Guiqiang Li Department of Architecture and Built Environment, University of Nottingham, Nottingham NG7 2RD, UK; Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China Yuehong Su 1 Department of Architecture and Built Environment, University of Nottingham, Nottingham NG7 2RD, UK e-mail: yuehong.su@nottingham.ac.uk Gang Pei 1 Department of Architecture and Built Environment, University of Nottingham, Nottingham NG7 2RD, UK; Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China e-mail: peigang@ustc.edu.cn Hang Zhou Xu Yu Department of Architecture and Built Environment, University of Nottingham, Nottingham NG7 2RD, UK Jie Ji Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Hefei, Anhui 230026, China Saffa Riffat Department of Architecture and Built Environment, University of Nottingham, Nottingham NG7 2RD, UK An Outdoor Experiment of a Lens-Walled Compound Parabolic Concentrator Photovoltaic Module on a Sunny Day in Nottingham A lens-walled compound parabolic concentrator (lens-walled CPC) has a larger half ac- ceptance angle than a mirror CPC for the same geometrical concentration ratio of 2.5X, so it would be more suitable for the building-integrated application as a stationary solar concentrator. Based on our previous work, an outdoor experimental study of a sample trough lens-walled CPC PV module under sunny condition in Nottingham is described. The experimental results provide the verification of actual larger half acceptance angle obtained by the lens-walled CPC in comparison with a mirror CPC of the same size. Along with the analysis of the projected incidence angles, the experimental results also indicate that the lens-walled CPC of 2.5X orientated east–west may be a good choice for high latitude area as a stationary solar concentrator to give a satisfactory whole year performance. [DOI: 10.1115/1.4024929] Keywords: lens-walled CPC PV, outdoor experiment, half acceptance angle, orientation 1 Introduction Use of low concentration solar concentrators is an option for building-integrated photovoltaic (PV) systems, which can be in- stalled either on the fac¸ade or roof, and they could be based on op- tical reflection or/and refraction [1]. For high concentration, a tracking system is usually required with high precision [2–5], resulting in requirements of high technology and difficulties to integrate with the ordinary residential buildings. In comparison, a low concentration system without tracking requirement has more potential for building application as a stationary concentrator. Brogren et al. [6] study the optical efficiency of a PV-thermal hybrid CPC module for high latitudes. Use of the optimized antireflection-treated glazing and reflectors could further increase the electric power yield. Gajbert et al. [7] made an optimization of reflector and module geometries for stationary, low-concentrating, facade-integrated photovoltaic systems. Similar asymmetric con- centrating collector systems for facade integration have been eval- uated through measurements [8–10]. Additionally, many researchers have paid attention in this category, and have chosen incorporation of bifacials PV cells [11–17]. The optical concentration ratio of a stationary solar concentra- tor could be largely increased by using dielectric material due to the increased acceptance angle [18]. The examples of dielectric static-concentrators have been presented [19]. Zacharopoulos et al. made a three-dimensional optical analysis for two dielectric, nonimaging concentrating covers in building-integrated 1 Correspondence authors. Contributed by the Solar Energy Division of ASME for publication in the JOURNAL OF SOLAR ENERGY ENGINEERING. Manuscript received November 5, 2012; final manuscript received May 15, 2013; published online September 16, 2013. Assoc. Editor: Santiago Silvestre. Journal of Solar Energy Engineering MAY 2014, Vol. 136 / 021011-1 Copyright V C 2014 by ASME Downloaded From: http://asmedigitalcollection.asme.org/ on 09/27/2013 Terms of Use: http://asme.org/terms