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International Journal of Photoenergy
Volume 2015 (2015), Article ID 537538, 10 pages
http://dx.doi.org/10.1155/2015/537538
Research Article

Electrical and Thermal Performance Analysis for a Highly Concentrating Photovoltaic/Thermal System

Department of Thermal Science and Energy Engineering, University of Science and Technology of China, No. 96 Jinzhai Road, Hefei, Anhui 230027, China

Received 9 July 2015; Revised 11 October 2015; Accepted 12 October 2015

Academic Editor: Elias Stathatos

Copyright © 2015 Ning Xu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A 30 kW highly concentrating photovoltaic/thermal (HCPV/T) system has been constructed and tested outdoors. The HCPV/T system consists of 32 modules, each of which consists of point-focus Fresnel lens and triple-junction solar cells with a geometric concentrating ratio of 1090x. The modules are connected to produce both electrical and thermal energy. Performance analysis has been conducted from the viewpoint of thermodynamics. The experimental results show that highest photovoltaic efficiency of 30% and instantaneous thermal efficiency of 30% can be achieved at the same time, which means the total solar energy conversion efficiency of the HCPV/T system is higher than 60%. The photovoltaic efficiency increases with direct irradiance when the direct irradiance is below 580 W/m2, but it remains nearly unchanged when the direct irradiation is higher than 580 W/m2. The instantaneous thermal efficiency decreases during water heating process. However, the electrical performance of the system is not affected obviously by water temperature. Highest exergetic efficiency of 35.4% can be produced by the HCPV/T system. The exergetic efficiency is mainly affected by irradiation level, which is similar to the characteristics of photovoltaic performance.