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A hybrid solar lighting/ thermal system utilized a parabolic solar dish as a solar collector illustrated in this paper. A two-axis tracking system was developed and employed to improve the energy output of a concentrating solar system (CSP) that produces hot water and light. During the daytime, sunlight is transmitted by fiber optics to an indoor photovoltaic PV device to generate electricity, or it can be used directly as daylighting. The heat generated is used to heat water. The findings show that the proposed system is a low-cost, high-performance approach for solar energy use in building energy efficiency, and readily available tracking components and tools. The experimental work shows that the maximum efficiency of the hybrid solar lighting/ thermal system controlled with a dual-axis solar tracking system was 32.2%.

E nergy consumption has increased with the population increase, and fossil fuel dependency has risen and causing pollution s . Solar energy is suitable to provide society's thermo-electric needs. Thermal e nergy storage -based concentrated solar receivers are aimed at store heat energy and transportable to the a pplications. A cavity receiver with two- phase change materials (PCM) is experimentally investigated using a parabolic dish collector to act as the solar heat battery. The selected PCMs are MgCl 2 .6H 2 O and KNO 3 -NaNO 3 . PCMs are chosen and placed as per the temperature zones of the receiver . The outdoor test was conducted to determine the conical receiver's storage performance using cascaded PCM s. The complete melting of PCM attain s at an average receiver surface temperature of 230 ° C. The complete melting of the PCM in the receiver took around 30 minutes at average radiation around 700 W/m 2, and heat stored is approximately 5000 kJ. The estimated number of cavity receivers to be charged on a sunny day is about 10-15 according to the present design and selected PCMs, for later use

This study aims to propose a simulation as well as mathematical model to carry out the performance assessment and efficiency improvement of a stand-alone Parabolic Solar Dish Stirling (PSDS) system. The simulation for a 25 ​kW PSDS system is performed in the System Advisor Model (SAM) under the environmental conditions of Jamshoro, Sindh, Pakistan. The results show that the city has a good potential of direct solar irradiance with yearly average value of 1719.15 ​kWh/m2/y. The system can generate yearly 38.6 ​MWh with overall system net efficiency of 23.39%. Whereas, the maximum energy of 3.38 ​MWh is produced in month of January, due to high solar irradiance. However, the lowest energy of 2.15 ​MWh is produced in July, due to the monsoon spell in selected city. Furthermore, from the techno-economic analyses of the proposed system, the levelized cost of energy is found to be 0.13 $/kWh, which is quite low. As the Stirling Engine (SE) works at higher temperature, so, increasing the diameter of concentrator results more thermal energy at the cavity. The solar radiations are high around the solar noon, therefore, the operating temperature can damage the hot-side of SE due to thermal overloading. In future, to protect the hot-side of SE, it is recommended to use thermo electric generator.

[EN]Small-scale hybrid parabolic dish concentrated solar power systems are a promising option to obtain distributed electricity. During the day, solar energy is used to produce electricity, and the absence of sunlight can be overwhelmed with fuel combustion. This study presents a thermo-economic survey for a hybridized power plant in different regions of Spain, considering the local climatic conditions. The developed model considers the instant solar irradiance and ambient temperature dynamically, providing an estimation of the power output, the associated fuel consumption, and the most relevant pollutant emissions linked to combustion. Hybrid and combustion-only operating modes at selected geographical locations in Spain (with different latitudes, mean solar irradiances, and meteorological conditions) are analyzed. The levelized cost of electricity indicator is estimated as a function of investment, interest rate, maintenance, and fuel consumption actual costs in Spain. Values of about 124 e/MWhe are feasible. Fuel consumption and emissions in hybrid operation can be reduced above 30% with respect to those of the same turbine working in a pure combustion mode. This model shows the potential of hybrid solar dishes to become cost-competitive against non-renewable technologies from the point of view of costs and reduction in gas emission levels in regions with high solar radiation and low water resources., University of Salamanca Grant Number PC-TCUE18-20-002, Junta de Castilla y León of Spain Grant Number SA017P17.

Here we propose a forced air circulation system to reduce the convective heat loss across the aperture of a dish concentrator. The function of the proposed system was validated with computational fluid dynamics (CFD) simulations. Compared to a concentrator without such a system, the modified solar dish cavity receiver could clearly reduce the convective heat loss and its fluctuation in the receiver. In the best case studied, the convective heat losses could be suppressed by up to 58%. In addition, two types of air circulation modes (clockwise and anticlockwise) were compared, showing that the anticlockwise mode yields better performance.

This work presents a preliminary thermodynamic assessment of a Concentrating solar power (CSP) system made up of a micro gas turbine (MGT) coupled with a parabolic dish concentrator. The thermal engine characteristics are representative of state-of-the art of MGTs (Net power=31.5kWe Turbine Inlet Temperature (TIT)=850°C) while the “solar section” (thermal receiver and parabolic mirror) performance are modelled in accordance with current research outcomes. The overall system is designed and a second law analysis is reported. An estimate of yearly electricity yield is performed (83.98 MWhe) and the obtained sun-to-electricity efficiency (about 18.3%) reveals energetic competiveness with other CSP solutions (parabolic trough and solar tower). A simplified economic analysis (Levelized cost of electricity (LCOE) is 165.7 €/MWh) highlights how Solarized Micro Gas Turbine (SMGT) is a promising CSP technology whose improvements perspective can drive dedicated R&D activities.

In this paper, the effects of cavity surface materials on the radiative flux distribution of solar cavity receivers have been studied with the help of a ray-tracing methodology. Three metallic substrate materials (Inconel 600, austenitic stainless steel 253 MA and Kanthal APM) and two coating materials (Pyromark® 2500 coating and YSZ TBC coating) were selected as the candidate cavity surface materials. The results show that the flux distribution and the total optical efficiency are much more sensitive to the absorptivity on the cylindrical surface than on the bottom. By using high absorptivity coating on the cylindrical surface and low absorptivity coating on the bottom, the radiative flux on the bottom can be controlled at a low level, and it can help to reduce the cavity length for an impinging receiver with jets on the cylindrical surface. Furthermore, the radiative flux distribution on the cylindrical surface can also be tailored to meet various design requirements by applying different coating designs on the cylindrical surface. QC 20170103

The roadmap for the hydrogen uptake passes through the development of near-zero emission and/or renewable technologies for hydrogen production. This is the rationale for the investigation of renewable power-to-fuel, namely the coupling between high temperature electrolysis and concentrating solar power. The proposed plant is conceived to supply hydrogen for a small refuelling station. It is based on solid oxide electrolyser cell technology, which performs water electrochemical reduction, in order to produce a target of 150 kg d−1 of hydrogen. The plant is integrated with a parabolic dish solar field designed to provide both electricity and thermal energy, necessary for the electrolysis reaction to take place. Specifically, a modular multi-dish configuration is selected, in which electric power is produced by 30 kWel solarized micro-gas turbines placed in the dishes’ focus. In addition to considering a pure renewable power input, a hybridization with natural gas is considered to face the variability of solar resource. Once a yearly H2 yield is estimated, a preliminary economic analysis is carried out and the levelised cost of hydrogen is subsequently obtained. It is found that the system can be operated at a nominal solar-to-hydrogen efficiency above 30%, with a solid oxide electrolysis cell efficiency around 80%. In hybrid conditions, 10 parabolic dishes (9 generating electricity through the micro-gas turbines, 1 supplying heat to the solid oxide electrolysis cell) are needed to produce the target 150 kg d−1 of hydrogen. In conclusion, the competitiveness of the plant is evaluated in comparison with other solar fuels technologies.

This paper investigates the coupling of parabolic dish concentrator with air micro gas turbine engine (net power output equal to 32.9 kWel). With the aim of increasing the conversion efficiency of the incoming solar radiation, a high temperature system (up to 1100 °C) has been considered: this solution implies the adoption of a ceramic expander coupled with a high temperature indirectly-irradiated solar receiver. A flexible Matlab® suite has been developed for the plant sizing and for the part-load simulation; in addition, the model is able to handle general solar field configurations through the computation of reciprocal shading effect. The obtained yearly sun-to-electric efficiency (26.48%) reveals the energetic advantage over other CSP technologies that can mitigate the technological issues and consequently higher investment cost, related to high operating temperatures. The potential of a hybrid version of the dish is also discussed.

The objective of this research was to design a low cost parabolic solar dish concentrator with small-to moderate size for direct electricity generation. Such model can be installed in rural areas which are not connected to governmental grid. Three diameters of the dish; 5, 10 and 20 m are investigated and the focal point to dish diameter ratio is set to be 0.3 in all studied cases. Special attention is given to the selection of the appropriate dimensions of the reflecting surfaces to be cut from the available sheets in the market aiming to reduce both cutting cost and sheets cost. The dimensions of the ribs and rings which support the reflecting surface are optimized in order to minimize the entire weight of the dish while providing the minimum possible total deflection and stresses in the beams. The study applies full stress analysis of the frame of the dish using Autodesk Inventor. The study recommends to use landscape orientation for the reflective facets and increase the ribs angle and the distance between the connecting rings. The methodology presented is robust and can be extended to larger dish diameters.

Renewable energy resources like solar energy, wind energy, hydro energy, photovoltaic etc. are gaining much importance due to the day by day depletion of conventional resources. Owing to the lower efficiencies of renewable energy resources, much attention has been paid to improving them. The concept of utilizing phase change materials (PCMs) has attracted wide attention in recent years. This is due to their ability to extract thermal energy when used in collaboration with photovoltaic (PV), thus improving the photoelectric conversion efficiency. In this paper, the objective is to design and fabricate a novel thermal energy storage system using phase change material. An investigation on the characteristics of Potash Alum as a phase change material due to its low cost, easy availability and its usage as an energy storage for the indoor purposes are taken into account. The use of a latent heat storage system using phase change materials (PCMs) is an effective way of storing thermal energy and has the advantage of high-energy storage density and the isothermal nature of the storage process. In the current study, potash alum was identified as a phase change material combined with renewable energy sources, that can be efficiently and effectively used in storing thermal energy at compartively lower temperatures that can later be used in daily life heating requirements.A parabolic dish which acts of a heat collector is used to track and reflects solar radiation at a single point on a receiver tank. Heat transfer from the solar collector to the storage tank is done by using a circulating heat transfer fluid with the help of a pump. The experimental results show that this system is capable of successfully storing and utilizing thermal energy on indoor scale such as cooking, heating and those applications where temperature is below 92 °C.

Concentrating solar power (CSP) is a solar thermal technology that generates electricity from thermal energy through the sun.The electricitycan be generated with four different types of CSP technologies that include Parabolic Dish (PD) systems. In order to make this technology more practical, the efficiency of the solar technology should be improved.Solar concentration is one of the main aspects that can affect the system’sefficiency. This paper reviewed solar secondary concentrators and discussed their designs and performance. Besides, their strengths and weaknesses were compared. Generally, thesecondary concentrators couldincrease the solar concentration of the solar technologyup to 93 percent.

Organic Rankine Cycle (ORC) power generation systems may be used to utilize heat source with low pressure and low temperature such as solar energy. Many researchers have focused on different aspects of ORC power generation systems, but none so far has focused on the patent landscape of ORC system applications. As such, the objective of this study is to identify published patents on ORC system applications, particularly for solar energy. Four (4) technologies were identified in ORC application for solar energy: parabolic dish, parabolic trough, solar tower, and linear Fresnel reflector. A methodical search and analysis of the patent landscape in ORC system applications for solar energy published between 2007–2018 was conducted using the Derwent Innovation patent database. From the approximately 51 million patents in the database from various countries and patent agencies, 3859 patents were initially identified to be related to ORC applications for solar energy. After further stringent selection processes, only 1100 patents were included in this review. From these 1100 patents, approximately 12% (130 patents) are associated with parabolic dishes, about 39% (428 patents) are associated with parabolic troughs, approximately 21% (237 patents) are associated with solar towers, and about 28% (305 patents) are associated with linear Fresnel reflectors. Published patents on solar tower technology are currently on an increasing trend, led by China. All of these patents were published in the past 11 years. From this study, further researches on ORC application are still ongoing, but ORC application for solar energy has the potential to advance; allowing the world to ease issues related to over-reliance on fossil fuel.

“Solar salt” (potassium and sodium nitrate mixture) is an option for a latent heat storage to be used with solar heat collectors. As the salt melts at about 210 degrees C it can be suitable as a heat storage for cooking applications. A solar salt container to be illuminated directly by the sun rays in should be heated from the top. One way of achieving this is to position the storage below a primary parabolic dish, this having a center hole to allow the rays from a secondary reflector to hit the top plate of the storage. A double reflector system becomes more sensitive to surface imperfections and to the solar tracking accuracy. A 2m diameter parabolic dish with a secondary 0.2 m diameter reflector has been considered as a test system for direct illumination of a heat storage. The optical performance of the system is investigated by means of a ray tracer. The ray tracer is described and a sensitivity study is made with respect to solar tracking accuracy, the effect of mirror tiles instead of smooth surfaces, the positioning and size of the secondary reflector and the effect of illumination of a the top plate from the side (the top plate remaining horizontal during the daily sun movements). A focusing effect is obtained by slightly lifting the secondary absorber above the point of the common focus of the primary and the secondary. The primary reflector should be as smooth as possible, the secondary reflector is less sensitive and could be surfaced with 1-2 cm mirror tiles with acceptable performance. A 10 cm diameter absorber dish is the minimum size, a 20 cm dish is more tolerant for tracking accuracy and for low solar angles. A large absorber dish also reduces the risk of superheating the top plate which has conduction based heat transfer to a salt storage.

Presented at World Renewable Energy Congress XI, 2010, 25-30 September, Abu Dhabi, United Arab Emirates Cyprus is planning to develop in the next few years one solar thermal power plant with a capacity of about 50 MW. Therefore, in this paper solar power systems are analyzed with respect to their technical characteristics, the cost of electricity produced and the land area required. The latter is very important for Cyprus as seaside areas are very expensive. Such a solar power station however should be located near the sea close to an existing power station. An additional reason is that such a solar plant can be combined with solar desalination to produce fresh water from seawater which is also a precious commodity for Cyprus. Based mainly on their industrial maturity and the advantages mentioned in this paper, the parabolic trough system seems to be to best one to apply. From a preliminary investigation of the various possible areas the author believes that the Vasilikos area near to the existing Vasilikos power station is the most suitable for such a system to be installed

The numerical study of combined laminar natural convection and surface radiation heat transfer in a modified cavity receiver of solar parabolic dish collector is presented in this paper. A two-dimensional simulation model for combined natural convection and surface radiation is developed. The influence of operating temperature, emissivity of the surface, orientation and the geometry on the total heat loss from the receiver is investigated. The convective heat loss from the modified receiver is significantly influenced by the inclination of the receiver whereas the radiation heat loss is considerably affected by surface properties of the receiver. The Nusselt number correlations are proposed separately for both natural convection and surface radiation based on large set of numerical data for a given range of parameters of practical interest. It is observed that the convection and radiation heat losses are found respectively 52% and 71.34% of the total heat loss at 0� inclination and 40.72% and 59.28% at 90� inclination for the modified cavity receiver with an area ratio of 8 and 400 �C. The convection and radiation numerical procedure is validated with other models. The results obtained from the present numerical procedure are in reasonable agreement with other well-known open cavity models. � 2007 Elsevier Masson SAS. All rights reserved.