Enhanced water yield of solar desalination by thermal concentrated multistage distiller

Solar-driven evaporation for desalination has recently attracted much attention because of its high solar-thermal efficiency, simple structure, low cost, and little environmental impacts. In this paper, we reported a thermal concentrated multistage distiller for solar desalination application. The distiller consists of a thermal concentrator connected to a multistage evaporator-condenser structure. The thermal concentrator with a high solar absorptance of 0.935 and a low emittance of 0.150 on the upper surface can efficiently convert solar radiation into heat for high temperature vapor generation and reduce radiation loss. The multistage distiller with concentric expansion evaporator-condenser structure can efficiently recover the latent heat of vapor, and reduce the heat losses and water diffusion resistance. As a result, a high water yield of 2.2 kg m(-2) h(-1) was achieved in a 6-stage distiller under solar intensity of 1 kW m(-2) and 3 times (3 x) thermal concentration. The outdoor tests in rooftop demonstrated that the water yield can reached 3.9 kg m(-2) per day even at a low solar intensity of 415 W m(-2). This novel design with enhanced water yield provides an effective approach to harvest sunlight for small-scale solar desalination in remote regions.