Photovoltaic Thermal Research Articles

Comparative Study of Photovoltaic Thermal Performance with Water and Aloe Vera Heat Extracting Fluids

Crystalline solar panels are widely used in households and for public road lighting. Mono-crystalline panels are well-known for their higher efficiency and long service life. However, their efficiency decreases as the module temperature increases under consistent solar radiation conditions. To enhance module power generation and efficiency, effective temperature reduction techniques are necessary. This study investigates the use of water and aloe vera fluid as cooling agents for a mono-crystalline photovoltaic thermal (PVT) system. The system was designed with a circulating mass flow rate of 0.016 kg/s or 1 LPM (liter per minute) and tested under the climate conditions of Phnom Penh city, Cambodia. The specific heat of aloe vera fluid was determined and found to be 4236 j/kg·K. The optical efficiency of PVT systems using water and aloe vera fluid was compared in this paper. The experiment results indicate that cooling with aloe vera fluid led to a 0.21% higher electrical power generation compared to water cooling, due to more effective temperature reduction and thermal heat absorption rate of aloe vera fluid is higher than water 32.41%.

An experimental assessment of a solar PVT-PCM thermal management system in severe climatic conditions

Solar photovoltaic thermal (PVT) collectors incorporating phase change material (PCM) as an active-passive cooling approach represent a promising solution for thermally managing PV panels. This needs to be experimentally evaluated in harsh outdoor conditions. Therefore, this study examined the electrical and thermal performance of solar PVT systems in comparison to a reference PV panel during six distinct summer days in Riyadh, Saudi Arabia. A thermal camera was utilized to precisely capture the difference in temperature variations between the two PV panels over the study periods and to examine different options for the PVT collector. On Day 3, near noon, the highest solar irradiance of 1019 W/m2 led to the highest power of the PVT, with an increase of 5.75 % over the reference panel. The highest ambient temperature of 47.69 °C was recorded on Day 1 with 901.4 W/m2 irradiance, providing 10.58 % electrical efficiency of the PVT, an increase of 5.9 %. On Day 6, the PVT module was equipped with eight rectangular metal conduits that were filled with PCM with a transition temperature range of 41–48 °C. This simple-to-implement design added additional passive cooling for the system through the exterior surface of the metal conduits, along with the PCM contribution. The PTV-PCM option led to the best performance, with an 8.05 % improvement in electrical power and efficiency over the reference PV and 71.16 % and 81.50 % thermal and combined PVT efficiencies, respectively. The importance of cooling the PV panel in such challenging circumstances was illustrated by the 2 %–3.24 % increase in electrical output for every 1 °C decrease in the temperature of the cells.

Enhancing Hybrid Photovoltaic-Thermal System Efficiency with Boron Dipyrromethene Dyes.

A library of boron dipyrromethene (BODIPY) compounds was studied to assess their efficacy as components of a working liquid in hybrid photovoltaic-thermal (PVT) systems. Two series of BODIPY dyes were investigated: series I included alkylBODIPYs with varying substitution patterns, while series II included 1,3,5,7-tetramethyl-substituted BODIPYs featuring electron-rich aromatic groups in the meso position, such as naphthalene, anthracene, and carbazole. Series II dyes were designed to exhibit luminescence downshifting due to enhanced UV absorption (300-400 nm) and excited-state energy transfer, leading to visible-region fluorescence under UV excitation. Samples of PVT liquids based on decalin and containing each individual BODIPY dye were tested on a standard a-Si solar cell to evaluate their impact on solar energy conversion efficiency. The thermal behavior of the working liquid and the cell during the illumination cycle was monitored, alongside the cell's electrical characteristics. Energy conversion pathways and the overall effects of the dyes on the system performance were scrutinized. Results indicated that all BODIPY dyes enhanced both the electrical conversion efficiency (up to 2.41% increase) and thermal energy generation (up to 6.87%) compared to the solvent alone. These findings highlight the potential of BODIPY dyes to significantly improve the performance of PVT systems.

Prediction of key performance indicators of multi-effect vacuum membrane distillation systems integrated with PVT and Organic Rankin Cycle

The study presented a numerical simulation conducted using MATLAB® to analyze the performance of a poly-generation system. This system comprises solar collectors, a Photovoltaic-Thermal (PVT) system, an Organic Rankine Cycle (ORC), and a multi-effects vacuum membrane distillation (V-MEMD) system. The study investigates the impact of changes in operating conditions of the water stream on the performance of the V-MEMD system. The optimal performance values observed include a water flux of up to 13 kg/ m2·h, a GOR of 5.5, a SEEC of 49 kWh/ m3, and a STEC of 145 kWh/ m3, with each parameter reaching its optimum at different operational settings. The paper explores the impact of different working fluids in the ORC system on water and power generation. It also discusses recent research on combined PVT and ORC systems in Riyadh, Saudi Arabia, considering the region's specific meteorological conditions. The findings reveal that the highest electricity generation occurs in June, with the ORC system producing 18,540 kWh when R123 is used and the PVT system generating 13,536 kWh. The cumulative electricity output for the year reaches 266,564 kWh. Moreover, the V-MEMD system produces 1333 m3 of water over the year, with the highest water yield of 178 m3 observed in June.

Optimizing photovoltaic thermal systems with wavy collector Tube: A response Surface-Based design study with desirability analysis

A comprehensive simulation model and predictive analysis are employed to investigate the performance of a photovoltaic thermal (PVT) system with a wavy collector tube. Response surface methodology and desirability analysis are utilized to develop a robust model that considers five critical design variables: collector wavelength, amplitude, diameter, panel width, and fluid inlet velocity. The complex interactions between these variables and their impact on the system’s energy and exergy outputs are thoroughly examined. Single and multi-objective optimization techniques are strategically applied to maximize the PVT system’s performance under various operating conditions. The results reveal that the wavy tube configuration achieves superior electrical and thermal energy efficiency compared to the conventional straight-tube design. The system’s performance is significantly enhanced by optimizing the collector amplitude, inlet velocity, diameter, wavelength, and panel width. The optimized wavy-tube PVT system demonstrates remarkable overall energy and exergy efficiencies of 85% and 14.67%, respectively, outperforming the baseline straight-tube system’s efficiencies of 72.41% and 12.72%. This research provides valuable insights into the optimal design of PVT systems and contributes to the advancement of PVT technology. The findings highlight the potential for widespread implementation of highly efficient and sustainable PVT systems in the renewable energy sector.

Investigation on the radiative characteristics of ZnO-SiO2 nanofluids in spectral splitting photovoltaic/thermal systems

The application of nanofluid spectral splitting technology in photovoltaic/thermal (PV/T) systems has attracted more attention. In this study, zinc oxide and silica nanoparticles were selected to prepare ZnO-SiO2-H2O mixed nanofluids with different concentrations to investigate the radiative characteristics and their effect on PV/T system. An experimental system was established to measure nanofluids transmission properties in 0.36–2.5 μm, and the radiation characteristics were further analyzed using Mie scattering theoretical model. Besides, thermodynamic model was established to investigate the influence of mixed nanofluids on PV/T system performance. Results indicate that Mie theory can predict the radiative properties of mixed nanofluids well. The ZnO-SiO2-H2O nanofluids have better filtering performance than that of ZnO-H2O nanofluids under same particle concentration. When the mass ratio of ZnO/SiO2 is 0.01 %/0.05 %, the filtering efficiency of the nanofluid achieves 46.18 %. Increasing the concentration of SiO2 can regulate the transmittance of the ZnO-SiO2-H2O nanofluids and improve the PV/T system efficiency by 5 %. Based on ZnO nanofluids, the addition of SiO2 further optimizes PV/T system performance, increasing the system merit function (MF) value The nanofluid spectral splitting PV/T system for Si cells with a ZnO/SiO2 mass ratio of 0.003 %/0.056 % can reach a MF value of 1.342.

Performance assessments of ground source heat pump assisted by various solar panels to achieve zero energy buildings in cold climate conditions

This paper aims to perform a comprehensive performance analysis of a solar-assisted ground source heat pump (SAGSHP) system connected to various types of solar panels to enhance overall energy efficiency. While previous studies have examined integrating solar panels with heat pumps, comprehensive solutions like those presented here and performance evaluations in the zero energy building context have been lacking. This study developed various scenarios using three types of solar panels, photovoltaic (PV), photovoltaic-thermal (PVT), and solar thermal collectors (ST), to explore their simultaneous use. TRNSYS software was employed to analyze the complex system, comparing it to a conventional natural gas boiler system as a baseline. The findings revealed that the on-site energy use intensity (EUI) decreased from 78.6 kWh/m2 to 53.3 kWh/m2, a reduction of approximately 33 %, due to the SAGSHP's implementation. The combination of PVT and PV panels emerged as the most suitable option for the SAGSHP, aligning with the net zero energy concept. The SAGSHP system achieved a low EUI of 10.4 kWh/m2 in terms of primary energy. Additionally, the solar fraction, indicating the proportion of solar energy used, reached approximately 90 %. Thus, this study underscores the significance of evaluating various solar panel configurations during the preliminary design phase of SAGSHP systems to optimize energy performance and progress toward zero energy buildings.

Optimization of Lamps Configuration for a Large-scale Indoor Solar Simulator for PV Panels and Solar Collectors

The current study presents investigations of a solar simulator design, development, and performance characterization for the application of photovoltaic (PV), thermal collector, and photovoltaic/thermal (PV/T) indoor experiments. The study highlights the research outcomes of the lamp configurations and numbers in the simulator to achieve an acceptable radiation distribution in the targeted area as per the ASTM standards. Tungsten Halogen lamps were used to mimic solar radiation due to their proximity to the solar spectrum of the visible and infrared band and relatively low cost. The results indicate that a solar simulator of Class-C for spatial uniformity and Class-A for temporal uniformity can be achieved with the application of Tungsten Halogen lamps if arranged properly and a range of radiation flux can be obtained to replicate the variation of solar flux during the daytime. It was observed that three to six lamps of 1kW arranged in specific configurations can provide solar radiation varying from 378 to 969 W/m2 mimicking the daytime solar flux variation on an experimental area of 1200 × 520 mm2.

Transition towards net zero emissions: Integration of a PV/T system with a hydroelectric generator and the impact of demand-side management

With the aim of diversifying different energy sources and achieving net zero emissions, hybrid renewable energy sources (HRES) represent the future of the world. However, several HRES simulation software do not integrate the Photovoltaic/thermal (PV/T) system. This article designs an optimal design model for a tri-hybrid Photovoltaic/thermal/hydroelectric (PV/T/H) system for a rural locality in the North Cameroon region. The two Demand Side Management (DSM) strategies used reveal that the DSM strategy significantly reduced the energy cost by 59 % and the emission by CO2 22 % compared to the No-DSM mode. Although the use of battery storage (BSS) is used in both cases, the optimal solutions obtained thanks to the multi-objective optimization method implemented on Matlab led to 418 PV/T panels, 2 MH generators, 2 diesel generators (DG) and 217 PV/T panels and 1 DG for DSM and No-DSM mode respectively. This study is a demonstration of the effect of dynamic tariffs and active demand management technologies on PV/T/H modeling and optimization. It also reveals the need to hybridize PV/T with other energy systems to increase performance and achieve net zero emissions.

Integrated machine learning models for predictive analysis of thermal and electrical power generation of a photo-thermal system at Catania, Italy

The Photovoltaic-Thermal (PV/T) system is designed for producing both electrical and thermal energy. Its efficiency is improved when temperature-sensitive PV cells are cooled using nanofluid coolants. However, the current models for predicting PV/T system performance with nanofluid cooling are limited. In order to fill this gap, this study aims to develop machine learning models to predict the electrical and thermal efficiencies of a water-based PV/T system. Three types of machine learning algorithms from the supervised learning method were selected in this study because of their ability to handle complex data and provide accurate predictions: the Multi-layer Perceptron (MLP), the Gradient Boosting Regressor (GBR) and the Light Gradient-Boosting Machine (LightGBM). Initially, the models are trained and validated using data consisting of 15,540 samples from a water-based PV/T system. On the basis of the results obtained, the MLP algorithm proved to be the best for the prediction of electrical energy, with an R2 value = 0.9906, against 0.9709 and 0.99 respectively for the other GBR and LGB algorithms, while the LGB algorithm proved effective for the prediction of thermal energy, with an R2 value = 0.983, against 0.983, 0.97 and 0.988 respectively for the GBR and LGB algorithms. Secondly, the best MLP and LGB models previously identified for the water-based PV/T system were adapted to predict, this time, the energy performance of an Ag/water nanofluid-based PV/T system. The results obtained show that these models are highly effective in predicting the electrical and thermal performance of the Ag/water nanofluid PV/T system, even in the absence of real data, making them very useful for real applications.

EduSolar: A Remote-Controlled Photovoltaic/Thermal Educational Lab with Integrated Daylight Simulation

This study presents a compact educational photovoltaic/thermal (PV/T) system designed for thorough performance assessment under simulated weather conditions. As an affordable educational tool, the system offers significant pedagogical value. The PV/T system features two photovoltaic modules: a thermally enhanced module and a standard one. The thermally enhanced module uses water as a coolant, which transfers heat from the PV cells to a fan-operated heat exchanger, with the coolant being recirculated to maintain optimal conditions. A halogen lamp, placed between the modules, simulates solar radiation to ensure effective electrical current generation. The system’s remote-control capabilities, managed via the Message Queuing Telemetry Transport (MQTT) protocol, enable real-time adjustments to the coolant flow rate, heat exchanger efficiency, and lamp brightness, as well as monitoring of electrical parameters. Experimental findings indicate that the PV/T module achieves a 7.71% increase in power output compared to the standard PV module and offers a 17.41% improvement in cooling efficiency over scenarios without cooling. Additionally, the numerical methods used in the study show a maximum deviation of 4.29% from the experimental results, which is considered acceptable. This study showcases a best practice model for solar training, applicable from elementary to university levels, and suggests innovative approaches to enhancing solar energy education.

Investigating the influence of nanofluid on photovoltaic-thermal systems concerning photovoltaic panel performance

Solar energy has much promise to replace the planet's finite supply of fossil fuels as it is sustainable and eco-friendly. Photovoltaic (PV) panels are one example of the proper technology that may transform solar energy into electrical energy. On the other hand, high temperatures may reduce photovoltaic cells' ability to produce power efficiently. As a result, a study was carried out to use the PV/T (Photovoltaic Thermal) collector system and evaluate the effects of CuO, TiO2, and Al2O3 nanofluids as cooling agents on the performance and operating temperature of PV panels. In Surakarta, Indonesia, an experimental study was conducted with nanoparticle concentrations of 0.2 vol% and a flow rate of 3 L/m at an intensity of radiation of 1000 W/m2. The results showed that, in comparison to uncooled PV panels, employing CuO, TiO2, and Al2O3 nanofluids in the PV/T system resulted in temperature reductions of 18.84 °C, 18.12 °C, and 17.62 °C, respectively. Moreover, measurements of the electrical efficiency produced by PV and PV/T panels using CuO, TiO2, and Al2O3 nanofluids showed that the respective values were 10.98%, 13.92%, 13.65%, and 13.39%. This study contributes to the development of solar energy technology by demonstrating the potential of nanofluid-based cooling devices to improve solar panel performance in hot conditions.

Applications of Graphene Nanoplatelets as Working Fluids in Photovoltaic Thermal Systems: A Review

Applications of Graphene Nanoplatelets as Working Fluids in Photovoltaic Thermal Systems: A Review

Numerical and experimental investigation of a single-body PVT using a variable air volume control algorithm

Photovoltaic thermal (PVT) collectors that can achieve maximum efficiency from solar irradiation can be critical concepts for meeting energy demand in residential applications. Even though there is much research on increasing heat transfer, multifunctional designs that provide homogeneous results are limited. This study explores the production of electricity and hot air from a novel design of a PVT. A new perforated copper plate design has been proposed to achieve maximum efficiency by providing homogeneous cooling in the PVT. Firstly, numerical analysis of this design was performed using Ansys Fluent software, then tested experimentally. The highest and average electrical and thermal efficiency of PVT are obtained as 17.62 %, 15.63 %, and 76.75 %, 43.68 %. In experiments conducted under winter conditions, the maximum temperature value in the PVT was measured as 41.54 °C. Moreover, the payback period of the PVT system was calculated as 6.1 years. The proposed PVT collector can be used as a new model for integrating solar energy in buildings with almost zero energy. Considering the eco-design, this PVT design can contribute net positive carbon, ecological footprint, and green manufacturing.

Performance enhancement of photovoltaic/thermal collector semicircle absorber tubes using nanofluid and NPCM

This experimental measurement examines Photovoltaic/Thermal (PVT) systems with semicircle absorber tubes, focusing on the impact of nanoparticle-enhanced phase change material (NPCM). Four PVT systems are analyzed, all using a standard PV module: a. PVT1: cooled by water; b. PVT2: cooled by water and NPCM; c. PVT3: cooled by nanofluid; d. PVT4: cooled by nanofluid and NPCM.The research evaluates their thermal, electrical, and overall performance and efficiencies at volumetric flow rates of 1–5 LPM under harsh outdoor conditions. The results reveal that the PVT4 system demonstrates the highest efficiency. At a volumetric flow rate of 5 LPM and a surrounding temperature of 47.94 °C, it achieves electrical, thermal, and total efficiencies of 12.70 %, 78.99 %, and 91.83 %, respectively. By enhancing the heat transfer between nanofluids and NPCMs, system cooling is enhanced and thermal efficiency is greatly increased. Additionally, the use of such systems notably reduced the surface temperature, exhibiting a decrease of about 35.09 % compared to the standard PV module while the use of nanofluid cooling only without NPCM caused a reduction of 29.93 % compared to the PV module. Importantly, the PVT4 setup outperforms the unenhanced PV module (PVT3) in overall efficiency by 14.04 %. In this study, PV modules are cooled by a heat exchanger made up of semicircular tubes attached to their backs. The study confirms that a PCM enhanced with nanoparticles performs well in the PVT system when semicircular absorption tubes are used. A significant reduction in surface temperatures is achieved with the use of this heat exchanger, resulting in remarkable thermal efficiency. As a result of this cooling effect, the PV module is more efficient than a traditional solar module in terms of electrical output. This type of system is likely to influence the development of more convenient and efficient solar energy systems. It is possible to use the heat absorbed by PV modules in other ways as well.

Assessment and analysis of polydimethylsiloxane-coated solar photovoltaic panels for cost-efficient solutions

Solar photovoltaic (PV) is a crucial renewable energy source in the fight against carbon dioxide emissions, aligning well with growing energy demands. However, solar PV efficiency naturally degrades over time, primarily due to uncontrollable outdoor factors such as irradiance, humidity, shading, soiling, aging, and temperature. These collectively lead to decreased efficiency in PV systems. Soiling on PV glass surfaces significantly impacts light penetration and subsequently reduces power generation. To combat this, a self-cleaning nano-calcium carbonate coating has been proposed. The effectiveness of this method is compared with a developed solar PV thermal (PV/T) system, evaluating both performance and cost-effectiveness. After six months of outdoor exposure, the coated glass solar PV achieved an efficiency of 7.6%, surpassing bare glass solar PV at 6.0%. Moreover, the coated glass solution boasts exceptional cost-effectiveness, incurring only an annual expense of 17.6 USD per panel compared to the PV/T system of 59.8 USD per panel. These findings highlight the potential of coatings to enhance solar PV performance and economics, particularly in addressing challenging uncontrollable factors like soiling.

Experimental study on the performance of enhanced air-cooled photovoltaic thermal energy-supplied manure treatment technology

Implementing renewable energy technologies for manure treatment to reduce energy consumption and environmental damage is steadily becoming more prevalent. In this work, an air-cooled photovoltaic thermal (PV/T) device was enhanced and constructed to provide energy for bio-composting manure treatment. Experiments were conducted to analyze the performance data such as air supply temperature, energy and exergy efficiency, and mass flow rate. When calculating the mass flow rate of the PV/T-supplied manure treatment technology, factors such as exergy efficiency, and hot air temperature must be considered. The results of the study indicate that the thermal performance of the developed equipment is adequate for manure composting treatment. The thermal exergy efficiencies of the V2, V3, and V4 cases are approximately 1/3 greater than the thermal exergy efficiency of the V1 case, indicating a considerable change in thermal efficiency. The mass flow rate of 0.020 kg/s is determined to be a more suitable set value. Its total exergy efficiency can reach 46.79%, and the apparatus could heat up to 43.63 kg/m2 of compost to begin the bio-composting process. This study lays the groundwork for future research and deployment of PV/T-powered manure treatment devices.

Day-ahead optimal scheduling considering thermal and electrical energy management in smart homes with photovoltaic–thermal systems

The environmental impact on the energy sector has become a significant concern, necessitating the implementation of Home Energy Management Systems (HEMS) to enhance the energy efficiency of buildings, reduce costs and greenhouse gas emissions, and ensure user comfort. This paper presents a novel approach to provide optimal day-ahead energy management plans in smart homes with Photovoltaic/Thermal (PVT) systems, aiming to achieve a balance between energy cost and user comfort. This multi-objective problem employs the Non-dominated Sorting Genetic Algorithm III as the optimization algorithm and the Nonlinear Auto-regressive with External Input to forecast the day-ahead meteorological variables, which serve as inputs to predict the PVT electrical and heat production in the thermal resistance model. The HEMS benefits from the time-of-use tariff due to the flexibility provided by the energy storage from a battery bank and a boiler. Furthermore, it performs a load scheduling for 10 controllable loads based on three feature parameters to characterize occupant behavior. A study case analysis revealed a cost reduction of approximately 66% in the solution close to the knee of the Pareto curve (S3 solution). The environmental impact on the energy sector has become a The PVT heat production was sufficient to meet the thermal demand of the showers. The proposed hybrid battery management model effectively eliminated the export of electricity to the grid, reducing consumption during peak periods and the maximum peak demand.

Parametric optimization for enhancing the electrical performance of hybrid photovoltaic/thermal and thermally regenerative electrochemical cycle system

Globally, the efficient utilization of solar energy has garnered significant attention. A hybrid system of photovoltaic/thermal (PV/T) modules integrated with thermally regenerative electrochemical cycle (TREC), i.e., PV/T-TREC has emerged recently and shows higher efficiency for solar-to-electrical conversion than a standalone PV system. However, there is a trade-off between the electricity generation from PV/T and TREC because the thermal energy from PV/T degrades the efficiency of the PV/T but improves that of TREC. Previous studies have failed to investigate this problem. This study therefore focuses on the key parameters that significantly affect the thermal output of PV/T, i.e., different PV materials, air gaps, heat storage tank volumes, and working fluids to investigate the maximum electrical efficiency of the hybrid system. The mathematical and transient-state numerical models are developed with the validation/refinement from the experiments. The results show that the hybrid system with PV material of cadmium telluride presents the best overall electrical efficiency of 25.37 %. The case of the air gap fosters the solar-to-electrical conversion. The electrical efficiency versus heat storage tank volume shows a convex curve, peaking at 200 L. The nanofluid performs the best. This study may help guide the practical application of such a high-efficiency electricity generation system.

Thermal and electrical performance evaluation of single and double pass photovoltaic-thermal solar collector with cross-flow baffles and varying transparency: A computational analysis

The present work deals with the development of a semi-transparent photovoltaic thermal (PV-T) solar collector (STPVT) through computational fluid dynamics (CFD) modelling using COMSOL Multiphysics. The study was carried out in three stages; firstly, the CFD model was developed for STPVT and validated with experimental data. Secondly, three different configurations of semi-transparent PV-T collector were investigated, i.e., single pass with PV module on top (SPC), double pass with PV module on top followed by glass cover and absorber plate (DPT), and double pass with PV module in between the glass cover and absorber plate (DPS). The absorber plate was incorporated with cross-flow baffles for improved thermal performance due to increased surface area and turbulence. The study found a thermal efficiency of 76.94 % for DPS configuration and a total heat utilisation of 289.63 W at 50 % transparency level, i.e., 2–4 times higher than other configurations. Furthermore, the DPS model was investigated for thermal and electrical performance with different PV module transparency levels (52,42,27,13 %). The DPS with 18 solar cells having 13 % transparency exhibited peak power density (8 %) at 717 W/m2 and 101.89 °C panel temperature, achieving superior thermal efficiency (84 %) and total heat utilisation (315.09 W), surpassing configurations with higher transparency.