Parabolic Trough Solar Concentrator Research Articles

Advanced optimization of elastic sheets for solar parabolic trough concentrators: integrating particle swarm optimization and genetic algorithms

Abstract The fabrication of solar parabolic trough concentrators using flat elastic sheets presents a straightforward and cost-effective method. This paper introduces an optimization technique centered on stiffness adjustment, harnessing elastic buckling to attain precise parabolic shapes in these concentrators. Through an enhanced Particle Swarm Optimization-Genetic Algorithm (PSO-GA), strategically punched holes are optimized on the flat sheet, allowing for the attainment of perfect parabolic shapes by controlling the chord length with a positional rod or cable. The efficacy of this approach is showcased not only through interactive finite element analysis and ray tracing software simulations but also via experimental sunlight concentration. A geometric concentration ratio of up to 145.16 is achieved, underscoring the effectiveness of this innovative concept. This approach facilitates the simple fabrication and transportation of flat mirror elements to field sites, where they can be assembled into parabolic trough concentrators, offering potential cost reductions and highly efficient solar energy solutions.

Performance comparison of a solar parabolic trough concentrator using different shapes of linear cavity receiver

This study presents a numerical investigation of a solar Parabolic Trough Concentrator (PTC) with various Linear Cavity Receivers (LCRs). A linear trapezoidal cavity receiver was simulated and analyzed optically and thermally in the PTC system. The performance of the linear trapezoidal cavity receiver was assessed at two different angles: 25° and 55°. Optical and thermal simulations were conducted on a PTC system with a novel linear wounded tubular trapezoidal LCR. Subsequently, the optical and thermal performance of the PTC system was compared with alternative LCR shapes, namely cubical, V-shaped, trapezoidal 25°, and trapezoidal 55°. Additional contribution of the present study is to conduct energy and exergy analyses on the optimized solar PTC system employing a soybean oil-based-MXene nanofluid with varying concentrations (0 %, 0.025 %, 0.075 %, and 0.125 % weight). The findings indicate that all LCRs exhibit optimal cavity-absorbed heat flux and optical efficiency when aligned with the focal line. Moreover, the cubical and trapezoidal cavity receivers, when equipped with the ideal aperture width, demonstrate the highest and lowest performance, respectively. The most favorable exergy performance is achieved by employing the nanofluid concentration of 0.075 % weight at an inlet temperature of 55 °C at about 4 %. Also, the thermal efficiency of the solar system was calculated as about 82 % with the application of the nanofluid concentration of 0.075 % weight at an inlet temperature of 25 °C. The research findings offer valuable insights into enhancing the performance of the solar thermal system to generate more power for the implementation of the 7th development plan in Iran.

THEORETICAL PERFORMANCE ASSESSMENT OF A PARABOLIC TROUGH HUMIDIFYING SOLAR COLLECTOR-BASED SOLAR STILL

In this paper, a parabolic trough humidifying solar collector-based solar still (PHSC-SS) is proposed. Its purpose is to apply some important performance improvement techniques to the flat plate humidifying solar collector-based solar still (flat plate HSC-SS), to significantly improve overall system performance. These included the use of parabolic trough solar concentrators and the design of humidifying solar collectors from evacuated tube collectors. The results reveal that, unlike flat plate HSC-SS, which must operate with a turbulent airflow regime to achieve optimum overall performance, PHSC-SS must operate with a laminar airflow regime and high inlet and outlet temperatures of air (at least 55 °C and less than 100 °C, at atmospheric pressure) in the heat collector element. For 900 W/m2 of incident solar irradiance, 2 m2 of solar collector area, and 0,00042 kg/s of air flow rate, the maximum energy efficiency, exergy efficiency and daily freshwater productivity of PHSC-SS were found to be 68,12%, 14,87% and 1,697 kg/h, respectively. Whereas for the same incident solar irradiance and solar collector area, and 0,1 kg/s of air flow rate, those of the flat plat HSC-SS were 72,9%, 1,12%, and between 1,07 – 2,923 kg/h (for inlet and outlet temperatures of air less than 30 °C, at atmospheric pressure), respectively. Although in some extreme cases freshwater productivity of flat plate HSC-SS can be higher than that of PHSC-SS, it should be noted that laminar airflow regime confers great advantages to PHSC-SS. These are higher air temperatures at condenser inlet (which ease water condensation process), no need of an auxiliary cooling device (needed in the flat plate HSC-SS), less mechanical vibrations of system, reduced condenser size, and less energy consumed by air blowers. Furthermore, the upper limit of the PHSC-SS is a PHSC-SS that operates without air flow, but rather by vaporization of water droplets at boiling point from absorber, followed by their suction to condenser, similarly to a flash evaporation.

Performance of a solar parabolic trough concentrator using vacuum linear V-shaped cavity receiver

The popularity of renewable energy is on the rise as fossil fuel resources continue to deplete and environmental pollution levels increase. Consequently, enhancing the performance of renewable energy systems has become a compelling subject of research. This study introduces an innovative structure, the Linear Cavity Receiver (LCR), as a receiver for solar Parabolic Trough Concentrators (PTCs). Notably, this novel structure incorporates a vacuum V-shaped LCR, marking a pioneering achievement worldwide. By adopting this configuration, the solar system’s thermal efficiency is enhanced through the reduction of heat losses. The results confirmed the superiority of the vacuum V-shaped LCR over a non-vacuum receiver in optimizing the performance of the solar PTC system. It was found that the vacuum linear V-shaped cavity receiver exhibited superior efficiency for larger cavity tube diameters, higher inlet temperatures, and lower volume flow rates. Moreover, this study showed that decreasing the cavity tube diameter, increasing solar radiation, reducing the working fluid (WF)’s inlet temperature, and raising the volume flow rate contribute to an increase in both cavity heat gain and the solar system’s thermal efficiency. It can be concluded that the thermal efficiency of the solar system was about 72.24 %, 71.6 %, and 69.9 % for cavity tube diameters 5 mm, 10 mm, and 25 mm, respectively. These findings hold great significance in the design of power-generating PTC systems, ensuring their optimal efficiency. Also, the results of this study can be used to improve energy governance by using more efficient thermal power systems.

Sensitivity analysis of the thermal performance of a parabolic trough concentrator using Al2O3 and SiO2/Vegetable oil as heat transfer fluid

This paper aims to highlight the use of different heat transfer fluid (HTF) configurations based on vegetable oils in Parabolic Trough Solar Concentrator (PTSC). Rapeseed and jatropha oils as innovative heat transfer materials combined with SiO2 and Al2O3 to obtain six (6) HTF configurations are used in a 1-dimensional PTSC model. The thermophysical properties of the nanofluids are determined from correlations derived from the literature, using Gauss-Seidel method from a numerical code developed in Matlab software. Model validation is obtained. Thermal sensitivity analysis shows that the use of rapeseed increases the thermal efficiency of the PTSC by around 4.21 % compared with jatropha. The use of nanofluids reduces thermal losses within the system due to thermal gradients. For a fixed irradiance and each 1 %–4 % increase in volume fraction, thermal efficiency increases by around 1.96 % when Al2O3/rapeseed is used and by 0.47 % when SiO2/rapeseed is used compared with rapeseed. Similarly, thermal efficiency increases by around 1.98 % when Al2O3/jatropha is used and decreases by around 0.20 % when SiO2/jatropha is used compared with jatropha. However, the positive effects of nanoparticles on thermal conductivity alone are not always sufficient to improve thermal efficiency, and thermal effects on heat capacity should also be considered.

Assessment of a parabolic trough solar thermal concentrator under two-phase flow conditions

In the present work, a mathematical model is developed to describe the heat, mass, and momentum transfer of a biphasic flow during its trajectory in the absorber tube of a parabolic trough solar concentrator (PTSC) for thermal processes in a transitory simulation, showing the evolution of the parameters in a dynamic system. The working fluid is water. The numerical solution of the model is implemented in C++ code. The model is validated with the results obtained from the DISS Project experiment. The results of the numerical solution have a maximum variation in the fluid temperature profile of 6.45 % and a maximum difference of 2.02 % in the outlet pressure of the fluid with respect to the experimental results. The case study consists of the analysis of a PTSC under different radiation conditions from two different cities in Mexico, Piedras Negras and Mexico City, on an average spring day. The results obtained allow us to analyze the behavior of the fluid temperature, the quality of the steam, and pressure drop through the absorber tube and time; under the conditions studied, the concentrator reached an efficiency of 52 %. It is observed that the model is sensitive to changes in climate.

Experimental Investigation of An Industrial Wastewater Treatment Unit Using Multi Filter Hybrid with Parabolic Trough Solar Concentrator

Experimental Investigation of An Industrial Wastewater Treatment Unit Using Multi Filter Hybrid with Parabolic Trough Solar Concentrator

Experimental investigations of the microscale concentrated photovoltaic/thermal system based on a solar parabolic trough concentrator

The world’s electricity generation from photovoltaic systems has been growing significantly for the last two decades. Nowadays, one of the most interesting trends in the conversion of solar radiation is the use of concentrating solar power collectors. Among other well-known technologies, quite a new solution is concentrated photovoltaic thermal installations, which use photovoltaic panels as a power converter. This paper presents the experimental works carried out on the prototypical micro-scale parabolic-through solar concentrator equipped with monocrystalline silicon solar cells located on the hexagonal receiver tube. The main goal of these investigations was to determine the possibility of enhancing the efficiency of photovoltaic solar cells by placing them under concentrated solar radiation. Obtained results showed, that the maximum power of tested solar cells increased approx. 29% from 14.40 ±0.50We to 18.60 ±0.60We using concentrated sunlight in comparison to efficiency measured in direct sunlight. It was demonstrated that the use of solar radiation concentrators is justified in the case of solar installations, even with low concentration ratio factors.

Numerical Study of Mixed Convection in Uniformly Heated Air-Based Tubular Cavity Receiver of Solar Parabolic Trough Concentrator with Different Boundary Conditions

Numerical Study of Mixed Convection in Uniformly Heated Air-Based Tubular Cavity Receiver of Solar Parabolic Trough Concentrator with Different Boundary Conditions

Internally shielded receivers for parabolic trough solar concentrators operating with supercritical carbon dioxide: Analytical assessment

An urgent need to enable the operation of parabolic trough concentrators at higher temperatures for higher efficiency of the coupled power cycles is manifested in the state-of-art literature. Supercritical carbon dioxide is a promising fluid for the next generation of these concentrators. However, the inflated radiative thermal losses at elevated temperatures are the main challenge, and the relatively large absorber diameters are questionable for supercritical pressures. This study proposes a novel 1-D analytical model, coupled with Monte Carlo ray tracing, for evaluating internally shielded receivers based on the absorber tube’s diameter and eccentricity, the heat shield’s opening angle, as well as the operating conditions. The results suggest that increasing the tube diameter reduces the performance dependency on tube eccentricity, but also reduces the optical performance. Shielding the receiver is favorable for opening angles up to 160°. The impact of operating pressure is marginal, compared to flow rate and temperature. A shielded receiver with an opening angle of 160°, eccentricity of −10 mm, and tube diameter of 50 mm maximizes the exergy efficiency up to 45.9%, whereas a receiver with corresponding values of 80°, −15 mm, and 80 mm, respectively, maximizes the energy efficiency up to 77.2%. Shielded receivers also boost the efficiency by up to 10.6%, compared to conventional 70 mm receivers. These performance enhancements are expected to elevate the efficiency of the integrated systems with minimal economic and environmental impacts due to the simplicity of the proposed solution.

Modeling and Performance Assessment of a Hypothetical Stand-Alone Parabolic Trough Solar Power Plant Supported by Climatic Measurements in Ipoh, Malaysia

Abstract 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.

Trough-Type Free-Form Secondary Solar Concentrator for CPV/T Application

Imaging concentrators like the parabolic trough solar concentrators have been widely employed for energy production in solar power plants. The conventional imaging solar concentrators form a non-uniform Gaussian distribution on receiving absorbers yielding the highest temperatures. The traditional CSP system normally truncated a peripheral region of heat flux to better use the central part. CPV/T systems using the waste heat recovery method can largely improve the total efficiency. However, for the CPV module, the coolant temperature was usually below 80 °C, which limited the applications of the thermal cycle such as the ORC system. In this article, a novel trough-type free-form secondary solar concentrator (TFSC) for PV/Thermal hybrid application has been proposed. Different from other CPV/T concepts using a combined PV panel and cooling tunnel/tube, the current concept separates the receiver in two parts. The secondary free-form reflector is generated by the geometric construction method, resulting in uniform heat flux in the edge region and high concentration in the central region. Through the ray tracing method, the optical properties have been verified. Sensitivity analysis of the concentrating structure is also conducted. The results provide supports for the design and applications of novel CPV/T systems.

Impact of the Thermophysical Properties of a Cuo-H<sub>2</sub>O-Based Nanofluid on the Performance of a Cylindrical Solar Concentrator

Sustainability in energy production, energy security, and global warming are major concerns facing the globe today. Cylindrical Solar Concentrator is extensively utilized for technologically advanced processes, heat, and power plant applications by utilizing daylight sunshine at no running cost. Numerous inputs and characteristics impact the concentrator's performance, with the type of heat transfer fluid and its mass flow rate being two of the most important. This paper gives a numerical investigation of the influence of thermo-physical attribute of CuO water-based nanofluids on the effectiveness of the Parabolic Trough Solar Concentrator in Ogbomosho weather condition (lat. 8o011, long. 4o111).The governing equations of nanofluids with laminar flow and steady state, using iterative relaxation techniques, as well as the efficiency of the concentrator, were solved. A C++ simulation program was developed to investigate the impacts of thermo physical parameters on concentrator efficiency, with nanoparticle sizes ranging from 1 to 10 percent and mass flow rates of 0.1 kg/s, 0.15 kg/s, and 0.2 kg/s, at a constant incident solar insolation flux of 186 W/m2. The results demonstrated that increasing the mass flow rate of the nanofluids improves the heat transmission properties. The thermo physical properties of CuO-based nanofluids and its effects on the performance of the solar parabolic trough collector are being examined. The impact of thermophysical attributes on thermal effectiveness results in improved thermal efficacy, heat transfer characteristics of nanofluids, and factors influencing its features in solar collectors, which determines its usability. The Parabolic Trough Collector system based on nanofluids is a promising technology with applications in green surroundings.

Thermal-Optical Evaluation of an Optimized Trough Solar Concentrator for an Advanced Solar-Tracking Application Using Shape Memory Alloy.

One of the modern methods for enhancing the efficiency of photovoltaic (PV) systems is implementing a solar tracking mechanism in order to redirect PV modules toward the sun throughout the day. However, the use of solar trackers increases the system’s electrical consumption, hindering its net generated energy. In this study, a novel self-tracking solar-driven PV system is proposed. The smart solar-driven thermomechanical actuator takes advantage of a solar heat collector (SHC) device, in the form of a parabolic trough solar concentrator (PTC), and smart shape memory alloy (SMA) to produce effective mechanical energy for solar tracking applications from sun rays. Furthermore, a thermal–optical analysis is presented to evaluate the performance of the solar concentrator for the simulated weather condition of Dammam City, Saudi Arabia. The numerical results of the thermal and optical analyses show the promising feasibility of the proposed system in which SMA springs with an activation temperature between 31.09 °C and 45.15 °C can be utilized for the self-tracking operations. The work presented adds to the body of knowledge an advanced SMA-based SHC device for solar-based self-actuation systems, which enables further expansions within modern and advanced solar thermal applications.

Design and development of solar hybrid distillation system for essential oil extraction from turmeric

The present study was conducted to design and develop the solar hybrid essential oil extraction system from turmeric at Department of Processing and Food Engineering, PAU, Ludhiana, Punjab. The developed system has six solar parabolic trough concentrator, steam generation unit, steam distillation unit, condensing unit and essential oil separator. A prototype of solar hybrid essential oil extraction system of 10 kg was designed and developed. The volume of steam distillation unit was 0.061m3 and volume of steam generation was 0.057 m3. The essential oil was extracted by using three turmeric grates size that is, 14.50 mm, 15.620 mm and 17.53 mm size. The smallest particle size (14.50 mm) having the highest essential oil yield (45 ml/kg) obtained from turmeric grates (P2, L42). The developed system was supplied additional 2 kW energy to extract oil from the turmeric grates. The results obtained from the study indicated that smallest grates size (14.50 mm) has the highest oil yield as compared to the largest grates size (17.53 mm). The steam generation and steam distillation unit has efficiency of 60 and 55.17%, respectively while the condensing unit having the efficiency of the 47.22%. The solar parabolic trough concentrators ensured energy saving of 21.53% and required 6.20 h extraction time. Developed system can be effectively helps in energy saving, reduced time required for oil extraction which makes the system more economical. Novelty impact statement In the developed solar hybrid essential oil extraction system, the oil extraction was performed by the steam diffusion mechanism, as there is no such technology available for the essential oil extraction through the steam diffusion from turmeric. The developed hybrid system ensures 21.53% saving of electrical energy and 17.33% saving of the overall extraction time for the essential oils from turmeric grates. It can be installed and operated on a rooftop, so no additional space is needed. The developed system act as a tool for the generation of the extra income for the farmers in term of value addition.

Highly Concentrated Solar Flux of Large Fresnel Lens Using CCD Camera-Based Method

Fresnel lens is a kind of lens that can concentrate sunlight up to a level of thousands of suns with small space occupation which is widely used in the research of sunlight concentration and transmission systems via optical fiber. Most studies on the concentrated flux of lenses use experimental methods to measure the flux distribution on the receiver of parabolic trough solar concentrators, solar power towers, and parabolic dish concentrators, while for Fresnel lenses, especially large-aperture Fresnel lenses such as the one in this manuscript, the simulation approach was mostly used. In response to this problem, this study has developed an experimental system for measuring the concentrated flux density of Fresnel lenses. A charge-coupled device (CCD) camera was used to capture the image of spot of large-aperture (968 mm) Fresnel lenses in the CCD camera-based method, and a heat flow meter was used to calibrate the spot brightness image obtained by the CCD camera. Experimental data show that the peak flux of concentrated spot can reach 4.06 MW/m2. This method confirms the simulation results of previous studies that using the rays tracing method, that is, the flux level of the Fresnel lenses can reach 5000 suns. The experimental results demonstrated the CCD camera-based method combined with a heat flow meter is competent in measuring the intensity of flux with a level of 5000 suns.

Performance Optimization of Solar Photovoltaic System using Parabolic Trough and Fresnel Mirror Solar Concentrator

An attempt has been taken to design parabolic trough and Fresnel mirror solar concentrator with the purpose of optimizing the output power of a photovoltaic system for both bright sunny day and cloudy day by using a 72-cell 5W photovoltaic solar panel. The PV system's efficiency has been analyzed in terms of output voltage, current, and power of the solar panel. Accordingly, to our expectation, we observed that on a bright sunny day, the output power improvement of the solar panel is 26.81% for the parabolic trough and 17.89% for the Fresnel mirror concentrator. On a cloudy day, both concentrators improve output power by 22.3% and 14.1%, respectively. In terms of power optimization of a photovoltaic system, the following has been discerned: a solar photovoltaic concentrator system with a parabolic trough is much more effective than one with a Fresnel mirror.

Hybrid solar desalination system for generation electricity and freshwater with nanofluid application: Energy, exergy, and environmental aspects

In this investigation, a hybrid energy conversion system is proposed and evaluated for energy, exergy, and environmental criteria for generating power and freshwater. The system comprises of a Humidifier Dehumidifier Desalination (HDD) system for producing freshwater, an organic Rankine cycle system for generating electric power, and a solar Parabolic Trough Concentrator for absorbing solar energy as the desalination heat source. Different working fluids including Al2O3, Cu, CuO, TiO2, and MWCNT nanoparticles in oil as the base fluid are examined. The influence of different nanofluids on the performance of the system is investigated as the main goal of this study. Environmental impacts of the suggested system are studied. Results show that the thermal efficiency of the Parabolic Trough Concentrator was with the application of Cu/oil nanofluid as about 62.4%. It is illustrated that the amount of freshwater production can be increased by raising the nanofluid concentration. The freshwater production varies between nearly 15.28 kg/h to 15.46 kg/h with the application of nanofluid. The organic Rankine cycle net work and total efficiency improved with increasing nanofluid concentration. Also, it can be concluded that the application of MWCNT/oil with a concentration of 5% volume fraction has shown the highest exergy efficiency of 4.7%. It was concluded the suggested desalination system with application of the solar organic Rankine cycle system, in addition to producing fresh water and power, significantly reduced amounts of CO2 emissions in the environment. Finally, it should be mentioned that the ideal system was analyzed and the gains from the use of nanofluids are very small.

Optimization of thermal efficiency on solar parabolic collectors using phase change materials - experimental and numerical study.

Solar energy is a one-of-a-kind renewable energy source that has many uses, and in the thermal applications, it is receiving more attention and is becoming more feasible. The present work presents numerical and experimental studies to investigate the performance of a parabolic trough solar concentrator (PTC) integrated with a thermal energy storage system. A new receiver design is built that stores thermal energy using phase change material (PCM). A concentric absorber tube with two different kinds of PCM - MgCl2·6H2O and erythritol (filling the annular-space of absorber tube) - were used to construct a PTC, and its thermal performance and thermal efficiency were investigated under two different HTF flow rates of 0.005 kg/s and 0.033 kg/s. Solar energy is transformed into heat, which is then used to store in the PCM before being discharged to cold water, which is the final heat transfer fluid in the receiver's inner pipe. The simultaneous studies of the PTC with and without PCM are investigated. A commercial Mat Lab's operating model through an imperialist competitive algorithm of the entire PTC system is presented, and the numerical results were compared to the experimental results, which were carried out with and without PCM in PTC. With the PCM in PTC (0.005 kg/s and 0.033kg/s), the HTF exhibited gain in peak temperatures of 11°C (erythritol) and 9°C (MgCl2·6H2O) at 0.05 kg/s, whereas the peak temperatures further increase to 14°C (erythritol) and 12°C (MgCl2·6H2O) respectively at 0.033 kg/s, as compared to HTF without PCM. Average thermal efficiency of PTC with HTF flow rate of 0.033 kg/s was highest with usage of erythritol (40.6%), among all the cases. The experimental and predicted thermal efficiency performance indices for different flow rates and PCM are found to be with a deviation of around ± 1.9%, demonstrating the accuracy of the developed numerical model.

Enhancing the energy utilization in parabolic trough concentrators with cracked heat collection elements using a cost-effective rotation mechanism

The risk of vacuum loss in linear solar heat collection elements (HCEs) is one of the major practical challenges that are facing the parabolic trough solar concentrator (PTSC) systems in concentrating solar power (CSP) plants. Despite the long-life span of CSP systems, HCEs are frequently replaced due to permeated hydrogen (due to saturation of getters) or leaked air (due to failures in end metal-to-glass welding or cracked glass shells). This study proposes a low-tech solution for boosting the performance of PTSCs with partial or lost vacuum through rotating the HCEs. A carefully validated integrated 3D optical-thermal model is developed and used to quantify the energetic and exergetic performances of PTSCs with rotated and fixed HCEs for both cases of lost and maintained vacuum. Both steady and unsteady simulations are reported using high-precision ground measurements of direct irradiance and meteorological parameters. As the rotational speed increases from 0 to 20 rad/s, the energy efficiency of PTSCs with new and damaged HCEs is improved by ∼47 and 52%, respectively, at a Reynolds number of 4000 and an inlet temperature of 350 °C. By rotating a damaged HCE at only 10 rad/s, maximum improvements of ∼26 and 53% in the useful heat gain are obtained, compared to non-rotating evacuated and non-rotating damaged HCEs, respectively, at the same operating conditions. Overall, the advantage of the proposed concept is more pronounced when the PTSC is operating at relatively low flow rates, high temperatures, or under high irradiance levels.