Parabolic Trough Solar Collector Research Articles

Numerical investigation of the overall thermal and thermodynamic performance of a high concentration ratio parabolic trough solar collector with a novel modified twisted tape insert using supercritical CO2 as the working fluid

Supercritical CO2 (sCO2) is favoured as the next-generation working fluid for advanced high-temperature and high-concentration ratio parabolic trough solar collectors (PTSC) due to the fluid’s low cost, availability and thermal stability at high temperatures. However, the lower thermal transport properties of sCO2 compared to conventional working fluids necessitate heat transfer enhancement of receivers using sCO2. In this study, a combined and extensively validated approach using Monte-Carlo ray tracing for optical analysis and computational fluid dynamics (CFD) for thermal and thermodynamic analysis were used to investigate the overall thermal and thermodynamic performance of a high concentration ratio sCO2-based PTSC with a modified twisted tape (MTT) inserts in the receiver. MTT inserts with twist ratios in the range of 2.0 to 4.0 and width ratios in the range of 0.75 to 0.95 were investigated. Results show enhancement of the heat transfer performance by up to 73% and thermal efficiency by 6%, and reduction of the receiver heat losses and circumferential temperature gradients when the MTT inserts are used. In addition to presenting results using the first law of thermodynamics, this study also considered the second law of thermodynamics by evaluating the entropy generation rates due to heat transfer and fluid friction irreversibilities. Results showed that the use of MTT inserts caused a reduction in the total entropy generation rates, with the lowest irreversibility occurring at a Reynolds number of 1,650,000 for a twist ratio of 2.0 and width ratio of 0.95.

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.

Energy/freshwater Sustainability in Urban Areas through a Novel Solar-Driven System with H2 production/liquefaction: Techno-Economic Evaluation and Multi-Objective Optimization

The application of solar-based power plants systems in cities offers various advantages. These include reducing reliance on fossil fuels, declining carbon emissions, and supporting efforts to address climate change. Additionally, solar energy enhances energy resilience, promotes economic growth, and generates employment opportunities through investments in solar infrastructure. The primary goal of the current investigation is to meet the daily energy requirements of environmentally friendly urban areas. The setup includes the utilization of various processes such as LNG regasification, parabolic trough solar collectors, dual-loop power cycles, reverse osmosis, and a unit for liquefaction and hydrogen production. The analysis shows that the evaluated plant generates a net output electricity of 1994 kW and has a levelized cost of electricity (LCOE) of 5.1 Cent/kWh. Furthermore, the system effectively caters to the water demand of 32.21kg/s and cooling requirement of 392kW for residential purposes. In addition, it exhibits the capability to generate hydrogen at a rate of 9.49kg/h, which is subsequently stored in a liquid state. The study findings indicate that adjusting the pressure of the compressor has a substantial influence on liquefaction work. Initially, the work increases with increasing pressure, reaches a peak, and subsequently declines. It is crucial to maintain the recommended pressure level of approximately 5MPa for optimal performance. This pressure level leads to an efficiency of 17.01% and a coefficient of performance (COP) of 0.16. According to the multi-objective optimization, the optimized system demonstrates a shorter payback period of 3.38 years compared to the baseline system's 4.03 years, despite having higher initial costs. Over a 20-year lifespan, the optimized system is more profitable, surpassing the baseline system by approximately $2.4 million.

Optimisation of Thermal Efficiency in Parabolic Trough Solar Collectors: A Numerical Simulation Study Across Seasonal Variations

Optimisation of Thermal Efficiency in Parabolic Trough Solar Collectors: A Numerical Simulation Study Across Seasonal Variations

Numerical study of parabolic trough solar collector’s thermo-hydraulic performance using CuO and Al2O3 nanofluids

The current study aims to boost the thermal and hydraulic performance of a parabolic trough solar collector by modifying the absorber tube with a porous obstacle insertion. The research investigates how porous media and nanoparticles together influence the system's thermal performance, considering factors like outlet temperature, average Nusselt number, average friction factor, thermal performance factor, and thermal efficiency at different mass flow rates. To achieve better thermal performance, the base fluid, water, is substituted with Copper Oxide (CuO)-water and Aluminum Oxide (Al2O3)-water nanofluids at concentrations ranging from 3% to 7% by volume. The experiments are conducted at 800–1000 W.m-2 heat flux on the outside tube surface. The finite element method discretizes the governing equations for 3-D fluid flow simulations conducted in COMSOL Multiphysics 6.1 software. The simulation is carried out considering four altered rates of mass flow, ranging from 0.015 kg.s−1 to 0.060 kg.s−1. The findings show that at a Reynolds number of 1428 and a 7% volume concentration, the maximum thermal performance factor recorded is 1.97 and 1.99 for Al2O3 and CuO nanofluids, respectively. Additionally, the absorber tube achieves maximum thermal efficiency of up to 77.93% and 79.03%. Also, the augmentation in the average Nusselt number ratio is 26.27% and 36.74% when using Al2O3 and CuO nanofluids, respectively, with the tube height-to-diameter ratio (h/D) set at 0.42. The average friction factor ratio was reduced by 2.9% using CuO nanofluids compared to Al2O3 nanofluids. Thermal efficiency was enhanced by 7.2% using a porous obstacle insert in the parabolic trough solar collector system compared to a non-porous system.

Performance study of parabolic trough solar collector using hybrid nanofluids under Jordanian weather conditions

Performance study of parabolic trough solar collector using hybrid nanofluids under Jordanian weather conditions

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

Performance analysis and machine learning algorithms of parabolic trough solar collectors using Al2O3-MWCNT as a hybrid nanofluid

The critical importance of developing solar energy technologies for sustainable power generation places a high priority on the crucial efforts to optimize the performance of parabolic trough solar collector (PTSC) systems. This study focuses on optimizing the volume frictions of the hybrid nanofluids (1% Al2O3− 2% MWCNT/Syltherm-800, 1.5% Al2O3− 1.5% MWCNT/Syltherm-800, and 2% Al2O3− 1% MWCNT/Syltherm-800) in order to attain the most effective performance of the PTSC system. A mathematical model to investigate the PTSC performance under various volume concentrations is developed. Furthermore, this study trained three machine learning models (Decision Tree, Support Vector Machine, and Artificial Neural Network) using the generated data from the developed mathematical model to predict the PTSC outlet temperature more quickly, with the goal of achieving higher accuracy with fewer inputs. The findings of this study indicate that the PTSC system exhibits higher thermal efficiency when utilizing a combination of 2% Al2O3 and 1% MWCNT/Syltherm-800, with an average thermal efficiency of 70.54%. Moreover, the Artificial Neural Network (ANN) was the most accurate model out of the three. It performed remarkably well, showing an astounding R2 value of 99.99%, a mean absolute percentage error (MAPE) of 4.8x10−5, a root mean square error (RSME) of 0.012, and a mean absolute error (MAE) of 0.0057.

Comparative study of silver-blood-based three binary nanofluids and thermal enhancement in a PTSC

This paper studies the similarity of silver-blood-based Carreau–Maxwell, Carreau–Oldroyd-B and Carreau–Jeffrey binary nanofluids on the parabolic trough solar collector. By the energy equations, Joule heating effects and nonlinear thermal radiation were integrated. The velocity slip condition by the solid–liquid interface was again worked out. In this model, magnetic field aspects and viscous dissipation were again taken into account. The converted construction was modeled into ordinary differential methods with the help of appropriate comparison applications. This governing relation on current flow problem was given graphically and determined mathematically by applying made-up MATLAB computational tool with the aid of renowned mathematical shooting methods bvp4c (Lobatto’s IIIa Formulae). This mathematical outcomes are given in tabular and graphical models. It was observed that the nonlinear thermal radiation aggregates the temperature profile. This skin friction was improved for greater values of magnetic parameter by 6.16%. Moreover, the local Nusselt number was reduced about developing values of radiation parameter into 71.78%. Moreover, these Casson–Jeffrey and Casson–Maxwell nanofluid models are more efficient than the Casson–Oldroyd-B nanofluid models.

A green hydrogen production system based on solar-assisted biogas steam reforming

In the context of a carbon–neutral world, biogas reforming technology has potential to realize the production of green hydrogen with distributed production. Traditional green hydrogen production system based on biogas reforming dependent on high temperature condition during the reforming process; besides, biogas is always identified as a free energy resource in existing studies. This study develops a new way for green hydrogen production based on solar-assisted biogas steam reforming. The heat demand in the digester is considered in the newly proposed system; thus, more reasonable conclusion in regard to system thermal performance could be draw compared with existing studies. An advanced biogas reforming process with high steam-to-carbon molar ratio by introducing a parabolic trough solar collector is designed. At the same time, coupled with the carbon capture scheme proposed by previous study, it has great potential to realize hydrogen production with negative carbon emissions. Combined with the carbon deposition analysis, system integrated thermal performances are compared within the margin of safety. High steam-to-carbon molar ratio in the new system obviously improves the hydrogen production rate, with a maximum increase of hydrogen yield reaching 24.21 kg/h. In addition, the heat supply capacity is also significantly enhanced, which can meet the heat load of the digester when the ambient temperature is 4.03 °C (the reference system is only 20.19 °C). In terms of the integrated thermal performance, the hydrogen production efficiency of the new system is 33.60 percentage points higher than that of the reference system. This study provides a new idea for green hydrogen production from the perspectives of low temperature condition and negative carbon emissions.

A Review of the Modeling of Parabolic Trough Solar Collectors Coupled to Solar Receivers with Photovoltaic/Thermal Generation

This paper is a summary of the last ten years of work on the study of parabolic trough collectors (PTCs) and compound parabolic collectors (CPCs) coupled to photovoltaic and thermal solar receiver collectors (SCR-PVTs). While reviewing the state of the art, numerous review papers were found that focused on conventional solar receiver collector (SRC) technology for solar thermal generation. However, there is a lack of review papers summarizing SRC-PVT hybrid technology for solar electric/thermal generation, which would be beneficial for researchers interested in this area of research. This paper provides a review of SRC-PVT hybrid technologies. The theoretical foundations for analyzing and modeling PTC and CPC concentrators coupled to SRC-PVT are described, with an emphasis on modeling through thermal resistances and energy balances. Additionally, this section provides a concise overview of previous studies that have addressed the modeling of PTC and CPC collectors coupled to SCR-PVT, as well as experimental information useful for the validation of new mathematical models of SRC-PVT.

Innovative new solar parabolic trough collector enhanced by corrugated receiver surface with PCM and turbulator inside

A solar trough parabolic collector (STPC) has a reflecting surface that is curved into the shape of a parabola. An implementation study on solar trough parabolic collector thermal performance with four different volumetric flow rate values showing the effect of the Reynolds number with multiple passive enhancement approaches was applied tothe solar collector. The first approach is to use a corrugated copper receiver tube, which increases the collector solar heat absorbed by increasing the receiver tube surface area and turbulence. The second enhancement method was done using paraffin wax PCM (phase change material). Phase change material is used as an athermal storage material for heat absorbed by the collector, increasing the outlet water temperature through the night while slightly affecting the day water outlet temperature. By applying this approach, the solar trough parabolic collector enhances the heat transfer rate by around 40 % for all the volumetric flow rates adopted in this work. The third solar trough parabolic collector enhancing method was done by adding a turbulator twisted tape inside the corrugated receiver copper tube. This approach method increases the solar trough parabolic collector performance by around 35 % for all selected volumetric flow rate values. Adopting the three enhancing techniques on solar trough parabolic collector increased the overall thermal efficiency to approximately 85 %. The solar trough parabolic collector heat transfer coefficient, pressure drop, and friction factor were also investigated. A comparison study with previous works was also adopted in this work, which proves a superior thermal performance of the Innovative solar trough parabolic collector of this work over the earlier studies work.

Investigation of the performance of a parabolic trough collector outfitted with annular absorber tubes

The current work recommends a novel absorber tube for parabolic trough solar collectors. Annular absorber tubes with and without spiral tape have been investigated as an alternative to conventional absorber tubes. This work employs numerical analysis through the usage of CFD code. The pitch ratio (P/D), width ratio (W/D), and height ratio (H/D) of the spiral tape are each different. Within the annular absorber tube, these ratios have an impact on the performance of heat transfers, pressure drop, and entropy generation. The results reveal that an annular absorber tube without spiral tape has a higher Nu ratio than a conventional absorber tube. In an annular absorber tube with P/D = 1.4, the Nusselt number increases. In an annular absorber tube, the spiral tape thickness ratio has no effect. The average Nu ratio is 24.5% greater at a height ratio of 0.3 than it would be in an annular absorber tube without spiral tape. The annular absorber tube's spiral tape's pitch ratio, thickness ratio, and height ratio all generate less total entropy than a conventional absorber tube does. The wall temperature of the absorber tube with the lowest spiral tape pitch ratio decreases, which results in a reduction in the thermal stress on the absorber wall. On the other hand, spiral tape and an annular absorber tube have a higher friction ratio. It exceeds the friction ratio of the annular absorber tube without spiral tape by 41.7 times.

Temperature homogenization control of parabolic trough solar collector field based on hydraulic calculation and extended Kalman filter

Parabolic Trough Collector fields serve as the heat-absorbing components in large-scale commercial solar trough power plants. However, they frequently encounter challenges related to uneven spatial distribution of solar irradiation and heat transfer fluid flow. These disparities often lead to temperature inhomogeneity across the field, thereby jeopardizing both the safety and economic efficiency of the collector field. To address these issues, this study first introduces a proportional-integral and feedforward based flow control strategy designed to stabilize the fluid outlet temperature in the collector field. Subsequently, a flow allocation scheme aimed at achieving temperature uniformity across individual collector loops is presented. This scheme relies on the effective irradiation estimates for each collector loop, calculated using the extended Kalman filter algorithm and a suggested hydraulic model. Simulation results demonstrate that these control strategies not only stabilize the outlet temperature of the collector field at the desired set value but also significantly diminish temperature variances among individual collector loops, with reduced computational overhead. The maximum temperature difference between loops can be reduced from 126.3 °C to 12.7 °C under uneven radiation intensity, ranging from 563 W/m2 to 885 W/m2, by the proposed temperature homogenization control strategy.

Thermal Performance Analysis of an Indirect Solar Cooker Using a Graphene Oxide Nanofluid

Solar energy has become an energy source for a wide range of uses, including in solar cookers, due to its availability, cleanliness, environmental friendliness, and sustainability. In this study, an indirect solar cooker was investigated by measuring its thermal performance using a Graphene Oxide (GO) nanofluid. Water, GO (250 ppm)-water, and GO (500 ppm)-water were used as heat transfer fluids. The experimental set-up consisted of the cooking part and a solar collector, which are the two essential elements in indirect solar cookers. The cooking part was a wooden box solar cooker, and the parabolic trough solar collector was a polished stainless steel structure. The solar cooker was assessed using the stagnation test and load test as well as energy and exergy measurements. According to the test results, the averaged F1 was 0.1 for the base fluid water, 0.11 for GO (250 ppm)-water, and 0.13 for GO (500 ppm)-water. In addition, using a GO nanofluid instead of water in the solar cooker, the system’s thermal performance, energy, and exergy efficiency were improved. The use of the GO (250 ppm)-water and GO (500 ppm)-water nanofluids instead of water in the system improved the overall energy efficiency of the system by 3.3 and 4.2%. Moreover, using GO (500 ppm)-water allowed for achieving superior performance.

Design, modelling, environmental, economic and performance analysis of parabolic trough solar collector (PTC) based cogeneration systems assisted by thermoelectric generators (TEGs)

Concentrating solar power systems (CSP) is a very efficient technology for clean and renewable energy production. It basically works on the principle of focusing the sun's rays with the help of a reflective surface. There are two types of CSP systems: point-focused and line-focused. Point-focused ones are parabolic dish collectors and solar towers. Line-focused ones are parabolic trough collectors (PTCs) and linear Fresnel reflectors. It is possible to reach focus temperatures over 1000 °C with point-focused CSPs. Line-focused CSP systems are used to obtain thermal and electrical energy at temperatures below 500 °C. Among CSP technologies, PTCs are widely preferred. While it can be used alone, it can also be used in combination with other power generation systems by creating hybrid systems. In this regard, hybrid PTC/TEG energy systems created with thermoelectric generators (TEGs) come to the fore. These systems have higher electrical and thermal efficiency values compared to traditional PTCs. In this study, CSP systems, PTCs, TEGs and hybrid solar energy systems-based PTCs were examined in detail. It is concluded from the study that the total thermal efficiency of PTC-TEG hybrid systems can be enhanced by up to %70 with respect to PTC systems.

Alternative Approach for Thermo-Hydraulic Modeling of Direct Steam Generation in Parabolic Trough Solar Collectors

Abstract The implementation of direct steam generation in linear concentrators is limited mainly by the complexity and the high demand for computational resources of the models developed to predict the installation behavior. With this in mind, we introduce an innovative methodology to characterize the thermo-hydraulic behavior of direct steam generation in parabolic trough solar collectors, with a strong focus on two-phase flow phenomena. Our proposed approach has resulted in a generalized function that eliminates the need for the convective coefficient h and enables accurate prediction of the flow pattern within the receiver. By comparing our model with experimental data from the literature, we achieved relative squared errors (RSEs) values of less than 3% for temperature and pressure calculations, thus validating the robustness of our methodology. The Taitel and Dukler diagram confirms an appropriate flow pattern, while intermittent flow is observed initially during boiling; the pressure drop, although slightly elevated compared to direct solar steam (DISS) loop results, remains within acceptable limits; and the model demonstrates suitability for assessing liquid water, phase change, and superheated steam temperature evolution along the loop. Moreover, we further showcased the practical application of our developed model by applying it to a specific case study conducted in Agua Prieta, Sonora (Northwest México). The validated model exhibits versatility and is applicable to various cases, including both concentrating systems for electricity production and solar heat for industrial processes.

Novel entropy generation and optimization for hybrid nanofluid flow via ribbed surface parabolic trough collector

This research paper focuses on the optimization of parameters for deformative receiver tubes to achieve prime choice of design for efficient energy absorption. The motivation of the current study lies in addressing the critical need for optimizing parameters of deformative receiver tube to obtain optimal design to enhance energy absorption efficiency in Parabolic Trough Solar Collectors (PTSC). Considering the diverse criteria involved in the design process, the application of a Multi Criteria Decision Making (MCDM) approach proves beneficial. The primary objective of this study is to identify the optimal combination of parameters (Reynolds number (Re), Relative V-rib height (Rh/ Dt), Relative streamwise pitch (PStm/Rh), and Relative spanwise pitch ratio (PSpn/Rh)) of the deformative receiver tube of PTSC) employing the multiobjective optimization based on ratio analysis (MULTIMOORA) method. Additionally, a novel Pythagorean fuzzy sets (PFSs) entropy-based approach is proposed for quantifying the weights of the criteria. The feasibility and practicality of the novel PFSs entropy and MULTIMOORA method are demonstrated through the application of the Technique for Order of Preference by Similarity to Ideal Solution method (TOPSIS), confirming the attainment of Re = 50000, Rh/ Dt=0.0135, Pstm/ Rh=56.67 and Pspn/ Rh=11.11, as optimal alternative parameters. This research offers valuable insights into optimizing deformative receiver tube parameters to improve thermal performance which benefiting researchers in the concerned field.

Numerical analysis on ammonia decomposition for hydrogen production in a membrane reactor assisted by a parabolic trough solar collector

Ammonia (NH3) has emerged as a promising hydrogen storage carrier due to its considerable hydrogen storage density, storage and transportation convenience, and zero carbon emissions during endothermic decomposition. By utilizing a parabolic trough solar collector to provide heat and integrating NH3 decomposition with a membrane reactor, a clean and sustainable method of hydrogen production can be achieved. This paper establishes a comprehensive numerical model for NH3 decomposition within a parabolic trough solar receiver/membrane reactor (PTSMR). The model incorporates heat and mass transfer in porous catalyst beds, membrane permeation, and reaction dynamics to accurately capture the intricate phenomena under actual operating conditions. Special attention is paid to the influences of inlet temperature, flow rate, flow pattern, and reaction pressure on NH3 conversion and hydrogen recovery. The results demonstrate that the temperature distribution within the PTSMR exhibits non-uniformity, and the temperature at the bottom is always higher than that at the top, especially at the outlet, where the temperature difference is more than 100K. The NH3 conversion rate in counterflow is higher than that in parallel flow, while the hydrogen recovery rate in parallel flow is higher due to the reverse permeation of hydrogen in counterflow. For a 2-mm-thickness catalyst bed, the addition of membranes increases NH3 conversion rate by 9% at a reaction pressure of 5 bar, compared to a 3% increase for an 8-mm-thickness catalyst bed. The PTSMR with a 2-mm-thickness catalyst bed obtains the optimum hydrogen yield rate.