Parabolic Trough Concentrator Research Articles

Numerical and experimental studies of thermal performance enhancement for parabolic trough solar collector using none-circulated CuO/synthetic oil nanofluid

PurposeOne of the existing and commonly used solar energy harvesting devices is the parabolic trough solar collector (PTSC). Because of their ability to operate in low and medium temperatures, parabolic trough concentrators are widely used in power generation plants and industrial process heating applications. Therefore, the investigation of how different operating conditions affect these devices’ overall efficiency has received a great deal of attention in the recent decade. This study aims to enhance the thermal performance of the PTSC and reduce the system cost.Design/methodology/approachIn the novel configuration, a noncirculated nanofluid absorbs solar radiation through a glass wall. The base fluid was synthetic oil (5W30), and the nanoparticles used were copper oxide. The heat captured is immediately absorbed by the water circulating inside the copper tube immersed in the nanofluid. ANSYS FLUENT 15.0 was used for carrying out computational fluid dynamics simulations for two models of single and triple copper tubes. The experimental results obtained from a test rig constructed for this purpose were compared with the numerical outcomes of the single copper tube model.FindingsThe findings of the simulation demonstrated that performance was superior for the single copper tube model over the triple copper tube model. The numerical findings of the single copper tube model were compared with the experimental results. The numerical and experimental results differed from 3.17% to 5.6%. Investigations were carried out to study the effects of varying the volumetric flow rate of (20, 40, 60 and 80 L/h) and water inlet temperatures of (300, 315 and 330 K) on the effectiveness and performance of the newly developed model. Additionally, two nanofluid volume fractions of 0.05% and 0.075% were used for investigating their effect on the performance of the novel configuration. According to the findings, the highest thermal efficiency of 55.31% was recorded at 0.075% concentration and 80 L/h volume flow rate.Originality/valueIn this study, a novel direct absorption solar collector configuration using a noncirculated nanofluid was designed to enhance the thermal efficiency of PTSC. This new approach makes it possible to boost the thermal performance of the PTSC and lower the system’s cost.

Design and thermodynamic analysis of an innovative parabolic trough photovoltaic/thermal system with film-based beam splitter

This study aims to find a feasible photovoltaic/thermal (PV/T) utilization method based on film-based beam splitting technology. In contrast with previous studies, the main novelty of this paper is proposing the design of an innovative PV/T system using both parabolic trough concentrator (PTC) and film-based beam splitter (FBS). The design approach of the PV/T system is presented. A new FBS used for this PV/T system is designed by using the Needle method, and its average reflectivity and transmissivity are 27.2% and 72.8%. By using Ray Tracing and Computational Fluid Dynamics (CFD) simulation methods, the performance evaluation of the PV/T system is conducted. The evaluation results reveal that when the East-West sun tracking error is 0.2°, the optical efficiencies of the photovoltaic module and the solar thermal collector tube (TCT) can be kept at 95% and 93.9%. Moreover, when the heat transfer fluid (HTF) in the TCT is selected to be the ethylene glycol, the operation analysis results demonstrate that the photoelectric efficiency of the photovoltaic module is 25.4% and the thermal efficiency of the PV/T system is 17.24%. The thermal performance of the system can be improved when the HTF flow velocity is increased properly or when the inlet HTF temperature is decreased. The technical feasibility of the proposed PV/T system can be revealed from the analysis results of this study.

Pilot scale continuous-flow solar water disinfection system by heating and ultraviolet radiation inactivating Acanthamoeba cysts and Bacillus spores

The consumption of biologically unsafe water and the resulting consequences persist especially in developing countries marked by resource-poor environments. Solar disinfection (SODIS) systems are the next step to upgrade SODIS for public drinking water supply on a community scale. In the present study, a continuous-flow system of solar water disinfection based on heating and ultraviolet (UV) radiation was developed and tested against Acanthamoeba castellanii cysts (1.38 ×103 cysts/L) and spores of Bacillus altitudinis 1.4 (1.8 ×104 CFU/mL). The system consists of a linear Fresnel solar collector (divided into infrared (IR) and UV radiation collector parts) coupled to a parabolic trough concentrator containing heat absorbers and quartz reactors fixed at its aperture and focus. Rotating wheels fixed at the base of the collector allow solar tracking in two axes. An apparatus composed of a secondary and heating tanks, as well as a retention and discharge pipe, allows the raw water to be heated until it overflows (at 92 ± 3ºC), flowing afterwards through the quartz reactors and being irradiated by UV (for 25 – 45 s). The system inactivated A. castellanii cysts (> 3 log/L) and B. altitudinis1.4 spores (2 log/mL), mainly due to the effect of heat. The daily productivity was 1200 L (flow rate of 3 ± 0.2 L/min, for 8 h). The system has the potential to be applied in the supply of safe drinking water on a community scale, with the cost of water being €0.0008 or €0.0004 per liter, using the version of the system with or without the UV part, respectively.

Modelling and simulation of a 1 MWe parabolic trough concentrator solar thermal power plant in different locations in Egypt

Modelling and simulation of a 1 MWe parabolic trough concentrator solar thermal power plant in different locations in Egypt

Performance optimization of larger-aperture parabolic trough concentrator solar power station using multi-stage heating technology

Performance optimization of larger-aperture parabolic trough concentrator solar power station using multi-stage heating technology

Development and economic evaluation of a CPVT system with PHP cooling; An experimental study

In this paper, the experimental investigation of the performance of a concentrated hybrid photovoltaic thermal solar system is sought. Accordingly, there is a parabolic trough concentrator receiver that consists of three components: a triangular duct, photovoltaic cells covering the duct, and a three-turn PHP. The PHP cools down the photovoltaic cells efficiently and regenerates waste heat. The duct is filled with a heat transfer fluid surrounding the PHP’s evaporator. The condensation section of the PHP is located outside the solar concentrator. Using a one-axis polar mechanism, the concentrator tracks the sun from east to west. The system experiment setup was fabricated and tested outdoors in Tehran’s climate. Different heat transfer fluids, including Glycerine, Ethylene Glycol, and Calcium Chloride water mixture, were tested. Given the enhancement of PHP performance, a variety of working fluids were tested, including graphene oxide nanofluid/water, acetone, and pure water. The experiments showed that graphene oxide nanofluid/water mixture provided the highest thermal performance. With the use of graphene oxide nanofluid/water (as a working fluid) and glycerine (as heat transfer fluid), experiment results showed a decrease of 7.84 °C in PV temperature and a consequent increase of 21.85% in electrical efficiency in best condition. Furthermore, the provided cooling system recycles a maximum of is 190.4 kJ of thermal energy equivalent 52.5% thermal efficiency, increasing overall efficiency by 74.35%. Lastly, the IRR of 65.41%, PBT of 1.04 years, and LCOE of 1.84 $/kWh demonstrate appropriate financial profitability.

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.

Performance Simulation of Solar Trough Concentrators: Optical and Thermal Comparisons

The solar trough concentrator is used to increase the solar radiation intensity on absorbers for water heating, desalination, or power generation purposes. In this study, optical performances of four solar trough concentrators, viz. the parabolic trough concentrator (PTC), the compound parabolic concentrator (CPC), the surface uniform concentrator (SUC), and the trapezoid trough concentrator (TTC), are simulated using the Monte Carlo Ray Tracing method. Mathematical models for the solar trough concentrators are first established. The solar radiation distributions on their receivers are then simulated. The solar water heating performances using the solar trough concentrators are finally compared. The results show that, as a high-concentration ratio concentrator, the PTC can achieve the highest heat flux, but suffers from the worst uniformity on the absorber, which is only 0.32%. The CPC can generate the highest heat flux among the rest three low-concentration ratio solar trough concentrators. Compared with the PTC and the CPC, the TTC has better uniformity, but its light-receiving ratio is only 70%. The SUC is beneficial for its highest uniformity of 87.38%. Thermal analysis results show that the water temperatures inside the solar trough concentrators are directly proportional to their wall temperature, with the highest temperature rise in the PTC and the smallest temperature rise in the TTC. The solar trough concentrators’ thermal deformations are positively correlated to their wall temperatures. The radial deformation of the SUC is much larger than those of other solar trough concentrators. The smallest equivalent stress is found in the SUC, which is beneficial to the long-term operation of the solar water heating system.

A tubular solar still integrated with a heat pipe

AbstractThe aim of this work is to explore the thermal performance of a tracked tubular solar still (TSS) with a parabolic trough concentrator in Baghdad (33.27° N, 44.37° E) in September 2022. The present tubular still is distinguished by its hexagonal glass cover. The effect of integrating the TSS with a heat pipe, the still tilt angle (10°, 15°), and the depth of saline water inside the still partitions on the productivity of freshwater are investigated. The results showed that using heat pipe enhances the freshwater productivity by 25%–40% and the efficiency by 25%. For the still integrated with heat pipe, as the water depth is increased from 5.5 to 6.5 cm the productivity of freshwater is increased by 16% and 20% for tilt angles 10° and 15°, respectively.

Numerical study of perforated obstacles effects on the performance of solar parabolic trough collector.

The current work presents and discusses a numerical analysis of improving heat transmission in the receiver of a parabolic trough solar collector by introducing perforated barriers. While the proposed approach to enhance the collector's performance is promising, the use of obstacles results in increased pressure loss. The Computational Fluid Dynamics (CFD) model analysis is conducted based on the renormalization-group (RNG) k-ɛ turbulent model associated with standard wall function using thermal oil D12 as working fluid The thermo-hydraulic analysis of the receiver tube with perforated obstacles is taken for various configurations and Reynolds number ranging from 18,860 to 81,728. The results are compared with that of the receiver without perforated obstacles. The receiver tube with three holes (PO3) showed better heat transfer characteristics. In addition, the Nusselt number (Nu) increases about 115% with the increase of friction factor 5-6.5 times and the performance evaluation criteria (PEC) changes from 1.22 to 1.24. The temperature of thermal oil fluid attains its maximum value at the exit, and higher temperatures (462.1K) are found in the absorber tube with perforated obstacles with three holes (PO3). Accordingly, using perforated obstacles receiver for parabolic trough concentrator is highly recommended where significant enhancement of system's performance is achieved.

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.

Evaluation of mono and hybrid nano-fluids on energy and exergy parameters of a photovoltaic-thermal system equipped with an eccentric parabolic trough concentrator

Considering the problems caused by the use of non-renewable energy, such as climate change, air pollution and environmental destruction, it is necessary to utilize alternative and renewable sources of energy, e.g., solar power, to meet the energy requirements. This study analyzed the electrical, thermal, and total (overall) efficiencies of a photovoltaic-thermal system equipped with a parabolic trough concentrator and an eccentric receiver (ECPVT). The experiments were conducted at three fluid flow rates of 2, 4, and 6 l/m with three nano-fluids (i.e., Al2O3, ZnO, and hybrid Al2O3-ZnO). The weight percentages of the nano-fluids were considered at 0.01 and 0.05, whereas the hybrid nano-fluids had the Al2O3 0.01-ZnO 0.05 and Al2O3 0.05-ZnO 0.01 compositions. According to the findings, the use of hybrid nano-fluids compared with the mono nano-fluids and the pure water in the ECPVT system improved the filling coefficient. Moreover, the filling coefficient was directly related to the increase in the fluid flow in all test conditions (i.e., use of pure water as well as mono and hybrid nano-fluids). The maximum electrical and thermal efficiencies were obtained at 14.8 % and 85.34 % when a hybrid nano-fluid was utilized at a flow rate of 6 l/m. As opposed to the pure water, the total efficiency increased by employing the Al2O3 nano-fluid up to 18.55 %, the ZnO nano-fluid up to 11.29 %, and the hybrid nano-fluid up to 23.39 %. Similarly, the findings revealed that the use of the Al2O3 nano-fluid affected different efficiencies more than ZnO. Compared with the pure water, the exergy efficiency increased by 2.05 %, 2.63 %, and 4.24 % when the mono ZnO 0.05, Al2O3 0.05, and hybrid Al2O3 0.05 + ZnO 0.01 nanoparticles were utilized.

Performance study of a new parabolic trough design under optical concentrator effect

• A new hybrid parabolic trough concentrator is proposed. • A new algorithm for the hybrid trough concentrator is presented. • The influence of the optical concentrator on the hybrid system performance is studied. • Results showed a maximum thermal efficiency of 86 % corresponding to 318.9 Watts as additional electrical power while the heat losses are reduced from 2.76% to 1.9%. • The chemical interactions within Therminol VP1 stay stable and the hydrogen production rate remains at 2.90µmol/kg/h, reducing the possibility of cracking problems. The production of thermal and electrical energy by conventional and hybrid parabolic trough concentrators is widely considered most important in the field of renewable systems. In this work, two main problems of parabolic trough concentrators were studied with the aim of minimizing them as much as possible, namely, the cracking of Therminol VP1 and heat loss. The cracking problem of Therminol VP1 is one of the major troubles of parabolic trough systems at high temperatures (400°C) due to its dramatic consequences, which decrease significantly the thermal and electrical efficiency of parabolic trough concentrator. To address these issues, the temperature of Therminol VP1 was automatically controlled by a new parabolic trough concentrator integrated with two different types of tubular thermoelectric generators. A new mathematical model was offered for this hybrid system. In addition, a set of thirteen non-linear equations were discretized using the finite difference method. The discretized equations were coded in MATLAB (2015a) software based on the Gauss-Seidel technique with an accuracy of 0.001. To confirm the predicted results of the new numerical model, a literature paper was used for comparison. The comparison between the predicted and literature results was in good agreement. The effect of solar concentrator ratio on the thermal and electrical performance of the new system was analyzed and discussed. The major results show that the maximum thermal efficiency of the new system up to 86 % corresponding to 318.9 Watts of additional electrical power. Also, the maximum storage of hot water at 95 °C and Therminol VP1 at 400 °C up to 251.5 Liter/Day and 383.8 Liter/Day, respectively. Additionally, the cracking problem of Therminol VP1 was effectively controlled. More precisely, the hydrogen generation rate was automatically stabilized at a low and stable value of 2.90 µmol/kg/h. In addition, the heat losses rate was reduced from 2.97% to 1.07% with increasing solar concentration ratio. These results represent a useful reference for the selection of this new hybrid parabolic trough concentrator in view of its developed and intelligent performance.

Enhancing thermal performance and sustainability parabolic trough concentrator systems in Djelfa's solar-integrated urban design

In this study, the coldest days of 2022 in the Djelfa region, Algeria, were determined using astronomical and climatic data. The timing of sunrise, sunset, and duration of sunlight, as well as changes in solar radiation intensity and air temperature, were analyzed. By converting solar radiation into heat and solving differential equations, the study examined water exit temperature, thermal energy, and total yield as outputs of a renewable energy converter. The effect of different glass coverings on these outputs was also investigated. The coldest day in 2022 was found to be the first day of January, with nine hours and 43 minutes of sunlight, a maximum solar radiation intensity of 670.34 MW/m?, and a maximum air temperature of 16.9?C. The outputs of the solar center followed a parabolic pattern for the first two parameters and increased over time for the remaining outputs, regardless of the glass type. However, using glass with a high emission coefficient, such as clear monochromatic glass, resulted in the highest values for the outputs: 52.57?C, 7.5 kW, 162 MW, and 70.62%. By understanding solar energy conversion and thermal behavior, the study contributes to energy-efficient designs and renewable integration, aiding in sustainable urban development. Findings can inform decision-makers in optimizing material selection, promoting resilient infrastructure, and advancing sustainable practices for a low-carbon future.

Experimental Performance Investigation of a Nanofluid Based Parabolic Trough Concentrator in Malaysia

Abstract— Concentrating solar energy system is a potential solar thermal technology, wherein parabolic trough concentrators (PTC) are becoming growingly popular. In this research, both analytical and experiment analyses have been done. The experiment has compared with analytical results. to examine the effect of different operating parameters. Water and water-carbon nanotube (w-CNT) are used to explore the performance of PTC system. Optimum receiver diameter is found 51.80 mm for the maximum efficiency of the collector. During optimization, mass flow rate and concentration ratio are found to be influencing on the thermal efficiency and heat removal factor. Investigations show improvement in heat transfer for added nanoparticles. Heat transfer rate is better in laminar flow than in turbulent flow. After analytical analyses, an experiment has been done using water and carbon nanotube and compared with analytical results. Results show that for every 1oC increase in outlet temperature heat gain and thermal efficiency with water increase at the rate of 0.02 kJ/s and 1.6% respectively. On the other hand, for w-CNT as HTF, for every 100 W/m2 increase in irradiance, heat gain augments at a rate of 0.23 kJ/s and thermal efficiency upsurges by around 7%. Flow rate of working fluids and solar irradiance are found to have respective negative and positive impact on thermal efficiency of the parabolic trough collector.

Construction of a parabolic trough concentrator for solar water disinfection

In the context of the current global environmental situation, one of the most relevant problems is undoubtedly that of water, not only because of the strong inequalities imposed by its geographical distribution, both in time and space, but also because of the economic and political decisions that determine our social relationship with this vital liquid (Peña, 2007). One of the biggest problems in the world today is the lack of access to fresh and drinking water. Add to this the problem of water pollution, and the picture gets worse. Pollution is caused by discharged waste, fertilisers, pesticides or chemicals that flow into fresh water and end up polluting salt water as well. In this regard, more than 1 billion people will suffer from water scarcity in the future due to pollution, overpopulation and climate change, which affect the sources of this essential resource (UN, 2020).

An Innovative Parabolic Trough Collector Design with a Twin-Cavity Receiver

An innovative parabolic trough concentrator coupled to a twin cavity receiver (PTC-TC) in evacuated tube conditions is investigated thermally and optically. The suggested design is compared with a PTC design with a flat receiver (PTC-F) in order to evaluate the efficiency of the proposed configuration. In the very first stages of the study, the optical efficiency was calculated for both collectors, and the optimum design was determined in the PTC-TC case. Then a mass flow rate independency procedure was conducted to ensure accurate results and to make a suitable comparison. The collectors were examined in a wide range of inlet temperatures ranging from 20 °C to 200 °C, and the thermal performance was calculated. Through the comparison process, it was revealed that the proposed collector appears to have higher thermal performance than the typical collector. In particular, there was a mean enhancement of approximately 8%, while the minimum enhancement was found to be greater than 5%. The simulation results regarding both configurations were verified through two models based on theoretical equations. In both geometries, the mean deviations in the verification procedure were lower than 5.6% in both the Darcy friction factor and the Nusselt number. The design and the simulations were conducted with the SolidWorks Flow Simulation tool.

Prototype of a novel hybrid concentrator photovoltaic/thermal and solar thermoelectric generator system for outdoor study

In this study, a novel prototype of a hybrid concentrator photovoltaic/thermal and solar thermoelectric generator system has been designed and constructed for combined heat and power production. In the developed hybrid system, both the solar cells and thermoelectric modules that share a common heat transfer medium are exposed to concentrated irradiance via a compound parabolic concentrator and a parabolic trough concentrator, respectively. To assess the performance of the hybrid system, a prototype of the hybrid system was built and tested under outdoor operating conditions, and the findings were compared with those of a transient numerical simulation conducted using ANSYS Fluent. The average PV temperature obtained during the test period at a flow rate of 3.8 L/min is 318.19 K which is ∼5.6% lesser compared with a conventional hybrid CPVT-TEG system. The outdoor trials show maximum electrical efficiency of 4.86% and thermal efficiency of 40% when the solar irradiance is greater than or equal to 1000 W/m2. The overall efficiency of the developed prototype is 3 times higher compared to a standalone PV system. The hybrid system helps to reduce carbon emission by 0.5 kg/h, with an associated environmental cost of 0.025 €/h.