A Self-powered Solar Saline Water Desalination System Combined With Photovoltaic/thermal Collectors And Heat Pump

There are many areas suffered from fresh water shortage,no matter in China or in the world.With the advance of China's Marine strategy,fresh water supply for remote islands and ocean-going ships has gradually become an important issue.Nowadays,solar seawater desalination is considered as one of the most effective measures to solve the problem of fresh water shortage in the 21st century because of the recent advances.In particular,Humidification and dehumidification(HDH)desalination,a technology that uses carrier fluids such as air or water for desalination,is very suitable for small-scale freshwater supplies in remote areas because of the simple equipment,low cost and good water quality.Nevertheless,most HDH systems rely on external power supplies.Also,nowadays,the efficiency of self-powered solar HDH seawater desalination system is unsatisfactory.Therefore,a self-powered HDH solar desalination system integrated with PV/T and heat pump is proposed and studied in this paper,and some of its related parameters are analyzed and optimized.After that,the system's annually dynamic operation simulation is studied in the thesis.Finally,two improvement schemes of the system are proposed.The following shows the specific works:(1)The steady-state mathematical model of the system is established,of which the key parameters are optimized by genetic algorithm.With this design result,based on the summer meteorological data of Haikou,China,the water production of the steady-state mathematical model reaches 16.44 kg/h,the heat efficiency reaches 113.88%,and the initial investment is 34,441 Yuan.(2)To figure out the annually actual operation situations,the annually dynamic simulation platform of the desalination system is built in TRNSYS software.The dynamic simulation shows that the system has higher water production in spring and autumn.Also,the system produces about 22 tons of fresh water a year,of which the cooling coil 1 produces a large proportion.The sensitivity analysis of two crucial parameters shows that PV/T module area play an important role on system performance,but the battery capacity has little effect on it.(3)Three improvement schemes,coupling storage tank,coupling solar thermal collector and coupling engine,are adopted to improve the original solar seawater desalination system efficiency.The annually dynamic simulation platforms of the three systems are built in TRNSYS software.Besides,the benefits of the three improvement schemes are studied and evaluated.