Experimental investigation of an asymmetric CPC concentrated solar interfacial evaporation device (CSIED)

Abstract

Interfacial evaporation has a high solar energy conversion efficiency. Although a series of studies have made significant progress, it is still in the laboratory stage as a whole. When interface evaporator is applied outdoor, there are some problems, such as low solar irradiance and low environmental temperature, which result in low surface energy flux density. Besides, it also has large convective and radiative heat losses, limiting evaporation rate. In study, we propose an asymmetric CPC (Compound Parabolic Concentrator) concentrated solar interface evaporation device (CSIED) using surface carbonized poplar as the interface evaporation material (IEM). The IEM floating on water is placed in a double-layer glass tube, which significantly reduces the radiation and convective heat loss. At the same time, it can form a channel for air to drive steam flow and promote steam diffusion. The experimental results indicate that, under a sunlight concentration ratio of 3.4, an air velocity of 0.16 m/s, and a horizontal total solar irradiance of 549 W/m², the CSIED achieves an evaporation rate of 1.69 kg/(m²·h), with average heat and mass transfer coefficients being 39.6 W/(m²·K) and 11.6 m/h, respectively. The solar thermal conversion efficiency of CSIED is 63.9 %.