Photovoltaic Thermal System Research Articles

Thermal analysis and thermal regulation of photovoltaic thermal system using serpentine tube absorber with modified multi-walled carbon nanotubes enhanced PCM

Thermal analysis and thermal regulation of photovoltaic thermal system using serpentine tube absorber with modified multi-walled carbon nanotubes enhanced PCM

Evaluation of photovoltaic thermal system performance with different nanoparticle sizes via energy, exergy, and irreversibility analysis

The PVT system efficiency generally depends on diverse factors, such as design parameters, solar radiation intensity, and the concentration and type of nanofluid, among other major factors. The present work focuses on the effect of nanoparticle size on a nanofluid-based PVT collector system with a spiral-flow absorber. Besides nanoparticle size, the system is experimentally investigated at various flow rates, nanoparticle concentrations, and different working conditions. Moreover, PV efficiency is also calculated and compared with thermal efficiency by employing both energy and exergy analyses. The rate of exergy loss in PVT is calculated in order to provide a appropriate understanding of the key factors that affect the overall performance of such systems. The most important factor significantly affecting the PVT net efficiencies is the absorber outlet temperature, which illustrates the trade-off between the temperature increase and the increase of the potential concentration factor.The nanoparticles are milled several times to produce four groups based on particle size, such as A (2-5 nm), B (22-29 nm), C (34-50 nm), and D (75-92 nm). The nanofluid thermal conductivity of groups A, B, C, and D compared to water increased by approximately 50.0%, 45.7%, 34.7%, and 21.4%, respectively. The viscosity of these aggregates increased compared to water by approximately 12.9%, 6.4%, 4.3%, and 3.2%, respectively. There were no observed changes in density with changing groups. The stability of the prepared aggregates was close to the superiority of group A with the smallest nanoparticles. Group A, due to its higher thermal conductivity compared to the rest of the fluids tested, provided the best electrical and thermal energy, but it consumed more pumping energy due to its high viscosity. Therefore, the results show that the electrical and thermal exergy of group A, as well as the entropy generation and irreversibility, were higher than the rest groups, which indicates higher losses. The data calculated hereby should be useful in determining the optimal operating condition of the nanofluid PVT based on nanoparticle size.

Investigating the impact of using different fluids as liquid spectrum filters on photovoltaic-thermal system performance

Investigating the impact of using different fluids as liquid spectrum filters on photovoltaic-thermal system performance

U-Turn Shape Effect on Effective Thermal Conductivity of Double Pass Photovoltaic Thermal (PVT) Systems Configuration

This study explores the thermal performance of double-pass photovoltaic thermal (PVT) systems by investigating the influence of turn shape on heat transfer characteristics using computational fluid dynamics (CFD) simulations. The aim is to evaluate various turn shapes, including half-circle, triangle, half-hexagon, half-octagon, and box, to determine their impact on turbulent intensity, effective thermal conductivity, and outlet temperature in PVT systems. The investigation reveals significant variations in heat transfer efficiency among the different turn shapes, with the triangle-shaped turn demonstrating superior performance across multiple parameters. The findings highlight that the triangle-shaped turn exhibits enhanced turbulence generation and heat exchange efficiency compared to other shapes. Specifically, the triangle-shaped turn achieves a maximum turbulent intensity of approximately 70%, surpassing other shapes which achieve around 60%. Moreover, the triangle-shaped turn displays a longer and more substantial area of high heat exchange, resulting in an effective thermal conductivity improvement of up to 20% compared to alternative shapes. Furthermore, the analysis indicates that the triangle-shaped turn exhibits a faster increase in outlet temperature, reaching steady-state conditions within 15 seconds, while other shapes require up to 19 seconds. These results underscore the significance of turn shape in optimizing the thermal efficiency of PVT systems.

Experimentally exploring the synergy of rotating twisted tape turbulators and hybrid nanofluids for enhanced photovoltaic thermal system performance

In the present study, it is experimentally investigated how the functionality of a photovoltaic thermal unit is affected by utilizing a rotating turbulator and a hybrid nanofluid at the same time. Twisted tape is used as turbulator and water-TiO2/Co3O4 is considered as nanofluid. Two perspectives of energy and exergy are used to analyze the functionality of the unit. The impacts of mixing ratio of TiO2:Co3O4 nanoparticles (1:0, 0.9:0.1, 0.7:0.3, 0.5:0.5, 0.3:0.7, 0.1:0.9, and 0:1), volume concentration of nanofluid (0 %, 0.1 %, 0.5 %, and 1 %), mass flow rate of nanofluid (20, 40, 60, and 80 kg/h), twist pitch of turbulator (10, 30, and 66 mm), and turbulator rotating speed (0, 100, 200, 300, 400, and 500 rpm) on the system functionality are examined. The highest overall energy efficiency of 73.28 % was achieved at a nanofluid concentration of 1 %, twist pitch of 10 mm, rotational speed of 500 rpm, and mass flow rate of 80 kg/h. Moreover, the highest overall exergy efficiency of 13.83 % was achieved at a nanofluid concentration of 1 %, twist pitch of 10 mm, rotational speed of 400 rpm, and mass flow rate of 20 kg/h.

Thermal performance optimization of a novel integrated photovoltaic thermal collector system

The construction industry is actively seeking energy-efficient solutions to reduce reliance on fossil fuels. Building-integrated photovoltaic thermal (PV-T) systems, combining electricity generation with solar heat utilization, have emerged as a promising technology. However, conventional PV-T systems often face limitations in achieving optimal PV panel angles for maximum solar gain while maintaining architectural aesthetics, especially when integrated into building facades. This study investigates the thermal performance of a novel photovoltaic thermal collector (PV-TC) system specifically designed to address these challenges. This system, intended for installation on south-facing building facades, allows for flexible PV panel angling design to optimize solar energy capture without compromising the building's aesthetic appeal. We employ a simulation-based optimization approach using EnergyPlus, Radiance, and a genetic algorithm to determine the optimal design parameters for minimizing annual energy use intensity (EUI) in Nanjing, China's climate. Our results demonstrate that a fan rate of 288 m³/h, a winter fan setpoint of 21 °C, a summer fan setpoint of 25 °C, and a PV panel angle of 41° achieve the lowest EUI of 92.33 kWh/m2. This optimized configuration effectively balances electricity generation with solar heat utilization, minimizing reliance on conventional HVAC systems. We further analyzed individual parameter influences, demonstrating that increasing fan rate consistently improves heat transfer efficiency, while optimal PV angle and fan setpoint temperature are crucial for maximizing solar heat utilization and nighttime cooling, respectively. By comparison it was found that the installation of the PV-TC system reduces the annual EUI by 22.7 %. These findings provide valuable insights for designing and operating high-performance PV-TC systems that address both energy efficiency and architectural integration concerns in buildings.

Unveiling potential: Hybrid nanofluid-driven strategies for maximizing electrical efficiency in Photovoltaic Thermal Systems with trapezoidal flow channel for coolant purposes

In this article, a photovoltaic thermal (PV/T) system is optimized using hybrid nanofluids composed of copper and aluminum oxide, with water as the base fluid for cooling applications. The PV/T system features a simple configuration, with mono-crystalline silicon above the flow channel, copper functioning as the absorber, and a trapezoidal-shaped flow channel. The inlet height of the flow channel is fixed, while the outlet height is variable, defining an aspect ratio that ranges from 0.4 to 1. Numerical modeling is carried out using COMSOL Multiphysics 6.0 through the finite element method, applying the two-dimensional incompressible Navier-Stokes and energy equations. The study focuses on analyzing cell temperature and electrical efficiency using both qualitative and quantitative approaches by varying the Reynolds number, aspect ratio, inlet temperature, and volume fraction of the hybrid nanofluids.Key findings: The results demonstrated a significant 37 % reduction in cell temperature as the Reynolds number increased from 100 to 400, and a 1.8 % reduction when the aspect ratio was minimized to 0.4. Additionally, cell efficiency improved by 8.4 % and 2.1 % as the Reynolds number increased from 100 to 1000 and the volume fraction from 0.01 to 0.1, respectively. These findings provide effective strategies for enhancing the electrical efficiency of PV/T systems. "The study suggests optimizing the cell efficiency of PV/T systems through a new configuration of the flow channel, focusing on adjusting the outlet height and the concentration of nanoparticles in the base fluid.

PV/T System Application for Renewable Heat and Electric Energy in Buildings: Performance and Techno-Economic Analysis

Electricity and thermal energy are used extensively in residential buildings. Meeting these needs with different systems cause loss of efficiency, and an increase initial investment cost which are critical when making investment decisions. Therefore, photovoltaic thermal (PV/T) systems are used to reduce the economic burden of home users. In this article, it is aimed to determine the performance of the PV/T system and to make an economic analysis by considering the instantaneous electrical and thermal efficiency. Net present value (NPV), payback period (PBP) and levelized cost of energy (LCOE) values were used to evaluate the system economically. The novelty of this study is the efficiency of the PV/T collectors, the ambient temperature as well as the main water temperature was taken into consideration and the heat and electrical energy to be produced were calculated by taking the efficiency values calculated on an hourly basis. Also, the losses and the annual degradation of the entire system are included in the calculation. As a result of the analyses, the LCOE, NPV, PBP, average electrical and thermal efficiencies were found as 0.0911 €/kWh, 2718.5 €, 6 years, 14.7% and 62.3%, respectively, for a project size of 8.96 m2 in a 25-year life cycle.

Energy and exergy analysis of a newly designed photovoltaic thermal system featuring ribs, petal array, and coiled twisted tapes: Experimental analysis

Photovoltaic systems suffer from electrical efficiency loss due to increases in surface temperature. To tackle this problem, Photovoltaic Thermal, consisting of photovoltaic and tube configurations attached to its back, is suggested. This study attempts to develop a new collector design in photovoltaic thermal systems. The new design features ribs and petal arrays on its inner and outer surfaces and a coiled twisted tape positioned inside it. The study also uses silicon carbide enhanced nanofluid (0.3 % and 6 % volume concentration) and phased changing material (1 % volume concentration) to boost the thermal efficiency further. Using an indoor solar simulator, the study investigates the effects of mass flow rate in the range of (0.1–0.85) kg/s, solar irradiances of (400–1000) W/m2, and coolant types of (water, 0.3 % and 0.6 % SiC enhanced nanofluid, water and nanophase changing materials, and 0.3 % and 0.6 % SiC enhanced nanofluid and nanophase changing materials). Besides revealing the relationship between all the parameters studied, the results report a maximum electrical energy efficiency of 11.2 %, thermal energy efficiency of 86.2 %, and total exergy efficiency of 15.3 %. The system reached optimal power production of 25.99 W using a photovoltaic module with a maximum power rate of 30 W.

Evaluating the energy and economic performance of hybrid photovoltaic thermal system integrated with multiwalled carbon nanotubes enhanced phase change material

Photovoltaic thermal (PVT) systems represent an advanced evolution of traditional photovoltaic (PV) modules designed to generate electrical and thermal energy simultaneously. However, achieving optimal and commercially viable performance from these systems remains challenging. To overcome this issue, in this research, multiwalled carbon nanotube (MWCNT) enhanced phase change materials (PCMs) integrated with PVT system to enhance electrical and thermal performance has been studied. An experimental investigation with three different configurations, PVT, PCM integrated PVT (PVTPCM), and MWCNT enhanced PCM integrated PVT (PVTNePCM) systems, was carried out under varying solar radiations and a water flow rate of 0.013–0.016 kg/s compared to conventional PV system. A two-step technique was employed to formulate the nanocomposites, and the energy performance of both PV and PVT systems assessed experimentally. The performance of PVTPCM and PVTNePCM systems was evaluated using the TRNSYS simulation technique. The formulated nanocomposite exhibited a 71.43% enhancement in thermal conductivity, a significant reduction in transmittance up to 92% and remained chemically and thermally stable. Integration of NePCM in the PVT system resulted in a notable decrease in panel temperature and a 25.03% increase in electrical efficiency compared to the conventional PV system. The highest performance ratio and overall efficiency for PVTNePCM were 0.55 and 81.62%, respectively, at a flow rate of 0.013 kg/s. The energy payback periods of PVTNePCM, PVTPCM, and PVT setup were 4.7, 4.8 and 5.6 years, respectively. Additionally, a significant improvement in thermal efficiency were observed for PVTPCM and PVTNePCM systems compared to water-based PVT systems, due to the energy stored in the thermal energy storage material.

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 (0.85–0.95), fin thickness (7–21 mm), fin height (7–21 mm), and fin inclination (−15°–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.

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.

Performance evaluation of different new channel box photovoltaic thermal systems

Current research has highlighted three major gaps in the literature: (a) a rarity of studies on photovoltaic thermal systems with channel boxes, (b) a lack of data on pressure drop and surface temperature distribution in these systems, and (c) absence of analysis regarding the impact of materials (metals and polymers) used in photovoltaic thermal systems on performance, cost, payback time and weight. The novelty of this paper lies in addressing these gaps by studying a new channel-box photovoltaic thermal system, varying the number of channels and the height of the collectors that distribute water to these channels, in order to identify the most efficient design in terms of electrical, and thermal efficiency as well as pressure drop. In addition, the impact of different heat exchanger materials (metals and polymers) on the performance, cost, payback time, and weight of photovoltaic thermal systems was investigated. 3D numerical simulations were carried out using COMSOL Multiphysics software, based on the finite element method, and validated by outdoor experimental research. The results show that the photovoltaic thermal system 8 design performs best, with a total efficiency of 89.42%. In addition, the aluminum photovoltaic thermal system stands out as the most cost-effective option, with a payback time of 0.823 y (300 d) and annual savings of $459.262, while being 38% lighter than the copper system. Based on this study, it is recommended that the photovoltaic thermal system 8 be implemented because of its exceptional performance and ease of implementation.

Numerical analysis on performance evaluation of photovoltaic thermal systems using ternary hybrid nanofluids and forced convection around copper cylinders

This study evaluates the performance of a photovoltaic thermal (PV/T) system using forced convection and ternary hybrid nanofluids, comprising water with cobalt, zinc, and silver. The PV/T system includes a glass absorber, polycrystalline silicon, and a flow channel with eight copper cylinders, positioned at 20 %, 40 %, 60 %, and 80 % along the channel, both above and below the flow path for optimal thermal conductivity. The working fluid is modeled under turbulent, steady-state conditions using the κ−ε turbulence model.Numerical simulations via COMSOL Multiphysics 6.0 evaluate the system's thermal and fluid dynamics, focusing on local Nusselt numbers and photovoltaic cell thermal efficiency compared to a baseline. The investigation spans Reynolds numbers from 10,000 to 100,000, nanoparticle volume fractions of 1 %–20 %, and aspect ratios of 0.1–0.3. The aspect ratio in this study is defined as the ratio of the height of a square obstacle within the flow channel to the total height of the flow channel. A supervised machine learning framework develops predictive regression models for system analysis. Results show fluid force at the outlet increases by about 1200 % and 1300 % for aspect ratios of 0.1 and 0.3 as the Reynolds number rises. The Nusselt number enhances by 420 % and 466 % at a 20 % nanoparticle volume fraction for aspect ratios of 0.1 and 0.3, respectively, with a 9 % improvement in photovoltaic cell efficiency. This work uniquely applies machine learning to derive regression equations for fluid force, Nusselt number, and electrical efficiency, an approach not previously explored in laminar flow studies.

Cooling of highly concentrated photovoltaic cells with confined jet impingement by introducing channel configurations

Appropriate cooling techniques are required to be integrated into highly concentrated photovoltaic cells to maintain the surface of the photovoltaic cell at a uniform temperature. This study focuses on cooling photovoltaic cells with confined jet impingement to reduce non-uniform temperature distribution and thermal and bending stresses to avoid hotspots and current mismatching problems, thereby improving the cell electrical efficiency. Channels are formed in an aluminium heat sink on the backside of solar cell layers such that the coolant strikes the heat sink surface at the centre and exits at the four corners of the module. Different designs of confined jet channel configurations are studied. The effect of the coolant mass flow rate on the hydrothermal performance of the concentrated photovoltaic thermal (CPV-T) system is examined for all channel configurations. The electrothermal performance of the CPV-T system is at its maximum with a quadrant mini-channel with a single inlet. The net electrical power generated by the PV cell is at its maximum of 30.5 W for a mass flow rate of 50 g/min with this channel configuration. Further, the pressure loss is minimal at 163 Pa at 25 g/min, and the temperature uniformity is also maximum, with a temperature difference over the cell surface of 6.3 °C at 50 g/min. The present study will be useful in the thermal management of highly concentrated photovoltaic thermal systems and high-temperature applications.

Energy-economic-environmental analysis of bifacial photovoltaic thermal (BPVT) solar air collector with jet impingement

Jet impingement cooling enhances photovoltaic (PV) system efficiency by using high-speed fluid jets to reduce panel temperatures, improving performance and longevity. The effectiveness depends on factors like fluid flow rate, nozzle placement, and distance from the panel. While it boosts energy output, it may increase energy use for fluid circulation and add complexity to the system. This research explores a groundbreaking approach to enhancing the efficiency of bifacial photovoltaic thermal (BPVT) systems by integrating jet impingement technology. A novel design featuring a jet plate reflector is introduced, offering the dual benefit of cooling the PV panels while simultaneously reflecting light to optimize energy capture. The study comprehensively analyses the system’s performance, including energy output and a detailed techno-economic and environmental-economic evaluation. The modelling in this study was validated and reasonably consistent with experimental results. The system's output air temperature and thermal efficiency are 302.07–318.75 K and 33.83–62.28 %, respectively. The temperature and electrical efficiency range for PV systems are 304.39–339.54 K and 9.39–11.22 %. Reduced mass flow rate and increased solar irradiation are the most economically advantageous operating parameters for the proposed system, resulting in lower annual pumping costs and more significant annual energy gains for the system. CBR variations range from 0.1363 to 9.3445, with an average of 2. Additionally, by using BPVT with jet impingement to generate electricity rather than fossil fuels, it is possible to reduce annual carbon dioxide emissions by approximately 1.61 tons and save RM93.51 annually. In general, the proposed method should be used to minimize environmental pollution.

Comparison with Carnot battery of an alternate thermal electricity storage charged by concentrated photovoltaic thermal system and resistance heater

In Carnot Batteries (pumped thermal electricity storage), which is known as a low-cost electricity storage method, electrical energy is stored as thermal energy and then converted back into electrical energy using a heat pump and a heat engine, respectively. In the studies carried out to date, different heat source scenarios, heat storage methods, and methods to improve heat pump and heat engine cycles have been applied to increase efficiency and reduce the cost of the Carnot Battery. This study’s novelty was using a concentrated photovoltaic thermal system and resistance heaters instead of a heat pump for the charge cycle in thermal electricity storage. This novel thermal electricity storage design aimed to reduce the levelized cost of storage of the system by eliminating the need for a heat pump and reducing the volume of the water storage tank. First, parametric analyses were performed for the specific variables of both energy storage systems. Afterward, the Carnot Battery and the proposed system were compared for the same electricity storage capacity. For charge/discharge times ranging from 4 h to 8 h and electricity storage capacities ranging from 0.5 MW to 2 MW, a 31.8 % to 58 % increase in round-trip efficiency and a 7.13 % to 20.67 % decrease in levelized cost of energy storage were achieved with the novel design.

Ultra-High-Efficiency Solar Capture Device Based on InAs Top Microstructure

Research on how to efficiently utilize solar energy can effectively address the current situation where excessive carbon emissions threaten the natural environment. The solar capture device, as the core component of the solar thermal photovoltaic system, can significantly enhance the absorption properties of the solar thermal photovoltaic system, which is of high research value in the solar energy application area. In this paper, a metamaterial broadband solar capture device based on the top microstructure of semiconductor InAs material is proposed. The model is fabricated from top to bottom with the semiconductor InAs material at the top with Ti material to make hollow cylindrical microstructures, and a combination of SiO2 material film, Ti material film, and Cu material film as the substrate. In addition to incorporating the properties of metamaterials, the model is also inspired by the quantum-limited domain effect of nano-semiconductors by using the incorporation of InAs top microstructures at the top to further improve the model’s absorption properties. The model was calculated to have an average absorption in the 280–2500 nm waveband of 96.15% and a weighted average absorption in the 280–4000 nm waveband of 97.71% at AM1.5. Results of calculating the model’s reflectivity in the 280–20,000 nm bands show that the reflectivity of the model is higher than 80% in all the bands after the wavelength of 7940 nm, so the model has a certain spectral selectivity. In addition, the thermal radiation efficiency of the model in the 280–2500 nm waveband, when it is used as a thermal emitter, is calculated to reach 94.40% in this paper. Meanwhile, the capture device has good angular insensitivity, which has high potential for practical applications.

CURRENT TRENDS IN PHOTOVOLTAIC THERMAL (PVT) SYSTEMS: A REVIEW OF TECHNOLOGIES AND SUSTAINABLE ENERGY SOLUTIONS

This systematic review explores advancements and challenges in photovoltaic thermal (PVT) systems, focusing on efficiency improvements, cooling mechanisms, material innovations, Internet of Things (IoT) integration, and cost and environmental considerations. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, 45 articles were analyzed to provide a comprehensive understanding of current trends and future directions in PVT technology. Findings reveal that cooling mechanisms, particularly liquid-based and nanofluid-based systems, are essential for maintaining high PVT efficiency under diverse environmental conditions. Material advancements, including phase change materials (PCMs) and nanotechnology, have enhanced thermal management and energy storage capabilities, yet their high costs and environmental impacts remain significant barriers to broader adoption. IoT and smart grid integration have transformed PVT system functionality by enabling real-time monitoring, predictive maintenance, and energy flow adjustments within connected energy networks. However, persistent challenges—including high initial investment costs, environmental concerns related to materials, and the need for adaptable designs—highlight areas for future research. Advancements in adaptive materials, sustainable cooling solutions, and digital automation are essential for developing cost-effective, resilient PVT systems that contribute to global renewable energy goals. This review provides a foundation for future research to address the identified challenges and maximize the potential of PVT systems in sustainable energy production.

Performance Assessment and Improvement of Photovoltaic-Thermal System based on Energy, Exergy, Economic and Environment Analysis

Performance Assessment and Improvement of Photovoltaic-Thermal System based on Energy, Exergy, Economic and Environment Analysis