Research On Solar Powered Membrane Distillation Cooling System

With the serious problem of lack of convention energy sources and awareness of energy saving and environmental protection, people begin to pay more attention to exploitation and using renewable energy such as solar energy. Solar technology is one of the 5 most important technologies in this century, it also becomes a country's main decision-making strategy of sustainable development. Membrane distillation (MD) is a new-style and high efficient technique of membrane separation, which can be adapted for desalinating seawater and brackish water, making purified water, concentrating solution, medicine and environmental protection etc. If MD can be driven by solar power, it will become a most competitive technique in water treatment field.There is so much brackish water and rich solar energy in the west of China, based on the membrane distillation system in our lab, the technology of solar powered refrigeration applied for the MD's cold side is discussed.It is feasible in technique to apply small sized absorption cooling system to membrane module cooling side. A solar powered single-effect LiBr absorption cooling device is designed to substitute the original electric refrigerator. The evaporator can be used as the cold channel in structure is proposed first time in this field. It optimizes construction of solar powered membrane distillation system.The cold side thermodynamic calculation program for solar powered membrane distillation is compiled by software Visual Basic 6.0. According to the experiment datum, the formulation of radiation on a horizontal surface in Huhhot and temperature of vacuum tube of solar heater is given in this paper. Then its database linked to the software is built. The designed program's interface is clear, frank, apt to operate and extend. The relationship between days of refrigeration and other parameters is also analyzed. After running the program, optimum results of computation is obtained (evaporation temperature is 5℃, temperature of cooling water is 25℃, temperature of driving hot water is 85.4℃and days of refrigeration is maximum).The PV system for MD is also designed in this paper, including PV solar cells, storage battery, inverter, and controller's capacity calculation and model selection.