Efficiency Of Solar Collector Research Articles

A hybrid solar/biomass active indirect kiln dryer for timber in the Democratic Republic of Congo

This paper presents a small-scale pilot project in the Democratic Republic of Congo of a hybrid kiln dryer for sawn timber powered by solar and biomass energy. The chamber’s thermal insulation comprised layers of vetiver grass, wood and clay, 100% biodegradable. Sun collectors and a supplementary furnace-burning biomass from the nearby sawmill provided the heating energy, while photovoltaic panels supplied electric energy for ventilation and electric devices. The climate was controlled through actuators operated by an electronic system for industrial kiln dryers. Despite relatively high production costs, primarily due to the photovoltaic system, the kiln allowed for good use of local labour and materials. Preliminary tests indicated an improved drying potential of the kiln compared external conditions with a consequent lower drying time and final MC. Data emphasised the influence of thermal energy in the drying rate: the extra power given by the furnace increased the drying rate from 0.4 to 1.4% day−1. The cost of energy ($/kWh) was calculated as 0.009 for the furnace, 0.05 for the solar collector and 0.14 for the photovoltaic. The conversion efficiency of solar collector resulted to be 48% against 14% of photovoltaic.

Thermal performance improvement for parabolic trough solar collectors integrated with twisted fin and nanofluid: Modeling and validation

The low thermal efficiency of parabolic trough solar collectors (PTSCs) is a major drawback that has hindered their development as a viable renewable energy resource. Among the available methods to enhance the thermal performance of PTSCs, installing internal fins within the collector tube is one of the most reliable, economical, and straightforward passive techniques. However, while internal fins can significantly improve thermal performance in turbulent flows, they also lead to a substantial increase in pumping work. Here, we demonstrate that with an optimal design of helical fins, the thermal efficiency of PTSCs can be improved without causing significant pressure losses through the receiver tube. The results proved that higher thermal efficiency and lower pressure losses were achieved when annular fins are replaced by an axial helical insert. Installation of a helical fin with 4 turns and a height of 4 mm led to a 4.5 % increase in thermal efficiency (η) while raising the friction factor (f) by 30 %. Optimal performance was observed with helical fins having 10 turns. For instance, at Re = 105, switching from 16 to 4 turns of 8 mm helical fins resulted in η and Nu enhancements, and f reduction of 1.6 %, 33 % and 64 %, respectively. While these changes were 2.0 %, 55 % and 54 % when n reduced from 16 to 10.

Energetic and exergetic analysis of jet impingement solar thermal collector featuring discrete multi-arc shaped ribs absorber surface

This study analytically examines the thermal, effective, and exergetic efficiency of a jet impingement solar thermal collector (JISTC) roughened with discrete multi-arc-shaped ribs (DMASRs). To accurately estimate the energy usage of the JISTC, these efficiencies are assessed using a parametric design and the temperature rise parameter. A numerical model of the thermal, effective, and exergy analyses of the STC is presented to examine its impacts on each design variable. Optimized parameters increase exergetic efficiency () by 2.77 times over smooth plates. A multi-objective optimization of the JISTC roughened with DMASRs is carried out. Effective and exergetic efficiency are used as objective functions to find Pareto front optimal solutions. Additionally, an economic, enviroeconomic, exergoeconomic, and energy payback time (EPBT) examination of the JISTC is presented in this investigation. According to the economic evaluation of the JISTC system, the energy cost is found to be 0.08 $/kWh and the exergoeconomic parameter ( is computed to be 0.26 kWh/$. The enviroeconomic analysis findings suggest that the JISTC can reduce approximately 51.15 tons of CO2 emissions per year. The energy payback time based on energy streams () is determined to be 0.34 years, while the energy payback time based on exergy streams ( is found to be 14.9 years.

IoT Based Solar Tracking System with Automatic Dust Monitoring System

The most plentiful energy source available to all living things on Earth is solar energy. One way to generate power from sunshine is via the Solar Tracking System. This form of electricity generating uses renewable natural resources. It just needs the most sunshine possible to produce energy. This system tracks light levels to their maximum. By tracking the sun's movement and modifying the panel's angle and orientation accordingly, the technology maximises the effectiveness of solar panels. Using a dust sensor and a nozzle to spray water on the panel when there is a greater accumulation of dust, the cleaning system is used to remove the accumulated dust from its panel surface. Furthermore, the dust sensor continuously tracks the amount of dust accumulating on the panels and, if needed, initiates an automated cleaning procedure. Wi-Fi is used to transfer the system's data through Node MCU, allowing for real-time monitoring and analysis. The suggested system improves the efficiency of solar energy collection.

Parametric analysis of system performance and cost of heating systems with heat pump and latent thermal energy storage

This paper presents a parametric analysis examining the impact of phase change material (PCM) melting temperature, latent thermal energy storage (LTES) volume, and solar collectors’ surface area on the performance and costs of heating systems integrating a heat pump and LTES by using dynamic system simulations. The computational models, implemented in TRNSYS software, and the numerical procedure were validated by comparing the numerical results with experimental measurements. The computational models represent the entire heating systems and thus consider the mutual interaction of heat production, distribution and automatic regulation system as well as a building which represent the heat load, in transient boundary conditions. Two main system designs with different LTES roles were considered – a system in which the role of the LTES is to provide more favorable operating conditions and a system in which the LTES role is to store the heat on a sufficiently high temperature to be used directly for heating. System performance was analyzed in terms of the share of renewable energy in total delivered energy, power consumption, stored energy in LTES, seasonal performance factor, average solar collector efficiency and total annual costs. The results showed that, regarding the system in which LTES was used as a heat source for the heat pump, a better overall performance and lower costs were observed in systems with PCMs with melting temperatures in range between 19 and 29 °C, compared to systems with PCMs with melting temperatures outside this range. For system in which the heat from the LTES was used directly for heating, the highest values of system performance criteria and the lowest cost were achieved with the PCM of 54 °C melting temperature. Almost all of the considered system performance criteria and total costs were higher when the LTES volume and solar collector surface area were larger as well.

The effect of adding hybrid nanoparticles (Al2O3–TiO2) on the performance of parabolic trough solar collectors using different thermal oils and molten salts

Enhancing the operational efficiency of parabolic trough solar collector (PTSC) systems is key to the advancement of solar energy technologies that enhance power generation sustainability. In the quest for efficient, environmentally friendly energy sources, solar energy systems have been a major focus of both researchers and industry. Adding hybrid nanoparticles (Al2O3–TiO2) to different base fluids of thermal oil or molten salts and then simulating the PTSC's energetic and exergetic performance is pivotal to efficiency enhancement. The focus of this paper will be on three thermal oils Syltherm-800, Therminol VP-1, and Therminol 75 that are used as base fluids with the addition of hybrid nanoparticles. Molten salts such as Solar Salt, Hitec, and HitecXL, which are considered different base fluid types, are also simulated with the same hybrid nanoparticle combination. The inlet temperature is found to be a determining factor in the choice of the base fluid. Inlet temperatures in the range of 300–650 K for thermal oils with the addition of Al2O3–TiO2 have improved the thermal and exergy efficiency of the PTSC by approximately 0.99 % and 0.59 %, respectively. Therminol VP-1/Al2O3–TiO2 has the highest average thermal efficiency among other thermal oils, with an average percentage of 71.68 %, while Syltherm-800/Al2O3–TiO2 has recorded the highest exergy efficiency of 24.1 %. At higher inlet temperatures above 500 K mixing Al2O3–TiO2 with molten salts has increased both energetic and exergetic PTSC performance by approximately 0.60 %. Solar Salt/Al2O3–TiO2 has the highest average thermal and exergy efficiency of 61.8 % and 36.1 %, respectively.

Achieving solar-thermal driven dual functional device utilizing flexible PDA coated sponge integrated thermoelectric module design for water purification and power generation

The design of an efficient solar energy collector for solar-thermal-driven water purification and power generation is a promising strategy to concurrently mitigate the shortage of fresh water and energy crises. However, harvesting low-grade thermal energy in an eco-friendly and cost-effective manner through solar-thermal materials for water evaporation and electric cogeneration remains challenging. Herein, we demonstrate a dual-functional device integrating solar-thermally driven water purification and thermo-induced power generation. This typical design, fabricated via polydopamine (PDA) tightly deposited onto melamine sponges (PDA@Sponge) via H-bonds, along with a thermoelectric generator (PDA@Sponge/TEG), showcases superior solar-thermal-driven dual-functional application. The critically structurally adjustable PDA@Sponge possesses excellent homogeneity and stability, weakening interfacial hydrogen bonding between water molecules, favoring the evaporation and overflow of water molecules. The optimal serrated design achieves a water evaporation rate of up to ∼1.50 kg −2h−1, with an efficiency of ∼ 94.04 % under one sun, surpassing the most of previous reports, owing to its special tip thermal localization effect and rational water transportation management. Simultaneously, the designed PDA@Sponge/TEG yields an open-circuit voltage and short circuit current of 55 mV and 22 mA, respectively, along with a maximal output power of 162 μW (40.5 μW/cm2) at a load resistance of 7.5 Ω, under one sun and room temperature. Notably, such a device, after multiple series connections, can charge a capacitor to 1.5 V within 1 min, capable of powering low-energy electronic devices such as smartwatches and LED lights. By efficiently integrating of multiple solar-thermal-driven processes, our research promotes the design of multifunctional devices to promise an approach for desalinating seawater, purifying wastewater, and powering low-energy electronics, especially in remote areas lacking power stations and/or water treatment facilities.

Exploration Of Key Approaches to Enhance Evacuated Tube Solar Collector Efficiency

Exploration Of Key Approaches to Enhance Evacuated Tube Solar Collector Efficiency

Impact of absorber surface coatings on the thermal performance of non-concentrating solar thermal collectors: An overview

In this critical evaluation, the impact of absorber surface coating on the thermal efficiency (%) of non-concentrating solar thermal collectors (STCs) is examined and discussed. Absorber surface coatings enable an almost instantaneous conversion of solar radiation into heat. To achieve high sunlight absorption capacity and low solar emittance, several types of selective solar coatings are continually being developed. This review article offers a novel aspect based on extensive research that has been published in the past related to the impact of absorber surface coating on the thermal performance of non-concentrating STCs. The article demonstrates the commonalities in the results by thoroughly evaluating all the coating types that have the potential to influence STC's performance. An exhaustive examination of the available research from several studies shows that absorber surface coating enhances the STC absorber's capacity to absorb heat.

A comprehensive review of the influence of nanomaterials on the thermal performance of a solar thermal collectors

The present review article investigates the utilisation of nanomaterials with the aim of augmenting the thermal efficiency of solar thermal collectors (STCs). A comprehensive analysis is conducted on the STC through the utilisation of nanomaterials, leading to an improvement in its performance. This evaluation highlights the similarities in the results through an in-depth discussion on several types of criteria that might impact the performance of STCs. In order to justify and, finally, explain the behaviour of nanomaterials for the purpose of thermal augmentation of STCs, analysis was carried out and is being discussed here. This review article presents a novel aspect that is based on an extensive investigation that was based on a significant amount of research that had been published in the past. The study indicated that the use of nanomaterials may boost the heat-absorbing ability of the STCs.

Compression-assisted absorption refrigeration cycle employing organic working pairs for ultra-low grade heat recovery

Solar absorption refrigeration technology is considered an ideal alternative to energy-intensive refrigerated warehouses due to its decarbonization and environmental friendliness. However, it faces challenges in competing with vapor compression refrigeration, such as high driving heat source temperature (>100°C) and a long payback period. In this paper, we address these challenges by focusing on cycle structure and working pair, and propose a compression-assisted absorption refrigeration cycle (CARC) using R32/dimethylacetamide (DMAC) as working pair. The aim is to significantly reduce driving heat source temperature by adjusting absorption pressure utilizing an auxiliary compressor, enabling the cycle to be connected to low-cost and efficient non-concentrating solar collectors, thereby effectively shortening its payback period. This cycle includes two operating modes: CARC mode powered by solar energy during the daytime and vapor compression refrigeration cycle mode driven by off-peak electricity at night, ensuring 24-hour cooling capacity for refrigerated warehouses. The results indicate that this cycle can flexibly utilize 60∼80°C solar hot water easily obtained as driving heat source and its evaporation temperature decreases to -20°C. To assess its performance benefits, a compression-assisted absorption refrigeration system is developed and implemented. By utilizing the limited roof area of a refrigerated warehouse, it can achieve an 18.2% reduction in electricity consumption and a 24.2% reduction in carbon emissions compared to the vapor compression one annually. Additionally, during peak electricity demand periods in summer, the system exhibits significant energy-saving effects, and its payback period is about 4.2 years. Ultimately, this cycle provides a viable solution for energy-saving and emission reduction in refrigerated warehouses.

Energy and exergy performance evaluation of a drying coffee beans system using a photovoltaic–direct solar dryer at different drying temperature conditions

This study investigates the impact of various drying temperatures on the performance evaluation of photovoltaic – direct solar dryers in the coffee bean drying process. The use of photovoltaic systems in solar drying provides opportunities for the future to support clean and eco-friendly renewable energy. Three drying temperature conditions were tested, namely 40°C, 45°C, and 50°C, with the optimum temperature obtained at 50°C. During the drying process, the weather appears to be very sunny and cloudless, resulting in an average solar intensity of 974.36 W/m2. Utilising this solar dryer, it takes 12–16 hours for the coffee bean drying process to achieve a moisture content below 12.5% by the SNI 01-2907-2008 standard, starting from an initial moisture content of 45%. The drying and solar collector efficiencies ranged between 0% to 54% and 67.33% to 88.24%, respectively. Energy consumption is directly proportional to drying efficiency, depicted as the energy utilisation ratio (EUR), with the highest EUR being 22.96%. Meanwhile, the exergy flow (inlet, outlet, and loss) is directly proportional to the solar intensity, forming an open downward parabolic curve, with the average exergy efficiencies obtained at temperatures of 40°C, 45°C, and 50°C being 53.95%, 54.72%, and 56.88%, respectively.

Investigation of Thermal Similarity and Performances of Solar Thermal Air Collector with Heat-Soaked Vehicle Cabin

This article explores the potential of vehicle interiors, which can reach temperatures of up to 120°C due to solar exposure, as efficient solar collectors. Comparative studies have been conducted on the thermal behavior of heat-soaked vehicle cabins and dedicated solar collectors, highlighting their potential benefits in heating, cooling and ventilation. Thermal soak tests reveal a remarkable similarity in thermal performance between the two, with minor temperature variations of up to 5.3°C between the equivalent components. These temperature deviations are mainly due to differences in absorptivity characteristics, in which the black absorber plate exhibits superior absorption capabilities compared to the grey interior cabin surfaces. Integration of ambient air through the inlets on the cabin floor helps with initial cooling of the hot soaked cabin. The collector benefits from a preheated air mixture (comprising heat-soaked cabin air and ambient air), which improves its operating temperatures. This characteristic is attributed to the synergistic integration of the two systems. By decoupling these systems and aligning the properties of the absorber plate, the cabin and the collector could become thermally identical. The potential of the heated vehicle cabin as a power generation source is underscored, which presents opportunities to supplement the energy demand in remote locations. This study illuminates the untapped potential of vehicular solar heat capture, highlighting its feasibility, diverse applications, and significant implications for sustainable energy strategies and community development.

Design of solar thermal absorption air conditioning system using CO2 with synthetic building load

Traditional air conditioning and refrigeration solutions rely on compressor-driven systems, leading to increased electricity consumption and intensified greenhouse gas (GHG) emissions. These systems primarily utilize synthetic refrigerants such as CFCs, HCFCs, and HFCs. Despite their advantages, these refrigerants are either banned or subject to restricted permissions under the Montreal Protocol (1987) and the Kyoto Protocol (1997) due to environmental concerns. According to the Paris Accord, ratified by 196 parties as of 2017, there is a global shift towards low global warming refrigerants and eco-friendly alternatives. COP27 reaffirmed global commitments to limit temperature rise to 1.5 °C, emphasizing urgent action and stronger climate plans to combat global warming. CO2 envisaged by ASHRAE is resurrected as a promising natural refrigerant with the advent of high-pressure technologies the design employs a solar evacuated glass tube collector (EGTC) with U-shaped copper tubes and flat plate collector (FPC) to harness solar thermal energy. An immersed heat exchanger's (HX) based thermal storage tank is incorporated to address the intermittency of solar energy. The CO2 refrigerant offers advantages over other natural refrigerants due to its low critical point.This research conducts a TRNSYS® simulation of a 35.2 kW absorption cooling system with synthetic building load driven by energy captured through FPC and EGTC using R-744, additionally supported by a supplementary boiler for traditional office timing. The system design comprises two solar collectors, the EGTC and FPC, integrated with two different cooling loop configurations (C1 and C2). In C1, the hot water that exits the generator of the absorption chiller is forwarded toward the immersed HX-based hot storage tank, which is connected to the solar and absorption cooling loop. In C2, the working fluid leaving the absorption chiller is diverted directly toward the auxiliary boiler/furnace, if the temperature in the storage tank falls below the necessary level (108.89 °C) and if the tank temperature is greater than this set point temperature, then the flow passes through the storage tank. Both system designs have been developed using TRNSYS, with dynamic simulations conducted throughout the summer.The solar fraction and collector efficiency are considered as key performance indicators to evaluate and compare the system's effectiveness. Then the optimization of system parameters is performed for all four cases (EGTC C1 & C2 and FPC C1 & C2) based on these key performance indicators, all configurations integrated with a fixed synthetic building cooling load. The optimum parameters are found for all four cases, and the optimum parameters for EGTC C1 & C2 are 100 m2, 4 m3, and 11° for collector area, storage tank volume, and collector slope respectively. Similarly, for FPC based configurations, these parameters are 200 m2, 32 m3 for C2 and 4 m3 for C1, and 20° respectively. The results revealed better C2 performance than C1, with EGTC outperforming FPC. The final results were computed for the EGTC based designs due to their high solar fractions, with EGTC C2 emerging as the optimal configuration, achieving a seasonal solar fraction of 0.649.

Enhancing Parabolic Trough Solar Collector Efficiency through Absorber Tube Rotation: A Computational Study

This work uses CFD simulations to examine how absorber tube rotation affects parabolic trough solar collector performance, including output temperature, thermal efficiency, and surface temperature distribution. Simulation results are closely matched to experimental data, with variances ranging from 0.54% to 4.63%. It examines how mass flow rates (0.01 kg/s, 0.015 kg/s, and 0.02 kg/s) and input temperatures (32°C to 38°C) affect system performance in stationary and rotational modes at 1 and 2 rpm. Tube rotation considerably improves thermal mixing in the heat transfer fluid (HTF), resulting in more equal temperature distribution and possibly improved heat transfer efficiency. Increased rotational speed causes complicated dynamics that slightly impair thermal efficiency due to centrifugal forces affecting fluid flow patterns. The study shows that thermal efficiency peaks in the morning, emphasizing the importance of climatic and operational factors on collector performance. DOI: https://doi.org/10.52783/pst.276

Machine learning predictions for enhancing solar parabolic trough collector efficiency with corrugated tube receivers

Machine learning predictions for enhancing solar parabolic trough collector efficiency with corrugated tube receivers

ТЕХНИКО-ЭКОНОМИЧЕСКОЕ ОБОСНОВАНИЕ УСТАНОВКИ СОЛНЕЧНЫХ КОЛЛЕКТОРОВ ДЛЯ ИНДИВИДУАЛЬНЫХ ДОМОВ

The hot water supply system of Perm uses solar energy. The aim of the study was to substantiate the economic efficiency of solar collectors and determine their payback period taking into account climatic conditions, equipment cost and economic criteria. The proposed technical solutions of solar energy using were analyzed and compared with electric heating. During the study, the authors defined the required minimum solar collector area for a household (taking into account the hot water standard for Perm) as a functional dependence of the amount of incoming solar insolation on the amount of using heat energy. We evaluated domestic and imported solar collectors on the required parameters. The value of the reduction in the payment for electric energy was taken as the income for the households. The economic efficiency was calculated based on the forecasted average electricity tariff, taking into account inflation from 2 to 16 %. The payback of a solar hot water heating system depends primarily on the cost of purchase, installation of equipment and on the discount rate. The practical significance is to substantiate the economic efficiency of solar collectors for consumers. The methodology and results of the study can be used in private residential construction and in justification of the use of alternative energy sources for Russian regions with low insolation.

Microwave wireless power transfer efficiency analysis framework for a thin film space solar power satellite

Space-based solar power systems (SSPS) envision the usage of focused microwave beams to transfer power from space to ground. To supply a large amount of power and to be able to focus a microwave beam efficiently, a large infrastructure must be assembled in orbit, thus, making the implementation of SSPS an arduous task. In the history of SSPS designs, aside from economical obstacles, technical obstacles such as large ohmic losses due to long DC lines in the structure, large rotary joints to decouple beam pointing and solar power collection, heating problems from power lines converging into a single point, and complex control mechanisms, manufacture, and assembly are present. A simpler implementation using multiple foldable thin film membrane satellite modules is proposed as a feasible design, born from the advancement of thin film electronics. Its economical feasibility is achieved through the reduced weight, large surface area, and membrane’s ability to be stowed. The thin film SSPS combines advantageous properties of past designs such as a simple structure, simple control mechanism, and a distributed power collection and transfer architecture avoiding the ohmic loss and heating problems. However, due to the thin film membrane hosting both the antenna and the solar cells, competition occurs between maximum solar power collection and high efficiency power transfer capabilities. In this paper, we propose a framework to analyze the performance of the thin film SSPS solar cell-antenna integration design in terms of the wireless power transfer efficiency and fuel consumption, from which we identified the trade-offs on designing and operating the station. We used this framework to analyze three different antenna element designs in combination with three different attitude control goals, and found out that the key aspects of the antenna design are beam width, radiation efficiency, and efficient solar cell integration.

Investigative analysis of the influence of diverse fin configurations on the performance of a dual pass solar air collector

This study conducts a thorough investigation into the thermal performance of the double pass solar air collector, with a specific focus on the effects of three distinct fin configurations: parallel, vertical, and opposed. It is significant as it delves into the realm of solar air heating efficiency, a critical component in the broader application of solar energy technologies. Utilizing the geometric details and experimental findings, this study broadens its scope by examining a range of mass flow rates, specifically 0.0036 kg/s, 0.0110 kg/s, 0.0146 kg/s, and 0.0183 kg/s. Such an approach allows for a comprehensive understanding of the double pass solar air collector’s performance across diverse operational scenarios. The methodology is Computational Fluid Dynamics, which facilitates an in-depth analysis of temperature and velocity contours in both XY and YZ planes of the double pass solar air collector. The results of this study indicate that the parallel fin configuration significantly enhances heat transfer, evidenced by notable temperature increases, especially at the lower end of the mass flow rate spectrum. Conversely, while vertical and opposed fins result in greater pressure drops, they do not proportionally increase the temperature in a similar manner to parallel fins. The study concludes with a strong recommendation for the incorporation of parallel fins in future double pass solar air collector designs, particularly in situations where lower mass flow rates are predominant. This study contributes significantly to both the theoretical and practical aspects of solar collector efficiency, offering valuable insights for the development of more effective solar heating solutions.

A Numerical Study to Improve the Efficiency of Solar Collector used for water heating using Phase Change Material

Solar water heaters are an effective technology for harnessing renewable solar energy to provide hot water for households and businesses. However, their efficiency can be impacted by factors like intermittent sunshine, heat losses, and low radiation intensity. The aim of this study is to increase the efficiency of solar water heaters through the use of phase change materials (PCMs). PCMs have the ability to store latent heat during phase change, releasing it later when needed. This study uses numerical simulations to analyze the effect of integrating different PCMs into a flat plate solar collector design. The findings could then be validated experimentally and applied to improve the real-world performance of solar water heating systems. The PCMs are placed inside the collector to absorb heat during the day and release it after sunset to continue heating the water. The research seeks to determine the optimal PCM properties, structure, and placement within the collector to maximize heat storage and transfer. The efficiency and performance of the solar collector system with different PCM configurations have been compared to those of a conventional collector without PCM. The outcomes uncover that the use of suitable PCMs can significantly improve the efficiency and heat output of the solar collector, especially during periods of low radiation and after sunset. The optimal PCM configuration maintains higher water temperatures for longer, allowing solar water heating to continue into the evening. The results may provide valuable insights for using PCMs to boost the efficiency of solar thermal technologies