A study on closed-loop hydronic cooling of photovoltaic panels under hot and arid climate conditions for renewable energy applications
Publication Date
June 15, 2026
Creator
Dirawi, Hazim
Abstract
The increasing global energy demand, along with the progressive effects of global warming, places a strong emphasis on the necessity of alternative and sustainable energy sources. Renewable energy technologies are considered the most promising options. Photovoltaic (PV) power generation has received considerable attention and has developed rapidly over the past few decades. However, the overall performance and operational lifetime of PV modules, particularly those used in hot and arid climates, need further enhancement since their high operating temperatures largely affect electrical efficiency and accelerate material degradation. Therefore, efficient PV cooling systems are required to reduce thermal impacts and improve the sustainability of PV systems, which leads to enhancing PV solar power generation and expanding the application of PV technologies in hot and arid climates.
A comprehensive analysis and review of the existing PV cooling technologies showed that there were considerable limitations and shortcomings in cooling performance, long-term viability and durability in hot and arid climates. To overcome these gaps, a closed-loop hydronic cooling of PV panels is proposed using an above-ground water tank or underground water tank with controlled flow and aimed to reduce the operational temperature and improve long-term thermal regulation of PV systems.
An experimental and detailed modelling framework was developed in order to evaluate the closed-loop hydronic cooling concept. The validated model developed using COMSOL Multiphysics verified a reduction in module temperature, enhanced electrical output, and reduced long-term thermal stress associated with PV degradation. A parametric analysis was used to identify the influence of design factors such as water tank size and shape, controlled intermittent flow (CIF), and insulation on system behaviour. Moreover, three novel PV cooling configurations are proposed: a closed-loop hydronic cooling system using an above-ground water tank (PV-AGWT), a closed-loop hydronic cooling system incorporating CIF and a PV module integrated with an underground tank (PV-UGWT) system. However, the PV-UGWT system demonstrated the highest thermal regulation and lower operating temperatures during diurnal cycles, the PV-AGWT system showed the largest annual PV net power output when compared to traditional PV and PV-UGWT systems. A PV-phase change material (PV-PCM) system was additionally examined with a PCM layer attached at the back of PV module for passive cooling management. Annual performance and lifetime estimations exhibit that the proposed cooling concept, particularly when operated under controlled intermittent flow (CIF), improve cooling performance and lower pumping energy consumption, resulting in a significant increase in PV module performance when compared to traditional PV systems.
Moreover, a techno-economic evaluation model has been developed to evaluate the economic viability, taking into account the long-term predictions of degradation in power production and the operational lifetime of PV systems. The techno-economic analysis was conducted to PV-AGWT, PV-PCM and the traditional PV systems. The results indicated discounted payback periods of less than 6 years for common PV and PV-AGWT systems, whereas the PV-PCM system could not be economically viable under the examined conditions.
To conclude, the proposed closed-loop hydronic PV cooling systems have demonstrated the capability to enhance the PV performance and mitigate operating temperature, thus increasing energy production and reducing PV module degradation. The proposed closed-loop hydronic PV cooling system, including controlled intermittent flow strategies and an above-ground water tank configuration, is shown to be the most promising technology investigated to realise reliable and efficient PV operation across hot and arid climate conditions. Nevertheless, further research is still required, especially to investigate the performance of PV cooling systems under whole-year outdoor experimental studies, to assess the long-term reliability.
Item Type
ethesis
Thesis Type
PhD
Supervisors
University of Nottingham
University of Nottingham
Wang, Qiliang
University of Science and Technology of China
Subjects (LC)
Associated Schools / Departments
Author URL(s)
UoN Repository URI
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