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This study investigates the technical and economic feasibility of a 20 M W parabolic trough solar thermal power plant (PTSTPP) located in Kenitra, Morocco, characterized by an annual average direct normal irradiance (DNI) exceeding 5.3 k W h / m 2 / d a y . Utilizing System Advisor Model (SAM) 2012.12.02 software, the plant is designed with Therminol VP-1 as the heat transfer fluid (HTF) throughout the solar field, coupled with a dry cooling system to reduce water consumption. The proposed thermal energy storage (TES) system employs HITEC solar salt as the storage medium, allowing for six full load hours of thermal energy storage. With a solar multiple (SM) of 2, the simulated plant demonstrates the capability to generate an annual electricity output of 50.51 G W h . The economic viability of the plant is further assessed, revealing a Levelized Cost of Electricity (LCOE) of 0.1717 $ / k W h and a capacity factor (CF) of 32%. This comprehensive analysis provides valuable insights into the performance, economic viability, and sustainability of a parabolic trough solar power plant in the specific climatic conditions of Kenitra, Morocco. [ABSTRACT FROM AUTHOR]

Clean drinking water and electricity production utilizing non-conventional sources of energy is the global demand for sustainable development. Ultrafast heat transfer fluids have delivered impressive results in photovoltaic (PV)-integrated solar thermal systems, in recent times. Efforts have been made for the productivity and electricity augmentation of solar still equipped with helically coilled heat exchanger and coupled with different integrations, viz., (a) partially covered N-photovoltaic thermal compound parabolic concentrator (N-PVT-CPC), (b) partially covered N-photovoltaic thermal flat plate collector (N-PVT-FPC), (c) N-FPC-CPC, and (d) N-flat plate collector (N-FPC). System design has also been modified by adding a roof-top semi-transparent PV module and built-in passive copper condenser (circulation mode), and effect of carbon quantum dots (CQDs) water-based nanofluids, nanoparticles volume concentration, and packing factor (ßc) of the PV module has been studied by developing generalized thermal modeling of the system (special cases). Overall, 41.1%, 21.52%, 22.01%, and 10.01% rise in evaporative HTCs is observed in FPC-CPC, PVT-CPC, FPC, and PVT-FPC integrations, respectively. Thermal exergy is found to be higher for FPC-CPC integration, and it follows the enhancement order as FPC-CPC (max-0.147 kW) > PVT-CPC (0.088 kW) > FPC (0.038 kW) > PVT-FPC (0.028 kW). In reference to the base fluid, significant enhancement in the daily productivity is observed for FPC-CPC (10.9%) and PVT-CPC (5.16%) integrations using CQD-NPs. The production cost of potable water has also been estimated for all the cases for n = 30 and n = 50 years life span and i = 4% and 8% interest rates, and it is found to be the lowest (0.014 $/L) for FPC-CPC integration using CQD-NPs (n = 30 years, i = 4%). [ABSTRACT FROM AUTHOR]

Large-scale systems have a lower levelized cost of electricity than small-scale concentrated solar power systems. Thus, the purpose of the present study is to evaluate the potential of using standalone small-scale concentrated solar power collectors in order to generate process heat at a moderate temperature, which directly utilizes thermal energy without the need to generate electricity. A parabolic trough collector (3.6m²) was designed and manufactured, including a dual-axis solar tracking system with and without an insulating function. An insulating cavity was incorporated to minimize the heat losses collected by the absorbed tube. The experiments were carried out during a time of high winds and unfavorable weather in Sabratha City. The findings of the experiments demonstrated that the produced temperature and the collected heat energy progressively increase until they reach their maximum value, and then gradually decrease. The maximum water temperature was 96°C at a flow rate of 0.5L/min, and the highest amount of heat energy was 550W/m². Wind speed showed an important impact on the produced temperature; therefore, various comparative experiments were carried out in the same climate condition; the experiment with the insulating function presented the least heat loss, and it takes a higher edge of 11% in terms of efficiency. In addition, the water temperature rose to 120°C where steam was generated at a zero flow rate, while the oil reached 194°C. In addition, a mathematical model was also implemented to theoretically study energy balance; with little expected discrepancy, its predictions and the experimental results agreed. In conclusion, the results presented reasonable markers of interest despite the poor environmental conditions during the experiments. [ABSTRACT FROM AUTHOR]

Concentrator photovoltaics (CPVs) have demonstrated high electrical efficiencies and technological potential, especially when deployed in CPV–thermal (CPV-T) hybrid absorbers, in which the cells' waste heat can be used to power industrial processes. However, the high cost of tracking systems and the predominant use of expensive multi-junction PV cells have caused the market of solar co-generation technologies to stall. This paper describes the development and testing of a low-cost alternative CPV cell based on crystalline silicone (c-Si) for use in a novel injection-molded parabolic hybrid solar collector, generating both, photovoltaic electricity and thermal power. The study covers two different c-Si cell technologies, namely, passive emitter rear contact (PERC) and aluminum back surface field (Al-BSF). Simulation design and manufacturing are described with special attention to fingerprinting in order to achieve high current carrying capacities for concentrated sunlight. It was determined that Al-BSF cells offer higher efficiencies than PERC for the considered use case. Solar simulator tests showed that the highly doped 4 cm2 cells (50 ohm/sq) reach efficiencies of 16.9% under 1 sun and 13.1% under 60 suns at 25 °C with a temperature coefficient of −0.069%(Abs)/K. Finally, options to further improve the cells are discussed and an outlook is given for deployment in a field-testing prototype. [ABSTRACT FROM AUTHOR]

This paper proposes an investigation of a novel design of receiver absorber tube (circular-trapezoidal shaped) for parabolic trough concentrator (PTC) system aiming at catching a part of the lost (reflected) solar rays due to effects related to the incidence angle deviation and thus improving the PTC's thermal performance. Although they are always present in PTC, the effects of the deviation angle are often not considered in the literature. These effects are considered here in view of presenting a better and more useful focal area, the optimal circular-trapezoidal absorber tube shape is determined according to the maximal limit of the deviation angle that allows catching the maximum amount of solar rays. The corresponding model is established considering it as a two-dimensional problem and the derived deviation angle coefficient is compared to that obtained for a traditional circular-shaped tube. Moreover, the energy balance model is adapted to simulate the thermal efficiency of the considered tubes as a function of the deviation angle with some assumptions. The obtained results prove that from a deviation angle value of 0.1 deg, the gain in efficiency becomes more significant; it can reach 5% and even be higher for a deviation angle value of 0.5 deg. Finally, comsol multiphysics software package was used to determine the pressure drops, temperature, and velocity field distributions, considering a deviation angle value of 0.2 deg. The results confirm that the proposed tube absorbs more heat than the traditional one. [ABSTRACT FROM AUTHOR]

Solar energy is not only the most abundant energy on earth but it is also renewable. The use of this energy is expanding very rapidly mainly through photovoltaic technology. However, electricity storage remains a bottleneck in tackling solar resource variability. Thus, solar thermal energy becomes of particular interest when energy storage is required, as thermal energy storage is much cheaper than electricity storage. The objective of this paper is to make a short update on the CSP (Concentrated Solar Power) market as of the year 2023. It is based on the CSP-GURU database, which lists information on CSP power plants all over the world. Although this database is open, it is not easy to find UpToDate analysis. An overview of this expanding technology is presented and offers readable figures with the most important information. This includes the evolution of installed capacities worldwide along with upcoming projects (under construction) and technological trends. The evolution of storage capacities and operating temperatures is discussed. Investment costs and levelized cost of electricity are also provided to obtain reliable data for comparison with other energy technologies. Specific land requirements are highlighted, along with overall efficiency. Relevant examples are discussed in this paper. Eventually, it outlines the evolution of the CSP landscape with useful information for scientific and educational purposes.

Solar energy is not only the most abundant energy on earth but it is also renewable. The use of this energy is expanding very rapidly mainly through photovoltaic technology. However, electricity storage remains a bottleneck in tackling solar resource variability. Thus, solar thermal energy becomes of particular interest when energy storage is required, as thermal energy storage is much cheaper than electricity storage. The objective of this paper is to make a short update on the CSP (Concentrated Solar Power) market as of the year 2023. It is based on the CSP-GURU database, which lists information on CSP power plants all over the world. Although this database is open, it is not easy to find UpToDate analysis. An overview of this expanding technology is presented and offers readable figures with the most important information. This includes the evolution of installed capacities worldwide along with upcoming projects (under construction) and technological trends. The evolution of storage capacities and operating temperatures is discussed. Investment costs and levelized cost of electricity are also provided to obtain reliable data for comparison with other energy technologies. Specific land requirements are highlighted, along with overall efficiency. Relevant examples are discussed in this paper. Eventually, it outlines the evolution of the CSP landscape with useful information for scientific and educational purposes. [ABSTRACT FROM AUTHOR]

The objective of this research is to investigate the implementation of two concentrated solar power (CSP) technologies in the 28 devoted locations in Egypt, in order to select the optimum site-specific CSP technology. This may be achieved by a validated thermo-economic simulation of power plants using the Sam advisory model and an investigation of the two proposed CSP technologies' configurations to fulfill the power plant's thermal demand. Simulations take into consideration the environmental, technical, financial, and economic aspects of the projects. Among many simulated parameters, three are considered to compare the two proposed technologies' configurations in the 28 locations utilizing geographic information system aid. Those parameters are the annual power production, the levelized cost of energy, and water consumption. A comparative analysis indicated that the solar tower requires 25% more land than the parabolic trough. The additional collecting area raised the net capital cost of the solar tower system by 15% over the parabolic trough model. As a result, the solar tower arrangement reduces the levelized cost of energy while increasing the yearly power generated and water required by the power plant. Simulation results favored the proposed solar tower configuration over the parabolic trough and recommended the implementation of such concentrated solar power projects in the central and eastern locations of Egypt. [ABSTRACT FROM AUTHOR]

Humanity is facing the challenge of reducing its environmental impact. For this reason, many specialists worldwide have been studying the processes of production and efficient use of energy. In this way, developing cleaner and more efficient energy systems is fundamental for sustainable development. The present work analyzed the technical feasibility of a solar-driven power-cooling system operating in a particular location in Mexico. The theoretical system integrates organic Rankine and single-stage absorption cooling cycles. A parabolic trough collector and a storage system integrated the solar system. Its performance was modeled for a typical meteorological year using the SAM software by NREL. The analyzed working fluids for the organic cycle include benzene, cyclohexane, toluene, and R123, while the working fluid of the absorption system is the ammonia-water mixture. The cycle's first and second-law performances are determined in a wide range of operating conditions. Parameters such as the energy utilization factor, turbine power, COP, and exergy efficiency are reported for diverse operating conditions. It was found that the highest energy utilization factor was 0.68 when the ORC utilized benzene as working fluid at ORC and ACS condensing temperatures of 80 °C and 20 °C, respectively, and at a cooling temperature of 0 °C. The best exergy efficiency was 0.524 at the same operating conditions but at a cooling temperature of −10 °C. [ABSTRACT FROM AUTHOR]

This paper presents a detailed analysis of the optical performance of circular trough concentrators with tubular receivers. First, a simple analytical formula for the achievable geometric concentration ratio as a function of the rim angle and acceptance angle is developed. Notably, the development reveals the existence of three distinct concentration ratio regimes: a first regime where the receiver is sized based on the reflection of the edge rays from the rim alone, a second regime where the receiver is sized based on the rim and the edge ray caustics, and a third regime where two reflections from the mirror are permitted. Several exemplary designs are proposed and further analyzed using Monte Carlo ray tracing to obtain transmission angle curves and receiver flux distributions. For an acceptance angle of 1 deg, the circular trough concentrator with circular receiver is found to achieve a maximum geometric concentration ratio of 7.695× with a peak flux of 30 suns. For large acceptance angles (10 deg), the circular trough achieves a geometric concentration ratio as high as 82% of that of a parabolic trough. This noteworthy performance, along with the fact that a circular mirror is amenable to an inflated polymer construction, makes this configuration promising for low-cost, low-concentration solar thermal applications. [ABSTRACT FROM AUTHOR]

The modernization, efficiency, and decarbonization of the energy supply systems are among the new challenges to be faced in the coming decades to achieve the targets and objectives dictated by European strategic policies. Despite the countless benefits related to renewable energy sources (RES) integration, this brings key challenges to the power system, such as the risk of imbalance between energy generation and demand, sudden changes in flows in transmission lines with a need for expensive and time-consuming upgrades, and the withdrawal of conventional generation systems with consequent demands for new solutions and innovation to support grid services. A potential solution to limit the huge intermittence and fluctuation in power generation from RES is Concentrated Solar Power (CSP) technology integrated with thermal energy storage. The aim of this paper is to discuss the potential benefits related to the use of CSP technology by presenting innovative industrial solutions developed in the Italian SOLARGRID Project, namely the hybridization of CSP–PV systems and the solar thermo-electric system developed by MAGALDI, the parabolic trough collector of Eni, and the new linear Fresnel reflector configuration of IDEA S.r.l. These plant and component solutions are developed for improving the technical performance of CSP technology and reducing the levelized cost of electricity, thereby fostering an effective and massive deployment and encouraging the creation of new business models. [ABSTRACT FROM AUTHOR]

This study investigates the technical and economic feasibility of a 20 MW parabolic trough solar thermal power plant (PTSTPP) located in Kenitra, Morocco, characterized by an annual average direct normal irradiance (DNI) exceeding 5.3 kWh/m2/day. Utilizing System Advisor Model (SAM) 2012.12.02 software, the plant is designed with Therminol VP-1 as the heat transfer fluid (HTF) throughout the solar field, coupled with a dry cooling system to reduce water consumption. The proposed thermal energy storage (TES) system employs HITEC solar salt as the storage medium, allowing for six full load hours of thermal energy storage. With a solar multiple (SM) of 2, the simulated plant demonstrates the capability to generate an annual electricity output of 50.51 GWh. The economic viability of the plant is further assessed, revealing a Levelized Cost of Electricity (LCOE) of 0.1717 $/kWh and a capacity factor (CF) of 32%. This comprehensive analysis provides valuable insights into the performance, economic viability, and sustainability of a parabolic trough solar power plant in the specific climatic conditions of Kenitra, Morocco.

In this work, a model to estimate circumsolar normal irradiance (CSNI) for several half-opening angles under clear skies was developed. This approach used a look-up table to determine the model parameters and estimate CSNI for half-opening angles between 0.5° and 5°. To develop and validate the proposed model, data from five locations worldwide were used. It was found that the proposed model performs better at the locations under study than the models available in the literature, with relative mean bias error ranging from −13.94% to 0.70%. The impact of CSNI for these different half-opening angles on concentrating solar power (CSP) systems was also studied. It was found that neglecting CSNI could lead to up to a 7% difference between the direct normal irradiance (DNI) measured by a field pyrheliometer and the DNI that is captured by CSP systems. Additionally, a case study for parabolic trough concentrators was performed as a way to estimate the impact of higher circumsolar ratios (CSR) on the decrease of the intercept factor for these systems. It was also concluded that if parabolic trough designers aim to reduce the impact of CSNI variation on the intercept factor, then parabolic troughs with higher rim angles are preferred. [ABSTRACT FROM AUTHOR]

This article proposes an innovative approach to improve the performance of solar cooling systems by utilizing a cascaded absorption cooling (CAC) system. This article also examines the viability of coupling an NH3-H2O absorption system with an H2O-LiBr absorption system to simultaneously satisfy both a refrigeration load and an air-conditioning load. Results of this analysis shows that the CAC system uses 7.1% less thermal energy than the sum of the energies used by the ammonia absorption system and the LiBr absorption system if they were to operate separately to meet the same cooling load. In addition, the article investigates the impact of a performance-enhanced parabolic trough collector (PEPTC) on the thermal and exergetic efficiencies of the solar cooling system. By employing a PEPTC, the area required for the solar field in a given solar cooling system will be reduced by 14% compared to the area required by a conventional parabolic trough collector (PTC). Combining the CAC system with the PEPTC results in a 22% increase in the overall efficiency of a cooling plant compared to a conventional PTC coupled with an ammonia system and a LiBr system in the same plant. In summary, it is suggested that the simultaneous utilization of the proposed CAC system and the PEPTC can considerably improve the efficiency of solar cooling systems. Doing so will lead to sustainable cooling alternatives. [ABSTRACT FROM AUTHOR]

The cogeneration system described in this paper is constructed based on a solar-assisted double-effect absorption cogeneration cycle with an adjustable cooling-to-power ratio. As a proposed technique to benefit from the ability to adjust the cooling-to-power ratio, this system is integrated with a cold thermal energy storage system. The procedure described here will be applied to a combined cooling and power system with a thermal energy storage capability for a large medical center in Jeddah, Saudi Arabia. Through an exergoeconomic analysis of the integrated system on a typical summer day in Jeddah, we found that the integrated system could fulfill the cooling and power demands of the medical center under study with an exergetic efficiency of 53.97%. From an economics perspective, the integrated system was found to deliver cooling and power with average unit costs of 222.89 $/GJ and 17.06 $/GJ, respectively. These costs were found to be lower than the unit costs of the respective cooling and power costs delivered to the medical center if they were obtained from an electrically-driven vapor compression system and the electric grid, respectively. For the case study investigated, it has been found that using the integrated system is a desirable approach due to the system's lower unit costs as well as its relatively short payback period. Additionally, it has been found that although cogeneration systems constructed based on the double-effect combined cooling and power cycle have higher exergy destruction and capital investment rates, they have a lower unit cost for the produced exergy in comparison with those of cogeneration systems constructed based on a single-effect combined cooling and power cycle. [ABSTRACT FROM AUTHOR]

Concentrator photovoltaics (CPVs) have demonstrated high electrical efficiencies and technological potential, especially when deployed in CPV–thermal (CPV-T) hybrid absorbers, in which the cells’ waste heat can be used to power industrial processes. However, the high cost of tracking systems and the predominant use of expensive multi-junction PV cells have caused the market of solar co-generation technologies to stall. This paper describes the development and testing of a low-cost alternative CPV cell based on crystalline silicone (c-Si) for use in a novel injection-molded parabolic hybrid solar collector, generating both, photovoltaic electricity and thermal power. The study covers two different c-Si cell technologies, namely, passive emitter rear contact (PERC) and aluminum back surface field (Al-BSF). Simulation design and manufacturing are described with special attention to fingerprinting in order to achieve high current carrying capacities for concentrated sunlight. It was determined that Al-BSF cells offer higher efficiencies than PERC for the considered use case. Solar simulator tests showed that the highly doped 4 cm2 cells (50 ohm/sq) reach efficiencies of 16.9% under 1 sun and 13.1% under 60 suns at 25 °C with a temperature coefficient of −0.069%(Abs)/K. Finally, options to further improve the cells are discussed and an outlook is given for deployment in a field-testing prototype.

This study presents a hybrid solar–geothermal power plant to produce power, heating and cooling. The proposed integrated power plant is composed of a flash–binary geothermal cycle, parabolic trough solar collectors, auxiliary heater, single effect LiBr–water absorption chiller and heat exchangers. The plant produces constant electrical power as well as heating and cooling required for a yeast production factory. The energetic and exergetic efficiencies of the solar–geothermal power plant for the proposed system under the steady-state condition with constant irradiance are evaluated at 10.78% and 23.1%, respectively. It also found that most of the exergy destruction in the power plant occurs inside solar collectors and auxiliary heaters. It was calculated that heat exchanger three and an absorption chiller would produce 1.97 MW of power, 4.03 MW of heat and 563.2 kW of cooling. Moreover, the variation of evaluation parameters based on the changes in solar beam irradiance is investigated. It found that increasing beam irradiance will result in increasing total exergy efficiency and reducing C ˙ tot , in constant heat input to the cycle. The share of the auxiliary heater in the plant's energy-providing and the fuel's mass flow rate would be decreased by increasing the solar beam irradiance. [ABSTRACT FROM AUTHOR]

This study presents a conceptual design for a concentrated solar power plant by using direct steam generation and a stand-alone power system based on a concentration of solar parabolic troughs. The system is located at the solar research site (SRS) of Universiti Teknologi PETRONAS in Ipoh, Malaysia. The model system uses an integrated turbine with 1.2 kW generators, and steam is generated by a flow loop powered by solar parabolic trough concentrators. An in-situ calculation of normal direct irradiance was conducted in SRS and used as an input for the mathematical model. The model was developed to assess the transient behavior of the system and the behavior of the projected power generation under seasonal variations and daily solar radiation. The parabolic trough power plant achieved the highest average output of 8.85% during the low rainfall season in March. [ABSTRACT FROM AUTHOR]

This paper reports on a parametric investigation of the thermal enhancement of a double-reflector parabolic trough collector when employing an in-line mixed V-shape (IMVS) ribbed absorber tube. Three heat transfer fluids (HTFs) are investigated, and a wide range of fluid inlet temperatures are studied. Various geometric parameters of the V-shape rib are analyzed to determine the optimum design of such a modification to the wall of the absorber tube. Results show that the HTF thermal oil Syltherm 800 is superior to the other HTFs that were studied. Results also show that a lower inlet temperature of the HTF leads to better thermo-hydraulic performance. The study provides a set of values for designing a V-shape ribbed absorber tube that produces optimum thermo-hydraulic performance. The optimum ribbed tube design shows a performance enhancement of about 64% compared to a smooth tube. [ABSTRACT FROM AUTHOR]

Advanced cleaning strategies for parabolic trough collectors at concentrated solar power plants maximize the yield and minimize the costs for cleaning activities. However, they require information about the current soiling level of each collector. In this work, a novel, data-driven method for soiling estimation with machine learning for parabolic trough collectors is developed using gloss values as a surrogate for soiling values. Operational data and meteorological data from the solar field Andasol-3 with changing time horizons are used together with various Machine Learning techniques to estimate the soiling of every collector in the field. The best results were achieved with a Decision Tree model, with a coefficient of determination of R 2 = 0. 77 from the maximum value of 1 and a mean squared error of M S E = 6. 14 for the determination of specific soiling values. A second metric to evaluate the quality of soiling predictions from the models classifies whether soiling is above or below a cleaning threshold was also investigated. Model results are compared to soiling measurements that indicate the need for cleanings. Cleaning recommendations are derived and compared with the current fixed-time cleaning schedule of Andasol-3. All models show an improvement over the cleaning schedule currently in use. The use of a Decision Tree model increases the detected necessary cleanings by 12.2 %, while the number of unnecessary cleanings are reduced by 14.3 %. This has the potential to reduce operational costs and increase the solar field yield. The dataset used in this work is made publicly available https://doi.org/10.5281/zenodo.7061913 , along with the code to reproduce all results, which can be found at https://doi.org/10.5281/zenodo.7554806. • Data-driven soiling model for parabolic troughs with process and meteo data. • Comparison of various machine learning models and dataset sizes. • Evaluation of model for soiling prediction and cleaning schedule optimization. • Investigation of the most important model inputs via permutation feature importance. • Code and dataset available at (https://doi.org/10.5281/zenodo.7554806 , https://doi.org/10.5281/zenodo.7061913). [ABSTRACT FROM AUTHOR]

• A compact solar collector was designed and optimized for integration with buildings. • Optical/thermal performances were analyzed through theory, simulation and experiment. • Annual optical and thermal efficiencies are 57.6 % and 30.6 % @ 250 °C, respectively. • The tilt angle within latitude ± 10.5° has little effect on the optical efficiency. • The efficiencies can improve by manufacturing accuracy, vacuum degree and emissivity. Process industry consumed 15 % to 30 % of the global energy, and 40 % of it is thermal energy demand in the range of 80 °C-250 °C. To produce mid-temperature heat, a new solar collector was designed with heat pipe evacuated tube, including several parallel micro-parabolic troughs, heat pipes, double-layer vacuum tubes contained in a compact frame and an external mechanical solar tracker. In addition, the selective absorbing coating (SAC) was applied on the inner surface of the vacuum tube, and the gap between the heat pipe and the vacuum tube was filled with heat transfer oil. Since the height of the designed collector was only 124.5 mm, it can be easily integrated with buildings. Genetic algorithm (GA) was used to optimize the structural parameters based on maximum obtained solar energy of the collector, and theoretical analysis and numerical simulation are carried out for optical and thermal performance of the collector. The analytical and numerical results showed that the annual average optical efficiency is 57.6 % and the thermal efficiency is 30.6 % at 250 °C when the normalized temperature difference is 0.23. By exergy analysis, the collector has a maximum exergy efficiency of 15.5 % with operating temperature of 204.4 °C, which is the station of the best thermal performance of the collector. Furthermore, theoretical model was verified to be valid by a prototype. Overall, the proposed collector is suitable for mid temperature industrial applications and integrated with rooftop. [ABSTRACT FROM AUTHOR]

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The efficiency of a Parabolic Trough (PT) Solar Power Plant heavily relies on its thermal performance. Modern technology has allowed for the creation of more efficient methods of producing steam and of collecting solar energy for thermal power generation. Ministry of New & Renewable Energy (MNRE) built and tested an 11.1 m2 parabolic trough concentrator (PTC). A system that generates steam indirectly by using concentrating solar power (CSP) is examined. The study examined absorbers' thermal properties, thermal efficiency of combined thermal exchangers, concentration ratio, heat efficiency, and steam generation to determine their influence on energy efficiency. The experimental findings display that 557.85 watts of energy are absorbed by the PTC receiver. The PT solar plant system has a thermal energy efficiency of 25 to 29 % and a concentration factor of about 200 on average. The parabolic trough concentrator generates a maximum of 9.1 kg.h-1 of steam.

The modernization, efficiency, and decarbonization of the energy supply systems are among the new challenges to be faced in the coming decades to achieve the targets and objectives dictated by European strategic policies. Despite the countless benefits related to renewable energy sources (RES) integration, this brings key challenges to the power system, such as the risk of imbalance between energy generation and demand, sudden changes in flows in transmission lines with a need for expensive and time-consuming upgrades, and the withdrawal of conventional generation systems with consequent demands for new solutions and innovation to support grid services. A potential solution to limit the huge intermittence and fluctuation in power generation from RES is Concentrated Solar Power (CSP) technology integrated with thermal energy storage. The aim of this paper is to discuss the potential benefits related to the use of CSP technology by presenting innovative industrial solutions developed in the Italian SOLARGRID Project, namely the hybridization of CSP–PV systems and the solar thermo-electric system developed by MAGALDI, the parabolic trough collector of Eni, and the new linear Fresnel reflector configuration of IDEA S.r.l. These plant and component solutions are developed for improving the technical performance of CSP technology and reducing the levelized cost of electricity, thereby fostering an effective and massive deployment and encouraging the creation of new business models.

We present a mathematical model built to describe the fluid dynamics for the heat transfer fluid in a parabolic trough power plant. Such a power plant consists of a network of tubes for the heat transport fluid. In view of optimisation tasks in the planning and in the operational phase, it is crucial to find a compromise between a very detailed description of many possible physical phenomena and a necessary simplicity needed for a fast and robust computational approach. We present the model, a numerical approach, simulation for single tubes and also for realistic network settings. In addition, we optimise the power output with respect to the operational parameters. [ABSTRACT FROM AUTHOR]

Renewable energy sources allow us to address climate change, as they cannot be depleted. The most common forms of Renewable Energy are solar, wind, Hydropower, and Geothermal. This paper will focus solely on Concentrated Solar Power (CSP), a form of solar power. This research was conducted to provide more insight into renewable energy sources, specifically Concentrated Solar Power. In addition, this study seeks to determine the potential of different CSP technologies in the USA. Through the System Advisory Model, simulations on three CSP technologies (Parabolic Trough, Power Tower, and Linear Fresnel Systems) were carried out for eight locations (San Bernardino, CA; Barstow, CA; Blythe, CA; Nye County, NV; Boulder City, Nevada; Harper Lake, CA; Indiantown, FL; and Kramer Junction, CA) at four different storage capacities (0, 4, 8, and 12 hours). Results indicated that the Power Tower system produced the highest energy levels regardless of location. The 8-hour and 12-hour storage produced better results. [ABSTRACT FROM AUTHOR]

Direct steam generation (DSG) in parabolic trough solar collectors is a feasible option for economic improvement in solar thermal power generation. Three‐dimensional Eulerian two‐fluid simulations are performed under OpenFOAM to study the turbulent flow in the evaporation section of the parabolic trough receiver and investigate the phase change, and pressure drop of water as a heat transfer fluid. First, the model's validity has been tested by comparing the numerical results of a laboratory scale boiler with the available correlations and semi‐correlations of boiling flows from the literature. Simulations agreed well with Rouhani–Axelsson correlation for horizontal tubes, with a mean relative error of less than 7.1% for all studied cases. However, despite a mean relative error of less than 13.19% compared to the experimental data in the literature, the reported pressure drop factor remains valid; overprediction remains tolerable for most engineering applications. Second, the scaling effect on the mathematical model, from laboratory to commercial‐scale configuration, was tested with experimental data of the DISS test loop in Platforma Solar de Almeria, Spain. The Monte Carlo Ray Tracing method under the Tonatiuh package allowed for obtaining the nonuniform heat flux distribution. Due to the large size of the evaporation section in the DISS loop (eight collectors), each collector is considered independently in the simulations. Thus, simulations follow each other, taking the numerical results of each collector output as input data in the next collector and so on until the last. The numerical results showed an excellent agreement for the void fraction with 3.53% against the Rouhani–Axelsson correlation. Frictional pressure losses are within a 17.06% error of the Friedel correlation, in the range of previous work in the literature, and the heat loss is less than 4.69% error versus experimental correlation. [ABSTRACT FROM AUTHOR]

Optical accuracy is a primary driver of parabolic trough concentrating solar power (CSP) plant performance, but can be damaged by wind loads, gravity, error during installation, and regular plant operation. Collecting and analyzing optical measurements over an entire operating parabolic trough plant is difficult, given the large scale of typical installations. Distant Observer, a software tool developed at the National Renewable Energy Laboratory, uses images of the absorber tube reflected in the collector mirror to measure both surface slope in the parabolic mirror and offset of the absorber tube from the ideal focal point. This technology has been adapted for fast data collection using low-cost commercial drones, but until recently still required substantial human labor to process large amounts of data. A new method leveraging advanced deep learning and computer vision tools can drastically reduce the time required to process images. This new method addresses the primary analysis bottleneck, identifying featureless, reflective mirror corner points to a high degree of accuracy. Recent work has shown promising results using computer vision methods. The combined deep learning and computer vision approach presented here proved highly effective and has the potential to further automate data collection and analysis, making the tool more robust. The method presented in this paper automatically identified 74.3% of mirror corners within 2 pixels of their manually marked counterparts and 91.9% within 3 pixels. This level of accuracy is sufficient for practical Distant Observer analysis within a target uncertainty. A commercial drone collected video of over 100 parabolic trough modules at an operating CSP plant to demonstrate the deep learning and computer vision method's usefulness in processing large amounts of data. These troughs were successfully analyzed using Distant Observer, paired with the new deep learning and computer vision algorithm, and can provide plant operators and trough designers with valuable insight about plant performance, operating strategies, and plant-wide optical error trends. [ABSTRACT FROM AUTHOR]

In this work, a model to estimate circumsolar normal irradiance (CSNI) for several half-opening angles under clear skies was developed. This approach used a look-up table to determine the model parameters and estimate CSNI for half-opening angles between 0.5° and 5°. To develop and validate the proposed model, data from five locations worldwide were used. It was found that the proposed model performs better at the locations under study than the models available in the literature, with relative mean bias error ranging from −13.94% to 0.70%. The impact of CSNI for these different half-opening angles on concentrating solar power (CSP) systems was also studied. It was found that neglecting CSNI could lead to up to a 7% difference between the direct normal irradiance (DNI) measured by a field pyrheliometer and the DNI that is captured by CSP systems. Additionally, a case study for parabolic trough concentrators was performed as a way to estimate the impact of higher circumsolar ratios (CSR) on the decrease of the intercept factor for these systems. It was also concluded that if parabolic trough designers aim to reduce the impact of CSNI variation on the intercept factor, then parabolic troughs with higher rim angles are preferred.

This paper presents a simulation model and parametric analysis of a parabolic trough thermoelectric hybrid system. The structure of the system under study mainly consists of a parabolic trough with a triangular receiver equipped with a photovoltaic layer and thermoelectric generators at its back. A thermal model of this system is described and simulated using MATLAB software. The thermal model is utilized to investigate the system performance by performing a parametric analysis. This analysis is conducted to analyze the influence of several parameters such as fluid and air velocities, fluid channel diameter, receiver side length, and the thermal conductivity of the thermoelectric generator on the performance of the system. The results reveal that the thermal efficiency increases noticeably by 6% and 21% when increasing the dimensionless tube diameter from 0.5 to 1 and the dimensionless receiver side length from 1.67 to 8.33, respectively. It decreases significantly by 23% when rising the air Reynolds number from 1.90 × 106 to 18.98 × 106, whereas the fluid velocity and thermoelectric generators thermal conductivity have a negligible effect on it. Furthermore, the electric efficiency is enhanced considerably by 36% and 14% when augmenting the dimensionless tube diameter from 0.5 to 1 and the fluid Reynolds number from 5982 to 19940 respectively. However, it is noticeably reduced by 13% when increasing the dimensionless receiver side length from 1.67 to 8.33, while it is affected negligibly when varying the air velocity (air Reynolds number) and the thermal conductivity of thermoelectric generators.

Hydrogen is believed to be the future energy carrier that will reduce environmental pollution and solve the current energy crisis, especially when produced from a renewable energy source. Solar energy is a renewable source that has been commonly utilized in the production process of hydrogen for years because it is inexhaustible, clean, and free. Generally, hydrogen is produced by means of a water splitting process, mainly electrolysis, which requires energy input provided by harvesting solar energy. The proposed model integrates the solar harvesting system into a conventional Rankine cycle, producing electrical and thermal power used in domestic applications, and hydrogen by high temperature electrolysis (HTE) using a solid oxide steam electrolyzer (SOSE). The model is divided into three subsystems: the solar collector(s), the steam cycle, and an electrolysis subsystem, where the performance of each subsystem and their effect on the overall efficiency is evaluated thermodynamically using first and second laws. A parametric study investigating the hydrogen production rate upon varying system operating conditions (e.g. solar flux and area of solar collector) is conducted on both parabolic troughs and heliostat fields as potential solar energy harvesters. Results have shown that, heliostat-based systems were able to attain optimum performance with an overall thermal efficiency of 27% and a hydrogen production rate of 0.411 kg/s, whereas, parabolic trough-based systems attained an overall thermal efficiency of 25.35% and produced 0.332 kg/s of hydrogen.

This is a new era where the world's energy consumption is so high and is likely to increase over 60% of current consumption by the year 2030. Therefore, renewable energy should be used most frequently. The most preferred alternative to fossil fuels is solar energy but converting solar energy into usable form is the most challenging part. The conversion to thermal energy is the one option. In the area of solar thermal power generation, a solar parabolic trough (SPT) collector is an effective method. Also, the use of passive methods to enhance the thermal performance of these parabolic trough receivers is currently the researcher's interest This review study is focused on different types of geometrical modification (Artificial roughness) used to enhance the thermal performance of SPT receivers. Based on the extensive study it has been found that conical strip insert is a very broad field for research as it can enhance the thermal performance up to 5–10 times. Also there are parameters associated with the conical strips like shape, pitch, angle of twist, slant angle, geometry angle, etc. which can contribute to better performance when used in SPT receiver. [ABSTRACT FROM AUTHOR]

This study examined an Organic Rankine Cycle powered by a parabolic trough collector and a two-tank thermal storage system based on the development of a mathematical model, for the conditions of the city of Itajubá in Brazil. First, geometrical optics and heat transfer models of the collector–receiver set were used to determine the thermal equilibrium of the solar thermal collector system and parameters such as the efficiency of the solar field, heat and optical losses, and thermal energy of the outlet fluid. Next, the thermal equilibrium of the Organic Rankine Cycle was found in order to establish its operational parameters. Finally, the behavior of the thermal storage system was analyzed through its modeling. Once the characterization of the storage system was completed, the integrated operation of the proposed system was evaluated. Given Itajubá's weather conditions, the results indicate that an electricity generation system can be implemented with the Solel UVAC Cermet selective coating for the absorber tube, water as the heat transfer fluid, and R-245fa as the working fluid. Based on the solar irradiation profile (1 March 2019), the parabolic trough collectors provided 63.3% of the energy required by the Organic Rankine Cycle to generate 7.4 kW, while the thermal storage system provided 36.4% of the energy demanded by the power generation block. Additionally, the results demonstrate the main conclusions that the turbine's efficiency was influenced by parameters such as rotational speed, which is affected by the turbine inlet temperature, which, in turn, depends on the behavior of the solar irradiation profile onsite. [ABSTRACT FROM AUTHOR]

Radiant heat and light emerging from the sun can be harnessed in a variety of ever-evolving technologies mainly consisting of thermal and photovoltaic. In this research, comprehensive and systematic description of solar thermal technologies supported by techno-economic analysis was performed. The research starts with the optimization and classification of these technologies with a prime focus on the implementation in the Kingdom of Saudi Arabia (KSA). Theoretical analysis was conducted to calculate the technical specifications of various solar thermal technologies for the purpose to assess the optimized technology for the KSA. A 10 MW parabolic trough-based plant is designed and simulated by using four different heat transfer fluids including nano-fluids and molten salts with four collectors for the purpose to conclude the optimized design. Hydrogen and oxygen gas were used in receiver assemblies to calculate the absorbance, emittance, and transmittance along with various other effective parameters. It was observed that under specific conditions, collectors, and receivers have different values which is then affect the efficiency of the system. The prime objective of the research is to present the up-to-date solar thermal technologies in the KSA and the feasibility of a solar thermal pilot plant. [ABSTRACT FROM AUTHOR]

During the gold extraction in opencast mining, many hazardous substances, such as cyanide, are spilled into the water bodies. This study's aim was to develop a novel rotary photocatalytic TiO2-based reactor to remove cyanide from polluted water using a rotary concentrator photoreactor (RCPR). This pilot-scale reactor was tested with synthetic cyanide water at concentrations from 0.05 to 50 ppm, varying the pH and commercial TiO2 load. The optimal conditions from experimental data were 87.4% of cyanide removal and catalyst load of 0.30 g/L at pH 9.5. Further, samples of cyanide water from an opencast gold mine were treated, achieving removal of 68.7% after 240 min. Our value-added is the rotary motion of the set of four glass tubes, achieving satisfactory performance, which is promising for cyanide wastewater treatment with a more compact footprint than a standard compound parabolic collector (CPC) solar photoreactor. Thus, it was possible to reduce mass and heat transfer limitations with a simple design by considering this photoreactor as a photocatalytic process intensifier. [ABSTRACT FROM AUTHOR]

Detecting receivers with broken glass envelopes in Parabolic Trough plants presents a crucial challenge in Concentrated Solar Power systems. While existing research has addressed this problem, some limitations persist, particularly in the context of data collection and the accuracy of the proposed methods. To overcome these challenges, we propose a fully automated and cost-efficient solution. Leveraging thermal camera data, we develop a novel cropping algorithm that achieves a 91% success rate in detecting the location of the receiver tubes without the need for labeled samples. Additionally, we introduce a luminescence-based filter for color images in Red–Green–Blue format to assess biases in the training and test sets. To solve our target problem we rely on Convolutional Neural Network architectures augmented with Hypernetworks as meta-learners. Our proposal is inspired by traditional voting methods but it is trainable end-to-end. In our test set, the image-based meta-learners obtain the best performance over all evaluation metrics. Furthermore, we provide experimentally driven insights to the weaknesses and strengths of our approach. Combining the experimental results with the luminescence-based filter, we achieve a robust method with a 95% F1-Score for detecting broken glass samples, including edge cases. Our approach surpasses the best individual learner by 2.1%–5.8%, depending on brightness conditions. [ABSTRACT FROM AUTHOR]

Solar thermal technology promises to be a significant component of the future renewable energy mix. As the most mature solar thermal technology, parabolic trough concentrators (PTC) are the focus of considerable research. Conventional PTC use evacuated receivers, which contribute 30% of the solar field cost, not including significant failure (55% due to broken glass envelopes and 29% due to loss of vacuum arising due to failure of glass to metal seal). We report a non‐evacuated receiver with a modular design for easier assembly and superior thermal performance for a PTC made of reflective strips of mirrored glass with a rim angle of 60°. The receiver performance is estimated using our own ray‐tracing software and computational fluid dynamics (CFD) simulations using a model that we have validated with our own experimental rig. Critical parameters like the width of the mirror strip, the emissivity of solar selective coating, insulation material, and reflectivity of optical cavity walls have been analyzed in this study. A scaled‐up model of the proposed novel receiver with a heat transfer fluid conduit diameter of 70 mm has been simulated to compare the performance with the commercial SCHOTT PTR® 70. The cost of this receiver is estimated to be $30/m as compared to up to $250/m for SCHOTT PTR® 70 with comparable performance. The modular nature of the receiver and reflector gives operational and maintenance flexibility and facile part replacement in case of damage, resulting in low‐cost operation. [ABSTRACT FROM AUTHOR]

Kuwait is a country with great potential for concentrated solar power (CSP) due to its high solar resource. The current work analyzes the potential of the application of CSP technology in the country and its particularities. Specifically, the current work examines a CSP plant with parabolic trough collector (PTC) technology and how this technology is affected in its performance depending on the location (inland or coastal) and the refrigeration system (wet, dry, or seawater cooled). The modeling methodology is based on a two-step approach: first, the Rankine steam power cycle is modeled in detail in a state-of-the-art steady-state simulation environment, obtaining the performance of the power cycle for each cooling technology; second, the power cycle performance maps are integrated into a detailed transient system-level simulation model of the complete CSP plant in order to perform annual yield simulations for the different representative locations of the climate of Kuwait. These results provide valuable information on both the potential of this technology for its more immediate application such as electricity generation and other future applications such as the desalination of seawater where the location must necessarily be coastal. [ABSTRACT FROM AUTHOR]

An investigation of performance for conventional single slope solar still with different surface geometry of basin absorber is reported in this article. Variation in surface geometry of the basin and its consequent effect on the hourly yield of the still is evaluated theoretically and compared with a conventional single slope solar still with unit basin absorber area as reference. An investigation of solar still with conventional (1 m² ), wire mesh large (1.004 m² ), wire mesh small (1.13 m² ), triangular cuts (1.29 m² ), semi cylindrical troughs (1.59 m² ), triangular corrugations (1.71 m² ), hemispherical depressions (1.79 m² ) and parabolic trough (1.80 m² ) as basin surface area value is investigated theoretically and wire mesh large, wire mesh small cases are also investigated experimentally. The mathematical model is utilized for arriving at respective heat transfer coefficient and hourly distillate yield values. The best suitable geometry of the still basin is reported based upon increment in heat transfer coefficients and hourly yield. The theoretical analysis is performed using MATLAB R2015a for climatic conditions of Raipur Chhattisgarh India for the month of June 2021 and the weather data is taken from the Indian Metrological Department (IMD), Pune, India. The cumulative hourly yield as obtained with respect to their respective surface area values is found to be 3.94, 4.31, 4.76, 5.68, 6.79, 7.35, 7.25 and 7.36 L corresponding to conventional, wire mesh large, wire mesh small, triangular cuts, semi cylindrical troughs, triangular corrugations, hemispherical depressions and parabolic trough respectively. The maximum deviation between the mathematically obtained and experimental values of hourly yield values is found to be 13.5% while the maximum deviation between the cumulative daily distillate yield is found to be 13.23% for wire mesh large. [ABSTRACT FROM AUTHOR]

• Use the camera to shoot at different angles to obtain a complete flux profile. • Inversion method of traversal combined operation based on simplified algorithm. • Identify the types and values of the optical errors in the flux profile. • Flux image-based diagnosis of the Gaussian slope, gravity deformation and align error. In practice, there are multiple optical errors existing in parabolic trough concentrator, which respectively have a unique effect on the flux distribution on the wall of the absorber, causing it to deviate from the ideal operating condition. Diagnosis for multiple errors is difficult. The effect of combined optical errors on the flux distribution can be modelled using convolution operations. In this study, the flux patterns under multiple types of optical errors are traversed and combined, and the actual flux distribution profiles of the parabolic trough concentrator measured by a camera-based method are compared to identify the Gaussian slope error, gravity deformation error and alignment error of the concentrator. This indicates that it is feasible to invert the flux profile on the absorber wall and diagnose the types and values of the corresponding optical errors of the concentrator. [ABSTRACT FROM AUTHOR]

The exponential population growth has led to severe fresh water availability issues around the world. Saudi Arabia is one of the countries that mostly rely on desalination process to satisfy their fresh water needs in desert regions. The distillation process has become too expensive due to the sharp rise in oil prices. Renewable energy is a promising source for the water distillation process. This work aims to design, fabricate, and test a solar still for purification of salty and brackish water. A semi-cylindrical solar still was designed and tested under Medina climatic conditions. The semi-cylindrical solar still connected with a parabolic trough solar concentrator was supposed to enhance the system performance and the system productivity by warming up the brackish or saltwater before it was directed to the basin. To calculate system efficiency, the temperatures of water in the basin, glass outside and inside surface, inside of the still, and the ambient were measured. It was found that the average intensity of solar radiation was about 729.8 W / m 2 per hour and the average system efficiency was found to be 23.38% without a parabolic trough. The system efficiency reached 29.5% by connecting the solar still with a parabolic trough. The maximum productivity of the solar still was found to be 1.8 L/h at peak time, with an average value of 0.9 L/h in May. [ABSTRACT FROM AUTHOR]