Performance Of Photovoltaic Thermal System Research Articles

Increasing the Utilization of Solar Energy through the Performance Evaluation of Air-Based Photovoltaic Thermal Systems

Photovoltaic thermal (PVT) systems are attracting a significant amount of attention in research because they can generate electricity outside of daytime hours, unlike photovoltaic (PV) systems, and can increase efficiency and collect additional energy by reducing the temperature of PVT panels. However, a somewhat lower amount of collected energy is used in the summer than in the winter, and research on this issue is lacking. In this study, first, we experimentally evaluated the performance of PV and PVT systems by season and verified the improvement in the performance of the PVT system. Second, experiments were conducted to verify the enthalpy reduction via mist cooling and dehumidification, and the temperature and humidity control effect via mist cooling and dehumidification was verified. Based on our research findings, we propose a model that can be integrated with indoor ventilation systems to increase the solar energy utilization of PVT systems. Using the PVT system, we improved the panel power generation efficiency by up to 5.89% and generated up to a 38.0% higher collection efficiency than that of the PV system. The air that passed through the PVT system was then subjected to mist cooling and dehumidification to reduce its temperature and increase its humidity, resulting in a 23.2% reduction in enthalpy.

A comprehensive investigation of porous media’s effects on the performance of photovoltaic thermal systems

Porous media in thermal collectors have been found to enhance the performance of photovoltaic thermal systems. However, there is a lack of comprehensive research on the benefits of using porous media in this context. This paper represents the first comprehensive study comparing various types of porous materials and their effects on system performance. The study employs a three-dimensional simulation to analyze the influence of factors such as material type, porosity, permeability, and thermal conductivity on module efficiency in top, middle, and fully filled configurations. In particular, it has been observed that each material has an optimum porosity, and there is little difference among metal foams, ceramic foams, and ordinary materials, such as aluminum and copper screens. Among the different configurations, the middle configuration had the lowest thermal efficiency improvement (∼17 %), the top configuration increased efficiency by ∼7 %, and the full porous configuration had the highest thermal efficiency improvement, 32 %. Materials with very low conductivity, such as wood, perform better in the middle than in the top configuration. Graphite, despite its high thermal conductivity, has low permeability, which leads to lower thermal efficiency compared to that of most other materials in the top configuration. In the full configuration and particularly in the middle configuration, graphite shows the smallest thermal efficiency improvement due to its significant longitudinal conduction heat transfer. Therefore, in these configurations, graphite is not recommended for use as a porous medium. Regarding added mass, metal foam materials add the most mass to the system, followed by ceramic foam materials, which present considerably lower figures. In all cases, the pump power consumption growth is negligible compared to the photovoltaic power output. In all materials and configurations, there was a small improvement in electrical efficiency, reaching 1.25 % in the full porous configuration. From a holistic perspective, this study showed that porous media can improve the overall equivalent power by up to 9.8 %, compared to a smooth channel.

Evaluating the Performance of Photovoltaic Thermal Systems in Varied Climate Conditions: An Exergy and Energy Analysis Approach

Evaluating the Performance of Photovoltaic Thermal Systems in Varied Climate Conditions: An Exergy and Energy Analysis Approach

The Influence of Nanofluid Characteristics on the Thermal Performance of Photovoltaic Thermal System

Optimal solar energy utilization can be achieved with a Photovoltaic Thermal (PVT) system, which simultaneously produces electricity and heat. PVT generally uses water as heat transfer fluid to cool the PV cells while transporting heat for other purposes. However, water has low thermal conductivity and capacity as a heat transfer fluid. Nanofluid, which is popular in heat exchanger applications, has also been researched and tested for use in improving the performance of PVT systems. The superior thermal conductivity of nanofluid could produce a PVT system efficiency of up to 89.75%. However, nanofluid applications in the PVT system still face challenges, especially in their preparation and properties. This study determines the properties of nanofluids that could improve the electrical and thermal performance of PVT systems. The authors found that preparation procedures for manufacturing nanofluids were essential for researchers to consider before applying nanofluids. Also, some disadvantages of nanofluids are still an obstacle in their application, especially economic issues and adverse environmental effects.

Numerical investigation of photovoltaic thermal energy efficiency improvement using the backward step containing Cu-Al2O3 hybrid nanofluid

The increasing demand for renewable energy sources, such as photovoltaic thermal systems, requires efficient cooling techniques to improve performance. Hybrid nanofluids have shown promise in enhancing the cooling performance of such systems. This work seeks to investigate the effect of varying parameters on the performance of a two-dimensional photovoltaic thermal system using hybrid nanofluids for cooling. This work aims to enhance the performance of two-dimensional photovoltaic thermal systems by using hybrid nanofluids for cooling. The hybrid nanofluids use water as their base fluid and contain a mixture of Copper (Cu) and Aluminia oxide. The photovoltaic thermal system is assumed to have a monocrystalline silicon absorber and a backward step as the flow channel. The conduction and forced convection process will occur on the top two layers of silicon and absorber, respectively, while forced convection will occur in the flow and heat transmission channel. The finite element software COMSOL 6.0 will be used to simulate the issue using the energy and Navier-Stokes equations in a two-dimensional, incompressible, and steady-state problem. A parametric study will be conducted by varying the inlet temperature, Reynolds number, volume fraction of Copper, and height downstream of the backward step channel. The results will be verified using a mesh-independent study and the heat transfer coefficient from the available literature. The study demonstrates that increasing the amount of Cu in the base fluid, the upstream channel's channel height and the corresponding Reynolds number improves the performance of the photovoltaic thermal system.

Emerging Trends on the Implementation of Nanomaterials for Improving the Performance of Photovoltaic Thermal Systems: Energetic, Exergetic, Environmental, and Economic Perspectives

This study presents an updated and constructive review that explores the impact of nanomaterials on the photovoltaic thermal (PVT) system performance from energy, exergy, environmental, and economic perspectives. The study employs the various PVT configurations using water, ethylene glycol, nanofluid, phase change material, and nanoenhanced phase change material, as well as a combination of these cooling media at different loadings, to overcome the increased photovoltaic (PV) module temperature levels in the presence of nanomaterials and improve both the cooling and thermal regulation of the PVT systems. The average PV module temperature, temperature gain across the working fluid, thermal, electrical, and overall energetic and exergetic efficiencies, exergy loss, payback period, cost of energy, and CO2 mitigation/year are some of the primary metrics used to evaluate the performance of PVT systems. The study concludes that the use of nanomaterial in PVT systems enhances the energetic and exergetic performance and these systems are effective in decreasing the entropy generation and exergy loss because of their improved heat transfer. The present study also concludes that payback time and cost of energy for the nanomaterial‐based PVT system are lower than that of conventional systems and these systems prevent greenhouse gases emissions in the ecosystem.

Performance assessment of a solar powered hydrogen production system and its ANFIS model

Apart from many limitations, the usage of hydrogen in different day-to-day applications have been increasing drastically in recent years. However, numerous techniques available to produce hydrogen, electrolysis of water is one of the simplest and cost-effective hydrogen production techniques. In this method, water is split into hydrogen and oxygen by using external electric current. In this research, a novel hydrogen production system incorporated with Photovoltaic – Thermal (PVT) solar collector is developed. The influence of different parameters like solar collector tilt angle, thermal collector design and type of heat transfer fluid on the performance of PVT system and hydrogen production system are also discussed. Finally, thermal efficiency, electrical efficiency, and hydrogen production rate have been predicted by using the Adaptive Neuro-Fuzzy Inference System (ANFIS) technique. Based on this study results, it can be inferred that the solar collector tilt angle plays a significant role to improve the performance of the electrical and thermal performance of PVT solar system and Hydrogen yield rate. On the other side, the spiral-shaped thermal collector with water exhibited better end result than the other hydrogen production systems. The predicted results ANFIS techniques represent an excellent agreement with the experimental results. In consequence, it is suggested that the developed ANFIS model can be adopted for further studies to predict the performance of the hydrogen production system.

Experimental investigation on optimal nanofluid-based PV/T system

Photovoltaic thermal systems working with different nanofluids and using deionized water as base fluid were investigated experimentally. The performance of nanofluids with 1% volume fraction was compared, including carbon, CuO, Al2O3, SiO2, and graphite nanofluids. It was observed that the SiO2 nanofluid shows the best solar absorbing property among them. It contributes to the best performance of photovoltaic thermal systems with an overall power of 2.609 W, followed by the systems using carbon, graphite, Al2O3, CuO nanofluid, respectively. An experiment for a separated PV system was conducted under the same conditions with an obtained electric power of 0.175 W, which is significantly lower than heat absorbing power and higher than that of a PV subsystem. We indicate that the PV system working with nanofluids can improve the overall outcomes in solar power generation.

Influence of absorber plate shape factor and mass flow rate on the performance of the PVT system

In this paper, a realistic mathematical model is presented to study the performance of photovoltaic thermal system (PVT). The model considers the effect of control parameters like shape factor (Z) and mass flow rate (m) simultaneously to optimize the efficiency of PVT system. Simulation process based on iterative method is applied to different types of absorber plate shapes namely v-groove and curved shape grooves. To the best of our knowledge curved groove absorber plates has not been considered in the past. Photovoltaic and outlet temperature, electrical and thermal energy and exergy efficiencies, pressure drop are evaluated as a function of mass flow rate using Nusselt and Reynolds number for different Z values. The results indicate fall in temperature both for PV and outlet temperature and rise in energy and exergy values and pressure drop with mass flow rate. It is predicted that efficiency of PVT system can be improved when the value of Z lies in the range (1.3≤Z<2) which corresponds to curve shape grooves in absorber plate. Further it is found that curved shaped grooves in the absorber plate can be a good substitute to V-grooves for low and high values of m.

Annual performance of photovoltaic-thermal system under actual operating condition of Dire Dawa in Ethiopia

As cooling of Photovoltaic panel by water improves the electrical conversion efficiency and produces warm water as a by-product, photovoltaic thermal system is being used for cogeneration of electrical energy and hot water. In this study, the annual performance of a glazed photovoltaic thermal system (combination of PV module and solar flat plate collector) with storage tank was investigated by the dynamic computational model. The model was developed using MATLAB under actual hot water demand condition for co-generation electrical energy at Dire Dawa in Ethiopia. The computational model determines the electrical energy production and temperature of water at different points and other components of the PV-T system within a given time interval. In addition summaries of monthly and annual incident solar irradiance, electrical energy generation, thermal energy transported to storage and thermal energy supplied as hot water to end users are computed, considering the hourly hot water consumption pattern and storage size effect. The simulation, which is conducted for 20 m2 PV-T system, consists of 12 panels with each 1.64 m2 module areas resulted in generation 803 kWh/year thermal energy and 310 kWh/year electrical energy. The annual average electrical efficiency, thermal efficiency, hot water end use overall efficiency and co-generation (PV-T) efficiency of the system were 15.4%, 50.4%, 38%, and 65.8% respectively. The fraction of solar energy in meeting the heating load for hot water generation was 44.5% for 60℃ hot water supply temperature. Hence, that PV-T system can only be used for water preheating meeting at maximum half of the heating load in tropical area.

Numerical investigation on the effect of different parameters in enhancing heat transfer performance of photovoltaic thermal systems

Abstract Photovoltaic thermal (PV/T) collectors that supply both electricity and heat are growingly becoming popular in household and other applications. However, efficient heat removal from backside of PV module is still a challenge that hampers its electrical as well as thermal performance. In the present research, an absorber-plate less thermal collector has been introduced and mathematical model of such a PV/T system has been developed, which is employed in COMSOL Multiphysics® software to simulate the heat transfer phenomenon in the system. Effect of different flow parameters on heat transfer and PV/T performance is thus studied numerically in the developed simulation model. Also, the effect of irradiation level and depth of the flow channel has been examined on the thermal as well as electrical performance of the module. Results reveal that PV/T electrical and thermal efficiency increase with both of Reynolds and Prandtl number. Heat transfer rate is observed to increase as high as 25.5% with increasing Reynolds number. A maximum reduction in cell temperature of 10.2 °C is obtained by increasing the channel depth. Elimination of absorber plate from thermal collector simplified the design reducing its weight and cost as well.

Improving Thermal and Electrical Efficiency in Photovoltaic Thermal Systems for Sustainable Cooling System Integration

Research into photovoltaic thermal systems is important in solar technologies as photovoltaic thermal systems are designed to produce both electrical and thermal energy, this can lead to improved performance of the overall system. The performance of photovoltaic thermal systems is based on several factors that include photovoltaic thermal materials, design, ambient temperature, inlet and outlet fluid temperature and photovoltaic cell temperature. The aim of this study is to investigate the effect of photovoltaic thermal outlet water temperatures and solar cell temperature on both electrical and thermal efficiency for different range of inlet water temperature. To achieve this, a mathematical model of a photovoltaic thermal system was developed to calculate the anticipated system performance. The factors that affect the efficiency of photovoltaic thermal collectors were discussed and the outlet fluid temperature from the photovoltaic thermal is investigated in order to reach the highest overall efficiency for the solar cooling system. An average thermal and electrical efficiency of 65% and 13.7%, respectively, was achieved and the photovoltaic thermal mathematical model was validated with experimental data from literature.

Simulation Study on Household Forced Circulation Photovoltaic Thermal System Based on Micro Heat Pipe Array

Abstract In order to assess the comprehensive performance of photovoltaic thermal system based on micro heat pipe array (MHPA-PV/T) systems in different regions of China, the mathematical model of the system was built. The reliability of the model was verified through the experimental data of four typical seasons, and the simulated results agreed well with the experiment. Then, this model was used to predict PV/T system performance in five typical cities of different regions in China. For the MHPA-PV/T system of two 195W peak power modules and the 100L capacity heat collecting water tank, model prediction results shows that the average thermal efficiency in Beijing, Changchun, Nanjing, Haikou and Xining were respectively 28.5%,27.8%,27.3%,31.5% and 28.3%, average electrical efficiency were 13.6%,13.9%,13.8%, 13.3% and14.0%, the total efficiency of solar energy utilization were respectively 42.1%,41.7%,41.1%,44.8% and 42.3%, the total generation capacity were 415.7kW·h,446.9kW·h,372.8kW·h,325.7kW·h and 471.8kW·h, the ratio of solar heat supply and demand were respectively89.6%,.79.9%,84.0%,105.8% and 80.5%.