Study on a passive concentrating photovoltaic-membrane distillation integrated system

The traditional photovoltaic-thermal desalination systems generally need to consume produced electricity to power their pumps and fans, thus fail to provide users sufficient household electricity. This paper presents a concentrating photovoltaic-thermal membrane distillation integrated system, innovatively combining concentrating photovoltaic and membrane distillation. Besides producing electricity and fresh water, it is designed with cultivation chambers to directly use the produced water for growing crops. The system could be fully embedded underground and operating passively when tempered glasses are used as its top transparent cover, which can also serve as pavement. In such a way, it has strong resistance to typhoons and saves land sources as well. Here, the system design scheme is introduced. An experimental setup is developed, during which the structural design and optimization method for the concentrator is given, to verify the system's feasibility. Mathematical models for the photovoltaic and thermal processes are established and well-validated via testing. The maximal overall efficiency is about 42% under solar radiation of 900 W/m², in which the system's electrical and water production efficiency is 10% and 32%, respectively. The system also performs well during the whole-day testing. There is more than 40% of solar energy can be utilized on sunny days.