The cooling methodologies of photovoltaic/thermal equipment are crucial not only to maintain optimal operating temperatures but also to improve the performance of the photovoltaic systems and prolong their lifespan. Traditional heat exchangers often require physical contact with the material to be cooled, posing challenges for specific projects. Therefore, this study introduces an innovative heat exchanger made of aluminum plate, allowing direct contact of the cooling liquid with the surface to be cooled. The thermal performance of the serpentine, coupled to a steel plate simulating a photovoltaic-thermal panel, was evaluated experimentally. CFD numerical simulations were conducted to analyze the thermal performance of the heat exchanger, providing valuable temperature profiles for single-phase flows. The outcomes showed that the simulated and experimental data agreed well. Particularly, when considering the outlet fluid temperature the mean absolute error between the simulated and experimental results was around 0.5 °C, with a relative error of aproximatelly 1.8 %. To evaluate the influence of the type of material that forms the serpentine, heat exchangers with two different polydimethylsiloxane (PDMS) serpentines were numerically investigated. The PDMS serpentine provided a more heterogeneous steel plate temperature profile compared to the aluminum one; however, such an issue can be corrected with geometry modifications, such as a greater width and cross-sectional area. For all flow rates, the steel plate temperature using aluminum serpentine presented a lower average temperature
than that with PDMS serpentine (an average of 6.3 % lower). The wide PDMS serpentine exhibited a better cooling performance than the narrow PDMS serpentine (an average of 92 %) since the heat transfer surface area was enhanced in the former case.The authors are grateful to Fundação para a Ciência e Tecnologia (FCT) for partially financing the research through projects PTDC/EMETED/7801/2020 and 2022.03151.PTD (https://doi.org/10.54499/2022.03151.PTDC) and UIPD/50009/2020-FCT and UIDB/50009 – FCT. A.S. Moita also acknowledges FCT for partially financing her contract through CEECINST/00043/2021/CP2797/CT0005, https://doi.org/10.54499/CEECINST/00043/2021/CP2797/CT0005 and for supporting R. Souza's contract through pro gram LA/P/0083/2020 IN + -IST-ID. J.E. Pereira also acknowledges FCT for his PhD Fellowship (Ref. 2021.05830.BD). G. Nobrega was supported by the PRT/BD/153088/2021 doctoral grant financed by the Portuguese Foundation for Science and Technology (FCT), and with funds from MCTES/República Portuguesa, under MIT Portugal Program. R. Lima is grateful for partial financial sup port through the projects, UIDB/04077/2020, UIDP/04077/2020, UIDB/00532/2020 and LA/P/0045/2020 (ALiCE), also funded by the Portuguese Foundation for Science and Technology (FCT). E.M. Cardoso is grateful for the financial support from Conselho Na cional de Desenvolvimento Científico e Tecnológico (grants number 458702/2014–5 and 309848/2020–2) and Fundação de Amparo à Pesquisa do Estado de São Paulo (grants numbers 2013/15431–7, 2019/02566–8, 2019/13895–2, 2020/03907–0, 2022/03946–1 and 22/15765–1)
