Performance And Analysis Of Flash Distillation Desalination Plant Based On PV/T

At present,water shortage is an important problem in the world.Solar seawater desalination technology will become one of the most effective measures to solve the shortage of fresh water resources in the 21st century,due to the factors which were abundant raw materials,low energy consumption and non-pollution.Now,based on the traditional solar seawater desalination system,countries optimize the development of new systems from two aspects:On the one hand,the aim is to increase freshwater production;On the other hand,from the perspective of improving the utilization rate of solar energy,develop water,electricity,cold and other multi-product joint production system which has high utilization rate of solar energy.Based on PV/T power supply and flash distillation,this paper designs and optimizes a solar seawater desalination system with dual-purpose power and water plant.The relevant parameters are analyzed theoretically and the operation characteristics of the system under variable working conditions are studied,the specific contents are as follows:(1)The structure size of the expanded evaporator is designed:the inner diameter is1.3m,the length is 3.45m,the total volume is 5.7272m~3,and the volume of a single head is 0.57517m~3.Based on Fluent numerical simulation,the heat and mass transfer characteristics inside the expanded evaporator were obtained.The influence of the installation platform in the flash device on the flash ratewas studied.(2)Desalination system with PV/T and flash distillation was established and the system mathematical model was established.Matlab software was used to calculate the performance of the system,the performance parameters of the system were obtained,and the system was optimized.Under the optimal scheme design condition,The photoelectric conversion efficiency of the system is 18.49%,the electric power is 599.11W/m~2,and the fresh water output is 12.55kg/h.Compared with the conventional photovoltaic system under the same parameter,the electric power is increased by 166.14W/m~2,and the fresh water yield of the conventional MSF system under the same parameter is also improved to some extent.(3)The effects of solar radiation intensity,inlet temperature and inlet flow rate on the system performance were analyzed.Under the same conditions of other design conditions,with the increase of solar irradiation intensity from 200W/m~2 to 1200W/m~2,the electrical power of the system increased from 122.06W/m~2 to 715.64W/m~2,and the fresh water output increased from 2.66kg/h to 15.58kg/h.Along with the seawater inlet temperature increased from 10?to 30?,the electrical system is reduced to 548.04W/m~2from 597.48W/m~2,fresh water production is reduced from 12.93kg/h to 12.49kg/h.As the seawater inlet flow increased from 60kg/h to 140kg/h,the electrical power of the system increased from 574.84W/m~2 to 610.12W/m~2,and the fresh water output increased from 10.85kg/h to 13.86kg/h.Based on this,the operation mechanism of the system under specific solar irradiation environment was studied.From 10:00 to 12:00 on a certain day in July 2018 in Beijing,the effect of quality regulation and quantity regulation is similar.The total water production is about 22kg and the total electricity production is about 1.06(kW·h)/m~2.From 16:00 to 18:00,the quality control method is superior to the quantity control method.The total water production amount of the quality control method is 9.75kg,1.28kg more than the specific quantity control method,the total electricity production amount is 0.453(kW·h)/m~2,and the specific quantity control method is 0.068(kW·h)/m~2 higher.