Evaluation of optimal dual axis concentrated photovoltaic thermal system with active ventilation using Frog Leap algorithm H. Gholami a , A.I. Sarwat b , H. Hosseinian a , A. Khalilnejad b,⇑ a Electrical Engineering Department, Amirkabir University of Technology (AUT), Tehran, Iran b Electrical Engineering Department, Center of Energy, Power & Sustainability (EPS), Florida International University (FIU), Miami, USA article info Article history: Received 13 April 2015 Accepted 11 August 2015 Available online 27 August 2015 Keywords: CPVT system Triple-junction cell Frog Leap algorithm Solar tracker Active ventilation abstract In this study, design and optimization of a concentrated photovoltaic thermal (CPVT) system considering electrical, mechanical, and economical aspects is investigated. For this purpose, each section of the sys- tem is simulated in MATLAB, in detail. Triple-junction photovoltaic cells, which are the most recent tech- nology, are used in this study. They are more efficient in comparison to conventional photovoltaic cells. Unlike ordinary procedures, in this work active ventilation is used for absorbing the thermal power of radiation, using heat storage tanks, which not only results in increasing the electrical efficiency of the system through decreasing the temperature, but also leads to storing and managing produced thermal energy and increasing the total efficiency of the system up to 85 percent. The operation of the CPVT system is investigated for total hours of the year, considering the needed thermal load, meteorological conditions, and hourly radiation of Khuznin, a city in Qazvin province, Iran. Finally, the collector used for this system is optimized economically, using frog leap algorithm, which resulted in the cost of 13.4 $/m 2 for a collector with the optimal distance between tubes of 6.34 cm. Ó 2015 Elsevier Ltd. All rights reserved. 1. Introduction In recent years, the concentrated photovoltaic thermal (CPVT) systems have been rapidly developed [1,2]. In these systems, the radiation is transmitted to cells, using reflectors. With this method, the incident radiation to the cells increases significantly [3–8]. The CPV consists of three parts including the absorber, concentrator, and solar radiation tracker. The absorber consists of the solar cell part and the thermal ventilation system. The concentrator focuses the radiation to the absorber. As the CPV works with the beam radiation, the absorber and concentrator should follow the position of the sun to maximize the incident beam radiation. In order to concentrate the radiation, two major technologies of Fresnel lens [9,10] and parabolic concentrators [11] can be used. Plus, in recent years, triple-junction solar cells have been widely investigated. In these systems, when increasing the current, the voltage increases in logarithmic scale [12]. Also, they are less affected by tempera- ture variation in comparison with silicon based samples [9]. Based on the level of concentration, there are three major concentrators with low, medium, and high rate of concentration. In a study in 2010, a solar system with low rate of concentration is discussed. The model was used to perform a sensitivity analysis in order to highlight the relevance of the leading working parameters (such as irradiance) in system performance [13]. In 2011, instead of implementation of conventional cells, the usage of cells with effi- cient operation such as GaAs with a linear concentrator is investi- gated [14]. In another study in 2011, a case study in Sweden, a low concentrating CPVT system is performed and a complete method- ology to characterize, simulate, and evaluate concentrating photo- voltaic/thermal hybrids is proposed [15]. In 2012, the operation of single and double-axis solar tracker system installed on the roof of a building is analyzed [16]. The obtained thermal power can be used for both heating and cooling purposes which are described in recent studies [17,18]. In 2013, performance analysis of a novel concentrating photovoltaic combined system is performed. Also, energy and exergy analyses of the system is evaluated, economical analysis is performed, and the experimental results are compared to data obtained by the con- trol system [19]. In 2014, the optical performance of a CPVT system is evaluated. The theoretical model of the optical performance of the system under real application condition was established and the outdoor experiment was carried out to compare the simulation evaluation [20]. In 2015, parametric performance analysis of a concentrated photovoltaic co-generation system equipped with a thermal storage tank is done. The system utilized dual-axis tracker http://dx.doi.org/10.1016/j.enconman.2015.08.033 0196-8904/Ó 2015 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +98 914 915 6215. E-mail address: akhal026@fiu.edu (A. Khalilnejad). Energy Conversion and Management 105 (2015) 782–790 Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman