Parabolic Concentrator Research Articles

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.

INVESTIGATION OF THE EFFECTS OF FLIPPED TRIANGLE PIPE INSERTS ON THERMAL EFFICIENCY IN A PARABOLIC TROUGH SOLAR COLLECTOR

In this study, the effects of different pipe inserts on the thermal efficiency of the system and the optimum operating conditions in a pipe exposed to direct and indirect, reflected from a parabolic concentrator, solar radiation were investigated experimentally and numerically. Experiments were carried out with three different factors (pipe insert array, radiation, and Re values) and four levels. The experimental plan was created by the Taguchi method in L-16 array with two repetitions and the conditions that make the thermal efficiency optimum were investigated. First, the pipe insert was designed and manufactured. As a result of the experiments, the highest thermal efficiency was determined to be achieved with the #3 pipe insert (with 4-cm spacing), under 700 W/m2 irradiance and at 1000 Re number. Then, the situation with the optimum conditions was modeled with the ANSYS Fluent and velocity contours, temperature contours, and pressure changes related to the flow and pipe insert were analyzed. In the case the novel pipe inserts designed in the scope of this study were employed, the thermal efficiency was found to have increased by approximately 58.38%, even under laminar flow conditions. The comparisons have revealed that the experimental and numerical results were in good agreement.

Modeling the heat balance of a solar concentrator heliopyrolysis device reactor

The article presents the principle scheme of the heliopyrolysis device with a solar concentrator and the mathematical model of the equations representing the heat balance of the heliopyrolysis reactor. Based on the mathematical modeling method, the energy balance of the heliopyrolysis reactor was theoretically studied, and graphs representing the temperature change of the reactor surface were obtained when the solar radiation falling on the concentrator was Ir=600÷900 W/m2 in the climatic conditions of the region of Karshi (Uzbekistan). Based on modeling in the SOLTRACE program, the graphs of the temperature field at different points of the solar parabolic concentrator are determined to change depending on the energy of the incident solar radiation. In the experimental device, it was determined that an average temperature of 200-300 ℃ can be generated in the reactor within one hour. Experiments show that in the conditions of the city of Karshi, it is possible to create a regime of 200÷500℃ sufficient for biomass pyrolysis through a parabolic solar concentrator in the daytime mode.

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 Study of Photovoltaic Performance Under a Compound Parabolic Solar Concentrator with a Nanofluid Spectral Filter

Experimental Study of Photovoltaic Performance Under a Compound Parabolic Solar Concentrator with a Nanofluid Spectral Filter

Studying the temperature regime of the heliopyrolysis device reactor

The article presents the principle of the heliopyrolysis device with a solar concentrator and the temperature measurement scheme at the characteristic points of the reactor. Pyrolysis of organic waste was carried out according to the experimental method in laboratory conditions. Experiments were carried out on samples of organic waste (rubber, polyethylene film, plastic bottle) with an initial moisture content of 5÷20% and a size of 4÷6 mm. Based on the relationship between the amount of solar radiation and the ambient temperature for the city of Karshi (Uzbekistan), the experimental results of studying the temperatures inside the heliopyrolysis reactor when various organic wastes are loaded are presented. 0.25h according to the height of the reactor in the experiment; 0.35h; 0.25h; temperatures on the inner surface at distances of 0.15 h were recorded using the Mobile-CASSY 2 thermometer. It was determined that an average temperature of 350÷450 °C can be generated in the reactor of the experimental device. Experiments show that in the conditions of the city of Karshi, it is possible to create a mode of 300÷500°C sufficient for the pyrolysis of organic waste through a parabolic solar concentrator in the daytime mode.

Design of the position control system of parabolic solar concentrators through collector by electrical drive

Design of the position control system of parabolic solar concentrators through collector by electrical drive

Design and performance analysis of a Scheffler reflector for ceramic materials sintering

This study aims to identify the factors enhancing the performance of Scheffler parabolic solar concentrators as part of the design of a solar kiln for firing ceramic materials, with a particular emphasis on the crucial role of the concentrator’s concentration factor in reaching the necessary sintering temperature of around 1000 °C. This challenge is addressed through a design methodology employing circular crossbars and rectangular mirrors, simplifying fabrication. The study further involves assessing and comparing concentration factors across multiple configurations, encompassing both traditional parabolic surfaces and rectangular mirrors. Findings indicate that using flat rectangular mirrors with dimensions of approximately (2.5 × 2.5) cm2 achieves performance levels comparable to those attained with parabolic surfaces. The Results also highlight the critical importance of accurately positioning the receiver’s surface to ensure optimal performance. Additionally, the study confirms that increasing the surface area of the dish offers significant advantages for achieving high temperatures.

Concatenated Backward Ray Mapping on the Compound Parabolic Concentrator

Concatenated backward ray mapping is an alternative for ray tracing in 2D. It is based on the phase space descrip tion of an optical system. Phase space is the set of position and direction coordinates of rays intersecting an optical line. The original algorithm is limited to optical systems consisting of only straight line segments; we extend it to accommodate curved segments. The algorithm is applied to the compound parabolic concentrator, a standard optical system that collects parallel light and reshapes it to a focused beam. We compare the accuracy and speed of the extended algorithm to the original algorithm and Monte Carlo ray tracing. The results show that the extended algorithm outperforms both methods.

Development of a bright MeV photon source with compound parabolic concentrator targets on the National Ignition Facility Advanced Radiographic Capability (NIF-ARC) laser

Compound parabolic concentrator (CPC) targets are utilized at the National Ignition Facility Advanced Radiographic Capability (NIF-ARC) laser to enhance the acceleration of electrons and production of high energy photons, for laser durations of 10 ps and energies up to 2.4 kJ. A large enhancement of mean electron energy (>2 ×) and photon brightness (>10×) is found with CPC targets compared to flat targets. Using multiple diagnostic techniques at different spatial locations and scaling by gold activation spatial data, photon spectra are characterized for Ephoton=0.5–30 MeV. Beam width and pointing variations are given. The efficient production of MeV photons at Ilaser≈2×1018 W/cm2 with CPCs is observed, with doses of >10 rad in air at 1 m for Ephoton>0.5 MeV; these exceed those previously reported with laser-driven sources. Using this source, sub-mm resolution radiographs are generated through large areal density radiograph objects. These results are promising for the development of bright MeV x-ray and particle sources on Petawatt class laser systems.

Investigation of photo-thermal performance of compound parabolic concentrator system for soil heating in facility agriculture

Aiming at the large carbon emissions of facility agricultural heating in severe cold regions in winter, a compound parabolic concentrator based soil heating system was presented. The system integrated with novel trough compound parabolic concentrator and was used for soil heating in facility agriculture. Following the structure of the compound parabolic concentrator, TracePro software was selected to trace the light in the compound parabolic concentrator. The variation trend of the light escape rate of the compound parabolic concentrator with the different incident angles was analyzed. Based on the calculation results, the performance of the solar collector system was investigated, and the impact of circulating air velocity on the photo-thermal performance of the solar collector system was explored. Research results indicate that when the circulating air velocity is 1.4 m/s and the average ambient temperature is about 28.9?, the temperature of the system outlet is up to 90.9?. The average instantaneous heat collection, maximum photo-thermal conversion efficiency, and unit area heat collection of the system are 740.6 W, 27.83%, and 0.8 MJ/m2, respectively. This research can effectively promote the efficient integration of the solar collector system in facility agriculture.

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).

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.

Performance analysis of a novel solar cogeneration system for generating potable water and electricity

PurposeThe utilisation of renewable energy sources for generating electricity and potable water is one of the most sustainable approaches in the current scenario. Therefore, the current research aims to design and develop a novel co-generation system to address the electricity and potable water needs of rural areas.Design/methodology/approachThe cogeneration system mainly consists of a solar parabolic dish concentrator (SPDC) system with a concentrated photo-voltaic module at the receiver for electricity generation. It is further integrated with a low-temperature thermal desalination (LTTD) system for generating potable water. Also, a novel corn cob filtration system is introduced for the pre-treatment to reduce the salt content in seawater before circulating it into the receiver of the SPDC system. The designed novel co-generation system has been numerically and experimentally tested to analyse the performance at Karaikal, U.T. of Puducherry, India.FindingsBecause of the pre-treatment with a corn cob, the scale formation in the pipes of the SPDC system is significantly reduced, which enhances the efficiency of the system. It is observed that the conductivity, pH and TDS of seawater are reduced significantly after the pre-treatment by the corncob filtration system. Also, the integrated system is capable of generating 6–8 litres of potable water per day.Originality/valueThe integration of the corncob filtration system reduced the scaling formation compared to the general circulation of water in the hoses. Also, the integrated SPDC and LTTD systems are comparatively economical to generate higher yields of clean water than solar stills.

Development of a model of combination of solar concentrators and agricultural fields

We have developed several prototypes of solar concentrators that are compact, light, and inexpensive. As an example of solar concentrators, we selected parabolic solar concentrators with plane mirrors that approximate the parabolic surface. The green energy is very important in modern world because of global climate change, which has caused disproportion in the ecological balance, population growth rates, an increase in demand for food and electricity against the backdrop of a decrease in arable land. They are now the main challenges to the development of agriculture and ensuring sustainable food security of many countries. In this paper, as one of the ways to address these challenges, the problems of combining crops with agrivoltaics are studied using the example of two countries – Mexico and Azerbaijan. The economy of both countries is based on oil production, relief and climate have many common features, which are expressed particularly in the abundance of solar radiation, the predominance of mountainous regions with remote and hard-to-reach settlements that need to create autonomous life support systems. A methodology is proposed for the evaluation of the impact of combinations of solar concentrators together with certain agricultural crops. The proposed mathematical model is simple and applicable for different cases of combination of solar concentrators and agricultural fields. The main problem for proposed solar concentrators is the automatization of the assembly process of these solar concentrators. We proposed two methods of assembly that is, using a parabolic rule and using a robotic arm with a stereoscopic vision system. Both methods are described in this article. The simulation of these processes was made with using software of SolidWorks

A Review of Linear Fresnel Collector Receivers used in Solar Thermal Technology

Linear Fresnel collectors (LFC) have, among the four technologies of concentrating solar power (CSP), the simpler technology. They have a one axis sun tracking, plane mirrors and a fix receiver. All these elements make them the most suitable for small scales CSP plants adapted to rural area of the Sub-Saharan region. The receiver is an important part of the LFC. There is a wide variety of receivers that differ in the shape of the absorber: mono-tube, multi-tube, plane. The shape of the secondary concentrator or its absence allows to categorize the receivers in a butterfly, compound parabolic concentrator, segmented parabolic secondary concentrator or trapezoidal receiver. Vacuum mono-tube receivers have heat losses between 200 W/m and 270 W/m at an absorber temperature of 350°C. A mono tube receiver at partial vacuum losses more than 350 W/m at 350°C. The lowest heat losses of a multi-tube receiver with a trapezoidal secondary concentrator can reach 500 W/m at an absorber temperature of 350°C. This paper discusses a comparative study of existing receiver designs in order to find the most suitable for rural areas in the sub-Saharan region, i.e. easy to design by hand and low cost. Although they do not have the best thermal performance, trapezoidal receivers with a black-painted copper multi-tube absorber and a glass cover seem to be the most suitable.

Improving angular response of crossed compound parabolic concentrators using rectangular entry aperture

A novel design of crossed compound parabolic concentrator (CCPC) that has a rectangular entry aperture is presented, which has the advantage of considerably improved angular response compared to a conventional CCPC that has a square entry aperture. It is found that the half acceptance angle of this novel design is 40° for a 4.0x rectangular concentrator when operating in the “east-west” direction, which is approximately 10° larger than that of a conventional square concentrator of the same concentration ratio. This is a substantial increase and completely unexpected because the design theory for this type of concentrators predicted a much smaller half acceptance angle of 26.6°. Experimental and simulation work reported in this paper confirms this discovery. The results reveals that the observed improvement is attributed to multiple light reflection inside the concentrator, which was not considered in the commonly employed design theory. An important implication of this work is that the multiple light reflection plays an important role in the angular response of the CCPC and its effect cannot be neglected in the design.

Mathematical Modeling and Simulation of a Compound Parabolic Concentrators Collector with an Absorber Tube

CPC solar collectors are a combination of new technologies that make it possible to generate heat from radiant solar energy by transferring heat between the absorber and the fluid. This study was performed based on heat transfer equations by proposing a mathematical model, as reported in the literature. A compound parabolic concentrators solar collector (CPC) numerical model was simulated and coded in Aspen HYSYS and MATLAB software and validated by comparing its results with other researchers and experimental results. The simulated mathematical model includes a two-dimensional numerical model to describe the thermal and dynamic behavior of the fluid inside the CPC solar collector absorber tube. Numerical simulations of the fluid flow equations inside the CPC solar collector absorber tube, along with the energy equation for the absorber tube wall, coating, insulation and reflector, and solar collector heat analysis, were performed repeatedly in MATLAB and Aspen HYSYS software. This method is the most appropriate and reliable method for solving equations for numerical convergence. The experimental results of the parabolic concentrated solar collector (CPC) were used to evaluate and validate the numerical model. A solar compound parabolic concentrators collector (CPC) with short reflectors was used. This collector includes a cylindrical absorber with a real density ratio of 1.8, a reception angle of 22 degrees and a length of 2.81 m, a width of 0.32 m, and an opening of 0.1764 m. Analysis and uncertainty of the proposed model were performed with the measured sample. In the thermal efficiency analysis, the average deviation of the model from the experimental results of other researchers was equal to 7%, for increasing the temperature by 9 °C. According to these results, a good correlation between numerical results and experimental results for this proposed model has been obtained.

Experimental investigation of solar‐powered food steamer based on parabolic dish concentrator for domestic applications

AbstractSteam cooking is beneficial over other cooking techniques like boiling since it preserves more vitamins lost during other methods. In this study, a novel solar food steamer (SFS) based on a parabolic dish concentrator (PDC) is designed and constructed for domestic food preparation. A straightforward fabrication process of a 2.626 m2 PDC with design calculations is also presented. The system's instantaneous energy and exergy efficiency evaluation has been examined from different tests over three consecutive days. The system's high energetic and exergetic efficiency was achieved in the case of sweet potato, that is, 72.83% and 15.14%, respectively. In the case of dried chickpeas, the maximum steaming duration of 70 min was attained, along with an energy efficiency of 47.74% and an exergy efficiency of 10.07%. In addition, an economic analysis was performed to determine the payback time in terms of cost and utility. The payback time for the proposed method is 2.4 years. The SFS may save 43 kg/month of carbon dioxide from escaping into the atmosphere; it can be considered an environmentally valuable device.