Theoretical And Experimental Study On An Internally-cooled Liquid Desiccant Dehumidifier

Dehumidification with liquid desiccant is an important way to utilize solar energy and industrial waste heat. In most applications of solution dehumidification in air conditioning, heat and mass transfer between moist air and liquid desiccant is carried out under adiabatic condition, the heat released by the absorption process causes the solution temperature go up, thus decreasing its dehumidification capacity. The introduction of cooling medium into the interior of the dehumidifier may be an efficient way to resolve this problem. At present the structure of internally-cooled dehumidifier has mainly two types:parallel plate and fin tube. The former uses conductive plastic as the base material, whereas the latter uses stainless steel as the base material. This thesis proposes a novel internally-cooled dehumidifier which is based on conductive plastic capillary tube, and studied its performance theoretically and experimentally. The main contents are listed as follows:1The heat and mass transfer between moist air, cooling water and LiCl solution were analyzed. Physical model was established to describe the dehumidifier. The model was discretized and numerically solved. The dehumidification effect was simulated for typical air conditioning situation. The impacts of structure parameters of the dehumidifier and the inlet conditions of three fluids on the performance were studied.2A dehumidification unit was made. LiCl solution was selected as the hygroscopic solution. PE-RT plastic capillary tube net used in floor radiation heating was chosen as the framework. Cotton wick was used the holdup material to wrap around the tube. A test rig was built and debugged in order to study the characteristics of the novel dehumidification unit. The impacts of air-solution flow rate ratio, inlet air moisture content, cooling water flow rate on the dehumidification performance were inspected. Comparisons were made between numerical calculation and experimental results. Relatively good consistency was observed.