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Solar energy is a valuable renewable energy source, and photovoltaic (PV) systems are a practical approach to harnessing this energy. Nevertheless, low energy efficiency is considered a major setback of the system. Moreover, high cell temperature and reflection of solar irradiance from the panel are considered chief culprits in this regard. Employing pulsating heat pipes (PHPs) is an innovative and useful approach to improving solar panel performance. This study presents the results of the power performance of a PV panel attached to a newly designed spiral pulsating heat pipe, while graphene oxide nanofluid with three different concentrations was used as a working fluid to maximize the efficacy of the solar panel. The study proved that the cooling method delivered high efficiency by reducing the temperature, especially in the middle of the day. Using nanofluid graphene oxide at concentrations of 0.2, 0.4, and 0.8 gr/lit as the working fluid can reduce the thermal resistance of PHPs by over 30%, 24%, and 15%, respectively. This, in turn, enhances the system's electrical power output by approximately 9%, 7%, and 6%, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a computational analysis of the thermoelectric efficiency of hybrid solar chimneys equipped with ventilated photovoltaic (PV) panels with multiple fresh air inlets. The problem addressed is the overheating of the photovoltaic cells, which reduces their electrical efficiency. The influence of multiple air inlets on the electrical and thermal performance of PV/T collectors is the focus of this study. The main objective is to reduce the overheating of the photovoltaic cells and improve their efficiency. This is achieved by using multiple passive ventilation sources instead of placing ventilation systems behind the photovoltaic panels to extract heat and distribute warm air. The implicit finite difference approach is used to discretize the governing heat and mass transfer equations, which are then solved using the Thomas algorithm and the iterative Gauss-Seidel method. The results are obtained by adjusting several important factors, including Raleigh and Reynolds numbers and chimney geometric aspects. The results show that the simultaneous addition of several fresh air openings improves the thermal efficiency by 68% and the electrical efficiency by 5% compared to a chimney with a single vertical duct. The study concludes that this system offers an effective solution for improving the performance of photovoltaic panels, thus contributing to clean energy production. [ABSTRACT FROM AUTHOR]

Micro gas turbines (mGT) have not yet succeeded in conquering the small-scale combined heat and power (CHP) market. One reason is that their electrical efficiency is not high enough to maintain a cost-effective operation. A two-shaft intercooled mGT has the potential to meet the current market demand. This technology maintains a high electrical efficiency even at part-load and coupled with its fuel-flexible combustion chamber, it is an ideal candidate for CHP concepts in a renewable future. In this paper, performance analysis on two-spool mGT is carried out with various fuel blends. Attention is given to the low-pressure and high-pressure compressors and the variation of surge margin by adding hydrogen and syngas. Two control strategies for the mGT are adopted. In the first scenario, the two shafts have equal rotational speeds while in the second, the speeds are controlled independently. As the engine is operated at equal speeds, the maximum performance with 100 vol. % of syngas is observed at 85% of the nominal load while 100 vol. % of hydrogen shows maximum efficiency at a load of 63.7%. At electric power lower than 60% and for high amounts of syngas in natural gas, the low-pressure compressor (LPC) operates closely to surge line. In the second scenario, the efficiency increases as the load decreases and the LPC runs in an efficient and safe operating region. Additionally, the amount of nitrogen in syngas affects the part-load performance of the two-spool mGT. [ABSTRACT FROM AUTHOR]

The combined thermal and photovoltaic technology in PV/T systems is considered as a greatly promising technology for smart buildings. Thus, investigations for enhancing the PV/T performance are still proceeding. This research presents an investigation for novel configurations of cooling jets for the PVT system. The linear and circular distribution for the inlet jets considering regular and irregular positioning for all the jets as new cooling configurations are implemented. Moreover, the proposed geometrical configurations are optemized regarding the performance to identify the most suitable configuration that achieves the optimum efficiency and temperature. Furthermore, a novel hybrid ANN model is presented for predicting the performance of the PVT systems. This model combines the multi-feedforward neural network (MFFNN) with an optimization technique called reptile search algorithm (RSA). The proposed model can process the studied parameters to predict the PVT performance parameters (top surface temperature, temperature un-uniformity, outlet temperature, and efficiencies). The proposed MFFNN-RSA model minimized the mean square error to less than 0.4857×10-3. The maximum temperature decrease achieved by the presented configuration reached 60.62K compared to the uncooled case, while the minimum temperature un-uniformity reached 1K and 6K for 400 and 1000 W/m2, respectively. The increase of the ambient temperature found to decrease the temperature un-uniformity in all the cases. The irregular jet with the linear distribution was found to achieve the optimum performance of the overall, thermal, and electrical efficiencies of 63.5%, 49.6%, and 14.25%, respectively. Furthermore, the electricity production cost was reduced by 11.6%, and the yearly CO2 emissions were reduced by 215.3 kg/m2 compared to the normal PV system. The proposed irregular-line distribution of the jets is found to be the best configuration regarding the temperature of the PV model and the overall efficiency considering the pumping losses.

One of the most affordable and readily available energy sources is solar energy. Humanity is in danger due to the lack of freshwater. Finding novel approaches to these issues that make use of solar energy has grown in popularity as a research area. The previous work presented was made to cool solar cells to increase their performance. The reverse-osmosis system is then fed by the cooling water. This study investigated the ideal conditions for cooling water fed into a reverse-osmosis system. Two identical solar cells were used for the current experiments. Water was used to cool one of the two cells. Measurements were made of the cell surface temperature, output voltage, current, and power. It was calculated to find the electrical efficiency of both cooled and uncooled cells. The cooled cell produced a maximum power of 6.75 W, according to the results. At 1:00 p.m., the gain power reached its maximum. The greatest efficiency gain, 50.2%, was observed at 4:00 p.m. Throughout the work that was presented, there was an 8% decrease in cell surface temperature. The water application value engine (WAVE) was used to simulate a reverse-osmosis system. The program's findings demonstrated that energy consumption dropped as feed water temperature rose. The findings of a case study conducted in a real water-desalination plant were confirmed. [ABSTRACT FROM AUTHOR]

This study focuses on the performance optimization of steam turbine inlet parameters using regression analysis. The input parameters considered are mass flowrate, temperature, and pressure, while the output parameters include power output, electrical efficiency (EE %), and overall efficiency (OE %). The analysis begins with the application of best subsets regression to determine the most influential variables on OE %. The results show that the best regression model includes mass flowrate, temperature, and pressure as significant predictors. The regression analysis further investigates the relationship between OE % and the selected input parameters. The analysis of variance (ANOVA) with a p-value of 0.003, the regression model is statistically significant. Among the predictors, mass flowrate has the most substantial impact on OE %, having a p-value of 0.001. Temperature, in contrast, does not exhibit a significant effect on OE %, as indicated by its p-value of 0.128. The coefficient values indicate that an increase in mass flowrate results in a higher OE%, while temperature has a relatively smaller impact. The results also indicate that mass flowrate and temperature significantly influence overall efficiency, while pressure has minimal impact. A two-parameter regression model comprising mass flowrate and temperature demonstrates a better fit than a three-parameter model. The two parameter regression model indicates that the plant achieves its highest overall efficiency of 64.91% when operating with a mass flowrate of 83t/h at 510 °C, while the experimentally determined overall efficiency is 63.16%. Overall, this study demonstrates the use of regression analysis to optimize the performance of steam turbine inlet parameters. The findings provide insights into the influence of mass flowrate and temperature on OE %, allowing for informed decisions regarding steam turbine operation and efficiency improvement. [ABSTRACT FROM AUTHOR]

The thermal performance of a photovoltaic (PV) system is highly influenced by cooling its surface temperature. In this study, a series of cooling modules are developed, including fin turbulators within a serpentine channel placed on the rear side of a photovoltaic/thermal (PV/T) system. These modules are designed to effectively cool the PV/T system, ensuring uniform temperature distribution and enhancing the system efficiency. The study examines fins at four different angles within the serpentine channel, namely 30°, 45°, 60°, and 90° The water was employed as a cooling fluid in the study, operated under laminar flow conditions, with five Reynolds number values, ranging from 250 to 1250 with 250 increment. Every PV/T system has 108 fins with an area of 600 mm2 for each. Numerical simulations were conducted to predict the flow fields resulting from each fin configuration in the serpentine channel. The electrical and thermal efficiency of the PV/T collector was evaluated for the fin configuration with better thermal performance. Results showed that fins oriented with 30° provided the best thermal performance, while fins at 90° orientation achieved maximum heat transfer coefficient. Moreover, the electrical efficiency of the proposed PV/T system could be improved by 0.8 % to 1.5 % compared to a standard PV/T system. In addition, the PV/T system demonstrated a remarkable thermal efficiency of up to 59 % at 90° fin orientation.

Endurance fuel calculations are used to determine the required volume of fuel tanks; annual fuel calculations are used to estimate the fuel consumed during a year of ship operations, primarily to estimate the projected cost of fuel as part of the life cycle cost estimate. These calculations depend on the fuel rates (kg/h) for different electrical and propulsion system configurations. The fuel rates in turn depend on factors, such as equipment efficiency, prime mover-specific fuel consumption curves, electrical loads, ambient temperature, propulsion loads, and the manner in which the power and propulsion systems, are operated. This paper details how to perform endurance fuel and annual fuel calculations, provides guidance for modeling system components based on data typically provided in data sheets, and provides guidance on the manner in which the power and propulsion systems are operated. Four examples are provided to illustrate the methods using the Smart Ship System Design modeling and simulation tool along with supporting spreadsheets. [ABSTRACT FROM AUTHOR]

Photovoltaic-thermal (PVT) systems are common in the conversion of solar energy to electrical and thermal energy. The performance of such systems depends on the environmental conditions in which these systems are applied. This paper presents a parametric study of a jet-cooling PVT system with a staggered distribution of the jets. A feedforward neural network (FFNN) is proposed as a novel predictive model for analyzing the characteristics of the PVT system and its thermal and electrical performance. Moreover, a novel optimization algorithm called archerfish hunting optimizer (AHO) is applied to obtain the optimal structure and elements of the proposed FFNN. The PVT system variables considered as inputs to the FFNN-AHO model are flow rate, wind speed, solar irradiance, and ambient temperature. The average temperature of the PV reaches a maximum of 45.84 °C, and the maximum temperature un-uniformity reaches to 3.59 °C. The studied PVT system achieved maximum electrical, thermal, and overall efficiencies of 14.23%, 54.43%, and 68.1%, respectively. Moreover, the results demonstrate that the FFNN-AHO hybrid model provides highly accurate PVT system performance prediction. The correlation coefficient between the actual and predicted data is close to 1, indicating a strong correlation and confirming the reliability and effectiveness of the FFNN-AHO model. [ABSTRACT FROM AUTHOR]

A novel micro-channel PV photothermal collector is investigated, comprising of PV cells and collectors. Its distinctive feature lies in the flow mode of its micro-channels. The novel micro-channel investigated in this study is composed of multiple drums, allowing for a non-parallel flow configuration. This distributional flow pattern facilitates enhanced contact between the water flow and the heat transfer surface, thereby resulting in significantly improved heat transfer efficiency. Characteristics and flow properties are studied to enhance the thermoelectric performance and broaden the application scope of PV photothermal collector technology. This study focuses on parallel micro-channels and three-passes microchannels for comparison, employing ANSYS FLUENT to simulate electrical and thermal efficiencies, temperature distribution, velocity field, and pressure field under typical operating conditions. The validity of the model is verified by comparing it with experimental panel surface temperature data. Within this framework, various inlet flow conditions are examined to investigate the collector's temperature profile, standard deviation of temperature distribution, pressure drops, and maximum velocity. Results indicate that under specific circumstances, the heat collection performance of parallel micro-channel PV photothermal collectors is inferior to that of three-passes micro-channel counterparts. Both types exhibit reduced efficiency during winter conditions, however, three-passes micro-channels experience a more significant decline at 22.4%, compared to 19.7% for parallel microchannels. In terms of flow resistance characteristics, parallel micro-channels demonstrate advantages in terms of pressure drops over three-passes configurations as they exhibit nearly 3935 Pa lower values under certain conditions. Regarding temperature uniformity in PV-photothermal systems, parallel micro-channel collectors outperform their three-passes counterparts. [ABSTRACT FROM AUTHOR]

Due to its widespread availability and inexpensive cost of energy conversion, solar power has become a popular option among renewable energy sources. Among the most complete methods of utilizing copious solar energy is the use of photovoltaic (PV) systems. However, one major obstacle to obtaining the optimal performance of PV technology is the need to maintain ideal operating temperature. Maintaining constant surface temperatures is critical to PV systems' efficacy. This review looks at the latest developments in PV cooling technologies, including passive, active, and combined cooling methods, and methods for their assessment. As advances in research and innovation progress within this domain, it will be crucial to tackle hurdles like affordability, maintenance demands, and performance in extreme conditions, to enhance the efficiency and widespread use of PV cooling methods. In essence, PV cooling stands as a vital element in the ongoing shift towards sustainable and renewable energy sources. [ABSTRACT FROM AUTHOR]

Based on the results of scientific research and production experience in smelting of ferrous-based alloys in electric furnaces, the technological methods of increasing the active resistance of bath using types of carbonaceous reducing agents with different electrical resistivities are considered. It has been shown that an increase in bath resistance, mainly due to the use of reducing agents with an increased electrical resistivity, helps to improve smelting parameters. As a result of the use of a number of reducing agents, the electric furnace operates at an increased operating voltage, the furnace power factor improves, the active power in the bath increases, the specific energy consumption decreases and the productivity when smelting ferrosilicon increases. Options for smelting are considered with an increase in the energy-technological criterion for the operation of a ferroalloy furnace. [ABSTRACT FROM AUTHOR]

Renewable energy resources are vital for addressing the universal concerns of air quality, energy security, and sustainable development. Solar energy has several benefits over other popular renewable energy sources, such as its accessibility and increased predictability. The device used for conversion of solar energy to electrical energy is known as photovoltaic panel, which is highly sensitive to the temperature. A significant reduction in efficiency is observed with an increment in temperature hence cooling of photovoltaic panel is highly desirable. Among the different cooling techniques, water cooling is attractive and widely used due to its good thermal properties and availability. Generally, panel cooling through water circulation in tubing is explored in past, however, these tubing structures are having some limitations such as heat transfer barrier, limited surface area, leakage issues, clogging and cost of material. These issues can be partially resolved by using direct contact water jacket cooling system. Therefore, the present study focuses on in enhancing the thermal and electrical characteristics of the solar photovoltaic module through a direct contact water jacketed cooling system. Initially, a 3D numerical model is developed and the outcome of the numerical model is compared with the experimental work. The results obtained are found in good agreement for solar cell temperature and water outlet temperature. The solar panel performance is investigated with different flow rates such as 0.01, 0.05, 0.1 and 1 cm/s. The direct contact water jacketed cooling system offers simplicity, light weight and cost effectiveness and is found promising over the indirect system. Temperature reduction up to 20 °C is observed over uncooled PV panel whereas enhancement in electrical efficiency up to 9.6 % is observed. The cooled PV solar cell maintain 40.2% low temperature compare to uncooled solar cell temperature. [ABSTRACT FROM AUTHOR]

The primary aim of the research is to improve photovoltaic thermal systems, with a particular focus on enhancing their efficiency and overall effectiveness by utilizing the Fresnel lens and nanofluid-based liquid spectrum filter with a dual-axis solar tracker. The study explores innovative techniques, including the application of nanofluid to cool the solar panel. This cooling not only increases the electrical efficiency of the solar panels but also extends their life span by effectively preventing overheating. Moreover, the research investigates the utilization of solar trackers, which optimize the collection of solar energy by continuously aligning the panels with the sun's position. The consideration of the parameters—flow rate, ambient air temperature, wind speed, and solar intensity—led to a significant improvement in the thermal and electrical efficiencies. The electrical efficiency increases from 15.5 to 19.6%, while the thermal efficiency increases from 52.6 to 58.7% by optimizing the considered parameters. This is a companion study of the photovoltaic thermal system that reveals the influence of new parameters. By implementing these advancements, the research significantly contributes to the development of sustainable and high-performance solar energy solutions suitable for diverse applications, spanning both residential and industrial sectors. [ABSTRACT FROM AUTHOR]

In this work, an innovative solar photovoltaic thermal (PVT) collector is developed that has a spiral shaped absorber tube fitted underneath the PV panel in such a manner that a bifluid cooling system extracts heat from the PV panel. The methodology adopted in the present study is to conduct a detailed computational investigation in order to understand the impact of important operating and environmental parameters such as mass flow rates and solar radiations on the overall performance of the bifluid PVT collector. One of the fluids, i.e., a nanofluid (Al2O3 in water) with nanoparticle volumetric fraction 5% is passed through the spiral tube, whereas a rectangular air duct is attached below the PV panel for extracting heat from it and delivering the same to the flowing air, thereby making a bifluid coolant system for the PVT collector. Detailed CFD simulations are performed in ANSYS Fluent 19.2 platform for analyzing the thermal performance of the collector. The effects of mass flow rate variations of each individual fluid and in combination (i.e., bifluid) on the PVT efficiency, i.e., thermal, electrical and overall efficiency are observed. The results indicate that with increase in mass flow rate of the fluids, these efficiencies increase up to a certain level but after that, there is only incremental increase with further increase of the latter. When the fluids are used individually or in combination, higher thermal and electrical efficiency are obtained with nanofluid mass flow rate less than that of air. Further, the bifluid is able to transfer heat effectively from the PV panel with less temperature variation between inlet and outlet. Out of all the combinations of varying mass flow rates of individual fluids and bifluid, the best bifluid combination is such that lead to an overall efficiency of 79% corresponding to nanofluid mass flow rate 0.0247 kg/s and air mass flow rate 0.034 kg/s. The computational model developed in this present study will help in designing and developing a more energy efficient, environment friendly and sustainable PVT technology for effective utilization of solar energy. [ABSTRACT FROM AUTHOR]

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Recognizing the pivotal role of the cooling method in enhancing Photovoltaic-Thermal (PVT) efficiency, this study delves into the combined application of two innovative techniques: a finned tube and a confined jet. Additionally, the integration of a TEG (Thermoelectric Generator) is introduced to amplify output power. The improvement in cooling efficiency is achieved through infusing a composite of Carbon Nanotubes (CNT) and Fe3O4 into the coolant. The investigation encompasses three distinct cooling system configurations: 1) the base case employing a conventional pipe, 2) a system with a finned-tube cooling unit, and 3) a setup combining a confined jet with a finned tube. The introduction of hybrid nanoparticles results in an overall performance boost of around 2.64 % compared to the base case. Furthermore, the efficacy of the nanofluid concentration (φ) in the base case surpasses that of the Finned Jet case by a factor of 3.86. Notably, an increase in irradiance magnitude and jet inlet velocity contributes to a commendable enhancement in thermal performance, registering approximately 8.66 % and 3.48 %, respectively. The incorporation of fins and confined jets yields substantial improvements, resulting in an 86.13 % enhancement in TEG performance and a commendable 26.42 % rise in thermal performance.

The research investigates the use of fins fastened to a solar panel's rear surface for passive cooling. The research compared solar modules with air cooling against modules with connected fins acting as a heat sink. The comparison was based on the former. The research studies the cooling of modules with fins using two different types of air: ventilation air and still air. By comparing the heat transmission by photovoltaic panels with and without fins, the research sought to analyses the effects of the environment and solar radiation on the performance of solar cells. The inquiry was done hypothetically. According to the findings, using fins for cooling reduced cell temperature and improved electrical and thermal efficiency. The estimated performance values of the PVT solar cell obtained by using the COMSOL program and the experimental measurements carried out during the daytime were reasonably in accord. The biggest reduction in cell temperature is (3.7ºC at noon), while the greatest increases in electrical and thermal efficiency are (16.54% and 58.3%, respectively). There is good agreement between experimental and numerical results.

Recycling the anode off-gas of the solid oxide fuel cells can effectively improve the system fuel utilization (U f , s y s ) under a low stack fuel utilization (U f , 1 ), prolonging the service life and reducing the power generation cost. A compact self-humidified anode off-gas recycle (SAOR) system fueled by natural gas is proposed and analyzed. Clear mathematical relationships for key physical quantities in all system components are derived. Analytical expressions concerning the controllable parameters, U f , s y s and the recycling ratio (λ), and the controlling targets, U f , 1 and the oxygen to carbon ratio, are presented to facilitate the accurate system control for high efficiency and moderate U f , 1 and free of carbon deposition. The core system model is found to agree very well with multiple sets of available experimental data. The SAOR system performance for representative fuel flow rates and U f , 1 and for all λ are presented. The results show the SAOR system can achieve a DC efficiency similar to, but with U f , 1 10% lower than the best known non-SAOR system, demonstrating the presumed superiority of SAOR system. The SAOR system is a promising low cost design capable of achieving high efficiency and durability and should be pursuit for commercial development. • Explicit math model for novel self-humidified anode off-gas recycle system presented. • Validation of the core system model by multiple data sets of available experiments. • Analytical relationship expressions for control parameters and system targets derived. • Very high efficiency with moderate stack fuel utilization is proven for the system. • System performance for many combinations of operating parameters revealed & analyzed. [ABSTRACT FROM AUTHOR]

This numerical study examines the thermal performance of solar photovoltaic (PV) with phase change material (PCM) as a heat sink under real ambient conditions. A mathematical model is developed to assess the comparability between PV and PV with PCM in a one‐dimensional unsteady state condition. The influence of PCM properties such as density, thermal conductivity, melting point temperature, and latent heat on the thermal performance of PV module is analyzed. The impact of altering PCM layer thickness is also explored. Results show that the PV‐PCM system can keep a nominal operating temperature for a longer duration of energy generation, which enhances the efficiency and lifespan of the PV module. The peak solar cell temperature for conventional PV without PCM is 81.8°C at 12.15 pm, while for PV with PCM, it is 74.8°C at 12.40 pm, indicating a reduction of 6.9°C or 9.3%. The deviation of maximum temperature between standard PV and PV‐PCM systems is 24.8°C or 35% diminished temperature, achieved at 10 am. [ABSTRACT FROM AUTHOR]

The finned heat sink was equipped with a confined jet to create an effective way for cooling of photovoltaic (PV) system in current work. In the bottom of PV layers, a thermoelectric generator (TEG) has been utilized to produce more electrical power. To create a temperature difference, the heat sink has been located in the bottom of TEG. The fluid is mixture of water with hybrid nanomaterial (TiO2–CuO). For simulating, finite volume approach has been chosen and code has been verified based on previous publication. Influences of inlet velocity (Vin), radiation intensity ("I") and inlet temperature (Tin) on electrical (ηPV) and thermal (ηth) efficiencies have been scrutinized. With increase in "I", the values of ηPV and ηth reduces about 5.94% and 14.3% while the amount of ηTEG for "I" = 4200 W m−2 is 3.47 times greater than that of "I" = 1200 W m−2. Greater value of Tin leads to lower values of ηTEG, ηPV and ηth around 28.2%, 2.5% and 13.72%. The amount of ηth and ηTEG intensifies about 1.13% and 2.76% with rise of Vin, respectively. Also, the increment effect of Vin on ηPV reduces around 24.8% in the existence of fins. [ABSTRACT FROM AUTHOR]

Solar photovoltaic (PV) panels and solar thermal collectors are two major technologies used to extract electrical and thermal energy, respectively, from solar irradiation. PV panels convert only 15–20% of incident solar radiation into electricity. The remaining radiation elevates the panel’s surface temperature, which badly affects the conversion efficiency and reduces the overall lifespan of the panel. Hence, in this paper, we investigate three cooling techniques developed in-house to maintain the PV panel’s surface temperature: passive cooling, active cooling, and combined cooling. A novel PV/T-PCM system was designed and fabricated to conduct a detailed experimental analysis of each of the cooling methods used on the performance of PV panel in the form of temperature and electrical efficiency of the panel. The temperature of the panel surface got reduced by a maximum of 36% at 1,050 W/m², and as an effect of that, the electrical efficiency was also improved by around 42% in the case of a combined cooling technique. Finally, empirical correlations were also developed to predict the electrical efficiency and PV panel surface temperature using the experimental data of present investigation considering investigated system and operating parameters. Based on the experimental results, the coefficient of determination (R²), for the correlation of electrical efficiency, was found to be 0.90 and 0.9188 for surface temperature that indicate good confidence level for both the correlations. As a result, the correlations and results are more important from an application standpoint for the design and development of the PV/T system. [ABSTRACT FROM AUTHOR]

The research investigates the use of fins fastened to a solar panel's rear surface for passive cooling. The research compared solar modules with air cooling against modules with connected fins acting as a heat sink. The comparison was based on the former. The research studies the cooling of modules with fins using two different types of air: ventilation air and still air. By comparing the heat transmission by photovoltaic panels with and without fins, the research sought to analyses the effects of the environment and solar radiation on the performance of solar cells. The inquiry was done hypothetically. According to the findings, using fins for cooling reduced cell temperature and improved electrical and thermal efficiency. The estimated performance values of the PVT solar cell obtained by using the COMSOL program and the experimental measurements carried out during the daytime were reasonably in accord. The biggest reduction in cell temperature is (3.7ºC at noon), while the greatest increases in electrical and thermal efficiency are (16.54% and 58.3%, respectively). There is good agreement between experimental and numerical results. [ABSTRACT FROM AUTHOR]

The frequency and the suction refrigerant state are complex in the actual operation of variable compressors, which leads to the variability of compressor performance under different operating conditions. The characterization and the modeling of the compressor have become hot research topics. For modeling, the electrical efficiency model of the compressor, which could be applied to the suction refrigerant state at both the superheated and the two-phase stages, the compressor frequency, the pressure ratio, and the evaporation temperature, is analyzed through experiments in this paper. The results show that the linear electrical efficiency decreases with the declining superheated temperature and the increasing suction vapor quality when the system is at the fixed and evaporating temperature. Moreover, the slope of the two-phase suction is above that of the superheated suction. In addition, the system's electrical efficiency at the fixed pressure ratio is inversely proportional to the evaporation temperature, and the electrical efficiency of the system at the fixed evaporating temperature is also inversely proportional to the pressure ratio. The higher the variation of the pressure ratio, the smaller the evaporation temperature influences. To demonstrate the precision of the model, the theoretical value is compared with a confirmatory experiment in this paper. The maximum relative error is 1.81%, and the minimum is 0.035%. [ABSTRACT FROM AUTHOR]

Photovoltaic (PV) technology is a more successful alternative to producing electrical power than conventional energy sources in the modern era. However, it suffers from low conversion efficiency at high operation temperatures. Therefore, PV cooling methods are crucial to improving technology efficiency and prolonging its lifetime. Photovoltaic/thermal (PV/T) is a key to producing thermal and electrical energy, employing different fluids, including nanofluids (NFs). This review paper analyses the improvement in the PV/T system using various cooling methods, including air-based, water-based, bi-fluid, nanofluid, and other passive cooling methods. This review focuses on employing mono (NFs) and hybrid (NFs) to improve the PV/T thermal and electrical performance, considering the PV/T design, nanoparticle type, concentration, and operational aspects. In addition, some insights have been delivered as a starting point for further research. Conclusively, the bi-fluids have remarkably enhanced the PV/T electrical and thermal efficiencies by up to 26 % and 85 %, while NFs showed enhancements by 24 % and 82 %, respectively. However, there is still a need for further studies to meet technical and economic concerns using these types of fluids for cooling purposes.

One of the most affordable and readily available energy sources is solar energy. Humanity is in danger due to the lack of freshwater. Finding novel approaches to these issues that make use of solar energy has grown in popularity as a research area. The previous work presented was made to cool solar cells to increase their performance. The reverse-osmosis system is then fed by the cooling water. This study investigated the ideal conditions for cooling water fed into a reverse-osmosis system. Two identical solar cells were used for the current experiments. Water was used to cool one of the two cells. Measurements were made of the cell surface temperature, output voltage, current, and power. It was calculated to find the electrical efficiency of both cooled and uncooled cells. The cooled cell produced a maximum power of 6.75 W, according to the results. At 1:00 p.m., the gain power reached its maximum. The greatest efficiency gain, 50.2%, was observed at 4:00 p.m. Throughout the work that was presented, there was an 8% decrease in cell surface temperature. The water application value engine (WAVE) was used to simulate a reverse-osmosis system. The program’s findings demonstrated that energy consumption dropped as feed water temperature rose. The findings of a case study conducted in a real water-desalination plant were confirmed.

The increasing demand for renewable energy sources, such as photovoltaic thermal systems, requires efficient cooling techniques to improve performance. Hybrid nanofluids have shown promise in enhancing the cooling performance of such systems. This work seeks to investigate the effect of varying parameters on the performance of a two-dimensional photovoltaic thermal system using hybrid nanofluids for cooling. This work aims to enhance the performance of two-dimensional photovoltaic thermal systems by using hybrid nanofluids for cooling. The hybrid nanofluids use water as their base fluid and contain a mixture of Copper (Cu) and Aluminia oxide. The photovoltaic thermal system is assumed to have a monocrystalline silicon absorber and a backward step as the flow channel. The conduction and forced convection process will occur on the top two layers of silicon and absorber, respectively, while forced convection will occur in the flow and heat transmission channel. The finite element software COMSOL 6.0 will be used to simulate the issue using the energy and Navier-Stokes equations in a two-dimensional, incompressible, and steady-state problem. A parametric study will be conducted by varying the inlet temperature, Reynolds number, volume fraction of Copper, and height downstream of the backward step channel. The results will be verified using a mesh-independent study and the heat transfer coefficient from the available literature. The study demonstrates that increasing the amount of Cu in the base fluid, the upstream channel's channel height and the corresponding Reynolds number improves the performance of the photovoltaic thermal system.

This study employs An evolutionary algorithm to set up a multilayer BP neural network. The goal is to solve the issue that BP neural systems converge slowly and readily fall into local optimal solutions. The genetic algorithm reaches an initial set of evolutionary generations and outputs a BP neural network’s most appropriate starting weights and thresholds. In the GA-BP model, the fitness value is calculated as the sum of the total errors between the network’s output and the desired output. A communication protocol device was used to gather performance information for the global solar PV/T system, and the GA-BP neural network model parameters were adjusted. The GA-BP model had a mean absolute error of 0.7% lower than the BP model’s for the forecast of electrical efficiency. The GA-BP model has an average relative error of 0.21 in forecasting heating power.

Advanced nanofluid with high stability is essential to meet the demands of the current industry and solar thermal systems. In industrial application, graphene oxide (GO) nanofluid formulated with ethylene glycol (EG)/water (W) is usually well-known for good stability along with high thermal conductivity. In this research, GO nanofluid is characterized for exploring its thermal, optical and suspension stability under certain conditions and then utilized as working fluid in photovoltaic thermal (PV/T) system for measuring its performance compared to those of water and Al2O3, TiO2 and hybrid Al2O3-TiO2-based nanofluids. The thermal conductivity, thermal stability, morphology and optical absorbance are characterized by using thermal analyzer, TGA, SEM and UV–vis analysis, respectively. The results revealed that the thermal conductivity of GO/EG:W nanofluid was increased by 9.5% at 40 °C compared to water. It also showed good stability with a zeta potential of 30.3 mV. The numerical implantation of GO/EG:W nanofluid performed by COMSOL Multiphysics software presented significant improvement compared to Al2O3/EG:W, TiO2/EG:W and TiO2-Al2O3/EG:W nanofluids with a concentration of 0.01 mass% to 0.1 mass%. The measured electrical and thermal efficiencies of the PV/T system were 13.5% and 76%, respectively, using GO/EG:W with 0.07 kg s−1 mass flow rate and 0.01 mass% concentration. The stated findings identified GO/EG:W nanofluid as more effective in enhancing PV/T system's performance than other tested working fluids. [ABSTRACT FROM AUTHOR]

Pongamia (Pongamia pinnata) is a prospective biofuel plant with 35 to 45% seed oil. The physical and chemical characteristics of pongamia oil are quite comparable to those of diesel. Pongamia seed oil has been considered as a possible biodiesel source for the past 10 years. The high viscosity and conradson carbon residue of pongamia oil, however, preclude its usage in this capacity. Thus, methyl ester was produced from pongamia oil by optimising the different parameters of transesterification reaction viz., reaction time (90 minutes), amount of catalysist (1.5 wt.%), amount of methanol (210 ml per liter of oil) and optimum temperature (50 °C) needed to complete the conversion of oil into methyl ester. The produced methyl ester was employed as fuel instead of diesel in the engine test using a single-cylinder, naturally aspirated, direct injection diesel engine. Parameters such engine speed, electrical efficiency, lower and higher heating values, and fuel consumption were investigated. Speed regulation and voltage regulation in the engine experiment provided clear evident that the biodiesel from pongamia oil could be used in an existing diesel engine without any engine modifications. The physical and chemical properties of the methyl ester were also estimated. The biodiesel produced from quality pongamia seed meets the cetane number (52.90) and iodine value (99) as per the biodiesel quality specifications and can be used in varied climatic conditions. [ABSTRACT FROM AUTHOR]

The photovoltaic solar collector (PV) works to provide electricity in normal weather conditions. This paper displays the flat plate PV/T collector produces electricity and thermal energy in overheating weather conditions. In this type of weather conditions, the intermediate efficiency of photovoltaic panels often drops. This occurs because the majority of the solar radiation that is absorbed by the PV panels is converted into heat causing them to operate at a high temperature. This result in reduced PV lifespan and intermediate efficiency. As a result, it has become necessary to use a variety of approaches to try and reduce its working temperature. The performance of PV/T solar collectors using an active air collector was implemented in the resent study. The COMSOL Multiphysics software simulation was used to investigate the effectiveness of the PV/T system. The findings of the simulation-based analysis demonstrated that the chosen model is the most successful in comparison to the model with no cooling. A Solar collector with porous metal was implemented in to reduce the PV temperature. According to the results of the numerical simulation, the metal grating's ideal angle of inclination with the horizon is 45 degrees, with a 20 mm increase in its contact area with the rear cell surface. [ABSTRACT FROM AUTHOR]

This work manifests the influence of different nanoparticles on the photovoltaic-thermal (PVT) system. The hybrid PVT (hPVT) systems provide thermo-electric energy by utilizing the module heat. The module heat is recovered for controlling the cell temperature using coolant in the channel. This work examines the impact of the type and volume concentration of different nano-fluids on the cell temperature, outlet temperature, thermo-electric efficiency of hPVT collectors. Copper (Cu), titanium dioxide (TiO2), and silicon dioxide (SiO2) dispersed in pure water are considered nano-fluids in this study. The investigation reveals that the outcomes of the PVT collector with copper-water as nano-fluid are superior to the other nano-fluids considered in the study. At 0.012 kg/s mass flow rate (MFR), the thermo-electric efficiency of the hPVT collector is 1.645% and 6.239% higher than the thermo-electric efficiency of the PVT at an MFR of 0.002 kg/s. It is also observed that with a 4% vol. concentration of Cu in the base fluid, the thermo-electric efficiency is considerably better than the efficiency at 2% and base fluid. [ABSTRACT FROM AUTHOR]

This study aims to estimate the performance of photovoltaic/thermal (PV/T) collector using alumina water‐based nanofluid with geothermal cooling through machine learning (ML) approach. A mathematical model is developed for the first law of thermodynamic analysis of nanofluid in PV/T system integrated with geothermal cooling and is validated with experimental results. Further, a machine learning‐based approach has been employed to simulate the cooling performance of a nanofluid cooling based PV/T system. In the study, Multi‐layer perceptron (MLP) is proposed for estimating the thermal and electrical performance of PV/T system based on design parameters like nanofluid concentration, Reynolds number, and time. The same is then compared with other state‐of‐the‐art machine learning techniques and it is evaluated based on various quality metrics such as mean square error (MSE), root mean square error (RMSE), and R2 test. The designed network is compared with the other ML algorithms available in literature like linear regression (LR), support vector machine (SVM) and decision tree (DT). The proposed MLP network is provided a significant outcome with an average accuracy of 98% and predicted PV panel temperature of 32.1–36.5°C for 0–18 sequences. It was also observed that electrical efficiency of PV/T system improved from 10.51% to 10.66% for 0–18 sequences through MLP predictions. [ABSTRACT FROM AUTHOR]

Despite their low electrical efficiencies, PVs are widely used to generate electricity from abundant solar energy. In order to maximize the utilization of incident solar energy, PVT collectors have been used to simultaneously generate electricity and thermal energy. Furthermore, combining PVTs with humidification-dehumidification (HDH) cycles can provide electricity and potable water in remote, arid rural areas that are not connected to the grid. In this paper, a PVT-air collector was coupled to an air-heated closed HDH cycle. Air was heated within the PVT collector and humidified by saline water spray inside the humidifier. Fresh water was produced by cooling humid air inside a dehumidifier that is cooled by saline water. The thermal and electrical performances of the PVT-HDH system were experimentally studied and compared to the electrical performance of a PV module with similar characteristics. The results demonstrated a significant decrease in PV temperature within the PVT-HDH system, which resulted in a 20% increase in the output power of the PVT-HDH system at midday compared to the identical PV module. In addition, the PVT-HDH system produced about 3.8 liters of water distillate for a PV module surface area of 1.48 m × 0.68 m, which contributed about 38% to the overall efficiency of the PVT-HDH system.

This work deals with the performance evaluation of novel flat photovoltaic–thermal (PV–T) modules under vacuum. Through a 1D (dimensional) steady-state-energy-balance numerical model developed in MATLAB, two different layouts are studied: the first consisting of a photovoltaic (PV) cell installed just below the glass encapsulating the flat panel, and the second where the PV cell is placed on the selective solar absorber (SSA). In both cases the thermal and electrical efficiencies have been evaluated at different SSA operating temperatures, in the range of 323 K to 423 K. The analysis has been conducted at different energy bandgap (Ebg) of the PV cell and assuming a variable transmittance or emittance of the PV cell, depending on the design. The two systems efficiency comparison has been carried out at the same operating temperature. Overall, this work highlights the importance of high vacuum insulation, which guarantees the reduction of convective thermal losses, and shows that the maximum energy is produced for PV cells with Ebg≈1.5-1.7 eV, depending on layout and operating temperature, by including the thermal output in the PV–T​ optimization. The energy and exergy efficiencies obtainable using the proposed PV–T​ systems are considerably improved compared to the results previously reported in the literature.

Due to its widespread availability and inexpensive cost of energy conversion, solar power has become a popular option among renewable energy sources. Among the most complete methods of utilizing copious solar energy is the use of photovoltaic (PV) systems. However, one major obstacle to obtaining the optimal performance of PV technology is the need to maintain ideal operating temperature. Maintaining constant surface temperatures is critical to PV systems’ efficacy. This review looks at the latest developments in PV cooling technologies, including passive, active, and combined cooling methods, and methods for their assessment. As advances in research and innovation progress within this domain, it will be crucial to tackle hurdles like affordability, maintenance demands, and performance in extreme conditions, to enhance the efficiency and widespread use of PV cooling methods. In essence, PV cooling stands as a vital element in the ongoing shift towards sustainable and renewable energy sources.

In the present study, the performance of a photovoltaic-thermal (PV/T) air collector is evaluated by revealing the temperature distribution and investigating the effect of the inlet and outlet air temperature and PV cell temperature. Solar PV/T collectors have been recently introduced as a promising solution for the global energy crisis. There is a lack of literature investigating the effect of changing duct depth and velocity, which this study explores. Two scenarios are considered: a PV system and a PV/T system. Equations for efficiency are derived based on thermal and electrical parameters. The simulation results were validated by a set of experimental results from a similar PV/T set-up. Simulations were carried out to a high degree of accuracy with ‘R’ values ranging between 0.881 and 0.952. The air duct improved the electrical efficiency of the PV module by 13.67 %. The PV/T system improved efficiency while limiting its variance throughout the day. It was found that increasing the duct depth reduced the electrical and thermal efficiency. The efficiency of the system improved with rising duct air velocity. Ideal design parameters were identified with a duct depth of 0.01 m and a duct air velocity of 2.5 m/s.

The increasing demand for renewable energy sources, such as photovoltaic thermal systems, requires efficient cooling techniques to improve performance. Hybrid nanofluids have shown promise in enhancing the cooling performance of such systems. This work seeks to investigate the effect of varying parameters on the performance of a two-dimensional photovoltaic thermal system using hybrid nanofluids for cooling. This work aims to enhance the performance of two-dimensional photovoltaic thermal systems by using hybrid nanofluids for cooling. The hybrid nanofluids use water as their base fluid and contain a mixture of Copper (Cu) and Aluminia oxide. The photovoltaic thermal system is assumed to have a monocrystalline silicon absorber and a backward step as the flow channel. The conduction and forced convection process will occur on the top two layers of silicon and absorber, respectively, while forced convection will occur in the flow and heat transmission channel. The finite element software COMSOL 6.0 will be used to simulate the issue using the energy and Navier-Stokes equations in a two-dimensional, incompressible, and steady-state problem. A parametric study will be conducted by varying the inlet temperature, Reynolds number, volume fraction of Copper, and height downstream of the backward step channel. The results will be verified using a mesh-independent study and the heat transfer coefficient from the available literature. The study demonstrates that increasing the amount of Cu in the base fluid, the upstream channel's channel height and the corresponding Reynolds number improves the performance of the photovoltaic thermal system. [ABSTRACT FROM AUTHOR]

The rise in the temperature of photovoltaic (PV) cells leads to a great reduction in their power output; therefore, having a cooling mechanism is critically important to keep the cells of practical benefit in hot climates. The use of wavy surfaces for effective cooling of PV cells seems very promising due to an increased turbulence intensity, generating secondary flows, and improved mixing fluid flows, and has never been studied before. Thus, this study numerically examines the impact of wavy channels with different wavelength (λ), amplitude (α) ratios, and the Reynolds number to reach an optimal geometry for the wavy channel utilized in PV/T collectors using ANSYS CFX. For this purpose, the Reynolds-averaged Navier-stokes equations are applied and the SST k-ω turbulent model is utilized. The results prove the strong impact of the wavy channels where a channel with wavelength & amplitude ratios of 0.1 and 1 has the most increase in the overall efficiency by 20.41% enhancement compared to conventional collectors. In addition, the highest increase in the Nusselt number is 69.7% at λ = 2 and α = 0.2 compared with the smooth channel. At α = 0.3 and λ = 3, the electrical efficiency can be enhanced by up to 1.66% at Re = 40,000. [ABSTRACT FROM AUTHOR]

The electrical efficiency of the solar cell is effectively increased by the cooling process. In order to create a hybrid collector, the current work addresses how to cool the PV panel using three different nanofluids, including CuO, ZnO, and TiO2. known as a photovoltaic thermal sun collector in numbers (PVT). The volume fraction of the nanoparticles was 0.1, 0.2, and 0.3 vol%. The PV panel was cooled using a copper tube that was attached to the rear of the PV and positioned to cover as much of the back as feasible. To compare them, three distinct flow cross sections (rectangular, square, and circular) were chosen. This numerical analysis was conducted with nanofluid flow rates of 0.5, 1, 1.5, and 2 L/min under solar radiation levels ranging from 450 W/m2 to 750 W/m2. The outcomes demonstrate the PVT system's electrical and thermal efficiency under various circumstances. When nanofluid was added instead of just plain water, the electrical efficiency rose. The cell with CuO/nanofluids had the maximum electrical efficiency at 450 W/m2, which was equal to 11.8%, while ZnO/nanofluids, TiO2/nanofluids, and water had 11.6%, 11.5%, and 10.8%, respectively. The CuO/nanofluids and rectangular sections provided the best value for the highest electrical efficiency of 11.5% and electrical power of 83.17 W. [ABSTRACT FROM AUTHOR]

Domestic RO systems are commonly installed in households for water purification and treatment, typically for drinking water purposes. While RO systems effectively remove impurities, such as dissolved salts, minerals, and contaminants from tap water, they produce a concentrated waste stream known as RO reject. This reject water contains the contaminants that were removed during the RO filtration process. This RO reject can be effectively utilized in other domestic, agricultural, and industrial applications. In this study, the performance of a photovoltaic/thermal (PV/T) system was experimentally examined by employing RO reject and MgO/water-based nano-fluid. Two 165 W polycrystalline solar PV modules were used to compare the performance of a PV/T and a PV module. The performance of the solar PV module was assessed in terms of cell temperature and electrical efficiency using a water- and MgO/water-based PV/T system. Furthermore, the thermal and overall efficiency of the PV/T module was also compared using different base fluids. The effect of the working fluid flow rate (3 LPM, 6 LPM, 9 LPM, and 12 LPM) and variations in the concentrations (0.10 wt.%, 0.15 wt.%, and 0.20 wt.%) of MgO nanoparticles were examined to evaluate the improvement in the performance of the PV/T system. The results indicate that the PV/T system's cell temperature was significantly reduced, and its electrical, thermal, and overall efficiency increased with an increased flow rate. The optimum concentration of nanoparticles and flow rate were determined to be 0.15 wt.% and 12 LPM, respectively. The findings suggest that MgO/water-based nano-fluids have the potential to enhance the performance of PV/T systems, and this study provides valuable insights for their practical implementation. [ABSTRACT FROM AUTHOR]