Solar Energy 208 (2020) 58–88 0038-092X/© 2020 International Solar Energy Society. Published by Elsevier Ltd. All rights reserved. Evaluation and comparison of different fow confgurations PVT systems in Oman: A numerical and experimental investigation Hussein A. Kazem a, b, * , Ali H.A. Al-Waeli b , Miqdam T. Chaichan c , Karrar H. Al-Waeli d , Anwer Basim Al-Aasam b , K Sopian b a Faculty of Engineering, Sohar University, Oman b Solar Energy Research Institute, Universiti Kebangsaan Malaysia, Malaysia c Energy and Renewable Energies Technology Research Center, University of Technology, Iraq d Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, Malaysia A R T I C L E INFO Keywords: Experimental Dynamic simulation PV/T Collectors Statistical analysis ABSTRACT The electrical effciency of photovoltaic modules reduces with increase in cell temperature. However, using photovoltaic/thermal systems to enhance thermal, electrical, and overall outcomes is an excellent option. In this study, three water cooling PVT systems that have variable fow channels (web type, direct type, spiral type) installed, tested, evaluated, and compared with conventional PV in terms of electrical performance. The systems were tested outdoor in Sohar, Oman. The water mass fow rate was tested at 40 kg/h. The proposed systems reduced cell temperature on average by a minimum of 3 � C. The temperature reduction improves the voltage, power, and effciency signifcantly. The highest average maximum voltage, current and power were observed for the spiral fow PVT system, which are 17.7 V, 2.89 A and 51.3 W, respectively. The overall effciency for the conventional PV, web, direct and spiral type PVT systems were around 7.8%, 18.5%, 28.0% and 35.0%, respectively. The spiral fow collector found to produce the best effciency compared to web and direct fow collectors. The results confrm that the use of the proposed PVT design is very suitable for the Sultanate of Oman and neighboring countries with similar environmental conditions. 1. Introduction One of the most signifcant matters of fact is that the entire globe is presently under the fear of depletion of energy reserves, and eventually, they are fnding out ways and resources of conserving fossil fuels. This urge of conservation is not just because the resources are quickly diminishing; it is also because of negative bearing these resources are having on the ecosystem. Besides these factors, fossil fuel prices are highly volatile with drastic infations (Al-Maamary et al., 2017a). Consequently, solar energy is the best resort to all these constraints, and it is also a clean and hygienic source of energy, which simultaneously conserves fossil fuel and safeguards the environment. This source of energy can be equally distributed to metropolitan as well as rural areas and lead towards a clean and pollution-free environment. PVT systems can generate both thermal energy as well as electric energy at the same instance of time, as the hybrid system utilizes both photovoltaic cells (PV) as well as the thermal collectors (Al-Waeli et al., 2017c). A voluminous amount of PVT confgurations proposed and developed that focuses on developing an improvised system with higher electrical and thermal productivity. The PVT system’s productivity is measured or estimated by summing up the system’s electrical and thermal outputs (Al-Waeli et al., 2018). The benefts of this system over the PV and solar thermal collector (ST) are as follows: i. The hybrid system occupies a smaller extent area compared to conventional ST and PV. ii. PVT system utilizes a comparatively lesser quantity of raw ma- terials to develop a much effcient system rather than setting up two separate systems. iii. The overall generated power can be enhanced by inducing appropriate fuid, which has a higher capacity to soak-up more heat when compared to PV module. iv. The system overall outcome is highly effcient in comparison to PV and ST, separately. PVT systems are classifed to simplify understanding of different types of these systems. The classifcation subjected to several * Corresponding author at: Faculty of Engineering, Sohar University, Oman. E-mail address: h.kazem@su.edu.om (H.A. Kazem). Contents lists available at ScienceDirect Solar Energy journal homepage: www.elsevier.com/locate/solener https://doi.org/10.1016/j.solener.2020.07.078 Received 24 February 2020; Received in revised form 21 July 2020; Accepted 23 July 2020