Photovoltaic Thermal Collector Research Articles

Combined Physics- and Data-Driven Modeling for the Design and Operation Optimization of an Energy Concept Including a Storage System

The industrial sector accounts for a huge amount of energy- and process-related CO2 emissions. One decarbonization measure is to build an energy concept that provides electricity and heat for industrial processes using a combination of different renewable energy sources, such as photovoltaic, wind turbine, and solar thermal collector systems, integrating also energy conversion power-to-heat components such as heat pumps, electric boilers, and thermal energy storage. The challenge for the industries is the economic aspect of the decarbonization, as industries require a cost-efficient solution. Minimizing cost and emissions together is a complex problem, which requires two major tasks: (I) modeling of components and (II) multi-objective coupled design and operation optimization of the energy concept. The optimal design and capacity of the components and optimal system operation depend majorly on component modeling, which is either physics-driven or data-driven. This paper shows different types of physics- and data-driven modeling of energy components for multi-objective coupled optimization in order to minimize costs and emissions of a specific industrial process as a case study. Several modeling techniques and their influence on the optimization are compared in terms of computational effort, solution accuracy, and optimal capacity of components. The results show that the combination of physics- and data-driven models has a computational time reduction of up to 37% for an energy concept without thermal energy storage and 29% for that with thermal energy storage, both with high-accuracy solutions compared to complete physics-driven models for the considered case study.

Analysis of a PVT-powered multi-effect mechanical vapor compression desalination system at different feed configurations: energy, exergy, and economic aspects

Energy, exergy, environmental, and economic analysis of an externally preheated multi-effect mechanical vapor compression (ME-MVC) desalination system coupled with photovoltaic/thermal (PVT) collectors was conducted.

Active heating of greenhouse integrated semitransparent photovoltaic thermal system with series connected semitransparent photovoltaic thermal air collectors

In order to fulfill the demand for energy and food security, an active heating of a controlled environment greenhouse integrated semitransparent photovoltaic thermal (GiSPVT) system with N-semitransparent photovoltaic thermal (SPVT) air collector for cold climatic conditions has been analyzed in this paper. The proposed SPVT air collectors are connected in series and integrated with GiSPVT. It is used to generate thermal as well as electrical energy to meet the daily requirements of users. Based on the energy balance equation which is a function of design and climatic parameters, an analytical expression for various variable parameters namely plant, room air, and solar cell temperatures have been derived. Numerical computation has been made in Matlab for computing the thermal, electrical, and overall exergy of the proposed system. Based on numerical computation, the following observations have been made: (i) From a thermal point of view, the packing factor (0.5, 0.8) of the semitransparent PV module plays an important role and it must be optimized for maximum thermal heating. (ii) The selection of a number of collector N is an important parameter to generate electrical energy as well as thermal heating of GiSPVT room air in an optimum way.

Energetic and exergetic experimental investigation of a hybrid photovoltaic-thermal solar collector under real weather conditions

Experimental results obtained using a photovoltaic thermal hybrid solar system are presented and discussed. This hybrid combination is an emerging technology that combines photovoltaic panels and solar thermal collectors in one bi-functional component providing both electrical and thermal energy. The main objective of this coupling is to improve the efficiency of the photovoltaic panels by reducing their operating temperatures and recovering the thermal energy they dissipate, using heat transfer fluids (water in the present study). A theoretical analysis of photovoltaic, thermal and photovoltaic thermal hybrid solar systems is presented. Both electrical and thermal performances of the proposed photovoltaic thermal prototype system are evaluated and analyzed under local weather conditions of Essaouira-Morocco (Latitude: 31.51,| Longitude: -9.76). A comparative study in terms of overall energy efficiency of photovoltaic thermal and conventional photovoltaic systems is conducted and discussed. The obtained experimental findings show that, unlike the conventional photovoltaic panel for which the overall efficiency does not exceed 8.22%, the hybrid system makes it possible to achieve a maximum overall efficiency of about 42.72%. The extracted energy?s quality and efficiency are evaluated through the exergy analysis of the proposed photovoltaic thermal system. The electrical and thermal exergy efficiencies recorded for the studied sytem are 9.78% and 3.07%, respectively.

Effect of Thermoelectric Cooling System on the Performance of Photovoltaic-Thermal Collector: A Review

Effect of Thermoelectric Cooling System on the Performance of Photovoltaic-Thermal Collector: A Review

Evaluation of fin configurations for an air-cooled hybrid photovoltaic-thermal solar collector

In this work, the examination of an experimental air-cooled photovoltaic-thermal (PV/T) module is introduced. Two different shapes of fin fixed to the copper absorber plate are examined for the classical unit of an air-cooled PV/T collector. Vertical and louver-shaped fins (with the same surface area) are investigated and thermally evaluated in this study. The experiments aimed to increase the temperature difference between inlet and outlet air to reach high thermal performance. The enhancement result showed that the thermal efficiency of the louver fin unit increased by 48% and 54% compared to the vertical fin and unfinned units, respectively. Thus, louver fins are better than vertical fins with the same surface area.

Evaluating the techno-economic viability of different solar collectors integrated into an adsorption cooling system in tropical climate conditions

The technology and performance of solar adsorption cooling systems have reached maturity, enabling them to meet the growing demand for air conditioning. High upfront and operating costs have, however, hindered the commercial spread of solar adsorption cooling systems. Comparing the solar adsorption cooling system with commercial air conditioners, the solar thermal system offers superior efficiency. In order to enhance the techno-economic potential of solar adsorption cooling in Malaysia, this study developed a combination of analytical and conceptual frameworks in the form of a multilayer computational network to identify the most efficient solar thermal system. TRNSYS, MATLAB, and REFPROP software were used to model and simulate the solar adsorption cooling system. A Particle Swarm Optimization algorithm (PSO) implemented in MATLAB and linked to TRNSYS was then used to determine the optimal components and variables for each solar thermal system. To determine the most efficient solar thermal system, a techno-economic assessment was conducted to evaluate the solar adsorption cooling system incorporating optimized solar thermal systems. The findings reveal that among the various types of collectors investigated, the evacuated tube collectors demonstrated the highest efficiency in providing the necessary heat energy for the adsorption cooling system. In contrast, the linear Fresnel reflector collector and parabolic trough collectors display exceptional performance, mainly under clear sky conditions. Meanwhile, the photovoltaic-thermal collectors exhibit the greatest energy-saving and techno-economic potential. This advantage arises from their ability to simultaneously generate power and heat, taking advantage of the cost disparity between electricity and natural gas in Malaysia.

Design and Performance Analysis of an Air-Based Photovoltaic/Thermal Collector in Winter

The most basic needs of the buildings in which we spend almost all of our time are electricity and heat demands. Especially in cold climatic regions, it is very important that both electrical energy and heating energy demand are met through the same system. The use of photovoltaic (PV), is increasing rapidly. Photovoltaic panels can transform solar energy into electrical energy with less than 20% performance. Photovoltaic-thermal(PV/T) collectors which can be mounted on facades of buildings or used as building envelopes, are one of the solar energy applications. With this collector, both electric energy and thermal energy demand is produced from solar energy. In our work, Photovoltaic panel and some kind of solar air collector have been taken into consideration. In order to determine the behavior of the air-based photovoltaic-thermal collector, an experimental setup and a measurement system have been established. The experimental setup consists of this measurement system, sensors that obtain data, and a data storage unit that can transmit temperature, humidity, and radiation data to the computer at the desired frequency. In order to determine the performance of the air-based PV/T collector, the efficiencies of both the PV and the solar air collector were calculated separately. To determine the performance of this collector, calculation criteria’s and model has been determined. When creating this model, the problem has been considered as time-dependent under irregular conditions. The theoretical analysis model, which was established to determine the performance of the air-based PV/T collector, was evaluated according to the winter climatic conditions of Izmir-Turkey.

Design and performance optimization of a novel zigzag channeled solar photovoltaic thermal system: Numerical investigation and parametric analysis

In order to overcome the drawbacks of traditional photovoltaic thermal systems, including their limited thermal power, low thermal exergy, and heat transfer fluid outlet temperature, it becomes essential to explore the optimal design configuration of the system for maximization both electricity and domestic hot water generation. Therefore, a detailed numerical modeling and comparative performance analysis on a solar photovoltaic thermal collector (PVT) are conducted under two novel structures of the cooling channels. The first system is a reference PVT collector with a classical straight zigzag-plated tube cooling channel (Case A), while the second PVT system proposes an innovative design of flow cooling channel which is divided into three equal zigzag-plated tube sections (Case B). Each section is also split into three double pass tubes and has a separate inlet and outlet in a staggered manner corresponding to the section that precedes and follows it. The two proposed PVT structures are investigated through computational fluid dynamic simulation under solar radiation values ranging from 200 to 1000 W/m2 and coolant flow rates varying between 0.001 and 0.005 kg/s using both water and air as coolant. The obtained results confirm the significant potential of the modified configuration (Case B) that yielded an improvement in the thermal efficiency by 7.23% and 15.75% for water-PVT and air-PVT system, respectively, over the reference PVT system (Case A). Also, the modified configuration (Case B) yielded an enhancement in the electrical efficiency by 4.0% and 4.6% for water-PVT and air-PVT systems, respectively. It can be concluded that dividing the cooling channel area into equally mini zigzag plate tube-shaped sections with multiple reciprocal entrances is regarded a feasible configuration for augmenting the performance of PVT collectors and maintaining a uniform coolant flow and reduced temperature distribution over the entire panel.

Venturi effect-based simulation of air-based PVT optimization

ABSTRACT Air-based photovoltaic thermal(PVT) solar collectors can convert solar energy into both electrical and thermal energy. However, the output efficiency was often low due to the limitation of the heat transfer capacity for air. Therefore, in this paper, an air-based PVT with the application of a novel rib was modeled and numerically simulated. The innovation of this paper was proposing a novel rib, which was based on the Venturi effect. First, the effects of the new rib control parameters on the performance of the PVT system were analyzed using orthogonal design tests. The result showed that the thermal efficiency of the best factors combination test was 51.16% when the solar radiation was 500 W / m 2 and the air inlet rate was 0.09 m / s . Second, analyzing the fluid flow characteristics and the enhanced heat transfer mechanism, this study found that the increased air velocity under the novel rib and the low-velocity vortex formed between the rib both negatively affected heat transfer. Consequently, this paper proposed a novel fin design coupled with curved fins to address the issues with the novel rib design, which achieved 55.12% thermal efficiency with the combination structure. Finally, we applied the combined structure to the PVT system, studied its thermal efficiency under real-world conditions, and compared it with the empty channel collector. The results showed significant improvement, with a 16.38% increase in thermal efficiency and the model exhibited excellent, stable performance.

Optimizing solar energy for wood drying under various climates: A comparative study of flat plate and photovoltaic thermal solar collectors

Wood drying is an important operation in many sectors, and harnessing solar energy for this purpose has received a lot of interest due to its sustainability and cost-effectiveness. In this work, we compare how two solar collector configurations namely, Flat Plate Collector and Photovoltaic Thermal collector, perform in a solar wood drying system. The moisture content of wood was reduced from 73% to 12% in four different regions: Errachidia, Meknes, Tangier, and Rabat. The Gauss–Seidel method is used to solve the governing equations for heat transfer after discretizing them via implicit finite differences. The effectiveness of the solar collectors was simulated through the TRNSYS software, and a numerical program was generated using the Python programming language. According to our research, the FPC beats the PVT collector because of its higher output temperatures dramatically shorten the time it takes for wood to dry. The study emphasizes how temperature and humidity affect drying, showing that faster drying occurs in hotter, drier locations. Furthermore, drying time can be saved by using FPC and PVT collectors compared to conventional open sun drying.The primary conclusions of this research are: In the FPC solar dryer, the drying time needed in Errachidia, Meknes, Rabat and Tangier was 144 h, 162 h and 171 h, respectively. While in the PVT solar dryer, it required 162 h in Errachidia, 171 h in Meknes, 180 h in Rabat and 189 h in Tangier. Further, the FPC collectors showed a range of 293 K to 347 K for the outlet temperature. The PVT collectors, however, showed a variable range between 295.9 K and 320 K. The drying periods and temperature ranges examined revealed that Errachidia was the most advantageous location, regardless of whether FPC or PVT collectors were used. In fact, the drying time that can be saved by using FPC is 41% while PVT is 31% compared to traditional open sun drying.

Numerical examination of exergy performance of a hybrid solar system equipped with a sheet-and-sinusoidal tube collector: Developing a predictive function using artificial neural network

Integrating cooling systems with photovoltaic-thermal (PVT) collectors has the potential to mitigate the exergy consumption in the building sector due to their capability for simultaneous power and thermal energy generation. The simultaneous utilization of nanofluid and geometry modification resulted in a synergetic enhancement in the performance of PVTs and thereby reducing their sizes and costs. In addition, there is still a lack of high accurate predictive model for the estimation of the performance of PVTs at a given Re number and nanofluid concentration ratio to be used in engineering design for the further product commercialization. To this end, the current numerical study investigates the exergy electricity, thermal, and overall exergies of a building-integrated photovoltaic thermal (BIPVT) solar collector with Al2O3/water coolant. The increase in nanoparticle concentration (ω) from 0 % to 1 % increased the useful thermal exergy and overall exergy efficiency (Exu,t/ Υov) by 0.3999 %/0.0497 %, 1.3959 %/0.2598 %, and 0.7489 %/0.1771 % at Re numbers of 500, 1000, and 1500, respectively, while Exu,t/ Υov exhibited a reducing trend at Re = 2000; 0.3928 %/0.1056 % decrease. In addition, the increase in ω from 0 % to 1 % caused the useful electricity and electrical exergy (Exu,e/ Υe) to be diminished by 0.0060 %/0.0025 % at Res 500 and 1000, and to be escalated by 0.0113 %/0.0055 % at Res of 1500 and 2000. Meanwhile, the Re augmentation, from 500 to 2000, improved the Exu,t, Exe, Υe, and Υov by 60 %, 1.26 %, 1.26 %, and 17.50 %, respectively, at different ω s. In addition, two functions were developed and proposed by applying a group method of data handling-type neural network (GMDH-ANN) to forecast the value of Υov based on two input values (Re and ω). The results showed high accuracy of the proposed model with MSE, EMSE, and R2 of 0.0138, 0.1143, and 0.99785, respectively.

Performance Simulation of PVT System Using TRNSYS for Varying Mass Flow Rates

Solar collector hybrids called photovoltaic thermal (PVT) collectors use solar energy to produce both electrical and thermal energy. System simulations are widely used as a first stage before testing in real-world applications to discover the best solutions and new applications for PVT collectors. Therefore, the construction of well-validated PVT collector models is a vital effort at this time. In this paper, the authors validated the experimental data with the simulation results obtained from TRNSYS software under similar conditions. The analysis was carried out with water as the working fluid, and at different mass flow rates for PVT collectors for varying operating conditions during the day. The authors compared outlet water temperature values from the PVT collector obtained through experiments and simulation. The minimum and maximum deviation of estimated outlet water temperature from the simulation is -3% to 8% respectively for different mass flow rates.

Energy and exergy analysis of photovoltaic thermal collectors: Comprehensive investigation of operating parameters in different dynamic models

The comparative analysis of a transient two-dimensional model and a lumped parameter model for photovoltaic thermal (PV/T) devices were presented, focusing on the energy and exergy performance under different operating conditions. The lumped parameter model involves the effective heat capacity for solar collectors and a zero-dimensional dynamic model for the calculation of the heat transfer coefficient. The study established both models and examines their differences in temperature distribution and computational results. Results indicate that the lumped parameter model, considering computational efficiency and simplified processes, serves as an effective tool for evaluating PV/T device performance, with a maximum relative error of 3.51 % in calculated results. Additionally, the impact of irradiance and flow rate on energy efficiency and exergy efficiency was investigated. After mass flow reaching 0.02 kg/m2/s, the thermal efficiency is 50.15 %, reaching a stable state. The research highlights the significant influence of operating conditions on the overall performance of PV/T collectors. The exergetic flow distribution of PV/T collector was obtained, with an overall exergy efficiency of 13.13%–14.96 % in different operation, and the research further analyzed the causes of exergy loss of PV/T collectors and possible improvement directions. The findings contribute to advancing the understanding and optimization of PV/T systems for enhanced energy conversion and exergy utilization.

Enhanced performance of photovoltaic thermal module and solar thermal flat plate collector connected in series through integration with phase change materials: A comparative study

The decline in photovoltaic cell efficiency due to temperature elevation, coupled with solar energy's inherent intermittency, presents challenges for solar systems, including photovoltaic panels and solar thermal (ST) collectors. The integration of phase change materials (PCMs) emerges as a promising solution to enhance thermal energy storage and regulation, thereby improving system performance and sustainability. This study investigates the performance of series-connected photovoltaic thermal (PVT) and ST systems with integrated PCMs from energy and exergy viewpoints, utilizing a 3D transient numerical simulation. The proposed system's performance is compared with that lacking a PCM across various heat transfer fluid mass flow rates. Suitable PCM selection based on melting temperature is explored, along with PCM layer thickness and nanoparticle augmentation. The research highlights that PCM integration effectively regulates PV cell temperature, enhancing electrical power and exergy rate. While increasing the mass flow rate improves thermal and electrical power, it reduces the thermal exergy rate. Comparing different PCMs (RT28 HC, RT35 HC, and RT44 HC), the RT28 HC PCM provides the lowest temperature of PV cells and the best electrical performance during the day. Moreover, increasing PCM layer thickness results in lowering PV cell and outlet temperatures and storing more heat. Nanoparticles added to PCMs lead to a marginal improvement in energy and exergy, especially for the system with RT28 HC. This analysis emphasizes PCM integration's role in enhancing solar thermal system performance, highlighting the importance of considering the PCM's melting temperature for effective thermal energy management.

Optimal evaluation of photovoltaic-thermal solar collectors cooling using a half-tube of different diameters and lengths

Photovoltaic Thermal Solar Collectors (PVTs) combine the advantages of photovoltaic (PV) and solar thermal collectors to produce electricity and heat simultaneously. This study proposes a numerical model to investigate the effectiveness of using half-circular tubes to improve thermal conductivity and increase the interaction area between PV panels and tubes. This enhances heat transfer from the PV panels to the working fluid (water) circulating through the thermal absorber. Additionally, the integration of phase change material (PCM) is explored to further boost thermal conductivity and generate hot water. The research focuses on modeling the cooling of solar PV panels using copper half-tubes. The PV panels measure 870 × 665 × 3 mm and generate a power output of 100 W. The study examines the impact of key variables such as tube diameter (three standard sizes: 10, 12, and 15 mm) and fluid flow rate (0.008 to 0.04 kg/s). Solar radiation equations are incorporated, and the finite volume approach, implemented in the ANSYS 19.0 software's CFX modeling framework, is used as the underlying methodology. The investigation culminates in an optimization process to determine the optimal operating conditions for the PV system. The results show that the highest electrical efficiency (13.15%) is achieved at a flow rate of 0.04 kg/s for 15 mm diameter tubes and 7 tubes in total. The peak thermal efficiency (74.28%) is observed under the same conditions. In conclusion, this study contributes to the understanding of enhancing PV/T system performance through innovative thermal management strategies and provides valuable optimization recommendations for achieving improved electrical and thermal efficiencies.

A non-dominated sorting genetic algorithm III using competition crossover and opposition-based learning for the optimal dispatch of the combined cooling, heating, and power system with photovoltaic thermal collector

A photovoltaic thermal collector (PV/T) is incorporated into the combined cooling, heating, and power (CCHP) system to decrease primary energy consumption, operation cost and carbon dioxide emission. Six CCHP scenarios based on three strategies are investigated for the energy utilization of the CCHP system. Also, a non-dominated sorting genetic algorithm III using competition crossover and opposition-based learning (NSGA-III-CO) is proposed for the six scenarios. The competition crossover determines the starting point of search in the decision space, and more potential regions can be exploited sufficiently. The opposition-based learning (OBL) carries out random searches and facilitates the convergence of the population. In addition, a constraint handling approach (CHA) is presented to decrease the constraint violations of the infeasible individuals and turn them into feasible individuals, and it guarantees the feasibility of the population. Experimental results suggest that each CCHP scenario with PV/T is more efficient than the one with photovoltaic panel (PV) and the one neglecting PV/T and PV, and it achieves the lowest primary energy consumption, operation cost and carbon dioxide emission. Also, NSGA-III-CO and the other three algorithms are applied to the six CCHP scenarios with PV/T, and it obtains the highest hypervolume and coverage rate for each scenario.

The effect of a reversed circular jet impingement on A bifacial module PVT collector energy performance

Photovoltaic thermal (PVT) technologies have a significant downside in addition to their numerous advantages. PVT technologies are constrained by the fact that its photovoltaic module gains heat due to exposure to solar irradiance, which reduces the photovoltaic efficiency. Jet impingement is one of the most effective methods to cool a photovoltaic module. An indoor experiment using a solar simulator was conducted on a bifacial PVT solar collector cooled by a reversed circular flow jet impingement (RCFJI) to evaluate the energy performance of the PVT collector. The study was conducted under a constant solar irradiance of 900W/m2 and flowrate (mass) ranging from 0.01 to 0.14 kg/s. Three bifacial modules with 0.22, 0.33, and 0.66 packing factors were mounted 25 mm above the RCFJI for cooling. The 0.66 packing factor module recorded the highest photovoltaic efficiency of 10.91 % at 0.14 kg/s flowrate (mass). Meanwhile, the 0.22 and 0.33 packing factors recorded a photovoltaic efficiency of 4.50 % and 6.45 %, respectively. The highest thermal efficiency recorded under the same operating condition was 61.43 %, using a 0.66 packing factor. Overall, the highest combined photovoltaic thermal (PVT) efficiency for 0.22, 0.33, and 0.66 was 56.62 %, 61.88 %, and 72.35 %, respectively.

Solar-Powered Adsorption-Based Multi-Generation System Working under the Climate Conditions of GCC Countries: Theoretical Investigation

In this study, transient modelling for a solar-powered adsorption-based multi-generation system working under the climatic conditions of the Gulf Cooperation Council (GCC) countries is conducted. Three cities are selected for this study: Sharjah in the United Arab Emirates, Riyadh in Saudi Arabia, and Kuwait City in Kuwait. The system comprises (i) evacuated tube solar collectors (ETCs), (ii) photovoltaic-thermal (PVT) solar collectors, and (iii) a single-stage double-bed silica gel/water-based adsorption chiller for cooling purposes. A MATLAB code is developed and implemented to theoretically investigate the performance of the proposed system. The main findings of this study indicate that among the selected cities, based on the proposed systems and the operating conditions, Riyadh has the highest cooling capacity of 10.4 kW, followed by Kuwait City, then Sharjah. As for the coefficient of performance (COP), Kuwait City demonstrates the highest value of 0.47. The electricity generated by the proposed system in Riyadh, Kuwait City, and Sharjah is 31.65, 31.3, and 30.24 kWh/day, respectively. Furthermore, the theoretical results show that at 18:00, the overall efficiency of the proposed system reaches about 0.64 because of the inclusion of a storage tank and its feeding for the adsorption chiller. This study analyzes the feasibility of using a combination of ETCs and PVT collectors to drive the adsorption chiller system and produce electricity in challenging weather conditions.

Performance investigation of a hybrid PV/T collector with a novel trapezoidal fluid channel

The photovoltaic-thermal collector (PV/T) is an innovative technology that combines PV cells and solar thermal collectors into a co-generation unit, enabling full-spectrum solar utilization. This research proposes and examines a hybrid PV/T system with novel trapezoidal fluid channels embedded in graphite, arranged in a parallel S-shaped structure under outdoor conditions of Beijing. Parametric discussions and daily performance analysis are conducted to assess its effectiveness and stability. A daily average of 12.7 °C reduction in cell temperature compared to PV modules results in a relative 5.20 % improvement in electrical output under the intensity of solar radiation is 597 W/m2. Similarly, the peak temperature of the water tank reaches 56.9 °C, and thermal efficiency is enhanced by 7.86 % over conventional sheet-tube PV/T collectors. For further optimization, a constrained adaptive particle swarm optimization algorithm (EPF-APSO) is constructed based on the experimental data, implementing a variable water flow rate (VWV) strategy. Compared to a constant water flow rate (CWV), the overall energy collected varies from 2.755 to 2.828 kWh per day, potentially reducing pump energy consumption by 17.93 %. The contribution of this paper provides references on structural and operational parameters optimization of PV/T collectors applying machine learning algorithms for better comprehensive efficiency.