Collector System Research Articles

Interaction mechanism of interfacial nano-micro bubbles with collectors and its effects on the fine apatite flotation

This study focuses on the −38 μm apatite as the research subject and investigates the role of interfacial nano-micro bubbles (INMBs) generated by decompression techniques in the collector system of sodium oleate (NaOl) and dodecylamine (DDA). The results reveal that INMBs enhanced the flotation recovery of apatite using the collector NaOl while it had a slight inhibitory effect on apatite flotation with the collector DDA. The impact of INMBs on the apatite flotation was notable in pH 8–9, which could be attributed to the negative surface charge of INMBs. XPS analysis indicates that INMBs did not alter the collector adsorption by which the reagent molecules bonded with the apatite surface. AFM imaging and adsorption capacity experiments further reveal that the INMBs resulted in an adsorption density reduction of the reagent. This drop could be attributed to the nucleation and growth of INMBs, which effectively cleaned the collector molecules from the mineral surface. The transmittance test findings show that INMBs could significantly promote apatite aggregation in the collector system of NaOl rather than DDA. Overall, the difference in the roles of INMBs on apatite flotation using different collectors is considered as the combined influences of negative “surface reagent cleaning” and positive “fine particle aggregation”.

Bridging the gap: A comparative analysis of indoor and outdoor performance for photovoltaic-thermal-thermoelectric hybrid systems

This research evaluates the performance of a hybrid thermal-thermoelectric photovoltaic air collector system (PV/T-TE) through experimental investigations. By integrating photovoltaic (PV) panels with thermoelectric (TE) modules, the system aims to enhance efficiency and energy output by converting waste heat into additional electricity. The study examines the impact of radiation intensity, ranging from 455.65 to 795.18 W/m2, on the system's performance, utilizing output temperature (To) and plate temperature (Tp) as key metrics. Managing waste heat in PV technology remains a challenge, impacting efficiency. Traditional PV/T systems generate both electricity and thermal energy but suffer efficiency losses due to inadequate heat management. Integrating TE modules into PV/T systems offers a promising solution, but optimal configurations and performance impacts under varying conditions are underexplored. Limited research focuses on PV/T-TE hybrid systems, with most studies addressing PV-TE systems. The objectives of this research are to experimentally assess the impact of integrating TE modules on the thermal and electrical efficiency of PV/T systems under varying radiation intensities and air mass flow rates. The methodology involves setting up a PV/T-TE hybrid system, conducting experiments under controlled conditions, and analyzing key performance metrics. The study explores optimal TE module configurations and installation techniques to maximize heat transfer and electricity generation. Comparative analysis with conventional PV/T systems establishes the superiority of the hybrid system. Findings indicate significant benefits from incorporating TE modules, enhancing energy output and efficiency by maintaining optimal PV panel temperatures.

Comparative Numerical and Experimental Analyses of Conical Solar Collector and Spot Fresnel Concentrator

This paper aims to compare the thermal performances of the conical solar collector (CSC) system and the spot Fresnel lens system (SFL) using water and CuO nanofluid as the working fluids. The studied CFD models for both systems were validated using experimental data. At an optimal flow rate of 6 L/min, the SFL system showed higher optical and thermal performance in comparison with that of the CSC system. In the case of the SFL system, the availability of a greater amount of solar energy per unit collector area caused an increase in thermal energy. Moreover, in the case of the CSC system, the non-uniform distribution of solar flux on the absorber’s outer surface leads to an increase in temperature gradient and heat losses. As a heating medium, the CuO nanofluid outperformed the water in terms of higher thermal conductivity and heat capacity. The average thermal efficiencies of 64.7% and 61.2% were achieved using SFL with and without CuO nanofluid, respectively, which were 2.4% and 0.5% higher than those of the CSC with and without nanofluid. CFD simulations show a 2.80% deviation for SFL and 2.92% for CSC, indicating acceptable accuracy compared to experimental data.

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.

Development of a DNI Forecast Tool Based on Machine Learning for the Smart Operation of a Parabolic Trough Collector System with Thermal Energy Storage

In the research project Smart Solar System (S3), the Solar-Institut Jülich (SIJ) developed forecast tools to predict the direct normal irradiance (DNI) in hourly resolution for the current day. The aim of the daily DNI forecast is to use it as input to enable a smart operation of a parabolic trough collector (PTC) system with a concrete thermal energy storage (C-TES) located at the company KEAN Soft Drinks Ltd in Limassol, Cyprus. The main focus in this work is on the development of a DNI forecast tool based on long short-term memory (LSTM), which is a recurrent neural network (RNN), and its comparison with a DNI forecast tool based on analytical algorithms (non-machine learning). Only the non-machine learning DNI forecast tool with hourly update was tested in real-life PTC plant operation since end of 2022. The comparisons between the three DNI forecast tools show that the potential of using machine learning is very high. Different comparisons were made including an evaluation of the accuracy of the tool (i.e. comparison of the DNI forecast data with DNI measurement data). The DNI forecast based on the LSTM network proved to be more accurate than the non-machine learning DNI forecasts when considering errors greater than ±100 W/m2. The error of the LSTM network compared to DNI measurement data was as follows: 43.6 % of the data was within ±100 W/m2, 74.8 % was within ±200 W/m2, 89.8 % was within ±300 W/m2 and 95.8 % was within ±400 W/m2.

Flotation of Copper Sulfide Ore Using Ultra-Low Dosage of Combined Collectors

Copper sulfide ores frequently co-occur with pyrite, presenting a significant challenge for their selective separation during beneficiation processes. Despite advancements in flotation technology, there remains a critical need for efficient methods to enhance copper recovery while suppressing pyrite interference, particularly without compromising the associated precious metals such as gold and silver. Current practices often struggle with achieving high selectivity and recovery while maintaining environmental sustainability. Here, we investigate the efficacy of a ternary collector mixture consisting of ammonium dibutyl dithiophosphate (ADD), butyl xanthate (BX), and ethyl xanthate (EX) for the selective flotation of copper sulfide from a complex ore containing 0.79% Cu and associated precious metals (0.233 g/t Au and 5.83 g/t Ag). A combination of lime and hydrogen peroxide as inhibitors was employed to suppress pyrite effectively under alkaline conditions (pH = 11.33). The results demonstrate that the optimized ternary collector system (ADD:BX:EX at a ratio of 1:0.5:0.5) significantly improves the copper grade and recovery at an ultra-low dosage of 10 g/t. The optimized flotation method using the combined collectors and inhibitors effectively separated chalcopyrite from pyrite, achieving a copper concentrate with 20.08% Cu content and a recovery of 87.73%. Additionally, the process yielded notable recoveries of gold (9.22%) and silver (26.66%). These findings advance the field by providing a viable and environmentally conscious approach to the beneficiation of sulfide ores, potentially serving as a blueprint for processing similar mineral deposits while minimizing reagent usage and costs.

Performance optimization for solar photovoltaic thermal system with spiral rectangular absorber using Taguchi method

Solar collector systems efficiently transform sunlight into energy that may be used to meet various needs. This research aimed to use the Taguchi method to determine the ideal operating parameters for a solar thermal collector with a rectangular spiral absorber. Controllable parameters including mass flow rate, solar radiation, and absorber design were manipulated during the energy recovery process, and features like PV temperature and outlet water temperature were used to assess the system’s effectiveness. The findings indicate that certain criteria significantly affect response indicators. The observed percentage contribution of absorber design, solar radiation, and the mass flow rate was 69.19%, 27.99%, and 2.83% in PV surface temperature. In comparison, the individual percentage contributions were 73.63%, 13.51%, and 10.57% for absorber design, solar radiation and mass flow rate for water output temperatures. The present model’s R2 values for PV and outlet water temperatures are 97.24% and 99.67%, respectively. The Predictive regression model was found in fine harmony and the maximum percentage error is limited to 0.68%. The maximum analytical electrical efficiency was observed with a spiral rectangular absorber of 14.57% at the lowest mass flow rate of 0.04 kg/s at the lowest radiation level of 600 W/m2. In comparison, maximum analytical thermal efficiency was observed with a spiral rectangular thermal absorber of 63.56% at the highest flow rate of 0.06 kg/s and the highest solar radiation level of 1000 W/m2. The analytical and experiment findings were in better agreement in this study, with the highest relative error of 7.52%. According to the study’s findings, the rectangular absorber-based PVT system is at its best at a higher mass flow rate to lower PV temperature and boost thermal energy recovery via water. The present research work can be extended for exergy, environmental, and economic feasibility analysis.

Thermal Performance Solar Flat Plate Collector and Influence of Flow Pipe Design

Flat plate collectors are commonly utilized in both domestic and industrial applications to minimize energy consumption. In this study, solar flat plate collector (SFPC)) with corrugated flow pipe with ten turns placed over flat absorber plate and covered with single glass layer was fabricated and tested, in Al-Mussiab city, Babylon, Iraq (latitude 32.5◦N and longitude 44.3◦E). This research presents the effect flow pipe shape about the SFPC's thermal performance. The designed solar collector utilized employing of 12.5 mm-diameter corrugated copper tubing that extended 19500 mm in total length. According to different rates of water flow namely (50, 100, and 150 L/h). The results indicated that the working fluid's greatest temperature differential between the inlet and outlet of solar collector (12.9°C) at volumetric flow rate (50 L/h). The maximum thermal efficiency (Ƞth) rate of solar flat plate collector was (77%) at (150 L/ h). These results encourage the development of solar collector system and eventually help the sustainable use of solar power in home applications, including solar water heating system.

Flat plate solar collector activated with alumina-silicon dioxide-copper oxide hybrid nanofluid: Thermal performance study

Flat plate collectors (FPC) play a crucial role in solar-powered desalination by harnessing sunlight to purify water. They are acclaimed for their simple yet efficient design, as their dark, flat surfaces effectively transfer heat to the desalination system, making them a preferred choice for sustainable water treatment. Nevertheless, the performance of FPC systems is hindered by the working fluid, which reduces the productivity of distilled water, particularly without the use of nanotechnology to enhance the fluid’s thermal properties. This study aims to enhance the performance of FPCs in desalination processes by integrating them with conventional still systems and employing hybrid nanofluids. These nanofluids, composed of alumina (Al2O3), silicon dioxide (SiO2), and copper oxide (CuO) nanoparticles at concentrations of 0.3 % in 50:50 combinations, namely Al2O3/SiO2, SiO2/CuO, and Al2O3/CuO, are introduced into the working fluid (water). The integration of these hybrid nanofluids is evaluated in terms of thermal behaviour, including thermal conductivity, outlet temperature, energy gain, water productivity, and thermal and exergy efficiency of FPC. Among the different combinations, the Al2O3/CuO hybrid nanofluid demonstrates the highest thermal conductivity, outlet temperature, energy gain, water productivity, as well as thermal and exergy efficiencies, reaching approximately 0.631 W/mK, 87.5 °C, 568.7 W, 124.3 ml/m2, 61.4 %, and 6.7 %, respectively. The Al2O3/CuO featured flat plate solar collector system has the potential for an optimum system of addressing the pressing global issue of water scarcity.

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.

Silicon porous disc featured parabolic trough collector functioned with paraffin: Thermal performance study

The advancement of renewable solar energy has potential for industrial heat exchanger applications, and its performance is enhanced by using nanofluid. Besides, the losses of heat during the energy transfer from solar to heat exchanger limit thermal performance and lead to reduced thermal efficiency. The conventional solar system functioning with nanofluid needs to be upgraded with an advanced thermal management system to limit energy loss and enrich the thermal performance of the overall system. The investigation aims to enrich the thermal performance of a parabolic trough solar collector (PTC), which features silicon porous discs and phase change material (PCM-paraffin). During the investigation, the flow of fluid ranged from 100 to 200 LPH with an interval of 50 LPH. Influences of silicon porous disc and phase change material melting phase on fluid temperature, temperature, energy stored, and thermal efficiency of the present system are experimentally investigated, and its values are related to conventional absorber performance without porous material and phase change material. The output results prove the significance of silicon porous and phase change material related to conventional absorber systems. The parabolic solar collector functioned with silicon porous material with phase change material phase on 200LPH spotted superior thermal performance including fluid temperature, PCM temperature, energy stored by phase change material, and average thermal & exergy efficiency of 84.2 °C, 98.5 °C 599.7 kJ, and 73.8 % & 15.1 %. These findings underscore the promising potential of porous medium absorbers in significantly elevating the efficiency of parabolic trough collector systems.

Development of a solar-ocean based integrated plant with a new hydrogen generation system

Considering the global urgency to decrease carbon emissions and shift to sustainable energy sources, combining solar and other renewables with hydrogen generation appears to offer an appealing answer. The combination of solar and ocean energies with hydrogen production, therefore, offers a great potential to improve energy efficiency and create a feasible route towards zero-emission energy systems. A new hybrid photoelectrochemical (PEC)-conventional electrolysis system was designed and incorporated into the proposed multigeneration system. The hybridized reactor combines the benefits of PEC and conventional electrolysis by using a developed bipolar anode to produce hydrogen continuously, even when there is no solar radiation. The main aim of this research is to investigate the integrated power process that utilizes solar power for several uses, such as generating electricity, producing freshwater, and synthesizing hydrogen. The proposed research involves integrating several components, including a solar through collector system, a combination of power cycles (steam and organic Rankine cycles), a multi-effect desalination (MED) unit, a new hybrid electrolyzer system, a wave energy system, and a hydrogen storage and refuelling station. The main outputs include 2.05 kg/s freshwater production, 0.125 kg/s hydrogen production, 16,284.24 kW net work rate, and 95,068 kW solar heat input. The highest exergy destruction rates were found in the solar collector (56,194.8 kW) and turbines T1 and T2 (6019.9 and 4627.6 kW). The overall energy and exergy efficiencies of the proposed system are obtained to be 15.83 % and 16.61 %, respectively.

Optimization of thermal photovoltaic hybrid solar dryer for drying peanuts

The drying of agricultural products is traditionally carried out using solar radiation. However, this process is time-consuming and also unreliable in locations having cold and humid environments. This study experimentally investigates an innovative air collection system integrated with a dryer. The study focuses on the drying analysis of peanuts utilizing three operational modes of a solar dryer: forced convection, natural convection, and traditional open-sun drying. Key parameters including solar radiation intensity, moisture extraction, and outgoing air temperature from the collector were studied. Solar radiation served as the primary energy source, driving the solar dryer's operation within a drying air temperature range of 33 °C–58 °C, applied to 8 kg of peanuts. Initially, the peanuts exhibited a moisture content of 72 %. The developed solar dryer subsequently reduced the moisture content of the peanut by 18 %. The study evaluated three key aspects: electrical efficiency, thermal efficiency, and overall thermal efficiency of the proposed hybrid collector and solar dryer system, conducted from 9 a.m. to 4 p.m. Results indicate that the forced convection mode of solar drying outperformed the other modes, demonstrating superior effectiveness. These findings hold significant implications for the advancement of solar dryer technology, offering valuable insights for the wider solar drying community.

Immune algorithm-based optimal design of collector system topology for offshore wind farm

Immune algorithm-based optimal design of collector system topology for offshore wind farm

New Insights into the Depressive Mechanism of Sodium Silicate on Bastnaesite, Parisite, and Fluorite: Experimental and DFT Study

The surface properties of bastnaesite and parisite are similar to their associated gangue mineral, fluorite, which makes the flotation separation of these two rare earth minerals from fluorite one of the industry’s most significant challenges. This study systematically investigates the inhibitory effects and mechanisms of sodium silicate (SS) on bastnaesite, parisite, and fluorite in an octyl hydroxamic acid (OHA) collector system through flotation experiments, various modern analytical methods, and DFT simulations. The flotation test results indicate that the inhibition effects of SS on the three minerals are in the order: fluorite > parisite > bastnaesite. Detection and analysis results indicate that SS forms hydrophilic complexes with Ca atoms on the surfaces of fluorite and parisite, enhancing surface hydrophilicity and inhibiting OHA adsorption, but its impact on bastnaesite is relatively minor. DFT simulation results show that OHA forms covalent bonds with metal ions on mineral surfaces, favoring five-membered hydroxamic-(O-O)-Ce/Ca complexes, and reacts more strongly with Ce atoms than Ca atoms. SS primarily forms covalent bonds with metal atoms on mineral surfaces via the SiO(OH)3− component, and OHA and SS compete for adsorption on the mineral surfaces. OHA has a stronger affinity for bastnaesite, whereas SS shows the highest affinity for fluorite, followed by parisite, and the weakest affinity for bastnaesite.

Experimental analysis of the synergistic impact of fan and nocturnal thermal insulation on enhancing the thermal performance of latent-energy-storage solar air collectors

Solar air collectors equipped with energy storage functionality are widely utilized to address the mismatch between heat demand and supply periods during winter, effectively facilitating heating needs. However, phase change energy storage flat plate solar air collectors are hindered by inefficiencies, primarily due to the low rate of convective heat transfer and substantial nocturnal energy losses, which considerably undermine the overall energy efficiency of these collectors. In response to these challenges, a forced convection approach utilizing a fan was adopted to augment the convective heat transfer rate, and insulation was applied to glass panes overnight to curb energy wastage. Two solar air collector systems were constructed and examined: a natural convection-based energy storage solar air collector (NCSAC-PCM) and another solar air collector incorporating forced convection with nocturnal thermal insulation (FCSAC-PCM-NTI). Comparative experiments revealed that the combination of forced convection with nighttime insulation in the latter design led to an elevation in the mean indoor temperature by 1.4 °C, alongside a decrease in the temperature gradient variation within the space during the test period. Furthermore, this integration significantly enhanced the energy efficiency by 53.71 % and the exergy efficiency by 11.45 %.

Feasibility study of a metal hydride-based solar thermal collector system

The present study aims to assess the technical feasibility of a novel Metal Hydride-based Solar Thermal Collector (MH-STC) system. This system includes a flat-plate solar collector integrated with a metal hydride bed, a hydrogen compressor, a photovoltaic panel, a hydrogen tank, and a water storage tank. This system combines the principles of a conventional solar thermal collector with the energy storage capabilities of metal hydrides, enabling the storage of surplus thermal energy. The LaNi5 alloy was used as heat storage material. A 3D-mathematical model is established and a numerical code written in Fortran-90 is developed to simulate the dynamic behavior of the proposed solar thermal collector. It was shown that the developed 3D-model produces computational results that are consistent with experimental data. In addition, to check the accuracy of the mathematical model and numerical approach, the relative errors in the mass balance and energy balance were calculated and values of 0.054 % and 0.18 %, respectively, were obtained.The simulation results offer insights into the system's technical feasibility, revealing an overall efficiency of 90.6 %, the water temperature at the collector outlet can reach 357.3 K, and a water volume heated of 230.4 L under the considered operating conditions. Moreover, the results indicate that the proposed MH-STC system exhibits significant potential as a viable alternative for thermal storage in domestic hot water systems.

Urofacial (Ochoa) syndrome with a founder pathogenic variant in the HPSE2 gene: a case report and mutation origin.

Urofacial syndrome or Ochoa syndrome (UFS or UFOS) is a rare disease characterized by inverted facial expression and bladder dysfunction that was described for the first time in Colombia. It is an autosomal recessive pathology with mutations in the HPSE2 and LRIG2 genes. However, 16% of patients do not have any mutations associated with the syndrome. Despite the importance of neurobiology in its pathophysiology, there are no neurological, neuropsychological, or psychological studies in these patients. A 30-year-old male from Medellín, Colombia, with a significant perinatal history, was diagnosed with grade 4 hydronephrosis on his first ultrasound test. At 4months of age, symptoms such as hypomimia, lagophthalmos, and recurrent urinary tract infections started to manifest. Imaging studies revealed urinary tract dilatation, vesicoureteral reflux, and a double collector system on his left side, which led to the diagnosis of UFS. Multiple procedures, including vesicostomy, ureterostomy, and enterocystoplasty, were performed. At 20years of age, he achieved urinary sphincter control. Genetic analysis revealed a founder pathogenic variant, c.1516C > T (p.Arg506Ter), in the HPSE2 gene, which produces a truncated protein that lacks 86 amino acids. This variant is classified as pathogenic according to the ClinVar database for UFS. The mutation age is approximately 260-360years, and the two alleles share a 7.2-7.4Mb IBD segment. Moreover, we detected European local ancestry in the IBD segment, which is consistent with a Spanish introduction. Neurological examination, neuropsychological assessment, and psychological testing revealed no abnormalities, except for high stress levels. Clinical analysis of this patient revealed distorted facial expression and detrusor-sphincter dyssynergia, which are typical of patients with UFS. Genetic analysis revealed a pathogenic variant in the HPSE2 gene of European origin and a mutation age of 260-360years. From a neurological, neuropsychological, and psychological (emotional and personality) perspective, the patient showed no signs or symptoms of clinical interest.

Toward a sustainable dairy industry in Mexico: optimization of a parabolic trough solar collector system with passive heat-transfer enhancement techniques and a machine learning approach

Toward a sustainable dairy industry in Mexico: optimization of a parabolic trough solar collector system with passive heat-transfer enhancement techniques and a machine learning approach

Investigating the influence of nanofluid on photovoltaic-thermal systems concerning photovoltaic panel performance

Solar energy has much promise to replace the planet's finite supply of fossil fuels as it is sustainable and eco-friendly. Photovoltaic (PV) panels are one example of the proper technology that may transform solar energy into electrical energy. On the other hand, high temperatures may reduce photovoltaic cells' ability to produce power efficiently. As a result, a study was carried out to use the PV/T (Photovoltaic Thermal) collector system and evaluate the effects of CuO, TiO2, and Al2O3 nanofluids as cooling agents on the performance and operating temperature of PV panels. In Surakarta, Indonesia, an experimental study was conducted with nanoparticle concentrations of 0.2 vol% and a flow rate of 3 L/m at an intensity of radiation of 1000 W/m2. The results showed that, in comparison to uncooled PV panels, employing CuO, TiO2, and Al2O3 nanofluids in the PV/T system resulted in temperature reductions of 18.84 °C, 18.12 °C, and 17.62 °C, respectively. Moreover, measurements of the electrical efficiency produced by PV and PV/T panels using CuO, TiO2, and Al2O3 nanofluids showed that the respective values were 10.98%, 13.92%, 13.65%, and 13.39%. This study contributes to the development of solar energy technology by demonstrating the potential of nanofluid-based cooling devices to improve solar panel performance in hot conditions.