Research On Heat And Mass Transfer Of Membrane Contactor Used For Liquid Desiccant Air Dehumidification And Absorption Heat Pump

The energy consumption of buildings in different regions of China is closely related to the climatic region where it is located.In the northern regions,the energy consumption for heating and domestic hot water is large.In the southern regions,the energy consumption for air conditioning is large because of the wet load.The focus of building energy conservation is to reduce the energy consumption of air conditioning,heating and domestic hot water.Membrane contactors have many advantages in terms of liquid desiccant air dehumidification and absorption heat pump due to their large heat and mass transfer surface area and ability to achieve indirect contact between fluid and fluid.Membrane contactors completely solve the problem of liquid solution droplets cross-over.Diluted solution can be regenerated with solar energy,geothermal energy,or industrial waste heat.Membrane absorption heat pumps can be able to be operated at atmospheric pressure.They have compact structures and high expandability.Moreover,salt solution can store energy.For air dehumidification,the heat and mass transfer mathematical model of cross-flow adjacent internally-cooled parallel-plate membrane contactor is established in this paper.The membrane contactor and air dehumidification experimental device are set up for verification.The heat and mass transfer characteristics,dehumidification performance and dehumidification efficiency in the membrane contactor are analyzed.For fluid heating,the single-layer counter-flow air gap parallel-plate membrane contactor and multi-layer hexagonal air gap parallel-plate membrane contactor are designed and fabricated.Absorption heat pump experimental devices are set up for experimental testing.The effects of different working conditions on the heating performance are studied.In addition,the mathematical model of coupled heat and mass transfer in a cross-flow air-gap hollow fiber membrane contactor is established.The temperature lift of solution and the total annual cost are the optimization objective.The coupled heat and mass transfer model of the membrane contactor is solve by multi-objective particle swarm optimization(MOPSO)algorithm.The effect of contactor length,contactor width,fiber outer diameter and fiber distances in different directions on the heating performance and total annual cost are studied.The optimal geometrical parameters of the membrane contactor are obtained.