Photovoltaic Module Temperature Research Articles

Performance analysis of solar-assisted ground source heat pump in severe cold regions

ABSTRACT Long-term operation of a ground source heat pump (GSHP) in severe cold regions leads to a gradual decrease in subsurface soil temperature, affecting system performance. This paper proposes a solar assisted ground source heat pump (SAGSHP) system consisting of solar photovoltaic thermal (PV/T) and GSHP. Through TRNSYS software, the system was analyzed for 10 years of dynamic simulation in a severe cold region. The results are listed below: (1) The SAGSHP system is capable of effectively lessening the maximal temperature of photovoltaic (PV) modules in Changchun, Shenyang, and Harbin, China, by 21.73%, 13.67%, and 19.10%, respectively. The power generation efficiency of PV modules in these three locations can be maintained at about 22% year-round. (2) After ten years of operation, the coefficients of performance (COP) of the heat pumps have increased by 5.70%, 6.80%, and 5.01%, respectively, relative to the first year, showing good stability. (3) The soil temperatures at all three locations were stabilized during the ten years of operation. This study provides a theoretical basis for devising and installing SAGSHP in severe cold regions.

The efficient strategy of operating the active cooling systems incorporated with photovoltaic panels for the three climatic regions: A case study

ABSTRACT Photovoltaic stations in Algeria are considered an effective solution to overcome the problem of its lack of electrical power and achieve the goals of sustainable development. The weather in Algeria is continental, it has three main climate zones from north to south, and the climate in Algeria is desert, which causes an increase in the temperature of photovoltaic modules and thus a decrease in their production of electrical power. Then the active cooling systems that use water as a cooling medium represent a good option to reduce the PV module temperature and thus increase electrical power generation rates. Due to the change in weather in Algeria from north to south and during the four seasons, in some periods, the operation of cooling systems is ineffective and leads to a decrease in the net output electrical power of photovoltaic stations. Therefore, this manuscript aims to develop an advanced strategy for operating active cooling systems incorporated with PV stations to achieve the highest net electrical power output from PV stations in Algeria. To achieve this goal, the theoretical study was conducted on three different regions in Algeria that express its continental climate, namely, Algiers (36°46′ N, 3°03′ E), northern Algeria, and Djelfa (34°40′ N 3°15′ E) in central Algeria and Ghardaïa (32°29′ N 3°40′ E) in southern Algeria, to get the optimal cooling strategies that achieve the highest net electrical power produced by PV stations. The simulation results presented that the average improvement in the electrical power generated from the PV panels incorporated with active cooling systems reached 15.1%, 17.8%, and 19.7% under the climate conditions of Algiers, Djelfa, and Ghardaïa, respectively. The optimal operating strategies of active cooling systems integrated with PV stations in Algeria increase the average net output electrical power of the PV stations by a rate reached 7.65%, 7.13%, and 4.91% for Algiers, Djelfa, and Ghardaïa, respectively.

Performance Assessment of Hybrid PV/PVT Collectors Incorporating Natural Water-Cooling Circulation

The present work investigates outdoor recitals and characteristics of hybrid PVT collectors and compares using non-cooled Photo-Voltaic (PV) collectors on a clear day at Khamshet, Pune, India. The hybrid PVT is designed, fabricated, and mounted on the terraces of the institute to ensure maximum radiation will fall on PV and PVT collector. The spiral circular thermal absorber is manufactured and placed at the backside of the photovoltaic to lower the surface temperature by extracting heat through water flowing through the absorber. The experimentation is performed at 0.03 kg/sec of water and natural cooling circulation is adopted for experimental work. The uncertainty analysis is also performed to ensure the accuracy of the results. The investigation observed that the PVT collector is superior to the PV system from electrical and thermal efficiency viewpoints. The cutback in PV module temperature was observed in a variation of 8.7-13.7%, which justifies using the water-cooling technique. The maximum electrical and thermal efficiency of 6.93 % and 52.7% were found for PVT collectors while sole maximum electrical efficiency of 5.62 % was found for PV collectors. This study concludes that the PVT collector has better performance characteristics than the PV collector and can be further enhanced using different fluid and thermal absorber designs.

Heat Pipe-Based Cooling Enhancement for Photovoltaic Modules: Experimental and Numerical Investigation

High temperatures in photovoltaic (PV) modules lead to the degradation of electrical efficiency. To address the challenge of reducing the temperature of photovoltaic modules and enhancing their electrical power output efficiency, a simple but efficient photovoltaic cooling system based on heat pipes (PV-HP) is introduced in this study. Through experimental and numerical investigations, this study delves into the temperature characteristics and power output performance of the PV-HP system. Orthogonal tests are conducted to discern the influence of different factors on the PV-HP system. The experimental findings indicate that the performance of the PV-HP system is superior to that of the single system without heat pipes. The numerical simulation shows the effects of system structural parameters (number of heat pipes, angle of heat pipe condensation section) on system temperature and power output performance. The numerical simulation results show that increasing the angle of the heat pipe condensation section and the number of heat pipes leads to a significant drop in system temperature and an increase in the efficiency of the photovoltaic cells.

Analysis of dust deposition law at the micro level and its impact on the annual performance of photovoltaic modules

Solar photovoltaic (PV) power generation is a promising clean energy technology, but dust affects its performance. This study, conducted in nine Chinese cities with varying climates and geographies, analyzed the physicochemical properties of dust and its deposition patterns at different inclination angles using microanalysis. Inclination angles were classified into three categories, and a dust density prediction (DDP) model was developed for each. The study also quantified the effect of different dust densities on PV module temperature in a controlled environment and created a PV module output power prediction (POPP) model to assess dust accumulation impacts on PV efficiency. It was found that dust insulation could increase PV module output power by 1.64 %–1.79 % at dust densities of 5–10 g/m2 and radiation levels of 400–800 W/m2. Combining the DDP and POPP models, a PV efficiency loss rate model was proposed to evaluate annual average PV efficiency and power generation losses at different tilting angles. Results showed an annual average PV efficiency loss of over 7 % at a 15° inclination angle and about 4.5 % at a 90° inclination angle. This study provides a framework for evaluating PV module mounting angles and cleaning intervals, optimizing solar energy systems for improved efficiency and returns.

Accurate short-term GHI forecasting using a novel temporal convolutional network model

Global energy demand is on the rise, driven by factors such as population growth and economic development.Utilizing renewable energy is crucial to meeting this energy demand in light of global warming and the depletion of fossil resources.One of the renewable energy sources that is extensively utilized in multiple countries worldwide is photovoltaic energy.While integrating photovoltaic (PV) energy into the grid offers substantial economic and environmental advantages, its intermittent nature presents challenges to maintaining grid stability at high penetration levels. Accurate solar energy estimations are essential for photovoltaic (PV) based energy facilities to enable early participation in energy markets and efficient resource planning. This study proposes and evaluates a Temporal Convolutional Network (TCN) model that can rapidly predict global horizontal irradiance (GHI) using univariate and multivariate approaches. To our knowledge, this is the first study to employ a TCN model for GHI forecasting. The univariate model solely considers GHI, while the multivariate time series models incorporate a combination of six variables: global horizontal irradiance, active power of a module plant, PV module temperature, wind speed, air temperature, and air pressure. The proposed model’s effectiveness is validated by comparing its performance to benchmark models, including MLP, RNN, GRU, and LSTM. The prediction models’ performance is evaluated using root mean square error (RMSE), coefficient of determination (R2), and mean absolute error (MAE). The results demonstrate that the effectiveness of univariate TCN models is evident in their performance for 5, 10, 15, and 20 min ahead short-term GHI forecasting, its mean absolute error (MAE) values achieved are 22.935 W/m2 33.47 W/m2, 36.9994 W/m2, and 41.9946 W/m2, respectively. The multivariate model, incorporating additional variables, yielded higher MAE values : 37.928 W/m2, 55.88 W/m2, 66.61 W/m2, and 74.82 W/m2, respectively. These results suggest that the TCN model’s capability to capture both long-term and short-term dependencies within the data contributes to its accuracy for GHI forecasting compared to other models.

Detecting clear‐sky periods from photovoltaic power measurements

AbstractA method for detecting clear‐sky periods from photovoltaic (PV) power measurements is presented and validated. It uses five tests dealing with parameters characterizing the connections between the measured PV power and the corresponding clear‐sky power. To estimate clear‐sky PV power, a PV model has been designed using as inputs downwelling shortwave irradiance and its direct and diffuse components received at ground level under clear‐sky conditions as well as reflectivity of the Earth's surface and extraterrestrial irradiance, altogether provided by the McClear service. In addition to McClear products, the PV model requires wind speed and temperature as inputs taken from ECMWF twentieth century reanalysis ERA5 products. The performance of the proposed method has been assessed and validated by visual inspection and compared to two well‐known algorithms identifying clear‐sky periods with broadband global and diffuse irradiance measurements on a horizontal surface. The assessment was carried out at two stations located in Finland offering collocated 1‐min PV power and broadband irradiance measurements. Overall, total agreement ranges between 84% and 97% (depending on the season) in discriminating clear‐sky and cloudy periods with respect to the two well‐known algorithms serving as reference. The disagreement fluctuating between 6% and 15%, depending on the season, primarily occurs while the PV module temperature is adequately high and/or when the sun is close to the horizon with many more interactions between the radiation, the atmosphere and the ground surface.

Improve The Conversion Efficiency and Electrical Output of The Solar PV System by Developing and Implementing a Cooling System

The performance of the grid-connected solar photovoltaic (PV) system in the present study is improved using cooling technology. This technology reduces the temperature of solar PV modules and thus increases their efficiency and lifespan. The current solar PV system has been installed in northern Baghdad in the city of Taji. This study included improving electrical power, conversion efficiency, and performance ratio. All of these improvements are achieved by cooling using water. The performance ratio (PR) and efficiency maximum values of the reference (unimproved) and improved solar PV modules are at 10:10 am at 88.30% & 96.30% and 13.4% & 14.6%, respectively. Improved and reference PV modules maximum solar radiation values occur at 12:00 pm at 1.91 W and 1.566 W, respectively. The maximum solar radiation values of the reference and improved PV modules are at 12:00 pm at 922.9 W/m2 and 1012.22 W/m2, respectively. The maximum daily gain of the power and solar irradiance are 22% and 10%, respectively. The significant innovation in the study is the successful performance optimization of the grid-connected solar PV system. Using different equations to study performance by following different behaviors. Along with improving and studying CIGS PV module performance.

Photovoltaic module temperature prediction using various machine learning algorithms: Performance evaluation

This paper presents data-driven models for photovoltaic module temperature prediction and analyzes the relation and effects of ambient conditions to module temperature. A total of 12 different machine learning and regression algorithms are implemented, with a large experimental dataset of 345,600 × 7. Prior to implementing those algorithms, data preprocessing is performed to prepare the datasets and determine the informative attributes for the models. Using PCA with module temperature as target to predict, the selected features for models' inputs were determined to be ambient temperature, solar radiation, wind speed, and relative humidity, and each algorithm is cross-validated and tuned with optimal performance parameters. Results show that while relative humidity is more likely to introduce less information to the model, other aforementioned features are the important parameters to predict the module temperature. While for linear modeling, LASSO algorithm provided the best performance, the ANN model demonstrated the best overall results as it produced the most accurate predictions with lowest errors. A similar performance is attained by the proposed non-linear model, KRR and Gradient Boosting algorithm, with a slight advantage to the KRR model. Furthermore, in comparison to experimental data, the ANN model and the proposed non-linear model provided an R2 values of 0.986 and 0.981, with a MAE of 0.982 and 1.476, and MSE of 2.181and 3.464, respectively. Moreover, the proposed model supplied accurate results when compared to models from literature in an out-of-sample testing, it also proven to be robust and accurate when used to predict the PV power output.

Al2O3/graphene/PVDF‐HFP radiative cooling coating reinforced heat dissipation of BIPV modules

AbstractBuilding integrated photovoltaic modules, applied to industrial and commercial buildings, generally used metal as the backsheet. In summer, the operating temperature of modules is as high as 70°C, resulting in instability of output power and service life. Therefore, it is very important to reduce the operating temperature of photovoltaic modules. In this work, Al2O3/graphene/poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVDF‐HFP) composite radiative cooling coatings were prepared and utilized for reinforcing heat dissipation of photovoltaic modules. The results indicate that 0.75 wt%Al2O3/1wt%graphene/PVDF‐HFP composite coating exhibited a thermal diffusivity of 3.24 μm2/s and an average emissivity of 0.94. The maximum temperature drop of the coating in the outer door reached 5.8°C. In addition, a mini photovoltaic module coated with the composite coating achieved the cooling effect of 2.4°C, and the output power and conversion efficiency were increased by 5.8% and 7%, respectively. This demonstrates that the heat conduction radiative cooling coating possesses potential applications for improving the reliability of photovoltaic modules.

Enhanced Solar Photovoltaic Power Production Approach for Electric Vehicle Charging Station: Economic and Environmental Aspects

In recent years, Electric Vehicles (EVs) are contributing a major share in Thailand and benefit the environment. Most of the EV charging stations are sourced from solar energy as it becomes a carbon-free source of energy production. Secondly, Thailand is rich in solar irradiance, and higher irradiance leads to higher power production. On the other hand, in tropical conditions, solar Photovoltaic (PV) module temperature increases following the solar irradiance due to high ambient temperature, resulting negative impact on the efficiency and lifespan of photovoltaic (PV) modules. Further, to increase PV power production, in this study, different rates of cooling strategies are proposed. The study found that reducing the temperature by 5% to 25% resulted in increased average power outputs of 5947.94W, 6021.43W, 6094.92W, 6168.41W, and 6241W, respectively. Notably, 25% of the cooling rate achieved higher production. However, it is lower than the nominal power production. Following that, economic analysis and environmental impacts are analyzed for Thailand’s EV charging station using a different cooling rate of PV module. Overall, it is concluded that, depending on the economic viability of the EV charging station, cooling technology can be applied, and it will benefit the EV charging station both economically and environmentally. To further enhance the solar PV power production approach for EV charging stations in Thailand, it is imperative to prioritize future endeavors towards optimizing cooling technology, integrating energy storage, and implementing supportive policies.

Development and improvement of a transient temperature model of PV modules: Concept of trailing data

AbstractThe development of a transient temperature model of photovoltaic (PV) modules is presented in this paper. Currently, there are a few steady‐state temperature models targeted at assessing and predicting the PV module temperature. One of the most commonly used models is the Faiman thermal model. This model is derived from the modified Hottel‐Whillier‐Bliss (HWB) model for flat‐plate solar‐thermal collector under steady‐state conditions and assumes low or no thermal mass in the modules (i.e., short time constants such that transients are neglected, and steady‐state conditions are assumed). The transient extension of the Faiman model we present in this paper introduces a thermal mass, which provides two advantages. First of all, it improves the temperature prediction under dynamic conditions. Second, our transient extension to the Faiman model allows the accurate parametrization of the Faiman model under dynamic conditions. We present our model and parametrization method. Furthermore, we applied the model and parametrization method to a 1‐year data set with 5‐min resolved outdoor module measurements. We demonstrate a significant improvement in temperature prediction for the transient model, especially under dynamic conditions.

DEVELOPMENT OF AN INSTALLATION TO REDUCE THE TEMPERATURE OF PHOTOVOLTAIC MODULES AND IMPROVE THEIR EFFICIENCY

. The main priority in photovoltaic panels is electricity production. The transformation of solar energy into electricity depends on the operating temperature in such a way that the lower the temperature is, the better the performance of the panels is. In the existing literature, different cooling techniques may be found. Most of them propose the use of air or water as thermal energy carriers. This paper is focused on the use of these cooling techniques in photovoltaic panels placed onto the roof of a greenhouse. So, the objective of this study is to ensure a low operating temperature which corrects and reverses the effects produced by high temperature on efficiency.

Experimental investigation of using the evaporative air cooling technique to enhance the performance of the photovoltaic module

Abstract In this experimental study, two techniques of photovoltaic thermal (PVT) collector with active cooling were used to enhance the performance of the photovoltaic (PV) module. The first technique was prepared by integrating the PV module with a forced air duct (PVTFC). At the same time, the second technique was the PV module integrated with a forced air duct including a direct evaporative cooling unit (PVTDEC). In these two techniques, the air was forced by an electrical centrifugal fan with variable speeds (1.5, 2.5 and 3.5 m/s) placed at the end of the duct. The output electrical characteristics of the PVTFC and PVTDEC modules were compared with the reference PV module. The obtained results showed a significant decrease in the temperature of the PV module, where the reduction in the temperature of the PV module was achieved between 5°C and 16°C and 21°C and 25°C in PVTFC and PVTDEC techniques, respectively. Accordingly, the voltage was dropped to 15.1 and 15.8 V in PVTFC and PVTDEC, respectively, as compared with the sharp decline of voltage for the reference PV module, which recorded 14.2 V at a maximum PV module temperature of 69°C. In addition, the maximum enhancement percentage of PV efficiency was achieved at a maximum airflow rate of 0.22 kg/s, where it was recorded between 3.5% and 6.2% in the case of PVTFC and 7% and 9.3% in the case of PVTDEC.

Assimilation of a novel thermal collector and phase change material in photovoltaic/thermal system - An energy and exergy based comparative study

The efficiency of the photovoltaic (PV) panel's solar energy conversion into usable power is significantly influenced by the elevated temperature of the PV cell. The hybrid photovoltaic/thermal (PV/T) system, on the other hand, is not very efficient overall because the collector profile was not chosen correctly and the PV module temperature changes too quickly, limiting its useful life. This research improved the performance of a PV/T hybrid system by employing a novel butterfly-shaped serpentine flow collector and Hydrated Salt (HS36) Phase Change Materials (PCM). The energy and exergy performances of the PV/T, PV/T-PCM systems are evaluated at diverse volume flow rates of water and compared with orthodox uncooled PV modules. The maximum average overall efficiency of the PV/T and PV/T-PCM systems is chronicled as 79.36 % and 94.05 % at 2 lpm water flow rate, respectively. The suggested PV/T and PV/T-PCM systems outclass the reference PV system in terms of total average exergy efficiency by 13.90 % and 23.54 %, respectively. The PV/T system integrated with a novel BSF profile and HS36 PCM showed more efficiency in capturing solar energy. It provides more opportunities for exploring and developing PV/T systems compared to the orthodox PV system.

Wind Velocity and Forced Heat Transfer Model for Photovoltaic Module

This study proposes a computational model to define the wind velocity of the environment on the photovoltaic (PV) module via heat transfer concepts. The effect of the wind velocity and PV module is mostly considered a cooling effect. However, cooling and controlling the PV module temperature leads to the capability to optimize the PV module efficiency. The present study applied a nominal operating cell temperature (NOCT) condition of the PV module as a reference condition to determine the wind velocity and PV module temperature. The obtained model has been examined in contrast to the experimental heat transfer equation and outdoor PV module performance. The results display a remarkable matching of the model with experiments. The model’s novelty defines the PV module temperature in relation to the wind speed, PV module size, and various ambient temperatures that were not included in previous studies. The suggested model could be used in PV module test specification and provide analytical evaluation.

Enhancing solar efficiency around the clock through simultaneous solar energy harvesting and radiative cooling

Despite global urbanization, a significant part of the world's population lacks access to the electrical grid. Photovoltaic (PV) cells offer off-grid electricity but face efficiency challenges and shortened lifespans due to prolonged exposure to high temperatures. While PV cells traditionally generate electricity only during daylight, our innovative system integrates radiative cooling (RC), thermoelectric generators (TE), and phase change materials (PCM). In comprehensive tests, our system effectively lowered the PV module temperature by 15 °C during daylight at 800 W/m2 irradiance. Under a clear night sky, it achieved a remarkable 20 % improvement in power generation (120 mV) compared to previous studies. This advancement positions our system as a continuous power source for sustained electricity generation in off-grid settings, contributing to temperature moderation and extending Photovoltaic module lifespan without compromising efficiency. To optimize performance, we used COMSOL software, analyzing factors like wind speed, ambient temperature, irradiation intensity, and the photovoltaic cell to thermoelectric generator area ratio. Insights from this analysis form the basis for future enhancements and upgrades.

Barriers and variable spacing enhance convective cooling and increase power output in solar PV plants

When the temperature of solar photovoltaic (PV) modules rises, efficiency drops and module degradation accelerates. Thus, it is beneficial to reduce module operating temperatures. Previous studies of solar power plants have illustrated that incoming flow characteristics, turbulent mixing, and array geometry can strongly impact convective cooling, as measured by the convective heat transfer coefficient h. In the fields of heat transfer and plant canopy flow, previous work has shown that system-scale arrangement modifications—e.g., variable spacing, barriers, or windbreaks—can passively alter the flow, enhance turbulent mixing, and influence convection. However, researchers have not yet explored how variable spacing or barriers might enhance convective cooling in solar power plants. Here, high-resolution large-eddy simulations model the air flow and heat transfer through solar power plant arrangements modified with missing modules and barrier walls. We then perform a control volume analysis to evaluate the net heat flux and compute h, which quantifies the influence of these spatial modifications on convective cooling and, thus, module temperature and power output. Installing barrier walls yields the greatest improvements, increasing h by 3.4%, reducing module temperature by an estimated 2.5 °C, and boosting power output by an estimated 1.4% on average. These findings indicate that incorporating variable spacing or barrier-type elements into PV plant designs can reduce module temperature and, thus, improve PV performance and service life.

Energy Analysis of a 20W Solar Photovoltaic Module: A Review

The solar photovoltaic (PV) system generates both electrical and thermal energy from solar radiation. In this paper, an attempt has been made for evaluating electrical output of solar PV panel installed at Ajat Instruments Nigeria Limited, Mokola, Ibadan, Nigeria. Using the first law of thermodynamics, energy/power analysis was performed. The operating and electrical parameters of a PV array include PV module temperature, open-circuit voltage, short-circuit current, fill factor, etc. were used. The reviewed formulas were used for the calculation of the energy/power efficiency of the PV system. Energy/power efficiency was calculated to be approximately 18%. Future studies should focus on modelling the efficiency of the solar panel. More investigation is required to define the optimum efficiency of the solar panel.

Investigation of the performance enhancement of building-integrated photovoltaic system using evaporative porous clay applied in different building's directions

The integration of photovoltaic (PV) modules with building's facades and roofs results in significant reduction in the PV module's efficiency owing to its temperature rising, as well as increasing in the building's indoor thermal gain. Thus, this study proposed cost-effective and eco-friendly passive cooling technique utilizing evaporative porous clay material to minimize the integrated PV module's temperature. An experimentally validated numerical study is being performed using different clay thickness and porosity to estimate the expected enhancement in the thermal and electrical performance of the building-integrated photovoltaic (BIPV) system. The experimental tests were carried out using prototype of small rooms integrated with PV panels installed with a water-saturated porous clay material to validate the presented transient numerical heat and mass transfer model. After that, the proposed system is being compared with another passive cooling mechanism using phase change material (PCM), and the results are then analyzed and compared. The findings showed a maximum reduction of 19.1 °C and 12.8 °C of peak PV temperature when the porous clay and PCM are utilized, while the building's side temperature reduced by around 11.2 °C and 10.9 °C, respectively. Further, porous clay achieved up to 9.8 % improvement in PV system's efficiency, with a maximum water consumption rate reached around 3.35 L/h.m2. Moreover, applying such a porous clay cooling approach resulted in a maximum reduction of 53.8 % in the building's annual thermal load. In the outcomes reported here, porous clay with the least thickness and highest porosity achieved more feasible cooling effects compared with PCM.