Performance Research On Multi-effect Tubular Solar Brackish Water Desalination Device

Nowadays,a series of problems comes out with the development of human society.Acute lack of fresh water supply and utilization of fossil energy have become serious problems that need to be solved rapidly.Because of the high installation cost and pollution,traditional desalination systems cannot satisfy the fresh water needs in places where are distributed in different regions.Thus,it is an effective way for desalination system to combine with solar energy heat usage technology to overcome the problem of fresh water shortage.Therefore,a multi-effect tubular solar brackish water desalination system is designed.Because of modular designed,the area required of the device is small and it has a highly thermal efficiency,which means the device can satisfy the fresh water needs in remote regions.The system structure and operational principles are introduced in this paper,and the internal heat and mass transfer of the device is studied.To verify the factors which effect the water production capacity of the device,a e xperimental system was fabricated and tested under stable operation conditions based on the indoor experimental result.Fresh water production capacity and PR(Performance Ratio)of the device under actual weather was investigated.In addition,to enhance the heat and mass transfer process of the device,a double-effect tubular solar still was established,the water production performance under conditions of heat recovery and filled with helium is investigated,respectively.Firstly,we set up a tubular solar brackish water desalination test board with different distance between evaporation and condensation surface in door,experimental research and analyze the effect of different distance on fresh water production performance of the device.The result shows that,with fixed heating power in 168 W,when the distance increase from 1.5cm to 2.5cm and 3.5cm,water production rate in unit condensation area decline 15.6% and 32.2%,respectively.Then,to research the effect of feed brackish water salinity on fresh water production performance of the device.A multi-effect tubular solar brackish water desalination device established.Experimental results shows that,when the operational temperature is stabled in 80?,the water production rate reduce 20.32% at a salinity of 10.5% compare with salinity of 3.5%.A multi-effect tubular solar brackish water desalination test board powered by plate solar collector and tested the water production performance under actual weather conditions was also established.When operate in sunny days,the highest water production rate is 1.06kg/h with the PR(performance ratio)is 1.34.At last,to development the water production performance of the device,the internal heat and mass transfer enhancement was studied,the water production performance of the multi-effect tubular solar brackish water desalination device under the heat recovery and helium filling condition was tested,respectively.The result shows that,when the operational temperature is 80?,the water production rate of the device under the condition of heat recovery can reach 0.707kg/h,which is 13.3% higher than that under the condition of non-heat recovery.When the fixed heating power is 335 W,the performance ratio of the helium filled device is 0.11,which is higher than air.The result shows,to enhance the internal heat and mass transfer process,recovery the heat loss and filled gas medium with high heat transfer coefficient can effectively enhance the water yield of the device.