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Summary: Photovoltaic thermal (PV/T) systems combine a hybrid photovoltaic (PV) module and a flat‐plate solar thermal collector. The hybrid design allows for simultaneou increase in thermal energy while providing cooling for the PV module. In doing so, the PV module temperature drops, and therefore the electrical efficiency increases. Another benefit of PV/T collectors is that they allow for the usage of thermal, and PV module in the same area and so that saved space for the consumer. This study presents a numerical (CFD) design and experimental evaluation of a PV/T system cooled by nano‐PCM and nanofluid. The selected nanomaterial and PCM were nano‐silicon carbide (SiC) and paraffin, respectively. Nano‐silicon carbide particles were employed with the paraffin to ameliorate its thermal conductivity. The study examined various aspects of the system such as the SiC particles' optimal mass fraction suspended in both water (base fluid) and paraffin, the optimum mass flow rate of nanofluid, voltage and current of the PV module, thermal energy of solar thermal collector, and the combined PV/T efficiency. The numerical and practical results were very close, which proves the validity of the hypotheses used in building the program. The significance of this study is demonstrated by the result as this design led to maximum thermal and electrical efficiencies of 72% and 13.7%, respectively. The proposed PV/T system introduced better stability of the generated power and thermal efficiency at peak time than the other two studied systems. [ABSTRACT FROM AUTHOR]

Summary: The use of photovoltaics has spread widely, and government agencies have begun adopting plans to deploy plants with large capacities, due to their environmental friendliness, low manufacturing costs, and high productivity. In the sunny countries where this technology should spread, the photovoltaics' energy conversion efficiency decreases due to the high temperature of which the cell's operate at; because a large part of the solar radiation is absorbed by the solar panels as heat, while the smaller part converts it to electricity. From here, the benefit of the shift towards the PV/T technology that works to reduce the photovoltaic modules temperature and improve their electricity produced along with yielded thermal energy which can be utilized in other applications. In this study, a thorough review of many recent research and studies published in the field of PV/T has been carried out. The present study was divided into several sections to clarify and focus on the effect of each technology separately. Researchers used one or more fluids to cool the solar panels, and their research dealt with many of these fluids, starting with air, water, oil, etc. Other researchers have tended to increase the thermal conductivity of liquid cooling fluids by adding many types of nanoparticles with high thermal conductivity. Other researchers have used variable‐phase materials to take advantage of the large storage of the latent heat of these materials. Other researchers have studied improving heat transfer of PCMs by mixing it with nanomaterials with high thermal conductivity. Others have also combined nano‐PCMs and nanofluids together in one system, and they have demonstrated, in theory and practice, that this technique exhibits higher energy collection and utilization than the other types of PV/T. At the conclusion of the study, some critical points are identified that work is still limited and needs more research efforts and studies. [ABSTRACT FROM AUTHOR]

• Increase of mass flow rate from 10 to 40 kg/h led to increase in useful heat gain. • Using spiral flow collector enhances electrical efficiency of PV modules. • PV/T with spiral flow channel outperforms PV/T's with direct and web flow channels. • Electrical efficiency of PV/T systems outperform conventional PV module. The electrical efficiency 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 flow 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 flow 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 efficiency significantly. The highest average maximum voltage, current and power were observed for the spiral flow PVT system, which are 17.7 V, 2.89 A and 51.3 W, respectively. The overall efficiency 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 flow collector found to produce the best efficiency compared to web and direct flow collectors. The results confirm that the use of the proposed PVT design is very suitable for the Sultanate of Oman and neighboring countries with similar environmental conditions. [ABSTRACT FROM AUTHOR]

The increase in the PV cell temperature ultimately causes a reduction in its effectiveness. One of the new methods used to retain that efficiency is to establish a hybrid photovoltaic thermal PV/T system. In this study, PCM has been employed with a cooling nanofluid circulation system in order to the control heat capacitance of the system to maintain electrical efficiency on the one hand, and to raise the overall efficiency on the other. Nano-SiC particles were used in paraffin-PCM and nanofluid to establish higher thermal conductivities and therefore higher efficiency. The design is tested outdoors in Selangor, Malaysia. The tests were conducted using a fluid flow rate of 0.17 kg/s. The proposed system reduced the cell temperature (30 °C) at the peak solar radiation period (12:30 AM to 1:30 PM), which was reflected positively on the PV/T system performance. The proposed PV/T-nano PCM-nanofluid system increased the open circuit voltage from 11–13 V to 20–21 V, the power from 61.1 W to 120.7 W, and the electrical efficiency from 7.1% to 13.7%. Besides, the system made use of the thermal energy gained as its thermal efficiency reached 72%. These results ensure the adequate use of the new design. [ABSTRACT FROM AUTHOR]

This paper aims to enhance the power production performance of the PV/T based on three cooling models using nanofluid, SiC-water and nano-PCM. The effect of solar irradiance and ambient temperature on the power productivity performance has been investigated based on sensitivity analysis that shows that electrical current and solar irradiance has more impact on power prediction than voltage and temperature. Also, three mathematical linear prediction models were developed and compared with the prediction of ANN models, and the results were verified and fit the experimental results. The comparison with published literature is made based on three common evaluation criteria that include the coefficient of determination R2, MSE and RSME. The proposed predicting models attained an excellent R2 result of 0.99 and MSE value of 0.006 and RSME of 0.009 for both P-M1 and P-M2 models. Besides, the P-M3 obtained an MSE value of 0.022. Finally, the proposed linear prediction models help to reduce the error in furcating future results and determine the best conditions for any solar system in an easy and fast way. • The study aimed to enhance the performance of (SiC-water and nano-PCM) PVT system. • A mathematical and ANN model for nanofluid and nano-PCM cooling PVT presented. • The proposed linear models are consistent with ANN model and experimental results. • The linear predicting models verified simple and accurate results. • The proposed PVT model electrical efficiency coincided with the literature results. [ABSTRACT FROM AUTHOR]

Summary: There are many photovoltaic/thermal (PV/T) systems' designs that are used mainly to reduce the temperature of the PV cell by using a thermal medium to cool the photovoltaic module. In this study, a PV/T system uses nano‐phase change material (PCM) and nanofluid cooling system was adopted. Three cooling models were compared using nanofluid (SiC‐water) and nano‐PCM to improve the performance and productivity of the PV/T system. Three mathematical models were developed for linear prediction, and their results were compared with the predicted artificial neural network results, results were verified, and experimental results were appropriate. Three common evaluation criteria were adopted to compare that the results of proposed forecasting models with other models developed in many research studies are done, including the R2, mean square error (MSE), and root‐mean‐square error (RMSE). Besides, different experiments were implemented using varying number of hidden layers to ensure that the proposed neural network models achieved the best results. The best neural prediction models deployed in this study resulted in good R2 score of 0.81 and MSE of 0.0361 and RMSE and RMSE rate is 0.371. Mathematical models have proven their high potential to easily determine the future outcomes with the preferable circumstances for any PV/T system in a precise way to reduce the error rate to the lowest level. [ABSTRACT FROM AUTHOR]

In the last four decades, greater attention has been paid to PV/T systems due to their advantages compared with PV or solar thermal systems alone. This paper aims to study various aspects of PV/T systems through the existing literature in order to highlight key points as future work in this field as well as illustrate different techniques used for such systems. In addition, PV/T systems are reviewed in terms of thermal and electrical side views. Furthermore, the analysis of solar thermal systems, various system applications such as air, water, air/water, phase change material PCM and Nanofluid systems are summarized. In light of most attempts to improve the PV/T system, more focus has been paid to the thermal rather than the electrical side. Furthermore, comparisons between PV/T systems in terms of performance parameters and efficiencies are presented. A critical review of many findings of previously conducted research is also discussed. It is found that the PV/T air heater system is promising for future preheating air applications. Moreover, it is suggested that the use of nanoparticles and water as base fluid improves the overall system efficiency. Furthermore, the PV side views require more attention in technical and cost terms. However, more research is essential to reduce the cost and, improve the effectiveness and technical design of such systems. [ABSTRACT FROM AUTHOR]