Collector Panels Research Articles

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

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

Sustainable hydrogen production by integrating solar PV electrolyser and solar evacuated tube collector with hybrid nanoparticles enhanced PCM

The investigation is motivated to analyze the influence of Phase change material (PCM), nano PCMs, and hybrid Nano PCM in sustainable hydrogen production systems. An emerging and highly effective method for hydrogen production involves the use of proton exchange membrane (PEM) technology, which separates water into its constituent parts through electrolysis. Its susceptibility to performance deterioration over time, however, demandsroutine maintenance and component replacement, which negatively impacts operational effectiveness and cost-effectiveness. In this study, the PEM system for electricity and water heating was integrated with the evacuated tube collector and photovoltaic panel to produce hydrogen. Additionally, hybrid Al2O3 and SiO2 nanoparticles with a combined concentration of 0.1 % in equal shares improved the thermal characteristics of PCM in heat exchangers. The research result shows that the heat exchanger of the ETSC circuit with the hybrid nanoparticles enhanced PCM demonstrated improved thermal performance as well as increased hydrogen production. With hybrid nanoparticles enhanced PCM in the heat exchanger, the maximum energy and electrical energy were observed as246.5 kWh and 44.7 kWh, respectively. The ETSC efficiency, electrical efficiency, and PEM electrolyser efficiency reached their highest points at 93.1 %, 15.5 %, and 39.2 %, respectively. Furthermore, hybrid nanoparticle-enhanced PCM produces an average of 25.9 g of hydrogen.

Contribution to the Optimization of the Energy Efficiency of Fixed Collector Panel and Solar Tracking Systems Aimed at Technical-Economic Forecasting

Contribution to the Optimization of the Energy Efficiency of Fixed Collector Panel and Solar Tracking Systems Aimed at Technical-Economic Forecasting

Assessing the efficacy of flat-plate solar collectors using nanofluids in the climatic context of Kirkuk city, Iraq

Solar energy is a key renewable energy source. Research and development have focused on enhancing the heat transfer coefficient, heat gain, and practical efficiency of solar systems. The aim of this study is to evaluate the performance of a flat solar panel collector using a nanofluid under conditions in the city of Kirkuk/Iraq, 35° latitude and 45° longitude, in terms of practical calculation of thermal efficiency. The study included making two solar collectors, one traditional and the other improved using a nanofluid (CuO). The CuO/Water nanofluid was prepared with a volumetric concentration of 0.25 % by mechanical mixing and then ultrasonic mixing to homogenise the particles and eliminate the agglomerations that form inside the fluid. Practical testing was conducted for the two solar collectors, one using distilled water and the other using the nanofluid, during four months (January, February, March, and April) of the year 2023. The experiments revealed that the efficiency progressively improves from 9:00 a.m. to 1:00 p.m. This increase is attributed to solar radiation’s decreasing intensity post 12:00 p.m., while thermal storage and minimised thermal losses continue to contribute. After 2:00 p.m., the efficiency dwindles due to the declining solar radiation intensity. The practical efficiency of a 0.25 % nanofluid (CuO) attains its zenith at a mass flow rate of 0.015 ls−1. Higher mass flow rates enhance heat transfer within fluid-filled tubes. The collector efficiency at this flow rate ranges from 31.66 % in January to 44.44 % in April.

How can solar panels collectors enhance energy efficiency? Utilization of the novel optimization techniques

Abstract Solar energy, which is widely acknowledged for its economic feasibility and sustainable nature, functions as a critical substitute for finite fossil fuels, effectively alleviating ecological consequences. The purpose of this study is to investigate the implementation of solar collectors as a means of harnessing the ample and unaltered solar radiation in Iran, specifically in locations situated within the solar belt. The incorporation of solar energy not only aids in the expansion of energy sources through diversification but also mitigates the rising expenses linked to fossil fuels. The preservation of natural resources, coupled with limited renewable energy options, further accentuates the importance of solar energy. The optimization of solar panel collector angles in photovoltaic systems assumes paramount importance for maximizing energy efficiency. This study, conducted in Yazd, Iran, utilized innovative mathematical and particle swarm optimization (PSO) models to assess ideal inclination angles. Results indicate peak solar energy absorption during June and July, contrasting with minimal absorption in January. The Klein model prescribes inclination angles based on γ values, while the PSO algorithm determines optimal slope and azimuth angles across various periods. Significant enhancements in energy generation, ranging from 23.24 to 25.02% across optimization models, were observed compared to a horizontal surface. These findings underscore the imperative of optimizing solar panel placement in urban settings to augment energy generation. Utilizing the optimal orientation for the photovoltaic power supply system can result in an annual reduction of 1169.6 kg of CO2 emissions in the building, emphasizing the positive environmental impact achievable through strategic solar panel configurations.

Study on a novel water heat accumulator below the north roof in Chinese solar greenhouse: System design

The studies of using surplus energy in Chinese solar greenhouses (CSGs) are the background to conducting the research for this paper. This study presents a novel water heat accumulator below the north roof. The experiment analysis method investigated the possibility of heat collection and release below the north roof. And its independent heat collection efficiency can reach 0.21 W·m−2. The materials, forms, and coverings of the collector panels have been optimally explored in the experiment. The experimental results show that the polyethylene bag-type collector is the best. The heat storage and release are 11.01% and 19.56% higher, respectively. The average increase in thermal resistance ranges from 0.009 to 0.018 K·W−1 by the influence of covering. The significant finding is that the correlation coefficient between water and air temperature was between 0.83 and 0.85, much greater than the correlation between water temperature and radiation. This paper aims to provide a new perspective on the active heat storage and release system in Chinese solar greenhouses.

Performance Evaluation of an Indirect-Mode Forced Convection Solar Dryer Equipped with a PV/T Air Collector for Drying Tomato Slices

This paper proposes an indirect-mode forced convection solar dryer equipped with a PV/T air collector. The PV/T air collector generates both heated air and electrical energy, which are used to force convection in the solar dryer. Experiments were carried out on selected tomato slices for which the temperature and humidity readings as well as the masses of the dried samples were instantaneously recorded for two days. A thermal analysis was performed on the solar drying system to investigate its performance. The PV/T dryer’s air temperature and velocity simulation using CFD modeling were validated by the experimental results for which the drying chamber was empty, without tomato slices. The experimental and numerical results were in good agreement. The difference between the CFD model and the experimental results for air temperature was around 1 °C (3%) and 2 °C (5%) for the solar collector and drying chamber, respectively. The average daily efficiencies of the collector, dryer, and PV panel for the solar drying system were estimated to be 30.9%, 15.2%, and 8.7%, respectively.

Highly porous copper foam coated with graphene flakes and silver nanowires to cool overheated solar air heaters

Solar air heaters (SAHs) transfer radiative heat to the air flowing under irradiated panels. However, excessive heating can induce thermal stresses and cause malfunctioning of solar devices. Thus, a method to cool the panels is essential. We developed a highly effective method for cooling an overheated solar collector panel by increasing the surface area using a highly porous metal foam supersonically sprayed with graphene flakes (G) and silver nanowires (AgNWs). Notably, convective cooling via the textured surface only reduced the surface temperature without affecting the total amount of solar heat collected at the radiated side. The effect of G/AgNW texturing and the highly porous metal foam on cooling was assessed. The best G/AgNW-coated foam afforded a temperature reduction of ΔT = 18 °C and a 25.3% increase in heff compared with the bare case. In addition, G/AgNW texturing significantly increased the amount of solar heat collected, with a temperature increase of ΔT = 81 °C, because the G/AgNW surface promoted the trapping of radiative heat waves, similar to the perfect black body of a Helmholtz jar. Therefore, augmentation with a G/AgNW layer is recommended for both the solar heat collecting and convective cooling sides of an SAH panel.

Solar dryer using evacuated tube solar thermal collector with thermal storage

A solar dryer was developed using an evacuated tube solar thermal collector and solar photovoltaic (SPV) panel to supply the electrical energy. Paraffin wax was packed in a well-sealed aluminum package and stored in the bottom of the drying chamber near the entrance of hot air enabling recharge and store thermal energy. A DC fan was used to supply hot air to the drying chamber. The chamber was made of locally available material with glass wool as insulation. The overall dimensions were 0.6 m × 0.55 m × 1.05 m with 7.0 trays having 0.25 m2 per tray. The capacity of the dryer is 5.0 kg. The maximum temperature that could attain inside the drying chamber during clear sunny days was 45 to 60ºC. The efficiency of the dryer is 27%.

A novel liquefied air energy storage system with solar energy and coupled Rankine cycle and seawater desalination

To improve the round-trip efficiency of liquefied air energy storage (LAES) system by energy cascade utilization, a novel LAES system with solar energy and coupled Rankine cycle and seawater desalination is proposed. The thermodynamic model of the coupled system is established, and the technical advantages of the coupled system are investigated in four aspects: system energy efficiency, exergy efficiency, round-trip efficiency, and desalination. The results show that the highest system energy efficiency and exergy efficiency are 33.57 % and 44.34 %, respectively. When the system is coupled to Rankine cycle, the maximum system energy efficiency can be improved by 6.01 %, and the maximum system exergy efficiency can be improved by 9.24 %. The round-trip efficiency of the system can reach up to 132.20 %, which is 26.87 % higher than the LAES system with only solar collector panels. Furthermore, the system can produce up to 7079.51 kg of fresh water per hour and achieve a maximum water production ratio of 6.61. The coupling of solar energy, Rankine cycle and desalination can not only improve the efficiency of LAES, but also provide a new idea for the promotion and application of LAES.

Numerical Study on the Optimization Design of Photovoltaic/Thermal (PV/T) Collector with Internal Corrugated Channels

This study presents a theoretical study on the super thin and conductive thermal absorber with built-in corrugated channels on the basis of previous field experiments. The flow and heat transfer characteristics of the corrugated channels are simulated to identify the factors affecting photovoltaic/thermal (PV/T) system efficiency. The influences of the structural parameters such as the corrugation number, the corrugation area, and the flow channel width on the water outlet temperature and heat collection are discussed in order to support the structural optimization design of the hybrid PV/T system. The simulation results were validated to be in good agreement with experimental results. The results indicate that increasing inlet water velocity leads to a decrease in the outlet temperature. It was found that the corrugation area and the flow channel width have impacts on the outlet temperature of the hybrid PV/T collector panel. When the flow channel width of the absorber plate is reduced from 4 mm to 3 mm, the outlet temperature attained is between 298 and 302 K, and the heat collection is in the range of 16.2–51.4 MJ/h. This led to an increase in the amount of heat collected by 18.6%.

Energy harvesting of building skins - an innovative renovation for gas-free heating

Within the framework of the Horizon 2020 project ‘ENVISION’ we have developed a new invisible façade integrated collector panel with a colored solar harvesting coating. This coating system and façade panel is developed with paint company AkzoNobel, prefab element producer Emergo and The Netherlands Organization of Applied Research (TNO). The potential of thermal collectors integrated in the façade is surprisingly high with an annual energy solar gain of 2.5 – 3 GJ/m 2 in a south oriented façade and still a 1 GJ/m 2 in a north facing façade.Within the framework of the ENVISION-project [1], the performance of these façade collectors were tested at SolarBEAT, the outdoor research facility for innovative solar energy products of TNO. The performance of these panels is measured for different coatings. Laboratory tests have shown that even for the white façade collector up till 35% absorption can be achieved, using a nano-technology modified coating system. This means that we can include the technology seamlessly in all buildings with different colors. It will be a new heat source for heat pumps, next to the commonly accepted sources; air and water (from for example ground loops).After testing the solution at SolarBEAT, the technologies are demonstrated in demonstrations in Italy and the Netherlands. In Italy, the demonstration focuses at connecting the harvesting panels to a district heating network of the University of Genoa. In the Netherlands, three social houses in Helmond and three social houses in Eindhoven have been renovated using the panels in combination with heat pumps. In Helmond a prefab façade with integrated panels was demonstrated, as well as separate panels on the façade walls. In Eindhoven, besides panels on the façade walls, also an energy shed was developed and shown.By using the façade collectors with a surface area of 15m 2 as a cold source for a heat pump, sufficient thermal energy is harvested to completely heat a reasonable insulated row dwelling for a whole year, including a strong Dutch winter. In principle, the technology can also be integrated in pre-fab Roof solutions as well as provide cooling next to heating.

Study and Feasibility of a Flat Collector Cooker using Vegetal Heat Transfer Fluid

Solar cookers currently produced are solar systems that use parabolic heat transfer to concentrate sun rays on a cooker. The new trend is focus on the cooker that uses a flat collector operating as a thermosiphon where the heat transfer fluid (oil) flows by natural convection. They are developed to address household needs at a lower cost, making them popular both in terms of research and use. Some of vegetable oils were previously investigated and which could be used as heat transfer fluids in such systems. A digital study using vegetable oil called "Kibi oil", an artisanal oil produced in Côte d’Ivoire, as a coolant, was conducted under poor weather conditions to calculate temperatures that could be reached in these cases. In the Sahelian zone, conditions are much better than these, and we can expect fairly excellent results.
 This study focused on temperature variation at different areas (1, 2, 3 and 4 specified in the diagram) of the cooker, on the mass flow of the fluid throughout the study day and to some quantities which enable to follow the performance of the solar collector of the stove. Sunlight measurements used are those of the city of Abidjan made in September, a very cloudy day with poor weather conditions. Temperature T3, very close to that of the hot plate, was around 110 °C between 10:30 am and 12:30 pm, which enables to cook certain dishes during this period. It should be noticed that at the exit of the flat panel collector, over the same period, the temperature is around 120 ° C. At that same time, the collector efficiency varies around 30%.

Reduction in Heat Loss of Flat Plate Solar Water Heater by Modification in Material and Properties - A Review

Efficiency of solar water heater is in the range of 25-35% as out of 100% solar insolation, only 45% solar insolation can be used for heating purpose while 55% was getting waste due to heat loss by conduction, convection, transmittance, absorbance and radiation through absorber plate, collector glass, insulation material, piping, support structure etc. Heat losses from the panel are considerable (more than 50 components) due to prolonged withstanding of heat & cool cycles, physio-chemical reaction, lumpy insulation, gasket rupture, heat and cool cycles, poor water chemistry, ambient factors like wind/rain etc., pipe internal scales, acid and scales formation, radiation, conduction and convection losses through solar panel, gasket erosion due to condensate and UV light cracking etc.Heat gain can be achieved if temp. difference reduced (i.e. heat gain equals to product of heat removal factor ,transmissivity and absorptivity factor with removal of product of heat coefficient with difference of inlet temperature , ambient temperature therefore efficiency increased up to 69 % as per calculation improving the variables and control without sacrificing the performance, going towards ideal Carnot cycle. The passive system design is preferred (as there is no external energy input neither the pumps for increasing velocity). There is tremendous scope for improvement of efficiency by reduction of heat loss by use/substitution of non-thermal conducting materials, changing the material of solar water heater with better characteristics, changing orientation, geometry etc. There are about three main areas to be worked out i.e. solar collector panel, water tank and the inlet and outlet piping network along with water quality and taps, fittings etc. Major advantages of efficiency improvement are like reduction in electricity consumption for domestic water heating by 70%, reduction in conventional energy problems like global warming, pollution, acid rain etc.( as no fossil fuel required), cheap energy cost (i.e. less expensive than natural gas), easiness in source availability i.e. (average solar radiation by earth in energy equals to 722 W/m2 as for every 20 minutes the Sun produce enough energy to supply earth its need of entire year which can be converted to heat), energy security, benefit of accelerated depreciation/tax saving, meeting of renewable energy obligation, low operating and maintenance cost, possibility of direct conversion of solar energy(using PV cells ), inexhaustibility, ease for transport etc.

Performance analysis and optimal charging time investigation of solar air heater with packed bed sensible heat storage device

The amount of stored thermal energy and the stratification in the packed bed thermal energy storage systems decrease in the afternoon because of the reduction in the solar power and solar-air heater panel's collector outlet temperature, so the charging process must be ceased at a particular instant. The optimal charging period is determined by considering the degree of stratification, energy/exergy stored, and the energy discharged during the 6 h of space heating. The proposed packed bed is divided into three sections lengthwise. Different bed materials have been placed separately in these regions regarding their volumetric heat capacity to promote stratification and sensible heat storage during charging. The bed's stratification level is determined via an exergy analysis to evaluate the discharge efficiency of the bed. The particle diameter and discharge air velocity on the system's thermal and hydrodynamic performance are inspected. The fan energy consumption during the discharge process is evaluated in the analyses. Distinctively, the air velocity is varied to obtain a minimum heat load of 18 kW for 6 h discharge process. A transient, one-dimensional finite-difference model is developed and validated with an experimental study conducted in the literature. Thermal energy storage and the stratification level are improved thanks to segmented bed by 85% and 135%, respectively.

PV panels application for water boilers

PV panels price decrease with average efficiency growth is a stable trend for modern solar energy technologies. In these conditions several companies proposed control systems for solar water heating, substituting solar collectors by PV panels. Advantages and disadvantages for such scheme application in Russian conditions are discussed in this paper. Results of PV water heater experimental testing in Moscow climate conditions and numerical simulation of collector versus PV panels in several Russian region are also given, as the development of earlier economic estimations. Both maximum power point tracking (MPPT) PV array control scheme and array with constant load discharge have been tested. MPPT revealed better efficiency, but special controller without battery application is needed.

Research of flat plate solar air collector in drying

Solar drying technology has been widely used in engineering fields such us chemical drying because of its low cost and low pollution advantages. In this review, the structural forms, materials and coatings of the heat-absorbing panels of flat plate solar air collector are classified, and the experimental and theoretical results of the performance level of the solar air flat panel collector are summarized. In indoor tests, the energy efficiency of flat plate solar air collector is 30% to 79%, and the energy efficiency of flat plate solar air collector in drying applications is 28% to 62%.

Designing a laser-cut panel for light collection for daylighting using a generalised mathematical model

The current daylighting requirements require a system that can maintain a uniform light output throughout the day while enabling deep and controlled penetration of sunlight. If such a system is simple to manufacture, inexpensive and incorporates no moving parts and maintenance, it can easily fulfil all the daylighting needs. This paper focuses on the development of such a system using laser-cut panels. Mathematical models for determining the dimensions of a laser-cut panel and its efficiency were developed. A laser-cut panel collector was designed based on these models and simulated. The results showed enhanced light output at light pipe end by up to 47 times and 32 times as compared to a flat plate collector in the month of June and December, respectively and up to nine times for a dome collector for the designed range of sun altitudes. For this range, the ratio of pipe output to input was up to 4.5 times higher than the other collectors. The light at diffuser side was more distributed for the laser-cut panel collector. The current design, however, did not provide appropriate reduction in illuminance at peak hours in June. This approach can easily be used for light collection without involving any complex mechanisms.

First principles versus artificial neural network modelling of a solar desalination system with experimental validation

ABSTRACT The present study mainly focuses on enhancing the performance of solar still unit using solar energy through cylindrical parabolic collector and solar panels. A 300 W solar panel is used to heat saline water by thermal elements outside the solar still unit. Solar panels are cooled during the hot hours of the day; thus, reducing their temperature may lead to an increase in solar panel efficiency followed by an increase in the efficiency of the solar still unit. The maximum amount of freshwater used in the experiment was 2.132 kg/day. The experiments were modelled using ANNs. Based on neural network simulation results, there is a significant correlation between experimental data and neural network modelling. This paper compares experimental data with data obtained from mathematical modelling and ANNs. As a conclusion, the artificial neural network prediction has been more accurate than the simplified first principles model presented.

Life-cycle ecological footprint assessment of grid-connected rooftop solar PV system

ABSTRACT Solar photovoltaic (PV) power generation system is generally considered to be land-intensive in view of the diffuse nature of solar energy. However, a comprehensive assessment in this regard would involve bio-productive land for all types of resource consumption during the lifespan of the system. This study presents such an assessment for a grid-connected rooftop solar photovoltaic (RSPV) system located in a tropical climate. The life cycle ecological footprint (EFT) methodology has been used to derive the results based on material & energy consumption, water & manpower requirements along with waste disposal. This methodology is illustrated through an existing 1 MWp RSPV system installed at an educational institution in India. The total EFT is evaluated as 22.69 global hectare (gha) per year, out of which the environmental impact of solar PV panels is 76% of the total. The EFT per kWP capacity is 0.454 gha/kWP and the EFT per unit solar panel collector area is 0.074 gha/m2. The EFT of the RSPV system per unit electricity generation is 1.59 × 10−5 gha/kWh. However, considering only emissions from the grid-electricity in India, an approximate reduction potential of ecological footprint through RSPV-based electricity is estimated as 95%.