Collector Model Research Articles

Hybrid Nanofluids in Solar Thermal Collectors: Size and Cost Reduction Opportunities

Solar thermal collector, an alternative way to harvest renewable solar energy, requires high heat transfer area. Hybrid nanofluid has potential to reduce the size of the collector due to its high thermal conductivity and low specific heat capacity. This study investigates the effects of Multi-Walled Carbon Nanotubes (MWCNT) combine with metal oxides, including Al2O3, CeO2, TiO2, ZnO at the volume ratio of 1:4 between MWCNT and metal oxides with a total of 1 vol.% in water. The investigation focuses on assessing this nanofluids with 1 kg/min mass flow rate for its effect in size and cost reduction. Following the validation of nanofluids properties predictor and the numerical model of flat plate solar collector with experimental data, the effects in terms of size and cost reduction is evaluated. In best case scenario, the use of MWCNT-TiO2 can reduce the size of flat plate solar thermal collector by up to 8.54% and cost by 5.15% compared to using water as the heat transfer fluid.

Theoretical and experimental investigation of a pilot-scale solar air-heated humidification dehumidification desalination system

Among the various humidification dehumidification desalination (HDD) system configurations, the air-heated cycle has demonstrated promising results in small lab-scale setup investigations, whereas pilot-scale studies are lacking. This study theoretically and experimentally investigates the performance of a pilot-scale flat-plate solar air collector-powered HDD unit. An optical-thermal model for a solar air collector and a transport model based on heat and mass transfer for the dehumidifier have been developed and validated using experimental data. The triangular-shaped turbulators on the absorber plate of a solar collector with relative roughness pitches of 2.3, 4.61, and 6.92 are built and optimized for maximum distillate yield. Perforated turbulators with open area ratios of 5.5 %, 12.25 %, and 21.8 % are evaluated. To reduce distillate production costs in the HDD system, naturally available wood apple shell with drilled holes is tested in the humidifier. Outdoor test results revealed that at an average solar intensity of 712 W/m2, the proposed system achieved a maximum distillate yield and gain output ratio of 17.34 kg/day and 0.65, respectively. Wood apple shell packing demonstrated better distillate yield, gain output ratio, and humidifier performance potential factor compared to the commercially available raschig ring and cascade mini-ring packings. Moreover, the optimal performance of the solar air collector with solid turbulators was obtained at a relative roughness pitch of 4.61 due to sufficient longitudinal space to effectively prevent flow separation and reattachment of the free shear layer. Turbulators with a 12.25 % open area ratio exhibited the highest Nusselt number and low friction factor.

DCS-YOLO: Defect detection model for new energy vehicle battery current collector.

The future trend in global automobile development is electrification, and the current collector is an essential component of the battery in new energy vehicles. Aiming at the misjudgment and omission caused by the confusing distribution, a wide range of sizes and types, and ambiguity of target defects in current collectors, an improved target detection model DCS-YOLO (DC-SoftCBAM YOLO) based on YOLOv5 is proposed. Firstly, the detection rate of defects with different scales is improved by adding detection layers; Secondly, we use the designed DC module as the backbone network to help the model capture the global information and semantic dependencies of the target, and effectively improve the generalization ability and detection performance of the model. Finally, in the neck part, we integrate our designed Convolutional Block Attention Module (SoftPool Convolutional Block Attention Module, SoftCBAM), which can adaptively learn the importance of channels, enhance feature representation, and enable the model to better deal with target details. Experimental results show that the mAP50 of the proposed DCS-YOLO model is 92.2%, which is 5.1% higher than the baseline model. The FPS reaches 147.1, and the detection accuracy of various defect categories is improved, especially Severely bad and No cover, and the detection recall rate reaches 100%. This method has high target detection model efficiency and meets the requirements of real-time detection of battery collector defects.

Integration of energy storage and determination of optimal solar system size for biomass fast-pyrolysis

This study presents a model and analysis of a heliostat field collector (HFC) system integration with fast-pyrolysis of biomass and determination of the optimal solar system size for this integrated system. Given the intermittent nature of solar energy, an auxiliary heater and a thermochemical energy storage system (TCES) are included. Four cases of HFC integration with the fast-pyrolysis process have been studied: 1) low solar radiation, 2) sufficient solar radiation, 3) high solar radiation, and 4) no solar radiation with available stored energy in TCES. The solar energy system was modeled and calculated using the Engineering Equation Solver (EES) software, while the fast-pyrolysis process and the TCES were simulated using the Aspen Plus software. A thermodynamic and economic analysis has been conducted to estimate the share of solar energy for different process configurations. Economic calculations have been conducted for three different heliostat filed areas: 4000, 8000, and 12000 m2. Solar fraction, investment and operational costs, as well as total cost were calculated for these three heliostat field areas. The results indicate that the optimum heliostat field area for the studied biomass pyrolysis plant is 8000 m2 and the average solar fraction of the required energy in summer is 0.39 and while it is 0.34 for the whole year. Simulation results considering this optimized heliostat filed area indicate that 6.27 t/h of bio-oil is produced from 10 t/h of hybrid poplar biomass. Implementing this solar-assisted system reduces CO2 emissions, increases efficiency of the system and lowers thermal energy requirement for the fast-pyrolysis process from 6 MW to 3.99 MW.

Contribution of bismuth melts to gold endowment in the Baolun gold deposit, Hainan Island, South China

Bismuth (Bi) melts and related polymetallic alloys can efficiently scavenge gold (Au) from Au-unsaturated aqueous solutions, contributing to the Au endowment in many hydrothermal deposits. However, original evidence for Au–Bi melts is often poorly preserved due to post-precipitation alteration. This complicates investigation of the liquid bismuth collector model in hydrothermal Au deposits. Here we present primary evidence for the occurrence of Au–Bi melt in hydrothermal systems through an examination of the Au–Bi phases and textures in the Baolun Au deposit (Hainan Island). This study found that maldonite, native bismuth, Au–Bi symplectite and Au–Bi melt blebs appeared successively following the precipitation of native gold. Notably, large Au–Bi melt blebs were well preserved in natural systems due to the rapid cooling of fluids. The mineral assemblages and their corresponding fluid physiochemical conditions suggest that the evolution of the ore fluids at Baolun was characterized by a continuous reduction in Au and Bi concentrations and Au/Bi ratios alongside decreasing fluid temperatures and sulfur fugacity (fS2). These observations offer direct evidence for Au scavenging by Bi melts in a mesothermal (275–450 °C), low-fS2 and reduced hydrothermal system, aligning well with the Au–Bi binary phase evolution established in metallurgy. As the fluid cooled further, the Au–Bi phases were subsequently overprinted by later Te–S-rich fluids, as evidenced by the formation of bismuthinite, jonassonite, and joséite-A around the Au–Bi phases. Importantly, our study reveals that the Baolun Au deposit ischaracterizedby a Au–Bi–Te hydrothermal system and that the metamorphic country rocks at Baolun are the major source of Au, Bi, and Te.

Energy and parametric optimization analysis of a novel double serpentine runner air-cooled PV/T assisted variable capacity air source heat pump system

Through different technologies, the solar energy and air source energy have been effectively used as renewable energies to address the heating problem in the cold area of Northwest China. However, there are very few researches on the comprehensive performance of heat transfer enhancement and airflow pressure drop in the solar collector, as well the dynamic matching performance between the air source heat pump system and energy load of building. To address the mentioned problems, we propose a novel double serpentine runner air-cooled photovoltaic/thermal collector assisted variable capacity air source heat pump (DSPV/TSAC-VCASHP) system. The summary of experimental and numerical results of the heat transfer characteristics of the double serpentine runner was used in the simulation model of the novel collector. The collector and air source heat pump system are connected in parallel with building room for space heating. The dynamic simulation model of the system was established and simulated using TRNSYS to study and analyze the power consumption, effect of key parameters, as well seasonal performance of the novel system. The simulated results show that the system could reach around 88 % power consumption lower than that of single air source heat pump system during the heating season.

Modeling and Numerical Simulation of a Parabolic Trough Solar Collector Connected to a Solar Tracker

Modeling and Numerical Simulation of a Parabolic Trough Solar Collector Connected to a Solar Tracker

Modeling and manufacturing of solar modules of different designs for energy supply of biogas plant

The article presents a description of the modeling and manufacturing of solar modules of photovoltaic, thermal and photovoltaic thermal designs intended to supply energy to a biogas plant intended for the production of biohydrogen and biomethane. Mathematical modeling of the photovoltaic module was carried out and the calculated temperature of the photovoltaic converters was determined, and also the photovoltaic module was manufactured using the process of sealing the photovoltaic converters with a two-component polysiloxane compound. Mathematical modeling of a solar thermal collector with water radiators in the form of a round copper tube, an oval copper tube, as well as a rectangular water cooling channel (“water jacket”) was also carried out, in which pressure losses and the amount of water heating were assessed. The distances between the rectangular channels of the water-cooling radiator for uniform heat removal were determined, and mathematical modeling of the thermal state of a solar thermal collector with a semicircular cross-section of the water-cooling radiator channel was carried out, after which the solar thermal collector was manufactured. Mathematical modeling of the total displacements of the components of a photovoltaic thermal module, the values of which do not exceed acceptable limits, was carried out, after which a photovoltaic thermal module was manufactured using the process of sealing photovoltaic converters with a two-component polysiloxane compound.

An experimental investigation of various trickle collector structures to enhance solar water heater efficiency

This study aimed to enhance the efficiency of the solar water heater (SWH) due to the increasing demand of renewable energy. It compared use three different solar collector models, namely Model A (square-shaped polycarbonate), Model B (v-corrugated zinc), and Model C (trapezoidal aluminium) to identify the most cost-effective configuration. The models were subjected to experiments in real operating conditions during the summer season in Indonesia. Various parameters, including solar radiation intensity, wind speed, inlet and outlet temperatures, and flow rate, were measured every 10 min from morning to afternoon. Additionally, the study employed a trickle and one-way flow rate system. The results showed that Model B achieved the highest total efficiency at 50%, followed by Models A and C at 47% and 34%, respectively. The 120 Lph flow rate exhibited better performance in absorbing useful heat energy than the 240 Lph flow rate. Based on these findings, all three models were recommended for the household-scale SWH applications. Model A showed the most promising economic value but had a shorter lifespan due to the tendency of polycarbonate to deform. In contrast, Model B and Model C, using zinc and aluminium, offered longer lifespans.

Numerical and Experimental Determination of Selected Performance Indicators of the Liquid Flat-Plate Solar Collector under Outdoor Conditions

The paper proposes applying an in-house mathematical model of a liquid flat-plate solar collector to calculate the collector time constant. The described model, proposed for the first time in an earlier study, is a one-dimensional distributed parameter model enabling simulations of the collector operation under arbitrarily variable boundary conditions. The model is based on the solution of energy balance equations for all collector components. The formulated differential equations are solved iteratively using an implicit difference scheme. To obtain a stable numerical solution, it is necessary to use appropriate steps of time and spatial division. These were found by comparing the results obtained from the model with the results of the analytical solution available in the literature for the transient state, which constitutes the novelty of the present study. The accuracy of the results obtained from the model was verified experimentally by comparing the measured and calculated history of the fluid temperature at the outlet of the collector. The calculation of the collector time constant is proposed in the paper as an example of the model’s practical application. The results of the time constant calculation were compared with the values obtained experimentally on the test stand. This is another novelty of the presented research. The analysed collector instantaneous efficiency was then calculated for selected outdoor conditions. The presented mathematical model can also be used to verify the correctness of the collector operation. By comparing, on an ongoing basis, the measured and calculated values of the fluid temperature at the collector outlet, conclusions can be drawn about the process of solar glass fouling or glycol gelling. The simplicity of the model and the low computational demands enable such comparisons in an online mode.

Energy and exergy analysis of a long-term nonlinear dynamic roll bond PVT solar collector model under Tunisian (North Africa) climatic conditions

Roll-bond type PVT modules drew little attention while offering a higher energy exchange area and an efficient heat transfer solution. Furthermore, comparative studies including exergetic assessment on PVT systems are very limited in the literature. In this paper, a novel and detailed nonlinear dynamic roll bond PVT model is performed under real-world weather conditions that provide reasonable and realistic system performance. By incorporating local solar, thermal, exergy, and electrical models based on five diode parameters, a thorough analysis is conducted. Likewise, a unique, rigorous exergy comparison between PV, thermal, and roll bond PVT systems is conducted. Results reveal that there appears to be a direct relationship between wind velocity and changes in ambient temperature which affect exergy efficiency. Higher irradiance and lower wind speeds lead to increased thermal losses, which lower the electrical exergy efficiency of the PV and PVT solar collectors.The exergy analysis reveals that a PVT system outperforms PV + ST, and findings show that for thermal and electrical parts, the yearly average efficiencies are 33.7 % and 12.27 %, respectively. Findings enable a fast and an accurate assessment of fill factor (FF), which is temperature-dependent, over the course of a year’s worth of PVT collector operation.

Анализ воздействия воздушных обтекателей на аэродинамические характеристики токоприемника при увеличенных скоростях движения

Objective: investigation of the aerodynamic interaction of the airflow and the pantograph, taking into account the uneven distribution of pressure on the side edges of the fairings. Methods: the research was conducted based on a theoretical approach that defines the methods of air mass mechanics using mathematical modeling on a computer with the use of software products that include tools for calculating hydrodynamics based on the method of CFD analysis in the Flow Simulation module of the SolidWorks software. Results: a solid-state model of the current collector with integrated air deflectors has been developed, which takes into account the interaction complex in the system “moving structure — deflector — current collector — nodes and elements of the contact suspension” in the context of aerodynamic resistance influence. Practical importance: an innovative system has been developed to optimize the aerodynamic characteristics of the current collector during its motion in the air environment, an air deflector that contributes to reducing the negative impact of aerodynamic resistance, reducing the turbulence of air masses and improving the efficiency of current collection.

Comparative analysis of machine learning models of linear Fresnel solar collector

Modeling solar plants, like Linear Fresnel Reflectors, plays an essential role in analyzing plant characteristics, assessing overall efficiency, designing appropriate controllers, and optimizing system's operation. Although physical modeling approaches are widely used, their accuracy when compared to real operational data is deficient. In this context, this paper conducts a novel and comprehensive investigation for an existing Linear Fresnel Reflector using six distinct machine learning algorithms namely, Multilayer Perceptron and LSTM Neural Networks, Random Forest, Decision Trees, Extreme Gradient Boosting, and K-Nearest Neighbours to forecast the useable output power of a linear Fresnel solar plant. Datasets between May 2018 and September 2019 with a 30-s time interval from a linear Fresnel plant located in Nicosia, Cyprus are used in this research. Seven distinct statistical metrics, in conjunction with the computation time are employed to assess the performance of the different machine learning models. The objective of this study is to further improve the prediction of Linear Fresnel Reflectors performance using machine learning model, in order to increase modeling reliability on an annual basis. Outcomes reveal that, among the various models considered, K-Nearest Neighbours demonstrated the most optimal performance with a coefficient of determination 98.81 % and a mean absolute percentage error of 1.975 %.

Full year performance analysis and steady state operation model for a stationary Shadeless solar thermal collector with a horizontal aperture for steam generation

This work documents a full-year performance of a new design of a non-tracking zero-latitude-tilt external compound parabolic concentrator (XCPC) solar thermal system called Non-tracking Asymmetric Shadeless (NASH) concentrator. The system has a horizontal-aperture design that offers several advantages in terms of land use efficiency because of zero row-to-row spacing, reduced capital costs, and improved heat management. The horizontal aperture (no tilt) design enables it to be scaled to a large area easily without lost area from row-to-row shading as experienced by a tilted design. The system was tested at the University of California Merced, Castle test facility for a full year. The data are analyzed to investigate the system efficiency and thermal energy generated during the year. The system generated 766 kWh/m2 during 2022 with annual efficiency of 41 %. A steady-state model is developed to predict the system performance based on the direct- and diffuse-light optical efficiencies, radiative and manifold heat losses, and observed soiling rate. The system efficiency decreased by up to 14 % over a month due to soiling in this test location. The model gives a good estimation of the steady-state operation during July and predicts the general annual trend of the generated thermal energy.

Numerical analysis of an innovative solar collector utilizing bistable composite laminates and macro fiber composite actuators

Innovative designs for solar collectors have attracted substantial academic and industrial interests owing to the high efficiency of solar panels in the recent past. This paper proposes the analysis and numerical design of a novel solar collector model composed of bistable laminates bonded with Macro Fiber Composite (MFC) actuators and solar cells. The bistable cross-ply laminate serves as the steering mechanism in this design by providing multiple stable shapes for the innovative solar collector design. Bistable morphing structures have received growing interest in aerospace structures and wind turbines due to their rapid shape-changing ability in response to changes in operating conditions, and this paper aims to integrate them more into the solar energy sector. The snap-through and snap-back motion of bistable laminates can be controlled by the voltage inputs of MFC actuators. The change of bistable laminate shape holds the solar cell in a position approximately at the latitude angle of the place to capture maximum solar energy. A systematic finite element parametric study has been performed to identify the optimum size and location of MFC actuators to achieve an energy-efficient snap-through and snap-back transition. As a result, a numerical design of a solar collector with six bistable elements has been proposed. In order to check the feasibility of the proposed designs, a numerical study has been performed to evaluate the total energy output and to optimize the solar panel tilt angle. ASHRAE’s solar irradiation model proposed in the literature has been used to identify the optimum solar panel tilt angle for maximum annual solar irradiation. This innovative solar collector model has demonstrated promising results, holds the potential for widespread application across various engineering domains, and paves the way for increased adoption of intelligent structures in everyday life.

Design and Analysis of Fugitive Dust Emission Collector

This creative project explores the design and analysis of a novel fugitive dust emission collector, with a focus on its application in stone crusher units and crematorium facilities. Recognizing the detrimental health and environmental impacts of dust emissions, this project proposes a multifaceted approach. The core solution involves a combined system, this captures and removes larger dust particles through established methods like cyclones or bag houses. Dry fog dust suppression system, this technology utilizes atomized water droplets to suppress smaller fugitive dust particles, preventing their airborne spread. This project delves into the specific needs of stone crusher units and crematorium facilities. Utilizing CAD software, 3D models of the emission collector will be created, incorporating considerations like material selection, efficiency and airflow optimization, integration with existing infrastructure. Computational fluid dynamics (CFD) analysis by Simulating airflow patterns and dust capture efficiency within the collector. Assessing the collector's ability to withstand operational loads and environmental factors. This project aims to achieve, reduced fugitive dust emissions, enhanced environmental compliance, improved operational efficiency. Overall, this creative project showcases an innovative approach to fugitive dust control, potentially leading to improved environmental and public health outcomes in diverse industrial settings

Mathematical Model of Parabolic Trough Collector with Fresnel Lens as Second Collector

Parabolic trough collectors (PTCs) have came out as a promising technology for harnessing solar energy for various applications including electricity generation and thermal heating. However, improving their thermal performance remains a critical challenge to maximize energy conversion efficiency. This paper presents a mathematical model for enhancing the thermal performance of PTCs by using a curved Fresnel lens as a second collector over the top side of the receiver. This enhancing has taken advantage of the space above the top side of receiver and increased the thermal efficiency of PTCs. The unsteady heat transfer equations with one dimension are used to simulate the effect of Fresnel lens on the receiver components beside the heat transfer fluid and compared with that without Fresnel lens. The results of this model are based on parameters of LS-2 model and environment of installation place whereas the water was chosen as heat transfer fluid with physical properties depending on Temperature. Al-Baydha city in Yemen is chosen as an installation place taking in consideration the variation of environment temperature in each month of the year and the inlet temperature of water and receiver‘s components are taken as the minimum temperature of the air. Keywords: Mathematical Model; Parabolic Trough Collector; Fresnel Lens ; Solar

Simulation model of a flat plate air solar collector

Simulation model of a flat plate air solar collector

Development of a Self-Regulating Solar Shading Actuator Based on the Thermal Shape Memory Effect

In the field of adaptive building technologies, this research introduces the development of a self-regulating solar shading actuator that utilizes the thermal shape memory effect. The study focuses on addressing the actuator’s performance under diverse environmental conditions. Thermal simulations were carried out during the development of the individual components of the actuator and for the prediction of specific switching temperatures. The investigation includes an analysis of the sunshade’s response to varying environmental conditions, emphasizing its effectiveness on clear summer days and identifying challenges during overcast periods. The critical coordination between the solar collector and the shape memory alloy (SMA) wire is examined, shedding light on the impact of SMA temperature dynamics on the actuation performance. Through the integration of simulation data and real-world measurements, the study validates the thermal model for the solar collector, establishing the robustness of the system’s operation. This research work contributes significantly to the development of intelligent actuators and outlines the importance of validation of SMA-based applications under real conditions.

An experimental investigation of the thermal performance of solar collectors utilizing finned aluminum can pipes

An innovative experimental study is presented to improve the performance of solar collectors designed for solar drying systems, focusing on the use of recycled aluminum can waste and the development of the air solar collector. The latter’s absorber is made up of 10 cans with a diameter of 65 mm, a length of 160 mm and a thickness of 0.3 mm, forming a cylindrical finned pipe. Several collector configurations under identical weather conditions, including four collectors with different rows of rods (4, 8, 12–14 rows) and a single collector, were analyzed and compared. The thermal performance of this new collector model was assessed on the basis of solar fluxes and collector inlet and outlet temperatures, collected during the month of September 2021. Experimental results revealed that this collector can increase the outlet temperature of air from 32°C up to 130°C, in the case of a 14-row collector. The study also showed that, at low flow rates, the can-equipped collector achieves an efficiency of 54% for the case of a 14-row collector, compared with 34% for the simple case, representing a 20% improvement over the single case. The study also showed that, at low flow rates, the can-equipped collector achieves higher outlet temperatures.