Dish Concentrator Research Articles

CFD Simulation of Solar Dish Concentrator with Different Cavity Receivers

CFD Simulation of Solar Dish Concentrator with Different Cavity Receivers

Optimizing Solar Dish Concentrator Efficiency with Nanofluids and Diverse Cavity Design

Optimizing Solar Dish Concentrator Efficiency with Nanofluids and Diverse Cavity Design

Techno-economic viability of sustainable solar co-generation using CPV cells in parabolic dish concentrators: A 20-year perspective

Solar co-generation is a cutting-edge technology that enables the instantaneous production of electricity and heat energy by employing concentrated solar power (CSP) systems. This study presents the development and experimental analysis of a novel small-scale solar co-generation system, utilizing concentrated photovoltaic (CPV) cells integrated into a solar paraboloidal dish concentrator (SPDC) for simultaneous electricity and heat production. The system, designed with a high concentration ratio, employs a CPV module composed of four 1 cm × 1 cm cells mounted on a flat receiver of a parabolic dish concentrator with an aperture area of 12.6 m2. Experimental results, obtained over three consecutive days, demonstrate that the CPV module achieves an electric power output ranging from 480 to 645 W daily, while the SPDC system generates thermal energy between 395 and 725 W. The economic analysis indicates a cost of ₹10.75 per unit of electricity, with a payback period of approximately 13.5 years, assuming a 20-year system lifespan. Additionally, the reliability of the CPV module and the impact of varying encapsulation materials were critically assessed, providing insights into potential improvements and long-term performance. The findings underscore the viability and economic potential of solar co-generation systems employing CPV technology, contributing to the advancement of sustainable energy solutions.

Analyzes and compares the optical characteristics for two types of solar dish concentrators

Analyzes and compares the optical characteristics for two types of solar dish concentrators

Experimental study of the energy and exergy performance of a solar parabolic dish concentrator integrated with thermal energy storage

Concentrating solar power is rapidly becoming a mainstay of solar energy systems, with the parabolic dish concentrator being a common and high-performing option for medium-temperature applications. This study investigates the thermal performance of a parabolic dish concentrator integrated with phase change material based thermal energy storage. Energy and exergy efficiencies are compared for a water-based storage tank in thermosyphon circulation mode, both with and without phase change materials encapsulation. Various phase change materials capsules were strategically positioned within the tank in a certain position, which satisfies the melting temperature of the studied phase change materials. Steam generation was also measured and correlated with solar irradiation intensity. This study aims to address the changes in energy and exergy efficiencies for the system integrated with latent heat storage encapsulation. Results show the highest overall energy efficiency 46.7% was achieved with copper cylindrical capsules, while the base case without phase change materials yielded the highest overall exergy efficiency 5.23%, closely followed by the copper cylindrical capsule 4.94%. Peak energy and exergy efficiencies reached 79.37% and 11.12%, respectively. The copper cylindrical capsules provided the optimal balance between thermal and storage performance without compromising efficiency.

Techniques to mitigate membrane displacement for vacuum-membrane solar-dish facets

The prospects of a multifaceted vacuum-membrane solar dish concentrator are considered in this work. The membrane depths of these facets can shift slightly due to varying ambient conditions throughout an operational day, leading to major focal point shifts and a reduced overall efficiency. The purpose of this work was to experimentally investigate different methods of membrane displacement mitigation. A controlled-environment (indoor) enclosure was employed to examine the effects of static ambient conditions, allowing for the independent manipulation of the surrounding pressure and temperature. Various manufacturing techniques were also investigated within the controlled-environment enclosure, which included alterations in pretension, changes in membrane thickness and adjustments to overall facet sizes. Furthermore, outdoor tests were conducted to determine how solar radiation and convection affected membrane displacement as well as to investigate the performance of various membrane depth control strategies using an Arduino Uno microcontroller. The indoor results showed that opting for a small facet would minimize membrane displacement. The results were supported by material tests and a finite element analysis. The outdoor test results indicated that solar radiation and wind affected the internal temperature and consequently also affected the membrane depth. Furthermore, a focus control system maintaining a constant differential pressure across the membrane achieved the required accuracy of ±2 mm membrane displacement limitation. However, another focus control system consisting of a Hall effect module actively monitoring membrane depth emerged as the most effective, with an increase of about 0.09 mm and a decrease of approximately 0.02 mm from an initial depth of 10 mm. This level of stability with a focus control system will ensure that the facet maintains a consistent optical performance, ultimately advancing the reliability and efficiency of low-cost vacuum-membrane technology.

Integrated solar dryer and distillation system with PCM and injection, powered by PVT panels and solar concentrator

This research introduces a novel hybrid system integrating solar drying, solar distillation, and photovoltaic thermal panels, aimed at drying agricultural products, producing clean drinking water, and conserving energy. The system enhances the drying air temperature using thermal energy storage materials and a solar dish concentrator connected to a hot water storage tank, ensuring continuous operation even after sunset. The solar distiller, equipped with energy storage materials and an air injection system, is integrated with an external condenser to condense water vapor before expulsion, thereby increasing freshwater productivity. The results revealed that the developed system achieved an accumulative freshwater productivity of 87.1 L per day. The rates of water removal from dried potato slices ranged from 0.18 to 0.91 kg/h between 8:00 am and 10:00 pm. Additionally, the system achieved a gain output ratio of 1.38, indicating a significant improvement in energy efficiency. This innovative system offers practical solutions to address energy and freshwater scarcity, especially in remote regions of the Middle East and North Africa (MENA) region, which are characterized by high solar irradiance. The implementation of such hybrid systems could contribute to sustainable development by reducing reliance on conventional energy sources and mitigating environmental pollution.

Optical and Thermal Modeling of a Cylindrical– Hemispherical Receiver

Receiver geometry optimization is a crucial domain in enhancing the efficiency of parabolic dish concentrators. This optimization necessitates thoroughly scrutinizing the receiver's optical and thermal characteristics. The present study engages in a cylindrical-hemispherical receiver's optical and thermal modeling. Set at an aperture of 0.150m, the receiver's height varies between 0.150m to 0.160m. Sol-Trace software is employed for the optical modeling to analyse the total amount of heat flux absorbed by the receiver that has been concentrated using parabolic dish. The diameter of the is taken as 3m, and the receivers placement is varied between 1.55m and 2.05m from the dish concentrator to obtain the optimal distance for absorbing maximum heat flux. From the results optimal distance has been observed as 1.8m from the dish concentrator. Maximum heat flux of 6664.56W has been absorbed by the receiver surface at this position. Additionally, thermal modeling using CFD has been conducted to calculate convective heat losses from the receiver under different wind conditions, such as varying wind direction and wind velocity. The maximum convective heat loss observed under head-on wind conditions is 772.73W, while under back-on wind conditions, it is 606.84W

Theoretical analysis of upward-heating multiple-effect diffusion solar still with parabolic dish concentrator

Upward-heating multiple-effect diffusion solar still (UHMEDS) coupled with a parabolic dish concentrator (PDC) was proposed and analyzed theoretically. UHMEDS has cover glass, several partitions and preheating cover, and wicks are placed on the upper surfaces of partitions and preheating cover. Saline water preheated on the preheating cover flows down the partitions by gravitational force. The lowermost partition of UHMEDS was heated by solar energy collected by PDC. The basic behavior of UHMEDS at Fukuoka, Japan was analyzed theoretically by modeling heat and mass transfer in the still. The theoretical results show that PDC can collect the sunrays to the lowermost partition of UHMEDS effectively, and the overall daily productivity of the still was predicted to be about 18.5, 24.5 and 10.4 kg/m2day on spring equinox, summer and winter solstice days, respectively, which values are almost equivalent to those of other types of multiple-effect diffusion solar still.

Optical analysis and design of a novel solar beam down concentrator for indoor cooking

This investigation provides the design and optical analysis of an innovative solar beam-down configuration, which can be a promising passive solution for indoor solar-based cooking, offering an eco-friendly and sustainable approach. The system uses a beam-down parabolic dish concentrator to concentrate the solar radiation onto a ground-mounted receiver module, which has a secondary optical module consisting of a secondary reflector-light pipe system. The receiver module is a well-insulated tank consisting of a receiver in contact with a primary heat transfer fluid. The thermal energy stored in the receiver module is transported via a secondary heat transfer fluid to and from the cooktop via a tube-in-tube arrangement, which induces a thermosyphon effect. A multi-variable optical analysis through an efficient ray tracing methodology has been adopted to identify optimal design values of optical components such as parabolic dish concentrators, secondary reflectors, and light pipe-receiver assemblies. The optimal optical design parameters and their corresponding ray trace analysis results are elaborated. It was found that the designed beam-down parabolic dish concentrator system provides an ideal thermal energy of 10.3 kWh per day at an average DNI of 650 W/m2. Further, this investigation provides a design for a beam-down parabolic dish concentrating system that may be used for efficient and sustainable solar energy solutions.

Energy-efficient production of sustainable industrial process heat with a parabolic dish-conical cavity solar collector

Industrial decarbonization in response to global carbon neutrality requires vast process heat to be supplied in a low-carbon manner. Solar energy is regarded as one of the most promising alternatives to fossil fuel applied for heat-driven industrial processes, however, lack of effective approaches to improve the solar-thermal conversion efficiency is a longstanding issue. Here, we propose an efficient approach to produce industrial process heat based on a novel concentrated solar collector, mainly consisting of a parabolic dish concentrator and a conical cavity receiver. Results showed that the collector was competent to supply the process heat meeting various low-temperature industrial occasions, and there was an optimum flow rate to achieve a trade-off between the outlet temperature of working fluid and thermal efficiency of the solar collector. The thermal efficiency of the proposed solar collector was 2.7%–27.5% higher than that of most other existing collectors used for production of low-temperature process heat, and such a superior solar-thermal conversion efficiency was a consequence of the reduction in energy losses between the solar receiver and surroundings as confirmed by the comprehensive energy analysis performed in this study.

Optical performance of a solar dish concentrator formed by the same size mirror located on parabolic frame

Solar dish concentrator with low cost and meeting the flux distribution is always pursued for the efficient utilization of concentrated solar energy. This paper investigates the optical performance of a solar dish concentrator formed by using a number of identical square mirror units arranged on a parabolic surface frame. The manufacturing of the mirror surface of this concentrator requires only one kind of mold, which has the significant advantage of low-cost manufacturing. Three common types of mirror units including the parabolic mirror (focal length fm), spherical mirror (radius Rm) and plane mirror are considered. The influence of key geometric parameters including the mirror width d (250–750 mm) and dimensionless parameters such as f1/D, fm/f1 and Rm/f1 (f1 is the focal length of parabolic frame) on its optical performance indexes such as the focused spot size (i.e., intercept width w), average local concentrator ratio (LCR), peak LCR and flux uniformity is analyzed using ray-tracing method, and the correctness of optical model and concentrator optical function is verified by outdoor concentrating experiments. The results show that the concentrator composed of parabolic or spherical mirrors can easily obtain a small circular focusing spot with high LCR and the intercept width can be easily controlled within 200 mm, the peak LCR can reach 34457 (average LCR is 12898), and average LCR reaches 14794 (peak LCR is 29497) at the smallest spot with w = 38.4 mm, which can be a low-cost alternative to parabolic dish concentrator. The concentrator with plane mirrors are easier to obtain square focusing spots with excellent flux uniformity, w can be controlled from 180 to 380 mm and uniform LCR is between 100 and 1400, which is very suitable for concentrating photovoltaic field.

Performance, economic, and statistical analysis assessment for the hybrid solar dish concentrator with turbine, generator, and reverse osmosis desalination unit

The development of a thermodynamically modeled hybrid commercial solar dish with reverse osmosis is conducted in this study with a rated concentrate thermal and a receiver temperature of 853 °C. To simulate and assess the performance characteristics of the suggested TJ-SDC/RO hybrid system in the city of Tianjin-republic of China, a theoretical model was created and built with MATLAB application. A daily and yearly performance study of the TJ-SDC/RO system under investigation is accomplished. Furthermore, energy analysis viability is achieved in order to evaluate the TJ-SDC/RO system’s life cycle. According to the findings, the suggested TJ-SDC/RO system can produce enough desalinated water to meet daily changes in solar radiation. In June of Tianjin-China’s climate, the superior efficiency of the Rankine cycle was 33.92 %, while the SDC-RO system maximum cycle efficiency peaked at 24.95 % with minimum production costs per unit of electricity of 0.0902 $/kW.h and average water production costs yearly 7.09 $/m3. A mathematical model by Minitab commercial software of the nonlinear regression technique is used with an adjusted R2 of 0.99999485, which indicates the accuracy and reliability of the prediction correlation.

Effects of Orange Waste Extract Produced by Hydrodynamic Cavitation on the Germination of Chenopodium album L. and Lactuca sativa L.

A byproduct from orange juice processing known as pastazzo represents a significant organic waste stream. Rich in essential oils and known for its inhibitory effect on plant germination, pastazzo could serve as a valuable input for agricultural purposes. This study assesses the effects of a 40% w/v orange pastazzo water extract (OPWE) produced by hydrodynamic cavitation on the germination of two species, one of economic interest (Lactuca sativa L.) and one common weed (Chenopodium album L.). Three dilutions of OPWE in water (25%; 50%; 75%) were compared to a control treatment in four experiments, using (i) seeds in Petri dishes; (ii) seeds in commercial substrate; (iii) C. album seeds and transplanted L. sativa in commercial substrate; and (iv) other weeds in an open-field plantation of L. sativa. Highly rich in limonene, OPWE applied at higher concentrations in Petri dishes caused the effective inhibition of germination in C. album and a germination delay in L. sativa. Similar results were observed in the germination of the two species in commercial substrate, with none of the dilutions affecting L. sativa biomass. In the field experiment, despite a relatively low number of weeds in the control treatment, higher OPWE concentrations reduced the number of grasses and forbs, largely confirming the inhibitory effects. We conclude that OPWE produced with hydrodynamic cavitation, an efficient and affordable method of extraction, represents an effective crop treatment due to the species-specific effects of its constituent limonene on plant germination. Further tests are essential to understand the extent to which OPWE interacts with other species and types of substrate.

Solar cavity receiver for melting zinc metal

Concentrating solar power technologies can be applied to reduce the cost and carbon footprint of zinc melting processes. This study aims to improve the knowledge related to small-scale solar melting using a dish concentrator. This technology can be applied to zinc production as well as a range of small-scale applications, such as casting, recycling, galvanisation, and thermal storage. An experimental and analytical analysis of a rotating cylindrical cavity receiver for the indirect melting of zinc metal using concentrated solar power is presented. A multi-facet parabolic dish with an incident area of 2.85 m2 was considered together with a rotating cylindrical cavity receiver. The receiver had an aperture diameter of 0.2 m and the capacity for housing 17 kg of zinc. Five experimental test runs were executed, during which up to 73.5 % of the zinc inventory could be tapped from the receiver in its molten state, and average thermal efficiencies of up to 42 % were achieved. A predictive analytical model considering wind speed, wind direction, and direct normal irradiance was developed and validated against experimental data. A heat transfer efficiency factor was experimentally determined to account for voids in the zinc feedstock. The model was used to predict that approximately 41 kg of molten zinc could be tapped from the experimental setup throughout a typical day with a peak direct normal irradiance of about 900 W/m2 and an average wind speed below 2 m/s. A case study highlighted that energy savings of 0.6 kWh are achievable per kilogram of zinc processed by concentrated solar power rather than the conventional induction furnace.

Numerical analysis of convective heat loss from a cylindrical–hemispherical receiver using a glass cover and an air curtain

AbstractIt is imperative to mitigate the convective heat loss from the receiver to improve the overall efficiency of the parabolic dish concentrator. In this study, the reductions of convective heat loss from the cylindrical‐hemispherical receiver are numerically analyzed and the model was validated by the experimental data from literature. In the first case, the impact of the glass cover on convective heat loss is examined under conditions of both natural and forced convections at various receiver orientations (γ = 0°, 30°, 60°, and 90°). Numerical results clearly demonstrate that the use of a glass cover significantly reduces the intrusion of surrounding air into the receiver cavity which leads to an enhancement of the stagnation zone inside the cavity and, as a consequence, a noticeable reduction in convective heat loss is observed. To perform analysis of the receiver with glass cover under forced convective condition, the wind velocities over the receiver are considered in the range of 1–6 m/s. The maximum reduction of convective heat loss using the glass cover is achieved to be 58.44% with wind velocity of 5 m/s at γ = 60°. In the second case, the influence of air curtain at the receiver aperture under natural convective heat loss conditions is analyzed. The analysis incorporates three variables: receiver orientation (γ = 0°–60°), nozzle width ( = 0.002–0.004 m), and nozzle outlet velocity ( = 0.5–3.5 m/s). The results show that the air curtain minimizes the outflow of receiver inside air and results in an improvement in the stagnation zone inside the cavity. The maximum effectiveness of the air curtain is found to be 43.2% at nozzle width of = 0.004 m and nozzle velocity of = 1.5 m/s at receiver orientation of 60°. It is also noteworthy that the optimal nozzle velocity decreases with the increase of nozzle widths.

Dish spliced concentrator with both uniform andfocused performance through a variable focallength.

We present a dish spliced concentrator (DSC) featuring hexagonal spherical sub-mirrors of uniform size. The DSC offers advantages over traditional parabolic dish concentrators, including a compact layout, cost-effectiveness, higher concentration ratio, and improved light uniformity. Its versatility allows for both uniform and focused light concentration by adjusting parameters like the focal length of the DSC, making it suitable for concentrating photovoltaic (CPV) and concentrating solar thermal (CST) applications. We design the DSC using three-dimensional (3D) vector rotation theory, implementing ray tracing and transmission characteristic analysis based on three-dimensional vector reflection theory. We establish a simulation model to evaluate the impact of geometric parameters on the DSC's optical performance.

An optimized approach for solar concentrating parabolic dish based on particle swarm optimization-genetic algorithm

Parabolic dish concentrators have demonstrated the highest thermal and optical efficiencies among the available concentrator options. This paper proposes a novel design approach for fabricating large parabolic dish concentrators by employing compliant petals optimized through Particle Swarm Optimization-Genetic Algorithm (PSO-GA). The design concept involves using cables to pull the outer corners of the petals towards the center, resulting in the creation of finely formed dish mirrors. These mirrors are constructed from thin, optimal-shaped metal petals with highly reflective surfaces. In addition, an analytical model is presented to optimize the bending stiffness of the petals by strategically arranging punched holes using PSO-GA. The proposed design concept is validated through the application of Finite Element Analysis and ray tracing software, specifically LightTools, as well as laboratory experiments. Based on the demonstration with a 1m-diameter parabolic dish, it was observed that a receiver surface with a radius of 3.5 cm could achieve an impressive sunlight collection efficiency of up to 98%. This innovative design approach offers several advantages, including simplified fabrication and transportation of flat mirror elements to field sites, which can potentially lead to cost reductions and highly efficient solar energy solutions.

Optical efficiency and convective heat loss of a cylindrical-hemispherical receiver used in parabolic dish concentrator

Optical efficiency and convective heat loss of a cylindrical-hemispherical receiver used in parabolic dish concentrator

Isolation and identification of a new Bacillus glycinifermentans strain from date palm rhizosphere and its effect on barley seeds under heavy metal stress.

Soil contamination by heavy metals is one of the major problems that adversely decrease plant growth and biomass production. Inoculation with the plant growth-promoting rhizobacteria (PGPR) can attenuate the toxicity of heavy metals and enhancing the plant growth. In this study, we evaluated the potential of a novel extremotolerant strain (IS-2T) isolated from date palm rhizosphere to improve barley seedling growth under heavy metal stress. The species-level identification was carried out using morphological and biochemical methods combined with whole genome sequencing. The bacterial strain was then used in vitro for inoculating Hordeum vulgare L. exposed to three different Cr, Zn, and Ni concentrations (0.5, 1, and 2mM) in petri dishes and different morphological parameters were assessed. The strain was identified as Bacillus glycinifermentans species. This strain showed high tolerance to pH (6-11), salt stress (0.2-2M), and heavy metals. Indeed, the minimum inhibitory concentrations at which bacterium was unable to grow were 4mM for nickel, 3mM for zinc, more than 8mM for copper, and 40mM for chromium, respectively. It was observed that inoculation of Hordeum vulgare L. under metal stress conditions with Bacillus glycinifermentans IS-2T stain improved considerably the growth parameters. The capacity of the IS-2T strain to withstand a range of abiotic stresses and improve barley seedling development under lab conditions makes it a promising candidate for use as a PGPR in zinc, nickel, copper, and chromium bioremediation.