PV Temperature Research Articles

Study on energy and exergy performance of a new hybrid perforated photovoltaic/solar air heater integrated with encapsulated phase change materials: An experimental study

The current study conducts energy and exergy analyses on an innovative hybrid perforated photovoltaic/solar air heater (PV/SAH) using passive and active methods to improve thermal and electrical efficiencies. Since increasing PVs’ temperature reduces their electrical efficiency, various techniques have been employed to handle this problem, employing effective cooling strategies. This study uses an experimental approach to analyze two cooling strategies: encapsulated phase change material (PCM) units as a passive method and forced-convection mechanism as an active method. Two scenarios were considered: hybrid PV/SAH with and without encapsulated PCM units at two mass flow rates of 0.05 kg/s and 0.07 kg/s. The results illustrate that the encapsulated PCM reduced the PV and outlet temperatures by 2 °C and 4 °C, and 3 °C and 1.5 °C at the mass flow rates of 0.05 kg/s and 0.07 kg/s, respectively. The lower the outlet temperature, the lower the thermal efficiency. Hence, using the PCM units decreased the thermal efficiency but improved the electrical efficiency. The PCM units caused a reduction in daily overall energy efficiency by 12.41 % and 8.36 % at the mass flow rates of 0.05 kg/s and 0.07 kg/s due to reducing thermal efficiency. Unlike the energy efficiency, the PCM units improved the daily overall exergy efficiency by 6.28 % and 8.71 % at the mass flow rates considered. Hence, using passive and active methods is a robust technique to improve the hybrid systems’ performance.

Thermal Management Enhancement of Building-Integrated Photovoltaic Systems using Coupled Heat Pipe and Evaporative Porous Clay Cooler

The building-integrated photovoltaic (BIPV) panel systems often lead to a notable decline in PV panels efficiency and lifetime due to their temperature rise because of inadequate cooling. This study investigates the performance of innovative cooling strategy of using a coupled heat pipes and porous clay cooler and compare it with other related three BIPV cooling systems configurations including a conventional BIPV cooling with and without air gap and a pure evaporative porous clay cooling. The aim is to improve the PV panel cooling, ultimately reduce the PV temperature and enhance the overall performance of the BIPV system as well as reducing the building indoor temperature and boosting energy efficiency within the building. The system model, comprising sets of transient equations for the different system configurations, was solved using MATLAB and confirmed with previous experimental findings. The results indicate that comparing with the traditional BIPV system, using BIPV/Clay cooling systems and the hybrid BIPV/Clay-heat pipe cooling systems achieved peak PV temperature reductions of up to 14 °C and 14.7 °C, respectively. Additionally, these cooling methods led to a maximum interior room temperature reduction of approximately 14°C and an average decrease of 8°C. Moreover, the hybrid BIPV/Clay-heat pipe cooling system demonstrates superior performance compared to traditional BIPV system, achieving the highest improvements in PV electrical efficiency, output power, and exergy efficiency, with gains of 7.8%, 6.4%, and 8.4%, respectively. Further, when the hybrid BIPV/Clay-heat pipe cooling system was employed, the clay cooling efficiency and clay exergy efficiency values improved on average by 30.2% and 29.7%, respectively, compared to the BIPV/Clay cooling system in addition to the increase of the lifetime of the PV panels due to isolating it from the contact with the water/water vapor of the clay cooling system. However, this hybrid approach resulted in a rise in electricity production costs from 0.077 $/kWh to roughly 0.138 $/kWh and extended the payback time from 7.38 years to 13.6 years. But, despite its initial economic drawbacks, the hybrid BIPV/Clay-HP cooling system demonstrates considerable effectiveness and long lifetime compared to other cooling configurations.

New hybrid system of PV/T, solar collectors, PEM electrolyzer, and HDH for hydrogen and freshwater production: Seasonal performance investigation

A new hybrid energy system of PV/T, flat plate collector, PEM electrolyzer, and humidification-dehumidification desalination is introduced here. A comprehensive mathematical model for the system seasonal performance is constructed and solved numerically using MATLAB software. A year-round comparison between the traditional PV/T performance and its concentrated counterpart indicates that the latter performs better compared to power, hydrogen, and freshwater production and system overall efficiency. The maximum monthly achieved PV/T efficiency, electrolyzer efficiency, desalination system Gain Output Ratio, and overall system efficiency are 52 %, 62 %, 4.8 %, and 44 %, respectively at a concentration ratio of 4 and maximum allowable PV temperature. The system produces 82,200 kWh of energy annually and provides 77,700 kWh and 1500 kWh to the electrolyzer and the electric heater, respectively. Moreover, the system produces an annual freshwater production of about 52,700 kg, out of which approximately 10,000 kg are consumed in the electrolysis process, and an annual hydrogen production of approximately 1120 kg.

Enhancing building energy efficiency: Numerical analysis of a hybrid thermoelectric ventilation system and earth-air heat exchange with photovoltaic-thermoelectric power integration for heating and cooling loads

The lack of studies on hybrid systems combining thermoelectric ventilation (TEV) and earth-air heat exchangers with a photovoltaic-thermoelectric generator (PV-TEG) as the power supply for the hybrid system is addressed in this research. This study aims to investigate the effectiveness and performance of such a combined system in providing the required thermal load of a building. To simulate the performance of TEV and PV-TEG systems, energy conservation equations for various components of the system were formulated for the quasi-state mode. The performance of the earth-air heat exchanger system was evaluated using the effectiveness-number of transfer units method. The resulting set of algebraic equations was then solved using a MATLAB code. Results indicated significant preheating (5.41–15.03 °C) and precooling (0.7–10.22 °C) effects during the daily hours of 15-February and 15-July, respectively. Additionally, the TEG component effectively reduced PV temperatures by 3.54 °C–16.99 °C in 15-February and 3.99 °C–21.54 °C in 15-July. The system also demonstrated a high monthly useful thermal energy output (1215–1584 kWh) in the cold months (December to March), contrasting with higher monthly useful thermal exergy (712–763 kWh) in the summer months. Furthermore, increasing the number of TEGs from 10 to 50 resulted in significant improvements in the yearly average energy and exergy proficiency indexes (PIya,en and PIya,ex) by 164.97 % and 459.82 %, respectively. The supply air mass flow rate and the length and depth of the earth-air duct were identified as the second and third most influential parameters affecting these indexes. Moreover, the system at CPV concentration ratio of 3 provided the highest PIya,en and PIya,ex of 1.512 and 14.65, respectively.

Performance optimization for solar photovoltaic thermal system with spiral rectangular absorber using Taguchi method

Solar collector systems efficiently transform sunlight into energy that may be used to meet various needs. This research aimed to use the Taguchi method to determine the ideal operating parameters for a solar thermal collector with a rectangular spiral absorber. Controllable parameters including mass flow rate, solar radiation, and absorber design were manipulated during the energy recovery process, and features like PV temperature and outlet water temperature were used to assess the system’s effectiveness. The findings indicate that certain criteria significantly affect response indicators. The observed percentage contribution of absorber design, solar radiation, and the mass flow rate was 69.19%, 27.99%, and 2.83% in PV surface temperature. In comparison, the individual percentage contributions were 73.63%, 13.51%, and 10.57% for absorber design, solar radiation and mass flow rate for water output temperatures. The present model’s R2 values for PV and outlet water temperatures are 97.24% and 99.67%, respectively. The Predictive regression model was found in fine harmony and the maximum percentage error is limited to 0.68%. The maximum analytical electrical efficiency was observed with a spiral rectangular absorber of 14.57% at the lowest mass flow rate of 0.04 kg/s at the lowest radiation level of 600 W/m2. In comparison, maximum analytical thermal efficiency was observed with a spiral rectangular thermal absorber of 63.56% at the highest flow rate of 0.06 kg/s and the highest solar radiation level of 1000 W/m2. The analytical and experiment findings were in better agreement in this study, with the highest relative error of 7.52%. According to the study’s findings, the rectangular absorber-based PVT system is at its best at a higher mass flow rate to lower PV temperature and boost thermal energy recovery via water. The present research work can be extended for exergy, environmental, and economic feasibility analysis.

Simulation of thermoelectric-photovoltaic system integrated with various shapes of cooling ducts filled with nanomaterial

Incorporating thermoelectric (TE) modules into photovoltaic/thermal (PVT) systems can markedly increase energy output by improving the overall efficiency of energy conversion. This research focused on the design and simulation of a PVT system integrated with a TE module, utilizing ANSYS Fluent. The study assessed four different tube cross-sectional shapes—circular, square, elliptical, and triangular—all with the same cross-sectional areas. Moreover, the investigation included the impact of Cu-alumina/H2O hybrid nanofluid at a 0.024 % volume concentration, fluid inlet velocity (ui), and solar radiation (G) on PV temperature (TPV) and the overall productivity. The outputs showed that the triangular configuration considerably reduced TPV compared to the other shapes. This configuration also generated the highest thermal power, reaching 130.84 W. Additionally, at ui = 0.19 m/s, the unit's thermal efficiency and overall electrical efficiency increased by 0.93 % and 0.22 %, respectively.

Maximizing thermal management of photovoltaic-thermal systems with proper configuration of porous fins and phase change materials

Effective thermal management is crucial to enhance the performance and longevity of photovoltaic-thermal (PVT) systems. Phase change materials (PCMs) offer a promising solution for absorbing excess heat from PV modules; however, their poor thermal conductivity limits their effectiveness. This work explores the incorporation of porous fins within PCMs to improve heat absorption and thermal regulation in PVT systems. A detailed mathematical model is developed to analyze the effects of varying fin porosity (0.85 to 0.95), fin thickness (7 to 21 mm), fin height (7 to 21 mm), and fin inclination (-15° to 30°) on PCM melting and PVT cooling performance. Results show that optimally configured porous fins significantly enhance PCM melting rates and heat extraction from PV cells. Incorporating optimal fins reduces peak PV temperatures by up to 5°C compared to PCM alone at irradiation rate of 1000 W/m2. Meanwhile, reducing the fin thickness from 21 to 7 mm accelerates the overall PCM melting rate by 14%. The cooling performance also shows a nonlinear increase with fin tilt angle, with maximum enhancement occurring at 15° downward tilt for the studied configuration. The optimized fin-enhanced PVT design achieves 3.1% higher electrical efficiency and 15% increase in thermal efficiency compared to conventional PCM-PVT systems without fins. Findings provide design guidance to harness porous fins for maximized PCM-based cooling of PVT systems.

Modelling and experimental investigation of cooling of field-operating PV panels using thermoelectric devices for enhanced power generation by industrial solar plants

The performance of commercial solar power plants degrades due to an increase in module temperatures for which standard PV-T air or water-cooling techniques are mostly used. In this study, a thermoelectric cooling system is studied for improving photovoltaic cell power efficiency and hence solar power generation. The cooling optimization requires solar cell temperature prediction of field operating PV modules, for which analysis of six models, is presented. The experimentation results show that TEC cooling maintains PV cell at 25 °C whereas PV cell without TEC operates at 55–63 °C, a higher temperature range, showing the effectiveness of the thermoelectric cooling system in precisely controlling PV cell temperature to operate at or near STC conditions in the field creating a temperature difference of 30–38 °C. The NOCT and Faiman model results are found close to the experimental values in comparison to other models. The potential for cooling and a corresponding increase in solar plant energy production is assessed using PV Syst modeling and simulation for three practical PV installation scenarios for 31 different climatic zone locations worldwide showing 6–27 % power loss due to elevated temperatures, which is not studied in previous studies adding novelty to the analysis. The results show that PV-TECS is an effective system to control the temperature of field operating PV modules, which can be used in future photovoltaic power plants. Field results and analysis of PV temperature models is crucial for the optimization and future development of PV-thermoelectric systems deployed under actual outdoor conditions as well as the expected cooling gains in different climatic locations. These aspects are collectively studied in the current work adding to the novelty of the study.

An experimental investigation into the use of biomimetic methods for thermal regulation and heat retention with PCMs in buildings

To meet the goal of net-zero emissions by 2050, integrating renewable energy into building energy supplies is a key solution, particularly through the application of solar energy. Due to the intermittent nature of solar energy, effective thermal regulation and heat transfer using thermal mass materials play critical roles in energy efficiency, safety, and performance in building applications. For solar electricity production in building integration, the high temperatures in Building Integrated Photovoltaics (BIPV) need to be regulated to avoid the reduction of solar power conversion efficiency and to maximize the utilization of excess thermal energy. This requires effective energy charging and discharging to meet energy demands.A biomimetic method has been experimentally investigated to enhance the thermal regulation and the thermal energy retention capacity of hybrid PVT-PCM/EG systems for building thermal management. By mimicking natural systems, the PVT-PCM-EG system promotes sustainability and energy efficiency, contributing to reduced energy consumption and lower carbon emissions. Based on the testing condition of around 480 Wm-2 and 15 °C, it is recommended that the combined two transient temperature PCM/EG A28 and A36 for the PVT-PCM/EG system can achieve the best performance for both heat retention and PV temperature regulation.

Enhancing Thermal Conductivity of Phase Change Materials Using Nanomaterials and its Effectiveness in Cooling Solar Cells

The latent heat storage system is considered the most promising technology in thermal energy storage (TES) because of its many advantages. This technique uses phase change material (PCM) as a TES medium. However, the low thermal conductivity (TC) of PCM is the major drawback of the system. Previous studies have shown that the addition of nanomaterials to PCM generally increases its TC. On the other hand, researchers tend to study the possibility of using enhanced PCM to cool solar cells. In fact, raising the solar cell’s operating temperature negatively impacts its efficiency. This problem is considered one of the biggest problems in solar energy systems, and researchers are still working to solve it. This paper focused on the possibility of enhancing the TC of paraffin by adding different shapes of silver nanomaterials to it (silver nanoparticles, silver nanowires and nanohybrid with silver nanoparticles and silver nanowires). Nanomaterials were added at volume fractions of 0.5% and 1%. Then, the study examined the ability to use this improved material to reduce the temperature of solar cells. We used the “Solidworks” program to create a 3D system, and then we used the “Ansys Fluent” software to simulate five cases; PV without PCM, PV with PCM, PV with PCM enhanced by nanoparticles, PV with PCM enhanced by nanowires, PV with PCM enhanced by nanohybrid (a mixture of nanoparticles and nanowires). The results show that using PCM enhanced by nanowire at a volume fraction of 0.5% gave the best results in decreasing the temperature of PV. The average temperature of PV declined by 14.9[Formula: see text]. In addition, the efficiency of PV rose by about 7.6%. Followed by using PCM enhanced by nanoparticles at a volume fraction of 1%. The average temperature of PV declined by 12.9[Formula: see text]. Moreover, the efficiency of PV rose by about 6.6%.

Year-round performance evaluation of photovoltaic-thermal collector with nano-modified phase-change material for building application in an arid desert climate zone

This study provides a comprehensive analysis of the energetic and thermoelectric characteristics of a solar photovoltaic-thermal (PVT) collector equipped with a nano-modified phase-changing material (NPCM) for PV cooling. The operational effectiveness of the collector is evaluated using various parameters such as PV temperature, electrical and thermal powers, melting time, PCM liquid fraction, and PV cooling duration. These factors are meticulously examined under different operating conditions of solar irradiance, ambient air temperature, and the thickness of the NPCM layer. Hail, Saudi Arabia, a city known for its arid desert climate, is chosen as the geographic setting for the study. A numerical methodology based on finite volume discretization is used to solve the governing mathematical models. The year-round performance of the combined PVT and NPCM unit is systematically assessed in terms of monthly averages across the four seasons, considering varying NPCM layer thickness over different time frames. The results indicate that an NPCM with a nanoparticle volumetric concentration of 5% and an appropriately chosen NPCM layer thickness provides effective PV cooling, with cooling durations ranging from 54 to 305 min throughout the year. In terms of electrical performance, months with high solar irradiance yielded a greater power output, peaking at approximately 52.5 Watts, while the winter months exhibited the lowest output. The thermal performance followed a similar pattern, demonstrating the significant influence of solar irradiance on thermal efficiency, with peak outputs reaching up to 225 Watts during high solar intensity months.

Enhancing the performance of photovoltaic using exhausted air from thermal comfort spaces

This paper presents an experimental investigation using the exhaust air from the central air conditioning system as cooling air for the PV modules. Experimental tests were conducted under harsh outdoor weather conditions in Baghdad, Iraq, during the summer session, where the recorded ambient temperature was around 33 to 47 °C. In this study, the exhaust air was flowing in the back side of the PV module to reduce the operating temperature of the PV module and thus improve its performance and electrical efficiency. The results show that the temperature of the PV module decreased from 62.42 to 47.42 °C, the output voltage increased from 14.28 to 16.17 V, the generated electrical power increased from 80.39 to 87.89 W, and the electrical efficiency increased from 13.88% to 15.18%. Overall, the enhancement percentage of the PV temperature, voltage, power, and electrical efficiency is 23.7%, 13%, 9.33%, and 9.33%, respectively, compared to the PV module without cooling.

Investigation of the addition of fins in the collector of water/Al2O3-based PV/T system: Validation of 3D CFD with experimental study

Photovoltaic solar cells, known for their high efficiency and durability, offer a promising renewable energy solution. However, they are susceptible to weather conditions, have low energy density, and require regular maintenance. Elevated operating temperatures can diminish efficiency, power output, and voltage. This study explores the incorporation of fins into PV/T system collectors using Al2O3 nanofluid, validated through 3D computational fluid dynamics (CFD) simulations and laboratory experiments conducted in Surakarta, Indonesia. The research reveals that adding fins to the system reduces PV temperature by expanding the heat transfer area from the collector to the working fluid. Working fluid Water/Al2O3, at 0.6 % concentration, exhibits the highest electrical energy conversion rates at 13.39 %. Adding fins also improves thermal performance based on the working fluid used. The use of fins concentrates the heat transfer flow in the fluid. The PV/T-Fin system has more temperature color contour distribution than the PV/T system. The direction of flow distribution is based on the geometry of the fins added to the PV/T system collector. In addition, when the viscous effect decreases, the temperature decreases towards the center of the flow. This research was validated using Mean Absolute Percentage Error (MAPE), with the most significant error observed in PV/T thermal efficiency being 13.5 %. ANOVA was used to analyze the impact of additional fins and working fluid factors on the PV/T system. The results indicate no significant difference in electrical energy conversion between adding fins and the working fluid Water/Al2O3.

Numerical investigation of the effect of operating conditions on performance of PV-PCM system

The photovoltaic module only manages to convert around 15% of the incoming light into usable electricity and the rest is lost as heat, reducing the module's overall efficiency. Hybrid photovoltaic thermal systems are therefore the best way to collect thermal and electrical energy. The cooling and heat storage benefits of PV cells are amplified using phase change materials (PCMs). In this article, a simple two-dimensional CFD model to forecast the temperature of the PV where it contacts the PCM. The findings of the numerical simulations show that PV systems equipped with PCM have been studied under a variety of situations. A contemporary thermodynamic study is performed to examine system behaviour under different operating settings by investigating the effect of some rather crucial aspects that have not been taken into account before. The research takes into account three instances, each with its own unique combination of wind speed, ambient temperature, and sun irradiation. It has been shown that the solar radiation is a key component for growth in the PV temperature. The findings show that an increase in PV temperature of 5–7°C is caused by an increase in solar irradiance of 1000 W/m2. The rise in wind velocity, heat dissipation rate increases resulting to the fall in the temperature of the PCM and glass, the decrease in PCM temperature leads to a further drop in glass temperature. More so than wind speed or solar irradiation, ambient temperature determines how quickly PV glass heats up. Furthermore, at an ambient temperature of 35°C, PCM is found to melt entirely in 435 min, whereas at an ambient temperature of 30°C, PCM melts up to a liquid fraction of 0.77 min. Therefore, the efficiency of the PV system improves dramatically as the outside temperature is lowered.

Experimentally thermal management of low-concentrated photovoltaic via new configurations of dimple/trapezoidal heat spreaders of different sizes

ABSTRACT This study experimentally investigates the influence of dimple (DHS), flat plate (FHS), and trapezoidal heat spreader (THS) cooling systems on thermal regulation of low concentrated solar cell (LCPV). It is performed at 1.5 and 2 HS/PV area ratio and HS thicknesses 1 and 2 cm under 3100 W/m2 solar irradiance. Results reveal that using DHS outperforms other cooling systems in terms of cell temperature and electric performance. Increasing HS area ratio and thickness significantly enhances PV performance. DHS, PHS, and THS achieve maximum PV temperature reduction of 44.4, 43.2, and 41°C and PV efficiency improvement of 16.89%, 14.87%, and 13.9%, respectively.

Investigation on different cooling strategies for photovoltaic thermal Systems: An experimental study

Since the convection in air photovoltaic/thermal systems (PV/Ts) is weak, this study analyzes different cooling strategies experimentally to improve the thermal/electrical efficiency of PV/Ts. Hence, a PV/T was fabricated and tested outdoors, considering three cooling strategies: unbaffled, solid baffled, and perforated baffled PV/Ts at two flow rates of 0.092 kg/s and 0.17 kg/s. Perforated baffles are a robust, novel method that improves convection, reduces PV temperature, and enhances efficiency. Furthermore, the lower the PV temperature, the higher the electrical efficiency. The experimental data reveal that the peak PV temperature in the perforated baffled scenario falls by nearly 15.6 % and 17.5 % compared to that in the unbaffled scenario at the flow rates of 0.092 kg/s and 0.17 kg/s, respectively. However, the outlet temperature increases in the baffled scenarios compared to the unbaffled one due to improvement in the convection mechanism. Using the solid and perforated baffles increases the peak outlet temperature by nearly 7.22 % and 12.38 % at the flow rate of 0.17 kg/s. Furthermore, the overall efficiency in the solid and perforated baffled PV/Ts improves by 17.29 % and 39.78 % compared to the unbaffled one at the flow rate of 0.17 kg/s. Hence, using perforated baffles is a strong method to boost the efficiency of PV/Ts.

Performance enhancement of porous clay cooler for BIPV applications using hollowed clay structures and metallic extended fins as evaporation and thermal conductivity enhancers

This paper investigates the employing of a passive evaporative cooling approach to mitigate the temperature rise of PV panels within building-integrated photovoltaic (BIPV) systems. The investigation explores enhancing the heat transfer capabilities of composite clay layers by incorporating thermal conductive materials such as iron-oxide and zinc-oxide. This enhancement aimed to improve the overall thermal properties of the composite clay structures, thereby boosting heat transfer rates. Additionally, two distinct designs were evaluated as well: one integrating hollowed clay layer and the other featuring a clay layer with extended fins to enhance both heat and mass transfer rates within the evaporative porous clay structure. A series of experiments conducted under real conditions using prototyped building rooms to simulate real BIPV systems to assess the cooling performance of the presented scenarios. The results revealed that the hollowed clay layer achieved the most substantial decrease in PV panel temperature, with a reduction of 16.5 % compared to the findings with a solid clay layer. In contrast, the composite Iron-oxide/clay layer demonstrated the smallest decrease in PV temperature at 11 %. Moreover, utilizing the hollowed clay structure led to a 6.3 % increase in average PV output power, as well as around 4.5 % enhancement in average photovoltaic’s efficiency compared to the outcomes observed with the solid clay layer. Moreover, incorporating the hollowed clay layer resulted in the most significant decrease in the building's annual load, achieving a reduction of 79.6 %. This signifies approximately a 2 % higher enhancement in cooling capabilities compared to utilizing solid clay layer. Further, the cost of electricity production decreased by 7.7 % (from 0.104 $/kWh to 0.096 $/kWh) following the incorporation of the hollowed clay layer, while the payback time was reduced by roughly 0.8 years compared to utilizing the solid clay layer and by 1.7 years in comparison to the non-cooled BIPV system.

Analysis of night behavior and negative running for PVT system

High absorption of PV benefits heat collection in the daytime, but the heat loss to the space/environment because of its high emissivity also should be noticed. Although there are many papers investigating PVT, few of them cover the night behavior and negative running during late afternoon. This paper supplements detailed studies on related content to draw people's attention to the night and late-afternoon operation that helps better strategy establishment and less heat loss. From experiments, the clouds help hinder the PV radiant heat exchange with space. Under clear night, the PV bottom temperature can be 6.88 °C lower than air temperature and the water tank's bottom temperature drops 2.8 °C. Because of the fluid viscosity, no apparent temperature stratification and flow occur in the PVT water pipe, causing even PV temperature. The higher the water temperature, the easier the negative running occurs during late afternoon, although the irradiation is still high at 521W/m2. Heat loss power and energy are −199W and 1791 KJ from 15:10 to 17:40. Based on different regressed linear correlations of different PVT systems, the effect of water temperature, irradiation, and ambient temperature on the negative performance is also comparatively studied.

ANALYSIS OF AUGMENTATION IN PERFORMANCE OF PV MODULE INTEGRATED WITH FINNED PCM BY THREE-DIMENSIONAL TRANSIENT NUMERICAL SIMULATION

The overall performance of PV-PCM integrated with rectangular straight fins is analysed by three-dimensional transient numerical simulations. The influence of fin lengths, number of fins (n), and inclination (θ) of the system is investigated and compared with the PV-only system, and an optimal system configuration is then identified. Finite element analysis is used to conduct the simulations using COMSOL Multiphysics 6.0. The PV front surface is subjected to a constant flux of 1000 W/m2 for 180 min, and the PCM employed is RT25HC. The results indicate that the average PV temperature tends to drop with increasing inclination and fin length, thereby enhancing the PV efficiency, with maximum improvement attained for the full fin case for a given inclination and number of fins. Compared to the PV-only system, the highest PV temperature reduction and PV efficiency enhancement are 59.65 °C and 45.1%, respectively, for the horizontal system of full-length fins with a number of fins equal to 6. The full-fin PV-PCM system with 6 fins and 45° inclination gives the highest instantaneous power output of 14.16 W. The melting rate of PCM is strongly related to the heat transfer rate inside PCM, and the lowest melting time is obtained for the 8-finned PV-PCM system with θ = 45°. The peak velocity magnitude for all systems with different fin lengths is also examined to analyse the extent of convection levels within PCM.

Improving the performance of solar photovoltaic thermal cells using jet impingement and phase change materials cooling technology

PV/T is designed to convert solar radiation into electricity energy; however, as the temperature rises, their efficiency decreases. This study evaluates experimentally and numerically the performance of PV/T systems. Two cooling methods were used: air jets for enhanced heat transfer and phase change material (PCM) as an energy storage source. Four cases were compared: case A (with PCM and jet), case B (with PCM, without jet), case C (without PCM, with jet), and case D (no cooling). The results were validated by experimental measurements under a solar simulator and the comparison between the experimental and numerical results is satisfactory. The findings show that case A (with PCM and jet) reduced the PV temperature by 21 °C and improved the electrical efficiency by 7.2 % compared with case D (no cooling). The highest electric and thermal efficiency of the PV/T system reached were 12.94 % and 79.1 % respectively at higher air flow rates in case A (with PCM and jet). The novelty of present study is the combination of jet impingement and phase change material, which can provide high electric and thermal efficiencies and allows 2 h’ work after sunset.