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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.

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]

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]

The objectives of this work carried out in the Central African Republic are to propose new correlations between the components of solar radiation and the sunshine duration on a horizontal surface on the ground, and then to make an evaluation of the solar potential in the cities of Bambari, Birao, and Bangui. Polynomial regression models were used and their parameters were estimated by the ordinary least-squares method. A statistical evaluation allowed us to compare the performance of the models. The best correlations are then used to estimate the global and diffuse radiation. In the city of Birao, the estimated global radiation is around 6 kW h/m²j and the diffuse radiation is around 2 kW h/m² j; in Bambari, the global radiation is around 5.4 kW h/m² j and the diffuse is around 2.3 kW h/m² j; in Bangui, the global radiation is around 5 kW h/m² j and the diffuse radiation is around 2.3 kW h/m2 j. The potential solar in all these regions is very favorable for small- and large-scale solar photovoltaic applications. [ABSTRACT FROM AUTHOR]

This article explores the patents of solar energy technologies in the organic Rankine cycle (ORC) applications. The conversion of low-quality thermal energy into electricity is one of the main characteristics of an ORC, making efficient and viable technologies available today. However, only a few and outdated articles that analyze patents that use solar energy technologies in ORC applications exist. This leads to a lack of updated information regarding the number of published patents, International Patent Classification (IPC) codes associated with them, technology life cycle status, and the most relevant patented developments. Thus, this article conducts a current investigation of patents published between January 2010 and May 2022 using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology and keywords. One thousand two hundred ninety-nine patents were obtained as part of the study and classified in F and Y groups of the IPC. The time-lapse analyzed was between January 2010 and May 2022. In 2014 and 2015, a peak of published patents was observed. China (CN) was the country that published the most significant number of patents worldwide. However, the European Patent Office (EP), the World Intellectual Property Organization (WO), and the United States (US) publish the patents with the highest number of patent citations. Furthermore, the possible trend regarding the development of patents for each technology is presented. A high-performance theoretical ORC plant based on the patent information analyzed by this article is introduced. Finally, exploration of IPC revealed 17 codes related to solar energy technologies in ORC applications not indexed in the main search. [ABSTRACT FROM AUTHOR]

Gas Technology Institute (GTI), together with its partners University of California at Merced (UC Merced) and MicroLink Devices Inc. (MicroLink) are developing a full spectrum solar energy collection system to deliver variable electricity and on-demand heat. The technology uses secondary optics in a solar receiver to achieve high efficiency at high temperature, collects heat in particles for low fire danger, stores heat in particles instead of molten salt for low cost, and uses double junction (2J) photovoltaic (PV) cells with backside infrared (IR) reflectors on the secondary optical element to raise exergy efficiency. The overall goal is to deliver enhancement to established trough technology while exceeding the heliostat power tower molten salt temperature limit. The use of inert particles for heat transfer may make parabolic troughs safer near population centers and may be valuable for industrial facilities.

Algeria's energy demands are tremendously growing, and on the African continent it ranks among the countries with the highest energy consumption. To counter its growing energy demand, the country is progressively adopting renewable energy technologies, although conventional energy technologies still play a central role in its electricity production. The huge solar energy potential in Algeria can be exploited and utilized to meet the country's growing energy demand with minimal greenhouse gas production. Given that concentrating solar power is viewed as one of the most promising alternatives in the field of solar energy utilization, this study investigates the viability of a 100 MW parabolic trough-based power plant at Tamanrasset, Algeria. The plant was simulated in the System Advisor Model software considering the actual electricity load profile of the targeted location and implementing two different condenser types: evaporative and air-cooled. By comparing the plant's electricity production to the city's real load, the plant was in position of supplying about 78% and 60% of the city's electricity demand during the winter and summer seasons, respectively. The results show that implementation of such CSP plants could play an important role in meeting the energy demand as well as mitigating climate change through greenhouse emissions avoided in electricity generation process. [ABSTRACT FROM AUTHOR]

Heat transfer in concentrating solar collectors like parabolic troughs has proven nowadays a very efficient method by using different passive techniques to increase the heat transfer rate. The use of passive techniques also increases the pumping power requirements to make the flow through the receiver. So, a number of researchers are working to find out the optimum performance conditions for parabolic trough receivers by using different types of inserts in flow paths. This paper presents a wide range of literature available for solar parabolic troughs in one place. Based on this extensive study, it is found that twisted tape inserts is a very wide field for investigation and the use of different shapes, pitch value, free space, and angle of twist tape are the parameters that can be considered for further studies to improve the performance of solar troughs. Also, various combinations of perforation and cuts on twisted tapes can be used to achieve enhanced performance. [ABSTRACT FROM AUTHOR]

The joint demand for power and freshwater is continuously increasing due to population growth, the rise of economic activity, and climate change. Integrated concentrating solar thermal power and desalination (CSP+D) plants may provide a key solution for the pressing freshwater deficit and energy problems in many regions of the world. Simulation tools with an accurate prediction of the yearly electric energy and freshwater production are needed. This paper analyzed the influence of the time step in the annual simulation of a CSP+D plant composed of a seawater multi-effect distillation unit and a parabolic trough concentrating solar thermal power plant, considering the location of Tabernas (Spain). A dynamic simulation tool of this system was developed, implementing the models in Engineering Equation Solver. The annual electricity and water productions obtained for the study case considered were 154 GWh and 3.45 hm3, respectively, using 5 min time steps, and 94 GWh and 2.1 hm3, respectively, with 1 h time steps. The results obtained show that a short time step interval (5 min) is recommended when using the detailed CSP model considered, which is prepared for simulation with short time steps. Step times of 1 h lead to excessive errors (about 30% in summer and 100% in winter), which underestimate the actual production. [ABSTRACT FROM AUTHOR]

Solar direct steam generation (DSG) systems are well suited for process steam applications and are able to provide steam at the pressure required by common industrial processes. Nevertheless, reliable control has always been a challenge for solar DSG system hindering its wider adoption. In this paper, a control strategy for solar DSG systems is presented. The control strategy is based on proportional-integral-derivative (PID) control theory combined with model-based feedforward control. Experimental data demonstrate that the control strategy provides good performance in terms of stability and setpoint tracking. The error in setpoint tracking for the load pressure controller is shown to be as low as ±0.005 MPa under real life conditions. The said strategy is currently implemented in two commercially operating plants providing solar steam for industrial processes. [ABSTRACT FROM AUTHOR]

In this paper, parabolic trough solar thermal plants are proposed. Two key parameters, solar multiple (SM) and full load hours of thermal energy storage (TES), are optimised by maximising the annual energy and minimising the levelized cost of electricity (LCOE). This work presents a comparative study, based on the 4E (energy–exergy–environment–economic) analysis, of the optimised plant with a reference plant. The performance evaluation of the optimised plant is carried out in eight different locations of Bangladesh. The result obtained shows that the salt plant has the best performance compared to that of the thermal oil plant. The salt plant requires a lower LCOE of 9.86 ¢/kWh. It also possesses a maximum capacity factor of 39.5% and generates the highest annual energy of 171.1 GWh. From the feasibility study, Cox’s Bazar is found as the best location of eight different regions of Bangladesh.

Solar energy is a long-established technology, which has zero CO2 emissions, and provides low-cost energy for a given area of land. The concentrator photovoltaic (CPV) has been given preference over the photovoltaic due to its high efficiency. In a CPV system, most of the solar cell area has been replaced with an optical concentrator. Various parabolic trough based CPV systems have been presented where a concentration of

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.

[Display omitted] • Eight absorbers with different simple geometries are used to address the attributes of the concentration ratio distribution over their surfaces. • A parabolic shaped absorber is found to provide a uniform distribution of the concentrated solar flux. • Operation with free absorber is found to result in a more uniform distribution as compared with operations with fixed absorber. • Two optimal shapes of the absorber have been obtained. Parabolic trough collector stands out as the most proven and widely adopted technology for concentrating solar power. A simple mathematical model based on dividing the trough's aperture and the surface of the absorber into small segments is developed herein. The model is used to investigate the influence of the design and operational parameters on the distribution of the concentrated solar flux over. In this study, eight absorbers with different geometries are considered and the effect of the rim angle, absorber's geometry, and operational mode on the distribution of the concentrated solar flux over their surfaces have been addressed. For all absorbers, it has been found that increasing the rim angle results in reducing the intensity of the concentrated solar flux with increase in its coverage area. The distribution of the concentrated solar flux over the surface of the parabolic shaped absorber (ABS.6) is found to be uniform over the portion of the surface located between its two rims. It has also been demonstrated that the operation under free absorber mode can help in redistributing the concentrated solar flux over the absorber surface resulting in a more uniform distribution compared to that over the surface of the fixed absorber. From the combined geometries of the investigated absorbers two optimal shapes are obtained and are found to perform much better than the circular absorber ABS.1. [ABSTRACT FROM AUTHOR]

Biomass conversion processes can be energy intensive. There is a need to seek renewable sources to meet such energy demand. In this study, a partial heat of pyrolysis from a concentrated solar power (CSP)-based solar heat collector is modeled. A numerical investigation of the flow in the heat collector element (HCE) of the CSP is performed. By using the finite volume formulation, the fluid flow behavior within the pipe of the HCE is simulated to determine the thermal absorption, heat losses, and efficiency obtainable from the solar irradiation on the receiver tube. Monte-Carlo Ray-tracing based software, soltrace, is used to estimate the incident heat flux on the LS-2 receiver with an average direct normal irradiance (DNI) value, based on a comparative performance study of three types of molten salts (i.e., the heat transfer fluids (HTFs)). The performance of three kinds of the LS-2 HCE (i.e., vacuum, air-filled, and evacuated types) is also analyzed in terms of heat loss and efficiency measurements respectively. HITEC provides the best performance in terms of stability in delivering the partial heat of pyrolysis for the gasification of food waste on moderate velocities of 0.75-2 m/s. Also, the pyrolysis of the feedstock is proposed with an operating feedstock rate of 0.19 kg/s and 0.17 kg/s for lower heating value (LHV) and higher heating value (HHV), respectively. It is anticipated that the combined heat of pyrolysis from the proposed dual heat cycle, comprising both the CSP and a biogas plant, will provide a solution to the demand for alternative power from biomass energy conversion. [ABSTRACT FROM AUTHOR]

In this study, it is aimed to conduct the thermodynamic and economic analysis of solar thermal power plants using parabolic trough collectors (PTC), linear Fresnel reflectors (LFR), and solar tower (ST) technologies for Cameroon. The analysis is performed for each power plant with the installed capacity of 5 MWe. Initial investment costs for the solar thermal power plants using PTC, LFR, and ST technologies are estimated to be 33.49 Million USD, 18.77 Million USD, and 36.31 Million USD, while levelized costs of electricity (LCOE) are found to be varying from 145.6 USD/MWh to 186.8 USD/MWh, 112.2 USD/MWh to 154.2 USD/MWh, and 179.2 USD/MWh to 220.4 USD/MWh, respectively. For the solar thermal power plants using PTC, LFR, and ST technologies, payback periods are obtained to be 6.57 years, 6.84 years, and 6.02 years, and also, internal rates on the return are calculated to be 21.03%, 20.42%, and 22.47%, respectively. Overall energy and exergy efficiency values are found to be 13.39% and 14.37%; 11.90% and 13.74%; 12.13% and 13.64% for the solar thermal power plants using PTC, LFR, and ST technologies, respectively. In conclusion, it is seen that LFR technology presents the best performance with the combination of thermodynamic and economic metrics for the deployment of solar thermal power plants in the countries in sub-Saharan Africa like Cameroon. [ABSTRACT FROM AUTHOR]

This paper gives a wind load simulation model in Siemens NX based on the actual field position of the parabolic trough collector (PTC) when the wind is blowing from multiple directions. The maximum displacement is 0.24 % of the aperture width, and the maximum stress value is 46.51 MPa. Cold airflow computational fluid dynamics (CFD) analysis was conducted to determine the airflow pattern in the vicinity of the PTC. It was revealed that there is no substantial turbulence zone in the area of the receiver tube, which means that heat loss from the receiver tube to the atmosphere will not be increased. The estimated figure of thermal efficiency has a total uncertainty of 1.89 %. The experiment is carried out in March, and the findings are compared to those obtained in December. The results reveal that PTC's thermal performance is better in March. When compared to December, the thermal efficiency of the existing PTC improved by 2.75 % in March. The optimum flow rate for March has been determined to be 3 L/min. The performance of Siemens NX is validated by an experimental result followed by a 0.4 % deviation. Siemens NX is in good agreement with experiment results. [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]

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. [ABSTRACT FROM AUTHOR]

Accurate calculation of water/steam temperature and pressure in the solar field of direct steam generation (DSG) parabolic trough is essential to power dispatch and control. However, it is very difficult to achieve satisfied accuracy in limited time because of the existence of two-phase flow that has complex dynamic characteristics. In this work, a new hybrid model is proposed, which is based on the heat transfer mechanism enhanced by artificial neural network. This hybrid model has two characteristics as follows. (1) A heat-transfer and hydrodynamic coupling steady-state mechanism model as a prior model, which is used to quickly obtain the prior values including mechanism factors that are then used as input to an artificial neural network (ANN) model. (2) An ANN model consisting of two four-hidden-layer back propagation (BP) networks. The inlet pressure and outlet temperature of solar field are modelled in the first four-layer neural network, and then the outlet temperature of solar field is analyzed in the second four-layer neural network to improve the simulation accuracy. This model is verified by the data from DISS plant on 26 June 2001, and can be used for control studies and dispatching optimization. The calculation results show that the mean absolute percentage error (MAPE) of predicted inlet pressure and outlet temperature are 0.48% and 1.14%, respectively, which are better than the results of BP model, general regression neural network (GRNN) model, hybrid model with one BP network mentioned in this paper, and the dynamic simulation model mentioned in the literature.

Parabolictrough solar collectors (PTSC) plays an important role in the heating offluids and in the generation of electricity . Inthis study, heat transfer and temperature distribution analysis was carried outfor the use of internal longitudinal fins with different geometries in aparabolic trough solar collector.Numerical analyzes were carried out fordifferent Reynolds (Re) numbers (2x104-8 x104) atsteady-state conditions and three different thermal oils were used as heattransfer fluid (HTF). The use of the internal fin with sinusoidal lateralsurface for all types of thermal oil increased the heat transfer and made thetemperature distribution in the fluid more uniform. Thehighest thermal enhancement factor was occurred for Syltherm 800 oil andsinusoidal fin geometry. With the use of Syltherm 800 oil, the thermalenhancement factor () increased by 40% and 44% respectivelyaccording to the Therminol VP1 and D12 oil type for the case with sinusoidalfin.

The aim of this study is to enhance the fermentation temperature inside the digester by supplying the required thermal energy to be within the desired optimum range (mesophilic range) for biogas production during winter “cold days”. Two 50 L digesters were used in the experiment that was conducted at Solar Energy Laboratory, Department of Agricultural Engineering, Faculty of Agriculture, Ain Shams University, Cairo. One is a treatment digester and the other is a control digester. The treatment digester is thermally enhanced by a parabolic trough collector, while the control digester operated at the ambient temperature. The experiment was conducted through December 2018 and January 2019. The results show that the average temperature in the control digester through the experiment was 21.5°C, while in the treatment digester it was 27.08°C. This means that the parabolic trough collector enhanced the fermentation temperature in the treatment digester by 20.6%. The total biogas yield of the control digester and the treatment digester was 9684.7 mL/kg. T.S. and 24649.69 mL/kg. T.S. respectively. By comparing both productivities, it was found that the productivity of the treatment digester was 2.5 times more than the productivity of the control digester.