Liquid and thin-film filters for hybrid solar energy conversion systems

Abstract

Abstract The concept of spectral selectivity in the design of combined photoquantum/photothermal solar convertors can be the basis for improving the overall conversion efficiency of hybrid solar energy systems. Spectral selectivity allows those photons not easily utilized by the photovoltaic (PV) system to be separated and channeled into a thermally decoupled loop. This paper presents an estimated performance analysis of a system that employs dichroic or spectrally selective beamsplitters (SSBS) developed by the authors. Preliminary analyses of the thermal and photovoltaic subsystems and the combined system using moderately concentrated solar radiation showed enhanced performance. Compared to a 12% net conversion efficiency for a conventional photovoltaic system, the photovoltaic component of a hybrid system reaches a 26% efficiency with respect to the 38% of the solar spectrum it receives from the beamsplitter. The remaining 62% of the spectrum not useful for photovoltaic conversion is collected as high-grade heat at an efficiency of 50%. Thus, the ability to extract and direct various portions of the solar spectrum to the appropriate system can increase the conversion efficiency of each process, reduce unwanted heating effects in the photovoltaic system, and reduce costs.