Comparative Study On Heat And Mass Transfer Performance Of Different Flow Type Solution Dehumidification Modules

The solution dehumidification air conditioning system has the unique advantage in the comfort and energy saving by the independent treatment of temperature and humidity and the use of high temperature cold source to deal with air. Due to volume and weight of the liquid desiccant air conditioning, it is restricted by the space. Solution dehumidification module is the heat and mass transfer device between air and solution in the liquid desiccant air conditioning. Improving the efficiency of heat and mass transfer of liquid desiccant module can reduce the volume and weight of the unit. Simple liquid desiccant air conditioning deal with air by using two-stage cross-flow dehumidification module. In theory, counter flow pattern has higher heat and mass transfer performance than cross flow pattern. But because the counter flow pattern has higher requirement in space, the development on commercial air conditioning is limited.In this paper, using two stage liquid desiccant units of as the prototype, using lithium chloride as desiccant, using the enthalpy difference lab as test platform, the two kinds of flow pattern of Liquid desiccant modules have been researched. At the same time, using the heat and mass transfer mathematical model based on the epsilon-NTU, the mathematical model based on the actual prototype has been established. in order to analyze the changes in the dehumidification module and calculate the performance of two kinds of flow patterns. The difference of heat and mass transfer characteristics of two kinds of flow patterns under different influence factors was analyzed by controlling the different factors affecting the dehumidification process.By comparison, it is found that the heat and mass transfer performance of the counter flow solution dehumidification module is better than that of the cross flow module. The counter flow pattern's advantage of heat and mass transfer comparing to the cross flow pattern, have different performance under different influencing factors. Counter flow pattern module have better performance in higher flow ratio, higher values of NTU,higher mass concentration of solution. Multi-stage modules of two kinds of flow pattern have been compared on performance. Cross flow module with the improvement of series,heat and mass transfer performance tend to be single stage countercurrent module. Two-stage counter flow solution dehumidification module can improve the ability for heat and mass transfer of the module, and it has practical value.