A high efficiency solar steam generation system with using residual heat to enhance steam escape

Abstract

Solar steam generation has become the most promising solar-thermal applications in recent years. Scientists often focus on the search for superior materials, efficient structures, while ignoring the use of residual heat from the water at the bottom. In this paper, a membrane distillation system that utilizes residual heat was added in a new solar house of a domestic hot water and drinking water supply system in the first place. The pDA-rGO-PTFE membrane as an excellent evaporator was characterized in solar steam generation system, which possesses good hydrophilicity capacity and high intrinsic absorption properties. And at the optimal concentration of 20mg/mL, the evaporation rate and efficiency of pDA-rGO-PTFE membrane could reach up 1.45kg·m−2·h−1 and 93.8% respectively in one sun (one sun=1kw·m−2). The PTFE membrane as a separator was applied in a membrane distillation system. Under average 0.66 sun in the natural environment, the average evaporation rate of a new solar house could reach about 1.10kg·m−2·h−1, and there is an additional 0.71kg·m−2·h−1 membrane permeation flux by the residual heat. In addition, the new solar house showed an excellent durability and desalination ability, the ions rejection rations of the collected condensate water were close to 99.8%. Hence, we conclude that further ideas of a new solar house were provided for solving water scarcity, domestic water consumption and the application of solar steam generation in the future.