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Gulf countries like the UAE are blessed with plenty of sunshine over the whole year. The solar photovoltaic system is an appropriate alternative for the production of electricity. Solar irradiance is partially converted into electricity and the remaining is dissipated as accumulated heat which elevates the operating temperature of the solar PV panel. The elevated temperature has adverse effect on the electrical performance of SPV panels. In this study, a unique back cooling, through the application of waste air from a centralized air conditioning system, is presented to compensate for the degradation of electrical power by the temperature. The experimental results have shown an average reduction of 18.05 °C in the operating temperature of the examined monocrystalline solar panel, which improves the generated electrical power by 8.65 % . In a typical clear day of July, an improvement of 0.97 % in the electrical efficiency of the SPV panel has been achieved through the proposed cooling strategy. The electrical energy produced by the cooled SPV panel is 677.89 Wh / day , as compared to 623.90 Wh / day of the reference panel. The results have justified the viability of waste air from the air conditioning system as a novel application of back cooling of SPV panels. The IR thermography is also employed to study the distribution of temperature and the estimation of the performance of SPV panels, along with the detection of the superficial defects. In the end, a new correlation is developed to accurately estimate the output power of the PV panel through IR measured temperature.

This work proposes an innovative statistical model by utilizing the response surface methodology (RSM) method to analyze a batch solar behaviour still. This investigation's main goal is to study the impact of the input factors (solar radiation, ambient temperature, water depth, and thickness of insulation) most influencing water productivity. The polynomial regression model derived from a numerical balance energy model to predict the solar's productivity still is established. The quadratic model is checked by a coefficient of determination (R2). An excellent fitting is attained between the forecasted results derived from the statistical model and the numerical simulation derived from the heat balance model. The results reveal that the importance of the influence in the order of impact on the amount of distilled water is water depth, solar radiation, ambient temperature, and thickness of insulation. A simple polynomial statistical model is stated in this investigation to determine and maximize the amount of distilled water from solar still based on the four considered input factors.

In the present study, an experimental setup for a PVT system is designed and fabricated to investigate the economic and environmental aspects of using different nano-oxides/water fluids. Selected coolant fluids are: pure water, ZnO/water, Al2O3/water and TiO2/water nanofluids. To make nanofluids, nanoparticles are dispersed in distilled water by 0.2% weight fractions (wt%), separately. Based on the experimental results the amount of annual emission reduction and cost saving are investigated for different coolants. Furthermore, the payback period of the PVTs is compared with that of a conventional PV unit. The results are presented in five different scenarios due to increasing of the electricity price, up to the final price and the government subsidies for the renewable energy sources (1st: 10% annual price increasing, with no subsidy, 2nd: linear increasing price, with no subsidy, 3rd: 10% the annual price increasing, 50% subsidy, 4th: linear price increasing, 50% subsidy and 5th: linear price increasing, 75% subsidy). From the energy viewpoint, by using pure water, PVT/TiO2, PVT/ZnO and PVT/Al2O3, the size reduction of the PVT system in comparison with that of the PV is 21, 32, 33 and 24%, respectively, and from the exergy viewpoint these values are about 5, 6, 7, 6%, respectively.

The main objective of this study is to assess the performance of solar Llthlum-Bromlde-H 2 O absorption air conditioning system for a conference hall under hot climate conditions. The goal is to replace conventional air condition system with compressor cycle consuming high electrical power with solar based absorption chiller (increase the integration renewable resources in the energy mix, and reduce the electrical power consumption and the greenhouse gas emissions). Modeling and simulation analysis was used in this study to calculate the cooling loads of the hall; test the daily performance of the solar absorption air conditioning unit; and determine the conditions to achieve and maintain cooling conditions (temperature and humidity) to meet the requirement of the conditioned space. The results show the maximum cooling load of the hall (total floor area is 280 m2) for the month of July in Sharjah is 52 kW, the maximum useful energy gained by the parabolic trough collector PTC is 79 kW (total area of the PTC is 133 m2 and the thermal efficiency of the PTC collector is 72%), and the average coefficient of performance of solar absorption system is 67%.

Modeling and Simulation analysis is performed in this study to investigate the thermal and electrical performance of a hybrid solar photovoltaic thermal (PVT) heat pipe. This investigation was performed for the first time under hot climate conditions. Mathematical models were developed for both the thermal energy as well as the electrical energy of the solar collector. The numerical results were validated with existing experimental data available in the literature. The numerical results compare well with the experimental data. The monthly thermal and electrical energies generated by the solar collector under Sharjah weather conditions were determined and analyzed. The results obtained in the course of this study show that the integration of heat pipes with solar PV (Solar PV/Thermal) collector offers better electrical power production compared to the classical solar PV module. The maximum monthly electric electrical energy output PV/T heat pipe and classical PV module were respectively, 116 kWh and 102 kWh. However, the maximum monthly thermal generated by the PVT heat is 400 kWh.

In the high concentrator photovoltaic (HCPV) systems with solar concentration ratios up to 2000 Suns, significant heat is generated in the used solar cell layer. This high generated heat requires an efficient and smart cooling technique to keep it operating at a safe operating temperature. In this paper, another ultra-high concentrator photovoltaic (UHCPV) system with a smaller cell area of 1 mm2 operating at a high solar concentration ratio (CR) up to 10,000 Suns is proposed. This smaller area requires a simple passive cooling technique even at high CR. The optimal dimensions of a passive cooling method using heat spreader are defined. A 3D thermal model for the multijunction solar cell with the heat spreader coupled with the multi-objective genetic optimization algorithm is used to define the optimal heat spreader dimensions . The model is validated with the results in the literature. The model is used to estimate the cell temperature generated electric power, and cell efficiency at different wind speed, ambient temperature, solar radiation, heat spreader length, thickness, and CR. The heat spreader dimensions were optimized for CR = 6000 suns, the optimal thickness and length were 2 mm and a of 47.5 mm, respectively. These dimensions are enough for the safe operation of the UHCPV at CR of 6000 Suns. As a case study, for a UHCPV module with a total number of cells of 10 by 10, the generated power is around 319 W at CR of 10,000 Suns. At the same condition, the monocrystalline silicon solar cell in the PERSEID SOLAR company can generate a maximum power of 144.9 W/m2. For the same area, for the UHCPV module, the generated electric power is around 319 W for 1 m2 of the module. Therefore, around 120% increase in the power can be accomplished with the use of the UHCPV module. In the UHCPV module, the total area of the cell is around 1 cm by 1 cm. Therefore, the module cost could be very low.

The photovoltaic thermal collector can provide thermal and heat power at the same time. In this paper, a photovoltaic/thermal sheet and tube collector has been numerically investigated. The paper focuses on the development of a hybrid solar collector PV/T. This model will be applied to optimize the operation of the PVT collector in the semi-arid climate. A mathematical model has been developed to determine the dynamic behavior of the collector, based on the energy balance of six main components namely a transparent cover, a PV module, a plate absorber, a tube, water in the tube and insulation. It has been validated by comparing the obtained simulation results with experimental results available in literature, where good agreement has been noted. Using our developed model, the heat and electrical power of sheet and tube collector has been analyzed for four typical days of year with the meteorological parameters of Monastir, Tunisia. Furthermore, the effect of solar radiation, the inlet water temperature, the number of glazing covers and the conductive heat transfer coefficient between plate absorber and PV module have been involved to identify their influence on the thermal and electrical efficiencies. The monthly thermal and electrical energies is also evaluated.

PV/T solar collector is an energy system designed to provide both thermal and electrical energies at the same time. In this paper, the dynamic simulation of a photovoltaic thermal collector is presented. The effect of different parameters, such as meteorological, design and optical parameters are investigated. Furthermore, evaluation and comparative economic analyses among different designs of PV/T sheet-tube collectors, conventional thermal solar collector and PV module is conducted under Monastir (Tunisia) climatic conditions. Numerical results show that the thermal and electrical efficiencies significantly depend on the studied parameters. It is also found that, in terms of economy, the uncovered PV/T collector yield the best performance among others.