Trough Collector System Research Articles

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.

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.

Experimental study of parabolic trough collector in series having a concentric copper tube in evacuated tube for air heating

ABSTRACT Currently, the utilization of solar energy for domestic purposes, particularly in applications such as space heating and hot water, is constrained to flat plate collectors and evacuated tubes due to its compact size, absence of tracking mechanisms, low maintenance, and cost-effectiveness. The objective of this study is to evaluate the practical effectiveness of a locally developed parabolic trough collector system through experimentation. In this configuration, two parabolic trough collectors with one-ended evacuated tubes and inner concentric copper tubes for double pass airflow were connected in series, exhibiting an average air temperature within the range of 130.22°C to 166.72°C, which indicates its potential for use in industrial and domestic applications. Solar intensity, thermal performance, and pressure drop were determined after the first evacuated tube (intermediate point) and after the second evacuated tube. The experiments were carried out on six separate days, with three distinct airflow rates of 0.0056 kg/s, 0.0038 kg/s, and 0.0021 kg/s. Results discovered that the maximum air temperature reached was 210.5°C. The maximum thermal efficiency observed was 39.31%, with an overall average thermal efficiency of 30.56%. Further, the maximum pressure drop achieved was 510 Pa at 0.0056 kg/s.

Photo-Thermal Optimization of a Parabolic Trough Collector with Arrayed Selective Coatings

This work aims at enhancing the photo-thermal performance of a parabolic trough collector (PTC) system by implementing multiple coatings arrayed along the receiver tube. For this purpose, a lumped-parameter model was developed in the radial direction of the receiver tube to compute absorber tube wall temperature and heat losses at various heat transfer fluid (HTF) temperatures. The HTF is a mixture of molten salt (60%wt. NaNO3 + 40%wt. KNO3). The lamped-parameter model was exploited by a 1D model developed in the axial direction to determine the HTF temperature profile along the tube. The 1D model was employed to calculate photo-thermal efficiency at different HTF temperatures considering six selective coating formulations. Consequently, the most photo-thermally efficient configuration of the PTC system was determined, encompassing three HTF temperature ranges characterized by three different selective coating formulations. These temperature ranges were 290–436 °C (low temperature), 436–517 °C (medium temperature) and 517–550 °C (high temperature). The respective tube lengths were computed to be 792 m, 566 m and 293 m, considering the reference operational conditions. The optimal configuration enhanced the overall photo-thermal efficiency by 0.5–1.9% compared to the single-coated configurations. Furthermore, receiver cost could be reduced because of the employment of the more expensive coating only at the final segment.

Enhancing optical and thermohydraulic performance of linear Fresnel collectors with receiver tube enhancers: A numerical study

Linear Fresnel collector system is a type of solar thermal utilization installation. It is mainly used to focus solar radiation on the receiver tube to generate high temperature thermal energy which can be applied in many aspects. This study investigates five different types of receiver tube models using water as the flowing medium, which leads to improving heat transfer performance by means of being equipped with enhancers. The optical results and thermohydraulic performance of the Linear Fresnel collector system are evaluated through Monte Carlo Ray Tracing and Computational Fluid Dynamics (CFD) simulation methods. The obtained optical results reveal that the distribution of energy flux density concentrating on the receiver tube surpasses that of the parabolic trough collector system. In order to maintain an energy reception rate of 90.0% or higher, the installation height range of the receiver tube should be between 1468–1532 mm. When the sun-tracking error increases from 0.0° to 1.0°, the overall optical efficiency of the Linear Fresnel collector system decreases from 98.9% to 79.7%. The thermohydraulic performance shows that the enhancers can generate a swirling flow as its main feature, which effectively promotes the homogenization of the temperature field and destroys the boundary layer near the receiver tube wall, thus greatly improving the convective heat transfer in the receiver tube. However, the introduction of the enhancers also means that the pressure drop loss of the receiver tube increases. Furthermore, the impact of the Kenics mixer's enhancer on heat transfer and flow characteristics is further amplified as the rotation rate decreases, owing to its alternating and complex structure. Through a comparative analysis of the influence of different receiver tube models on Nusselt number (Nu), Frictional resistance coefficient (f) and comprehensive evaluation criterion (PEC) under four rotation rate conditions (y = 6.3, 8.1, 11.34, 18.9), the conclusions present that the receiver tube with an enhancer at a low rotation rate has a larger Nu than that at a high rotation rate, while the Frictional resistance coefficient changes little at different rotation rates. Therefore, the PEC is higher when the receiver tube is equipped with a low-rotation-rate enhancer. Moreover, the receiver tube equipped with a Kenics mixer at a rotation rate of 6.3 was found to be the overall optimum case, with the PEC value varying from 1.47 to 1.73.

Hybrid Solar Thermal Energy System for District Heating Application

Solar district heating (SDH) systems can be good alternatives to conventional systems when they are optimized with hybrid configurations and thermal energy storage (TES). In this scope, a hybrid renewable thermal energy system (RTES) model has been built combining flat plate collector (FPC) solar system with parabolic trough collector (PTC) system via a heat exchanger and coupled with TES. To undertake the hybridization of the system, System Advisor Model (SAM) software was modified, which allowed control over configurations and more accurate modelling of heat transfer between the collectors. The model is first compared to an existing hybrid solar district heating systems (DHS) system in Taars, Denmark. The results showed a good correlation with an overestimation of only 6.4% compared to most recent heat output. Then the same system configuration was modeled in different geographic locations to investigate the impact of changes in direct normal irradiance (DNI) to the heat sink thermal output of the hybrid system. The results showed that the annual net thermal power output in California, USA can be three times more than the annual net thermal power output in Taars, Denmark. Finally, multiple hybrid configurations with varying solar field sizes were simulated based on the heat demand of two different university campuses DHS. The results showed that, retrofit applications of this hybrid DHS system coupled with TES could reduce the natural gas consumption of the existing systems between 25% and 41%. The use of hybrid RTES highlighted in this paper can be extended to many more opportunities.

DNI Forecast Tool for the Smart Operation of a Parabolic Trough Collector System With Concrete Thermal Energy Storage

This work presents a basic forecast tool for predicting direct normal irradiance (DNI) in hourly resolution, which the Solar-Institut Jülich (SIJ) is developing within a research project. The DNI forecast data shall be used for 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. On a daily basis, 24-hour DNI prediction data in hourly resolution shall be automatically produced using free or very low-cost weather forecast data as input. The purpose of the DNI forecast tool is to automatically transfer the DNI forecast data on a daily basis to a main control unit (MCU). The MCU automatically makes a smart decision on the operation mode of the PTC system such as steam production mode and/or C-TES charging mode. The DNI forecast tool was evaluated using historical data of measured DNI from an on-site weather station, which was compared to the DNI forecast data. The DNI forecast tool was tested using data from 56 days between January and March 2022, which included days with a strong variation in DNI due to cloud passages. For the evaluation of the DNI forecast reliability, three categories were created and the forecast data was sorted accordingly. The result was that the DNI forecast tool has a reliability of 71.4 % based on the tested days. The result fulfils SIJ’s aim to achieve a reliability of around 70 %, but SIJ aims to still improve the DNI forecast quality.

Thermal performance evaluation of an indigenously designed small-scale solar parabolic trough collector for manufacturing Indian milk products

ABSTRACT A small-scale solar parabolic trough collector system coupled with a jacketed vessel was designed and evaluated for its performance and quality of the products manufactured in it. The prototype having a 7.026 m2 aperture and 88.38° rim angle was installed in Mehsana, Gujarat, India. The study was conducted in May–June 2022 at different flow rates of sigma therm-k. The useful heat rate ranged from 567.82 W to 861.25 W. The daily average thermal efficiency was obtained in the range of 9.81–14.61% and maximum thermal efficiency achieved during the milk trials was 31.51%. Similarly, maximum absorber temperature achieved during stagnation was 193.4°C and during absorber fluid flow condition was 146.5°C. The maximum convective heat transfer coefficient of 49.5 W/m2K was calculated at Reynold number 1822 and Nusselt number 24.12. It was found that the quality parameters of manufactured milk products were at par with domestic food safety standards. Direct normal irradiance was found to be the most influencing factor followed by the initial milk load. The present system is a potential substitute for various small-scale Indian traditional heat-desiccated milk products, where higher thermal efficiency is not the primary requirement and emphasis is more on the importance of ease of operation.

Design and evaluation of solar parabolic trough collector system integrated with conventional oil boiler

Design and evaluation of solar parabolic trough collector system integrated with conventional oil boiler

Enhancing the efficiency of solar parabolic trough collector systems via cascaded multiple concentration ratios

Solar parabolic trough collector (PTC) technology is clean and economical. However, PTC technology suffers from relatively low optical and thermal efficiencies at high operating temperatures and concentration ratios (CRs). In this work, a novel strategy for cascadingly using solar collectors with multiple concentration ratios in one collector loop is proposed to reduce optical losses and improve the overall performance of the PTC system. Two systems were studied for implementation of the proposed strategy: an ideal system employing multiple optimal CRs in distinct collector loop sections and a multisection system employing multiple practical CRs. An integrated optical model and two-dimensional heat transfer model based on finite volume and radiation heat transfer methods were developed in this study. These models proved to be highly accurate in estimating the thermal properties of solar collectors. At operating temperatures between 293 and 393 °C, the optical efficiency of the multisection system was 6.7% higher than that of a conventional system with a single CR. Under the same conditions, the thermal efficiency was improved by 4.5%. This work is anticipated to provide a reference for solar collector design and a new avenue for enhancing the overall efficiencies of PTC systems.

Investigation of the Influence of Inner Geometries of the Receiver Tube of a Parabolic Trough Collector System Used for Water Heating

Solar collectors are devices that help to harvest solar thermal radiation and convert into other forms of energy. Because of its low fabrication cost and simple design, the Parabolic Trough Collector (PTC) is one of the finest alternatives for medium-temperature (i.e., in 80°𝐶𝐶-250°𝐶𝐶 range) needs among all types of concentrated solar collectors. The absorber tube or the receiver tube is one of the main critical components of a PTC. Thermal radiation of the sun falling onto a parabolic reflector is reflected to its focal line where the receiver tube is placed. Therefore, the performance of a PTC system significantly depends on Receiver Geometries (RGs). A locally developed PTC system with a new and accurate tracking system was designed and fabricated in the current study and steam generation inside the receiver was considered in the performance analysis. The experimental analysis was performed using seven different RGs. The experiments were carried out by measuring generated steam every 10 minutes for all the RGs, and simultaneously, solar insolation data was taken by a domestic solar Photovoltaic (PV) system with a capacity of 5 kW. The steam generation data was taken only when the power output of the reference solar PV system was ≥ 4kW. Having tested seven different RGs, the researchers were able to improve the steam generation to a maximum of 10.0% compared to the reference geometry using direct experimental data. This was 8.1% in accordance with the statistical approach via multiple linear regression model. A three-dimensional mathematical model for two-phase flow was formulated for a closed domain. Restricting this model into twodimensional geometry, the steam generation process was simulated as a TPF problem using ANSYS Fluent software. The volume fraction profiles clearly show the phase transition, which leads to evaporation and condensation inside the tube.

Developing optical and thermal models with experimental validation of parabolic trough collector for moroccan industrial heat applications

This work presents the development of advanced optical and thermal models for parabolic trough collector systems (PTCs) through an extensive experimental study utilizing a PTMx-24 collector from Soltigua company, installed at Green Energy Park (GEP) research facility. The optical model leverages Tonatiuh software, employing the Monte Carlo Ray Tracing (MCRT) method. Moreover, a MATLAB script was adjusted to account for Incidence Angle Modifier (IAM) fluctuations in the optical analysis, while incorporating receiver thermal parameters for the thermal analysis. This study assesses the potential of PTCs in the territory of Solar Heat for Industrial Processes (SHIP) over various seasons within a semi-arid climate, offering invaluable insights for sustainable energy utilization. The validation of the models was conducted across four distinct days characterized by diverse meteorological conditions. The optical model demonstrates a remarkable correlation of 97.04 % between the MATLAB script and experimental results. Additionally, results from Tonatiuh software exhibited an important accuracy of 95.92 %. The thermal model showcased outstanding precision, revealing a correlation of 98.5 % compared to experimental results, signifying its adaptability to collectors of varying geometries and parameters. These findings highlight the predictive potential of these models, aiding in the decision-making process to determine the system's performance on specific days with specific meteorological conditions.

Thermal performance analysis of eccentric double-selective-coated parabolic trough receivers with flat upper surface

The Parabolic trough collector (PTC) system combined with molten salt energy storage system has gathered increasing attention owing to its advantages of high operating temperature and stable power output. However, the substantial heat loss experienced by parabolic through receivers (PTR) under high temperatures imposes limitations on the thermal efficiency and power generation potential of the PTC system. In this study, a novel eccentric double-selective-coated parabolic trough receiver is proposed. The upper surface of the receiver is flattened to further reduce radiation heat loss. Various distances from collector focus are explored to determine the most suitable opening angle of secondary selective coating, ensuring the highest thermal efficiency. The results show that, although the eccentricity causes partial optical loss, the reduced upper surface area and the resultant larger secondary coating opening angle contribute to a significant reduction in heat loss and an improved thermal efficiency of the novel receiver. The thermal efficiency of the new absorber can be improved by up to 20.59 % (under direct normal irradiance of 600W/m2 and a receiver surface temperature of 600 °C). Furthermore, the higher the emissivity and the lower the absorptivity of the solar selective coating, the better the performance of the novel absorber tube.

Techno-economic analyses of solar thermal process heat integration at South African beverage producers

South Africa's industrial sector relies primarily on coal and gas to meet process heat requirements (700–750 petajoules per annum). Much of this energy is used to fire steam boilers operated at less than 200 °C. This study determines the viability of solar thermal technologies as a replacement for fossil fuels for the supply of steam in large beverage facilities in South Africa. The Gauteng and Western Cape provinces are considered, which account for two-thirds of South Africa's beverage production. The sizing of collector fields and potential solar fractions are determined using typical ready-to-drink beverage packaging hall energy requirements. The cost of heat from parabolic trough collector systems is modelled using quasi-dynamic simulations in Polysun, and heat storage configurations are optimised. This study demonstrates that solar thermal projects would be viable alternatives to heavy fuel oil, diesel, gas, and even coal - should the cost of coal remain above US$250 /tonne (2020 real-term values). Transition to solar thermal energy for process heat in this sector is thus strongly recommended.

Thermo-economic assessment of hybrid Kalina cycle and organic Rankine cycle system using a parabolic trough collector solar field

This study presents a solar powered hybrid power system consisting the Kalina cycle (KC) and a bottoming organic Rankine cycle (ORC). LS-2 parabolic trough collector (PTC) is modeled in solar field with two different kinds of working fluid: Syltherm 800 and MXene/Syltherm 800 nanofluid. MXene particle (Ti3C2) is used with 0.1 wt% due to their outstanding thermal absorption properties. The use of MXene-based nanofluid has shown remarkable thermophysical properties, resulting in a significant increase in the useful heat generated by 11.10%. The hybrid system utilizing the MXene-based nanofluid demonstrates a substantial improvement in work utilization. Moreover, the maximum energetic and exergetic efficiency achieved with the MXene-based nanofluid are 6.095% and 6.55%, respectively, indicating its superior performance in converting solar energy into usable power with greater efficiency. When considering the overall cost of the MXene-based solar field, it was found to be approximately 7.63% higher compared to the Syltherm 800-based parabolic trough collector system. However, the Levelized cost of electricity (LCOE) for the Syltherm 800-based solar field was calculated as 0.1351 $/kW-hour, while for the MXene/Syltherm 800-based solar field, it was slightly lower at 0.1324 $/kW-hour. Additionally, the Payback period was reported as 5 years and 9 months for the Syltherm 800-based solar field, and 5 years and 7 months for the MXene/Syltherm 800-based solar field.

Optimisation and techno-economic assessment of parabolic trough collector system in Malaysia, China, and the United States

We evaluated the economic feasibility of installing PTC plants in several sites in Malaysia, China, and the United States with high solar irradiation or solar power plants. The average values of LCOE, NPV and CF for PTC power plants installed in the United States under optimum conditions are 11.92 USD cents/kWh, 47.95 million USD and 75.40%. Meanwhile, Labuan and Coara in Malaysia are two sites that are ideal for the installation of PTC plants, while Datong in China is the most favourable location for the installation of PTC power plants among the locations evaluated. Therefore, an equation relating the DNI to the optimum LCOE can be established, which recommends installing the PTC power plant in locations with DNI higher than 5.98 kWh/m2/day to replace the coal-fired electricity plant. Abbreviations: Avg: Average; Ch: China; Com: Commercial; CPV: Concentrated Solar Photovoltaic; CSP: Concentrated Solar Power; EES: Engineering Equations Solver; EIA: Energy Information Administration; HTF: Heat Transfer Fluid; IEA: International Energy Agency; Ind: India; IRENA: International Renewable Energy Agency; LFR: Linear Fresnel Reflector; Lit Rev: Literature Review; M salt: A Quinary Salt mixture doped with Hybrid; Graphene/TiO2 Nanoparticles; Mal: Malaysia; PPA: Power Purchase Agreement; PTC: Parabolic Trough Collector; PV: Photovoltaic; Res: Residential; SAM: System Advisor Model; SDG: Sustainable Development Goal; SM: Solar Multiple; SPD: Solar Parabolic Dish; SPT: Solar Power Tower; STE: Solar Thermal Energy; TES: Thermal Energy Storage; UN: United Nations; US: United States

Novel closed-loop dual control algorithm for solar trackers of parabolic trough collector systems

Parabolic trough systems require accurate, reliable, and robust solar trackers to achieve their maximum thermal efficiency. This paper presents a dual closed-loop control strategy for single-axis solar trackers of parabolic trough systems. This strategy consists of the use of a dual control feedback through the integration of a typical photodiode-based solar sensors, to perform the coarse control, and a proposed shadow-based visual device that performs the fine position adjustment. A comparative analysis between a simple closed-loop control, typically used in parabolic trough systems, and the proposed control algorithm was conducted. Experimental tests were carried out for several days under different weather conditions. The experimental results showed that the mean solar tracking error obtained with the simple control was 0.97°, while the error of the proposed dual control was 0.21°; i.e., the error decreased by 78%, demonstrating greater stability and robustness of solar tracking. The proposed strategy proved to be a technically and economically feasible option to increase accuracy, reliability, and robustness in single-axis solar tracking systems of parabolic trough systems.

Thermal performance investigation of the newly shaped vacuum tubes of parabolic trough collector system

The parabolic trough collector (PTC) system is currently the most mature technology for concentrator solar power (CSP) plants. However, the huge radiative heat loss under high temperatures is one of the major obstacles restricting its thermal efficiency and development to the higher temperature. To reduce the radiative heat loss, this study proposes a newly shaped tube (NS-tube) with flatted upper and lower surfaces based on the Negative thermal-flux region theory. By considering different opening angles and tracking errors of the shaped tubes, an optical simulation is developed to analyze the heat flux distribution, and a heat transfer model is established to investigate the heat loss and thermal efficiency. Results show that the thermal efficiency of the NS-tube with optimum opening angles can be improved by 0.62%–4.64% compared to the original tube. The improvement effect is more obvious at high operating temperatures and low Direct Normal Irradiance. Additionally, the thermal stress variation is also analyzed by Ansys fluent. The result shows that the thermal stress of the NS-tube is even smaller than that of the original tube due to the uniform thermal flow effect caused by the flattened lower surface.

An experimental investigation of nanofluid, nanocoating, and energy storage materials on the performance of parabolic trough collector

Currently, parabolic trough collectors have been widely employed for medium-high heat generation applications such as heat generation processes and desalination applications. Hence, this study tries to enhance the thermal performance of the traditional parabolic trough collector by several methods, including the use of Nanotechnology and thermal energy storage materials. An experimental setup was carried out in Kafrelshiekh city, Egypt to investigate the influence of the enhancing methods used on the thermal performance of PTC. Due to its high accuracy and the fact that many recent articles used numerical techniques without validating their findings, the experimental method is used. The study's enhancing techniques involve the use of many passes of the absorber tube, the use of TiO2 nanofluid as the heat transfer fluid, coating the absorber tube, and without employing a vacuum, reducing thermal losses caused by the presence of air by using a thermal energy storage material (graphite) in the annulus. After that, a comprehensive comparison between all cases is performed to indicate the most effective method. The performed comparative investigation showed that there is an enhancement in the thermal efficiency by 39.3%, 54.2%, 57.7%, 70.5%, and 85.4% when using the new absorber tube configuration, coating the absorber tube, using TiO2 nanofluid as the heat transfer fluid, using the previous methods together, and finally using a thermal energy storage material (graphite) in the annulus with the last modified system, respectively, as compared with that of the reference parabolic trough collector system. Hence, the proposed system was the G PTC as it offered the highest average thermal efficiency and conserved an approximately constant efficiency that was close to the maximum value during the whole day.

A hybrid parabolic trough solar collector system integrated with photovoltaics

It is challenging to reduce the massive radiation heat loss from the parabolic trough solar receiver and enhance the solar utilization efficiency of the parabolic trough collector (PTC) system. On the basis of the negative thermal-flux phenomenon discovered in the PTC system, a novel PTC system integrated with photovoltaic (PTC-PV) panels is proposed in this study to effectively enhance the thermal performance and solar utilization efficiency of the PTC system. Four modes of the hybrid PTC-PV system are put forward for catching the optimum configuration. The mathematical models of the hybrid PTC-PV system in terms of photothermal and photoelectrical conversions are established. Additionally, a test rig of the hybrid system is built, and the experiments are carried out in an indoor laboratory with a solar simulator. Comparisons between the experimental and simulated results show that the model has an excellent prediction ability. Furthermore, a 12 m-length PTC-PV system using molten salt as heat transfer fluid is studied to validate its thermal, exergy, and overall performance. The results show that the hybrid PTC-PV system exhibits dramatic superiority in overall performance over the PTC prototype system. The heat loss of the solar receiver in the hybrid PTC-PV system is significantly reduced by 44.0 %, and the photoelectrical efficiency of the PV panel in the PTC-PV system is drastically enhanced by 118.3 % compared to that installed on the ground. Moreover, the overall and exergy efficiencies of the PTC-PV system can be improved by 14.3 and 13.7 %, respectively, at the inlet fluid temperature of 580 °C.