Design and Characterization of a Roof-Mounted Compound Parabolic Concentrator with Phase Change Material

Abstract

This paper presents the design, fabrication and performance of a roof mounted compound parabolic concentrators (CPC) with and without Phase Change Material (PCM) for electricity generation. A truncated Asymmetric Compound Parabolic Concentrator with concentration ratio of 1.83, acceptance-half angles of 60° and an absorber width of 125 mm was designed, constructed and experimentally characterised on the roof of the Simon Perry Building at Trinity College Dublin, Ireland (53.344295, -6.252416). A CPC and a reference PV system were tested under outdoor conditions with 4-cell PV strings. The first challenge of the project was to determine the power generation, efficiency and temperature of both systems and compare the results. The experimental results revealed that at solar incident radiation of 800W/m2, the CPC system increased the power and efficiency by 34 % (power by factor 1.34) and 22 % (efficiency by factor 1.22) respectively, compared with the reference PV system. However, the solar cell temperature in the CPC system increased by 74 % (temperature by factor 1.74). In order to reduce the temperature, a convective cooling system was introduced. The results showed that when the temperature increased by 22% (temperature by factor 1.22) compared with the reference PV system, the power and efficiency improved by 84 % (power by factor 1.84) and 65 % (efficiency by factor 1.65) respectively. The second challenge was to control the temperature by removing and storing the heat. In order to achieve this, an aluminium container with dimensions of 526 X 120 X 13 mm and thickness 2 mm was designed and manufactured. The container was filled with microencapsulated PCM (mPCM) powder and placed on the back of the solar cells in the CPC system. Experimental results showed that the CPC/PCM system increased the temperature of the solar cells by 2% (temperature by factor 1.02) and increased the power by 10 % (power by factor 1.10) compared with the reference PV system. In addition, the temperature in the PCM container was reduced by 17.1 ºC in 12 hrs, as it stored the heat.