Temperature Of Photovoltaic Panel Research Articles

Performance analysis of photovoltaic panel using machine learning method

Demand for energy is increasing as the world’s population grows, fossil fuels deplete on a daily basis, and climate conditions change. Renewable energy is more important than ever. Solar energy is the most accessible and cost-effective renewable energy source available today. Photovoltaic (PV) cells are the most promising way to convert solar energy into electricity. Wind speed, ambient temperature, incident radiation rate, and dust deposition are some of the internal and external variables that affect photovoltaic panel performance. Unwanted heat from the sun’s rays raises panel temperatures, reduces the amount of energy that solar cells can produce, and lowers conversion efficiency. Solar panels must be adequately cooled. The current research is focused on improving photovoltaic panel performance. The experimental system includes a fully automated photovoltaic panel, a microcontroller (NodeMCU8266), a DC pump, voltage and temperature sensors. The experiment was carried out with and without cooling of the PV panel. The findings suggest that keeping PV panel temperatures close to ambient temperatures improves performance. The Wi-Fi module collects real-time data on PV panel temperature, irradiation, ambient temperature, water temperature, and PV panel power output. The collected data was analyzed using machine learning. The PV panel’s performance was analyzed using the linear regression method.

A novel concentrated photovoltaic and ionic thermocells hybrid system for full-spectrum solar cascade utilization

Concentrated photovoltaic-thermoelectric generator (CPV-TEG) hybrid system can harvest the low-grade waste heat derived from photovoltaic cells to generate more electric energy. However, it is economically unfeasible due to the expensive cost of thermoelectric generators and higher photovoltaics temperature. Ionic thermocell based on thermogalvanic effect has a more inexpensive cost and ionic Seebeck coefficient of 1– 2 orders of magnitude higher than thermoelectric generators, which is promising for full-spectrum solar cascade utilization. In present work, a novel concentrated photovoltaic and ionic thermocells hybrid system (CPV-iTEC) is reported, aiming to comprehensively evaluate its feasibility. The ionic thermocell adhered directly to the photovoltaic panel consists the π-type multi-channels, electrodes and p/n-type redox electrolytes flowing in multi-channels, which can simultaneously cool photovoltaic panel and output electric energy for waste heat harvesting. A three-dimensional numerical model is proposed and validated by preliminary experiment to investigate the effects of structural and operating parameters on the performance of CPV-iTEC during energy, exergy and economic analyses. Results show that the optimal structural parameters of ionic thermocell are the 2 mm channel height and 1 mm width, showing a 7.18% higher energy efficiency than that of CPV-TEG at 10 concentration ratios. The presence of ionic thermocell can significantly decrease the photovoltaic panel temperature from 351.30 K to 325.14 K, and thus broaden the available concentration ratio from 1– 21 to 1– 39 compared with CPV-TEG, reaching a higher output power of 16.61 W. During the optimization of advanced redox electrolytes/electrodes, the energy efficiency can reach 49.63% at 21 concentration ratios, which is 5.06% higher than that of CPV-TEG, and show a 22.65% lower overall cost. The application of ionic thermocell in the full-spectrum solar cascade utilization of concentrated photovoltaic system is proved to be feasible with significant advantages of low cost, high performance, and flexible operation.

Enhancing Heat Transfer of Photovoltaic Panels with Fins

Photovoltaic power generation can directly convert solar energy into electricity, but most of the solar energy absorbed by the photovoltaic panel is converted into heat, which significantly increases the operating temperature leading to a reduction in the power generation efficiency of the panels. To reduce the working temperature of photovoltaic panels and improve the photoelectric conversion efficiency, this paper installs aluminum fins and air channels at the traditional photovoltaic cell back sheets and cools them with forced-circulation cooling through fans. The relationships between fin spacing, fin height, air channel inlet wind speed and panel temperature, power generation, and electrical efficiency were investigated. The results show that the temperature of the photovoltaic panel decreases and then increases with the decrease of the fin spacing during natural convection and gradually decreases with the increase of the fin height. The use of forced-circulation cooling technology can effectively reduce the PV panel temperature and increase the net power generation. When the solar radiation intensity is 1000 W/m2, the ambient temperature is 35°C, the fin spacing is 6 mm, the height is 80 mm, the inlet wind speed is 1 m/s, the net generating power reaches the maximum value, and the net generating power and the electrical efficiency are increased by 14.6% and 2.25%, respectively.

Numerical modeling and optimization of tube flattening impacts on the cooling performance of the photovoltaic thermal system integrated with phase change material

In this research, a computational fluid dynamics-based numerical simulation is performed to evaluate the influence of tube flattening on the cooling performance of a photovoltaic thermal system integrated with phase change material. Such a study is executed to obtain the four evaluation parameters, including average photovoltaic panel temperature, phase change material melting percentage, tube pressure drops, and the difference between the highest and lowest temperature points on the photovoltaic panel. To obtain the optimum percentage of tube flattening to optimize the cooling performance of the systems, multi-objective optimization by utilizing response surface methodology is done by considering some design requirements, including minimizing average photovoltaic panel temperature, maximizing phase change material melting percentage, minimizing tube pressure drops, and minimizing the difference between the highest and lowest temperature points on the photovoltaic panel. Finally, a parametric analysis is done to explore how certain critical factors (solar radiation, fluid mass flow rate, phase change material thermal conductivity, phase change material enthalpy of fusion, and phase change material melting point) affect the efficiency of the systems. The findings indicate that as tube flattening rises from 0 % to 75 %, the average photovoltaic panel temperature and the difference between the highest and lowest temperature points on the photovoltaic panel decrease which is a positive effect. Conversely, increasing the tube flattening results in an increase in the tube pressure drops and a reduction in the phase change material melting percentage. These changes adversely affect the cooling performance. Considering these impacts and conducting an optimization process, the ideal tube flattening value is 54.78 %. In this optimized state, the average photovoltaic panel temperature reaches 55.21 ˚C, phase change material melting percentage comprises 42.54 %, tube pressure drops is 184.8 Pa, and the difference between the highest and lowest temperature points on the photovoltaic panel is 33.42 ˚C.

An evaluation of the use of air cooling to enhance photovoltaic performance

The rapid rise in global energy consumption and its consequences on climate change has made incorporating renewable energy sources like solar photovoltaics into the building envelope easier. However, in spite of extensive uses and significant technological advances, the lower solar panel efficiencies caused by high temperatures remain a significant barrier to the viability of deploying photovoltaic technology in regions with hot climates utilizing computational fluid dynamics (CFD). This research examines the cooling effectiveness of air-cooled photovoltaic (PV) under the climate of Nablus - Palestine. This study presents a numerical model designed to cool solar panels using various air-cooled channel configurations. Rectangular fins made of high thermal conductivity materials such as copper were used in this study. The parametric study was based on the changing baseplate thickness, fin spacing, height, and thickness through a stepwise optimization process to enhance the heat transfer mechanism. The results show that the optimum design of average volume temperatures for the PV cell models in air-cooled channel configurations with and without fins were 40.28 °C and 42.58 °C, respectively. The optimum design was obtained at 3, 110, 60, and 4 mm for baseplate thickness, fin spacing, height, and thickness, respectively. This optimum design was responsible for the average PV panel temperature drop by 1.6 %, 1.3 %, 5.9 %, and 6.2 % for baseplate thickness, fin spacing, height, and thickness, respectively. The optimum design of an air-cooled cooling channel for PV is an important insight provided by this work, and it may help in the future development of more effective and affordable cooling methods.

Photovoltaic passive cooling via water vapor sorption-evaporation by hydrogel

Photovoltaic (PV) power generation, which converts sunlight into electricity, stands as a pivotal mode of solar energy utilization. The thermal effect poses a significant challenge for all types of PV panels under real operating conditions, as it diminishes both the photovoltaic conversion efficiency and the lifespan of the PV panels. This paper presents a novel passive cooling approach for silicon-based photovoltaic panels, employing night-time hygroscopic hydrogel adsorption, daytime desorption, and subsequent water evaporation for cooling. Both laboratory and outdoor experiments were conducted to validate this strategy. Experimental results reveal that under simulated laboratory light of 1 kW m−2, the hydrogel cooling layer delivers an average cooling power of 288.2 W m−2. It lowers the PV panel temperature by 9.9 °C and enhances both the maximum power and efficiency at equilibrium by 5.92% and 5.93%, respectively. Outdoor experiments in Beijing, China, during summer demonstrated that this method reduced the average daytime temperature of the PV plate by 7.1 °C and increased the average maximum power by 5.21%. The hydrogel layer's high hygroscopicity enables it to support passive cooling effectively all day. Passive cooling strategies for PV panels, leveraging the atmospheric water harvesting cycle, face fewer application constraints. They offer the potential to increase power generation and reduce CO2 emissions from PV plants both now and in the future.

Effect of dust accumulation on the performance of photovoltaic modules for different climate regions

In the past decade, solar photovoltaic (PV) modules have emerged as promising energy sources worldwide. The only limitation associated with PV modules is the efficiency with which they can generate electricity. The dust is the prime ingredient whose accumulation on the surface of PV impacts negatively over its efficiency at a greater rate. This research aims to explore the effects of dust accumulation on the energy output and operating temperature of polycrystalline silicon PV panels situated in two different climatic regions of Pakistan, i.e., Islamabad and Bahawalpur. In both the regions, one PV module is kept in ambient environment for six weeks to allow dust to deposit over its surface and perform experimental analysis with one clean module as reference for performance comparison. After six weeks of atmospheric exposure, dusty modules displayed significantly smaller efficiency as a function of different dust densities in the two regions. Dust samples from both cities are collected and analyzed to evaluate their structural attributes and composition. The PV module in Islamabad region had a dust layer over its surface with a density of 6.388 g/m2 and its efficiency was reduced by 15.08%. In Bahawalpur region, the dust density was observed to be 10.254 g/m2 which caused the output power to be slashed by 25.42%. Temperature analysis of modules shows that dust increases their temperatures which is also a quantity responsible for lower PV power generation with same amount of irradiance. The research findings are crucial for determining and predicting PV power degradation in two different atmospheres and determining the schedule of cleaning cycle.

A new real-time maximum power point tracking scheme for PV-BASED microgrid STABILITY using online DEEP ridge extreme learning machine algorithm

A new deep representation-based Maximum Power Point Tracking (MPPT) controller is proposed in this paper for accurate Control references calculation in Photovoltaic (PV) based Micro Grid (MG) operation. The deep representation is obtained by two-step estimation: Data dimension reduction and MPPT Tracker towards optimal computation. The considered deep learning architecture is targeted for N number (large scale) of PV-based DGs, connected locally in the distribution system (DC link extended to AC utility). The collected data of solar irradiation (in W/m2) and PV panel temperature (in oC) profiles of local DGs are subjected to data dimensions using Extreme Learning Machine (ELM) based on Moore-Penrose inverse technique. The compressed represented PV-DG data is further communicated to the Tertiary Control side MPPT Tracker, where Ridge Regression-based ELM is presented for estimating Maximum Power Point Power (PMPP) and Voltage (VMPP) values for kth instant. The initial randomness present in the proposed Deep Representation based Ridge Regression Extreme Learning Machine (DR-RRELM) is further minimized by adopting Huber's characteristic distribution-based likelihood estimator. The proposed MPPT scheme is effectively implemented for accurate control reference in DC-DC and DC-AC converters in the MG. The proposed controller is also suitable for stability improvement at point of common coupling (PCC). Three different case studies such as past data verification, stability analysis under various operating conditions, irradiant change and source power variation. The efficacy of the proposed deep representation-based MPPT scheme is evidenced in MATLAB-based simulation. The proposed technique provides better tracking ability, faster learning and effective reference generation. The case study with irradiation change is validated in TMS320C6713 (32-bit) based Hardware-in-Loop (HIL) validation.

Research on the Passive Cooling System of Solar Photovoltaic Panel Based on Hybrid Solar Chimney and Ventilator

The efficiency of solar photovoltaic (PV) power generation is significantly impacted by factors such as ambient temperature, surrounding wind speed, and the temperature of the solar PV panels. The power generation efficiency of these panels diminishes by approximately 0.5% for each incremental rise in their temperature. To mitigate this effect, two primary methods for cooling solar photovoltaic panels are considered: active and passive cooling techniques. This review paper delves into an extensive body of literature on solar passive cooling systems, highlighting the vital role of passive cooling technology in enhancing the efficiency of solar PV power generation. We investigate the structure and cooling effect of diverse passive cooling systems, with a specific focus on the application of solar chimneys and ventilators in cooling systems for solar PV panels. Our study reveals that solar chimneys, using buoyancy, can decrease the temperature of solar PV panels by as much as 15 degrees, thereby augmenting power generation efficiency. Furthermore, the deployment of ventilator technology can boost the efficiency of solar PV power generation to an impressive 46.54%. In conclusion, this paper proposes the synergistic use of solar chimneys and ventilators to improve solar PV panel efficiency, extend their lifespan, and reduce the environmental impact resulting from inefficient solar PV panels. This comprehensive approach should inform future practices.

Experimental investigation of Different types of Dust effect on the Grid-connected Rooftop Solar Power Plant

ABSTRACT The accumulation of dust and dirt not only reduces the power output of the solar power plant but also reduces the performance ratio, efficiency, and energy generation (kWh). In this paper, a 100-kWsolar power plant was selected for the experiment. Firstly, string identification and selection were done to find out the strings for the experiment. A total of 5 strings were selected for the experiment and there were 19 photovoltaic panels were connected to each string. Sand, Cement, Talcum powder, and dry leaves were deposited on string-1, string-2, string-3, string-6, and string-7 as reference strings. This paper investigates the performance of these materials on the operating voltage, DC current, power, energy (kWh), performance ratio, and efficiency. However, the impact of these materials on the photovoltaic panel temperature was also investigated. It was calculated that the output power of the photovoltaic panel string-2 (cement), string-3 (Talcum powder), string-1 (sand), and string-6 (Dry leaves) was reduced by 81.4%,53.4%, 9.8%, and 0.9% compared to the reference string and minimum photovoltaic panel temperature was observed in the case of Talcum powder. After completion of the experiment, the selected string was manually cleaned with water and it was observed that sand and trash of dry leaves were easily cleaned by water but Cement and talcum powder needs high-pressure water and wiping with a microfiber cloth to prevent these substances from the surface of the photovoltaic panels. Also, some future studies are suggested in the end section of the research paper.

Evaluating the impacts of fin structures and fin counts on photovoltaic panels integrated with phase change material

Metal fins synergized with phase change materials (PCMs) provide good thermal management for photovoltaic (PV) panels, and the performances largely depend on the shapes and counts of the fins, and the layouts of the cavity. This work first compares the thermal behaviors of one fractal fin or one straight fin in the cavity with height H (mm)-width W (mm) of 80-75, 100-60, 120-50, 150-40, and 200-30, respectively. The results show that one fractal fin can accelerate the PCM melting and further lower the PV temperature by 2 °C than one straight fin. Moreover, a more desirable cavity with the dimension of 120-50 is clarified by comparing the PV panels average efficiency during 0∼180 min versus the energy input. Next, comparisons of the fin counts N = 1, 2, 3, and 4 reveal that raising the fin count N to 2 reduces the PV panel temperature by 2.3 °C, and the fin counts cause most of the difference. Ultimately, a suitable PCM thickness of 40 mm is selected by considering the PV panel temperature along with the weight and cost of the systems. This study aims to promote the development of finned PV panels integrated with PCMs.

Evaporative cooling of photovoltaic panels in dry and hot climatic conditions

ABSTRACT Solar photovoltaic (PV) technology is a popular choice among other renewable energy sources, but its electrical efficiency decreases with a rise in PV panel temperature. Previous studies on passive cooling with phase change material (PCM) based approach face limitations of temperature drop and leakage issues. To address this issue, an evaporative cooling method that can enhance panel efficiency is investigated. The present study demonstrated a simple, optimized, and cost-effective evaporative cooling for hot and dry climate conditions. The system consists of jute cloth attached directly to the PV panel backside and water flowing from the top header to the jute cloth under gravity has been experimentally investigated in outdoor conditions during summer. The electrical and thermal characteristics (with and without cooling) of the panel were measured. The finding shows that the jute cooling in PV panels leads to a substantial reduction in average temperature by 18°C and a corresponding increase in electrical efficiency by 10.31%. The jute-cooled panel shows an average and maximum output power improvement of 4.33 and 7.10 W, respectively, compared to the referent panel, while consuming only 0.55 l of water per hour. The study also investigated the effect of water failure on jute cooling and water ingress to the junction box. In the event of water cooling system failure, the panel’s temperature increases by an average of 6°C in comparison to the referent panel. Furthermore, the proposed evaporative cooling system shows a cost-incurred payback period of 7 years against the referent system of 5 years.

Passive Cooling Method Analysis & Optimization of PV Solar Panel Heat Sink

The development of solar photovoltaic (PV) systems in arid climates is hindered primarily by high temperatures, which adversely affect system performance and lifespan. This manuscript presents a comprehensive approach to address this challenge by developing an analytical model for predicting the temperature of PV panels under a passive cooling system specifically designed for arid environments. The analytical model takes into account the crucial relationship between solar panel temperature and its conversion efficiency. By applying Kirchhoff's and Ohm's laws for a complex circuit, the model accurately calculates the heat flux within the solar panel system, allowing for the determination of temperatures for each layer in the system. The study deduces closed-form analytical expressions that describe the temperature, output power, and conversion efficiency of the solar panel as functions of various factors, including solar irradiance, ambient temperature, emissivity, wind velocity, tilt angle, and dimensions of fins. These expressions provide valuable insights into the thermal behaviour of the system and enable the evaluation of its performance under different environmental conditions.

Enhancing photovoltaic panel efficiency using a combination of Zinc Oxide and Titanium Oxide water-based nanofluids

The efficiency of a photovoltaic (PV) panel decreases as its temperature increases, which is caused by an increase in solar irradiation. To maintain high electricity efficiency, it is necessary to keep the PV's operating temperature low. Therefore, a cooling system is needed to decrease the temperature of PV panels, especially when solar irradiation is high. Hybrid nanoparticles have attracted considerable interest in the field of PV cooling because of their distinctive characteristics and potential uses. They have the ability to significantly improve the performance and efficiency of solar panels. By offering advantages such as effective heat dissipation, improved heat transfer, favorable optical properties, increased stability, and cost-effectiveness, hybrid nanoparticles play a critical role in enhancing PV cooling. Leveraging these unique attributes, hybrid nanoparticles hold the potential to elevate the efficiency, reliability, and overall performance of photovoltaic systems. This study involved a three-stage process. The initial two stages focused on identifying the optimal concentration of Zinc oxide water-based nanofluid and Titanium oxide water-based nanofluid. The third stage sought to determine the ideal combination of these two nanofluids. Throughout each stage, five identical PV modules were utilized and placed adjacent to one another. During the experiment, one PV module was used as a base, while the other four were coated on their backside with a specific concentration of the corresponding nanofluid type. During the study, K-type thermocouples were employed to measure the hourly averaged backside temperature of each module. These thermocouples were attached to the backside of the modules to obtain accurate readings. Additionally, a GL 220 midi logger was utilized to record the voltage, current, and power of each PV throughout the duration of the experiment. Based on the findings of the study, it was found that in general, the performance of each PV was improved upon the coating process, with the best PV panel performance obtained when using a mixture of 0.4% TiO2 and 0.2% ZnO concentration by increasing the output power by 22.81% and increasing the efficiency by 29.47%.

Increasing solar panel output with blue-green roofs in water-circular and nature inclusive urban development

With an increasing demand for climate resiliency, water sensitivity, nature inclusiveness and energy efficiency in dense urban environments, the call for layered and multifunctional use of rooftops is rising. Vegetated roofs combined with Photo-Voltaic (PV) installations are an example of multifunctional and more effective use of available space, and well-irrigated systems could have an enhanced cooling effect. This research investigated a blue-green capillary irrigated solar roof with grey (shower-) water suppletion, with a constructed wetroof for grey water purification. Two full-scale commercial PV systems on twin rental apartment blocks in Amsterdam were analyzed, on a blue-green roof (BGR) versus a bitumen roof (BiR). The energy output, PV panel temperature, relative humidity and air temperature under the panels were monitored during 5 warmer months (June–October 2022). On average, a solar panel on the BGR is expected to produce 4.4% more energy than a solar panel on the BiR at similar irradiation. A clear difference in panel temperature on the roofs is only seen when the surface temperature of the roofs differs by at least 4.64 °C. Otherwise, other factors such as wind or albedo have probably more influence on the PV panel temperature and thus on PV power output.

Hybrid Cooling System for Solar Photovoltaic Panel

Solar photovoltaic (PV) panel is one of the renewable sources of energy and produced daily nowadays. Solar panel systems have efficiency influenced by different factors, such as ambient temperature, solar panel temperature, sunlight, weather, and irradiation. The increasing of the temperature of the solar PV panel decreases its efficiency and lifetime. Thus, to maintain and decrease the temperature of the PV cell, cooling system is required. This paper presents the hybrid (water and air) cooling system method for solar PV panel. The method has been designed and developed to lower and stable the operating temperature of the system considering different weather conditions. The results revealed that the hybrid cooling system has shown improvement of output power solar PV panel as compared with water cooling system only. Furthermore, the proposed method managed to improve efficiency approximately to 4.5%.

Nano-capillary aluminum finned heat sink for ultra-efficient evaporative cooling

Aluminum finned heat sinks are commonly used for cooling electronics and high-power systems through convective heat transfer, but their cooling efficiency per unit volume is a major bottleneck to further improve performance or compactness of device/system. Here we report a new strategy including surface modification and system design that for the first time allowed commercially available aluminum finned heat sinks to perform capillary-driven water evaporation from entire surface of fins for significant cooling enhancement. The capillary wicking ability was attributed to a nanostructured surface resulting from the surface modification. Experimental results showed that the passive cooling power of this nano-capillary evaporative finned heat sink (EF-HS) was about 7.8–8.4 times higher than that of a regular (unmodified) heat sink under natural convection. The new strategy can potentially reduce the fin height, cut material costs and save space without compromising heat dissipation efficiency, which is favorable for both large-scale power systems and compact devices. Using photovoltaic (PV) solar panel cooling as an example, the EF-HS with only 9 mm fin height was able to reduce the PV panel temperature by 15.5 °C (26.4%) in a windless condition and increase the energy conversion efficiency by 12.7%.

Experiment study on startup characteristics and operation performance of PV/T solar assisted heat pump water heater system driven by direct current variable frequency compressor

The use of renewable energy can alleviate climate warming and environmental pollution. PV/T (photovoltaic/thermal) system has been widely concerned and rapidly developed owing to its capability of generating electric and thermal energy simultaneously. In the article, a PV/T solar assisted heat pump water heater system driven by direct current variable frequency compressor was proposed to meet the growing needs of residents for domestic hot water. This system was tested in different working conditions in Lanzhou, and the startup characteristics and operation performance were evaluated. The results indicate that at the same ambient temperature, low speed is conducive to the continuity of the refrigerant cycle and improves the system performance. In this system, the initial water temperature of the water tank was 23.1 °C and after 2.5 h it reached 53 °C. The average power generation efficiency is 13.64%, the average thermal efficiency is 26.42%, the overall efficiency is 62.69% and the average COP (coefficient of performance) is 4.87. Compared with traditional PV (photovoltaic) modules, the average temperature reduction is 11.2 ℃. With the increase of solar radiation intensity, the electrical power of the system will increase and the electrical efficiency will decrease. The average daily electrical efficiency of PV/T system is 13.64%, which is 6.25% higher than that of uncooled PV panel. In addition, controlling a proper compressor speed is crucial for enhancing system performance. The PV/T collector can remarkably reduce the temperature of PV panel, improve power generation efficiency and comprehensive utilization efficiency of solar energy.

A numerical examination on the use of phase change materials to improve the sun-tracking photovoltaic panels' performance

The power generation of a photovoltaic (PV) panel is inherently affected by the amount of solar radiation striking the panel and the PV temperature. Tracking PV panels reach higher temperature than fixed panels due to more received radiation. Phase change materials (PCMs) are widely used as a passive method for cooling fixed PV panels. The melting dynamics of the PCM is very different during tracking compared to previous research carried out on fixed panels due to the changing orientation. A tracking PV-PCM system is numerically modeled in this research, and the temperature distribution and convection in the PCM are analyzed. The numerical results are presented as temperature-time curves for several different positions inside the PCM container, liquid fraction and streamlines in melted PCM, and isothermal curves. The temperature variation shows that the temperature of solid PCM increases rapidly in the initial time, reaching the melting temperature. The PCM changes from the solid phase to the liquid phase at a constant temperature. After complete melting, the PCM temperature increases over time. The PCM temperature changes were compared at two different distances from the photovoltaic panel. The streamlines show that the PCM starts to melt near the heated wall at the container's top corner. The melted PCM expands toward the down of the container due to vortex circulation created in the molten material. It is observed that the increase in PV panel temperature between 1.5 and 7 h is only 5.3 K, showing that using PCM is an effective method for absorbing heat from the PV panels during melting. Results show that the temperature of PV panel with PCM is on average 6.9 K lower than that without PCM.

The use of both metallic-insert and TiO2/water nanofluid to improve the performance of photovoltaic modules; experimental study

A photovoltaic (PV) power plant is an effective way to convert sunlight into electricity. This technology is rapidly developing around the world, since it can be harvested in many parts of the earth. But increase in the cell temperature is a weak point of PV cells. In this research using TiO2/water nanofluid is experimented to overcome the problem. Moreover, integrating metallic-insert is also used inside the copper tubes, as a novelty. In the assessments, both energy and exergy analysis were performed. Besides, the difference between the electrical efficiency of PV module and system is distinguished. The results showed 25, 27.6, 28.2 and 30.5 °C decrease in PV panel temperature for water, water + insert, TiO2/water and TiO2/water + insert cases, respectively. The overall efficiency of the system shows that 7% enhancement is obtained, when the insert is used. Furthermore, it was found that TiO2/water + insert attained to 1.7% less entropy generation. Finally, a comparison between the results of this study with other similar researches in using TiO2/water nanofluid as coolant of PV module had been presented and the benefit of using insert was proven, too.