| The growing popularity of traditional refrigeration and air conditioning system brings people better living conditions,but also brings a lot of new social problems:serious energy consumption,poor comfort,threatening grid safety,pollution of the environment,and so on.The liquid desiccant air conditioning system has been developed to solve these shortcomings.The liquid desiccant air conditioning system driven by heat pump has not only a stable operation,energy saving,but also helpful to provide people with a more comfortable living environment,which has now become one of the hot spots in the field of air conditioning.In this paper,the experimental platform of HPLD system was set up with low concentration LiCl solution as dehumidifier,and the dehumidification performance,regeneration performance and system performance of the unit were studied by experimental researches and theoretic analyses.Firstly,the structure,workflow and characteristics of the system are introduced.The workflow of system includes the liquid desiccant cycle,the heat pump cycle and the air cycle.The character of the liquid desiccant cycle is that,dehumidification and regeneration self-cycles as well as an interstage cycle is designed,which can effectively reduce the heat exchange rate between dehumidification liquid desiccant and regeneration liquid desiccant to strengthen the dehumidification effect and improve the system performance.And the character of the heat pump cycle is that,to hand the condensation heat,two condensers are installed in series,which can be fully effective use of condensing heat to achieve the dynamic matching of the system.In addition,the main components of the system and measuring instruments are also described.Secondly,the dehumidification performance of low temperature and low concentration solution was studied experimentally and theoretically.The solution concentration range is 18.37%?28.01%and the solution temperature range is 9.4??23.2?.The mathematical model of heat and mass transfer in dehumidification process is established,and empirical correlations coupling heat and mass transfer coefficients were presented.The calculation results from the the model and correlations were compared with experimental data to verify the accuracy and suitability.Finally,the mathematical model was used to analyze the effects of solution and air parameters on dehumidified rate,heat and mass transfer coefficient,dehumidification efficiency and the moisture resistance.Then,theoretical and experimental studies on the regeneration process using condensation heat are performed.The concentration range of the liquid desiccant was 18.51%?28.17%and the temperature range of the liquid desiccant was 37.8??47.9? about the experimental study on the regeneration performance.The mathematical model of heat and mass transfer in the regeneration process was established,and empirical correlations coupling heat and mass transfer coefficients were presented.The calculation results from the model was compared with experimental data to verify the accuracy and suitability of the model.Then,regeneration performance of liquid desiccant was studied base on the model.Finally,the effects of different condensation heat distribution on condensation heat utilization rate were calculated.Finally,the overall performance of system using LiCl solution with low concentration as the liquid desiccant is studied experimentally.Based on the method of controlling a single variable,the study focuses on the effects of six system controllable parameters on condensation temperature,evaporation temperature,system power consumption,cooling capacity and energy efficiency of the unit.The six system controllable parameters include dehumidifier air inlet flow,dehumidifier solution inlet flow,regenerator air inlet flow,regenerator solution inlet flow,interstage solution circulation flow and solution concentration.The study reveals the dynamic matching relationship among the parameters of the system under the condition of low concentration solution. |
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