet load needs to be adjusted,the air supply volume of the unit should remain unchanged and the air supply moisture content should be changed to make the unit run under a higher COP.3)It studies the operation characteristics of liquid desiccant air conditioning in summer and winter,with superior overall operation effect,which can realize cooling dehumidification in summer and heating humidification in winter.4)The heat pump heat recovery liquid desiccant air conditioning can well meet the requirements of indoor cooling and dehumidification in summer,while the total heat recovery efficiency and latent heat recovery efficiency of the unit in actual operation are about 57.8%～60%and 53.5%～56.5%,with good energy saving effect.Finally,based on BP neural network,it creates the GUI interactive interface of heat pump precooling liquid desiccant air conditioning through this interface to analyze the influence of outdoor air temperature and humidity on evaporation temperature,condensation temperature and COP of heat pump unit,then explores the applicability of heat pump precooling liquid desiccant air conditioning at different altitudes.The results show that with the increase of outdoor air temperature and moisture content in summer,the evaporation temperature and COP of the unit will decrease,while the condensation temperature increases,then the variation range of evaporation temperature is smaller than that of condensation temperature.The increase of outdoor air temperature and moisture content in winter leads to the expansion of evaporation temperature and COP,along with the decrease of condensation temperature.On the other hand,the evaporation temperature,condensation temperature and COP of the heat pump unit show a declining trend with the decrease of atmospheric pressure,but the overall decrease of COP is not large,which indicates that the heat pump precooling liquid desiccant air conditioning still has certain applicability in areas with lower atmospheric pressure,that is,areas with higher altitudes.In order to discuss the operation characteristics of heat pump pre-cooling liquid desiccant air conditioning and heat pump heat recovery liquid desiccant air conditioning,this paper provides theoretical guidance and technical support for the popularization and application of this technology in the independent control system of temperature and humidity. |
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