Study On Solar-driven Humidification Dehumidification Desalination System With Evacuated Tube Collectors

Desalination technology is one of the important ways to solve the global shortage of freshwater resources.The traditional large-scale seawater desalination technology has high initial investment,large area,and the supply of fossil energy,which is not suitable for islands and remote brackish water areas.Humidification and dehumidification seawater desalination technology has the characteristics of small device scale and easy coupling with low-temperature heat sources such as solar energy and geothermal energy,and has received extensive attention.This paper designs and builds a humidification and dehumidification seawater desalination system with evacuum tube heat collection,and conducts theoretical analysis and experimental research on it.The main research work and conclusions are as follows:1.A mathematical model of each component of the humidification and dehumidification desalination system was established,and the effects of seawater flow,seawater temperature,air flow,and condensate water temperature on the water production of the system were studied.The results show that the freshwater production of the system increases with the increase of the inlet seawater temperature and seawater flow rate of the humidification chamber,first increases and then decreases with the increase of the inlet air flow rate of the humidifier,and decreases with the increase of the cooling water temperature.2.The system is simulated by TRNSYS.The results show that the optimal installation inclination angle of the evacuum tube collector has a great relationship with the use time and azimuth angle of the collector.When the collector is placed due south,the difference between the ratio of the energy received by the collector in each month and the maximum energy month is 0.69 at the maximum.When the collector is placed due west,the difference between the ratio of the energy received by the collector in each month and the maximum energy month is 0.4 at the maximum.In order to make the collector get more direct radiation,when the collector is placed in the south and used in the winter half year,the inclination angle of the collector can be appropriately increased at the local latitude;when the collector is used in the summer half year,the collector The inclination angle can be appropriately reduced at the local latitude;when the collector is used throughout the year,when the inclination angle of the collector is at the local latitude,the received energy is the highest.3.In the parameter optimization of the evacuum tube collector,when the collector area is increased by five times,the fresh water production per unit area of the device is reduced by 17.6%;at the same time,when the volume of the collector hot water storage tank is increased by five times,the annual output of the device is reduced.Freshwater production fell by 6.9%.4.In the test under indoor conditions,when the inlet water temperature of the humidification chamber is 80?,the highest fresh water production rate of the system is 5kg/h;the maximum water production of the device increases by half an hour when the heating time increases,and the highest performance coefficient of the system is 0.93.5.In the test under outdoor conditions,when the preheating time of the collector is 4 hours,the seawater flow is 200 kg/h,the maximum hourly water production of the system is 1.31 kg/h,the cumulative water production throughout the day is 8.46 kg,and the maximum performance parameter is 0.64.Average performance parameter 0.502.Compared with cloudy weather,the water production of the system increased by 8.3%in sunny weather,and the Coefficient of performance increased by 6.8%.