Experimental Analysis And Numerical Simulation Of A Multistage Hollow Fiber Membrane Modules Liquid Desiccant Dehumidification System

With the rapid development of economy and society, the request for indoor air quality isgetting higher and higher. The indoor air humidity control is particularly important. Thetraditional methods of dehumidification have insurmountable disadvantages, such as directcontacting of air with liquid desiccant. The multistage liquid dehumidification system basedon hollow fiber membrane modules can be a good approach to overcome the shortcomings oftraditional dehumidification technology, so it has good prospect in the future.The multistage liquid dehumidification system based on hollow fiber membrane modulesstudied in this paper combines traditional liquid desiccant dehumidification technology withmembrane dehumidification technology. Hollow fiber membrane modules are used asdehumidifier and regenerator, so the problem of air mixing with desiccant solution can beavoided. The desiccant solution is cooled down by the second-stage module used in thissystem, and then it can be further used to dehumidification. This can effectively reduce energyconsumption in dehumidification and regeneration cycle. Air is dehumidified by liquiddesiccant dehumidification combined with cooling dehumidification to enhance the systemperformance. A hollow fiber membrane module is adopted to replace metal heat exchanger,thus can avoid erosion problems. The major work includes the following aspects:(1) The multistage liquid dehumidification system based on hollow fiber membranemodules is divided into three parts: the heat pump systems, the air circulation systems, andthe solution circulation system. Each part is designed and built. The data measuringinstruments is selected and bought.(2) The mathematical model of the hollow fiber membrane module is established by theFortran language. The steady thermodynamic model of the compressor is constructed. Thedistributed parameter model of the finned evaporator is established. The models of thermalexpand valve and reservoir is built too. The model of the whole system is composed of theabove part with the sequential modular method.(3) The experimental research and the simulation is conducted under standard workingconditions and various environmental temperature or humidity. At the standard workingcondition, the results show that: the simulation meets the experimental data well, and themaximum error is7.10%. The dehumidification capacity of the system is1840.16g/h, thecooling power is2.17kW. The COP of the system is2.71. Under the conditions of variousenvironmental temperature or humidity, the dehumidification capacity decreases with theincrease of air inlet temperature, but the variation is not substantial. The cooling power and the COP are nearly unchanged with the increase of air inlet temperatures. Thedehumidification capacity, the cooling power and the COP are increase with the increase in airinlet humidity.