A. Cappelletti, M. Catelani, L. Ciani, M. K. Kazimierczuk and A. Reatti, "Practical Issues and Characterization of a Photovoltaic/Thermal Linear Focus Solar Concentrator," in IEEE Transactions on Instrumentation and Measurement, vol. 65, no. 11, pp. 2464-2475, Nov. 2016. doi: 10.1109/TIM.2016.2588638 URL: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=7518644&isnumber=7586143 1 1 Abstract— This paper presents some practical issues and experience acquired in the design and experimental verification of a 2 small-size solar concentrator producing both electrical and thermal power. The device is a low concentration Photovoltaic/Thermal 3 (PV/T) solar system with a 20 suns (20x) concentrator factor and suitable for integration on building roofs. It consists of four small size 4 (1930x250x166 LxWxH mm) linear focus semi-parabolic mirrors mechanically linked and driven by one stepper motor and tracking 5 the sun along one single axis. Sun-rays are concentrated on strings of mono-crystalline cells with conversion efficiency of about 18%. 6 One of the main features of this device is that the parabola mirrors are designed to have their focus inside the mirror profile so that the 7 solar receiver is installed inside the parabolic concentrator. As a result, each single concentrator height is as low as 166 mm. The solar 8 energy that is not converted into electricity by solar cells is recovered by a cooling medium flowing in an aluminum structure on which 9 the PV cells are mounted. The paper presents an overall description of the device, an electrical layout of the by-pass diodes of the solar 10 receiver utilized to reduce the end-losses, a method based on voltage measurement to derive solar cell temperature inside the receiver 11 and a set of results derived from experimental validations performed on a device prototype. The paper also describes the monitoring 12 system utilized for measurements on the solar concentrator and derives an overall efficiency of solar energy conversion in both electric 13 and thermal generation as high as 61.5%. The predicted values were in a good agreement with experimental test results. 14 15 Keywords — Photovoltaic/thermal (PV/T) system, solar concentrator, solar panels, thermal tests, power electronics, monitoring 16 system, data acquisitions. 17 18 Practical Issues and Characterization of a Photovoltaic/Thermal Linear Focus 20x Solar Concentrator Alessandro Cappelletti 1 , Marcantonio Catelani 2 , Member, IEEE, Lorenzo Ciani 2 , Member, IEEE, Marian K. Kazimierczuk 3 , Fellow, IEEE, Alberto Reatti 2 , Member, IEEE 1 Department of Industrial Engineering DIEF, University of Florence, Via Di Santa Marta 3 50139 Florence, Italy, alessandro.cappelletti@unifi.it 2 Department of Information Engineering, University of Florence, Via Di Santa Marta 3 50139 Florence, Italy, marcantonio.catelani@unifi.it, lorenzo.ciani@unifi.it, alberto.reatti@unifi.it 3 Department of Electrical Engineering, Wright State University, 3640 Colonel Glenn Hwy, Dayton, OH 45435, USA marian.kazimierczuk@wright.edu