Experimental Research On The Performance Of Heat And Mass Transfer In A Membrane-Based Enthalpy Heat Exchanger

On one hand the enegry problem is becoming more and more serious,but on the other hand the people take more and more attention to the indoor air quality.Therefore the air conditioning system should create a comfortable and healthy inhabitant environment but consume a little energy.The usage of the enthalpy heat exchanger can enable the air conditioning system to introduce plenty of fresh air under the condition of not increasing energy consume or even saving energy,and consequently, improve the indoor air quality. The plate enthalpy heat exchanger is a kind of total heat exchanger and has a high energy recovery efficiency and no moving components,so it is a better enthalpy heat exchanger rather than others.A kind of membrane-based enthalpy heat exchanger was designed and made in this work. A reliable test rig had been designed and constructed to investigate and analyze the heat and mass transfer performance and the air resistance property of the membrane-based enthalpy heat exchanger. The study indicates that the heat and mass transfer efficiency depends on the heat and mass transfer performance of the membrane material, the temperature and humidity of the fresh and exhaust air, the wind speed and the configuration of the exchanger. The heat exchange efficiency decreases with the rising of the wind speed, but the decreasing extent of the sensible heat exchange efficiency is smaller than that of the latent one. And the heat exchange efficiency increases with the rising of the temperature and humidity differences, but the temperature's effect on the sensible heat exchange efficiency is lower than the humidity's effect on the latent heat exchange efficiency.The fresh air consumption per mass flux was calculated by the temperature and humidity measured outside in the typical weather of winter and summer in Beijing. And the energy consumption recovery of the sensible heat exchanger and the enthalpy heat exchanger was compared and analyzed. The study indicates that it is better to use the enthalpy heat exchanger than to use the sensible heat exchanger in Beijing.Through analyzing the energy saving of once return wind system and fan coil units with fresh air system using the enthalpy heat exchanger, the result indicates that whether or not energy is saved depends on the air conditioning system, and the refrigeration resouce device, but the the amount of the saving energy only depends on the air conditioning system.The energy saving percent of using the enthalpy heat exchanger in once return wind system is higher than in fan coil units with fresh air system.