China
Africa
Explore chapters and articles related to this topic
Hybrid Plants for Thermal Energy Production
Published in Dimitris Al. Katsaprakakis, Power Plant Synthesis, 2020
The main operating feature of the LFR systems is the use of Fresnel reflectors. The performance of these reflectors is based on the exploitation of the Fresnel lens phenomenon, which enables the construction of concentrating reflectors with high aperture and low focal length, leading to the reduction of the required materials quantities for the construction of the reflectors and the subsequent drop of the manufacturing and procurement cost. Additionally, in LFR systems, the solar radiation is concentrated by a number of Fresnel reflectors at the same receiver, unlike the parabolic collectors, where each collector is equipped with its own receiver. At the same time, the one-axis tracing system is also maintained in this technology, as in parabolic trough collectors. The Fresnel reflector lines are installed along the east–west direction, so the reflectors are oriented to the north–south axis.
Solar Energy for Biofuel Extraction
Published in Vladimir Strezov, Hossain M. Anawar, Renewable Energy Systems from Biomass, 2018
Haftom Weldekidan, Vladimir Strezov, Graham Town
Linear Fresnel reflectors use long and thin segments of mirrors to focus sunlight onto a fixed absorber/reactor located at a common focal point of the reflectors. The reflectors are made from cheap flat mirrors and can concentrate the sun’s rays 30 times. The operation temperature at the focal line is 150°C, but, with the use of a secondary concentrator, temperatures of up to 300°C can be reached. Additionally, if a compound parabolic collector is integrated with linear Fresnels, the optical and capture efficiencies can be improved to 60% and 76%, respectively (Feuermann and Gordon, 1991, Nixon et al., 2010). The reactor used with linear Fresnel is separated from the reflector field and is stationary. The capital and maintenance costs are much lower than the other types of solar collectors (Feuermann and Gordon, 1991, Nixon et al., 2010).
The history of concentrating solar power and large-scale engineering projects for the Mediterranean Region
Published in Sharlissa Moore, Sustainable Energy Transformations, Power, and Politics, 2018
The remainder of this chapter discusses the history of CSP as situated within visions of the desert frontier, starting with a brief overview of solar technologies. Solar photovoltaic panels use the sun’s light, generating electricity through the photoelectric effect, in which photons knock electrons loose from atoms. In contrast, CSP uses heat from the sun to generate electricity. Early versions of the technology used the sun’s heat to cook food, pump water, and power a steam engine to achieve a variety of tasks (see Figure 2.1 for an example). Contemporary CSP plants are similar to conventional thermal power plants, but the heat comes from the sun rather than from fossil fuel combustion. The most widely deployed CSP design today is the parabolic trough design, a precursor of which can be seen in Figure 2.2. Simply put, parabolic mirrors reflect the sun’s light onto tubes attached to the mirrors, and a heat-transfer fluid is used to transfer the sun’s heat to water to produce steam for a steam turbine to drive a generator (see Figure 2.3). The second most deployed contemporary design is the CSP central tower (or power tower) plant, which consists of a field of heliostats, or garage-door-sized mirrors (or set of mirrors), that concentrate sunlight onto a central power tower receiver, using the heat to produce steam for a steam turbine. Another design is the concentrating linear Fresnel reflector, which uses long, thin mirrors to concentrate sunlight and utilize its heat. The least deployed CSP design is the Dish Stirling engine, which looks similar to designs from the 1800s. The technology is a mirrored dish concentrator with a receiver attached to the dish’s focal point. The Stirling engine uses the sun’s heat to heat a gas that expands to drive a piston and crankshaft. It is highly efficient, but there are numerous barriers to the commercialization of Dish Stirling engines. Additionally, while these dishes could be deployed in a distributed configuration, such as in backyards, most CSP technologies today are designed to be integrated into a centralized grid system.
A comprehensive review of solar tower CSP systems using TES and molten salts
Published in International Journal of Ambient Energy, 2023
Cristiana Brasil Maia, Lucas Rodrigues Neumann, Gabriela de Andrade Oliveira, Ígor Marques Alves, Magdalena Marta Walczak, Pedro Paiva Brito
A comprehensive review of the solar power technologies, including CSP technologies, was performed by Khan and Arsalan (2016), reporting higher capacities in PTC (10–300 MW), followed by linear Fresnel reflectors and solar towers (10–200 MW), and by parabolic dish (0.01–0.025 MW). The average solar-to-electricity efficiency is 11–16% for PTC, 13 for linear Fresnel reflectors, 7–20 for solar towers, and 12–25% for parabolic dishes. All but parabolic dishes can work with storage systems. In a summary, the main advantages of PTC are being the most mature CSP technology and the ability of heat production at higher temperatures. Nevertheless, the use of oil-based heat transfer media restricts output to a moderate stream. Linear Fresnel reflectors are cheaper than PTC and have a higher concentration of sunlight, but are less efficient and present difficulties to include storage systems into their design. Solar towers are economically proven, have increased efficiency, and are able to generate electricity in the absence of the sun, but require a large land and daily maintenance. Parabolic dishes present the highest efficiencies; nevertheless, have high costs, lack flexibility, and require a large amount of equipment.
An overview of concentrated solar energy and its applications
Published in International Journal of Ambient Energy, 2018
Pushkaraj D. Sonawane, V. K. Bupesh Raja
The linear Fresnel reflectors, shown in Figure 4, are generally flat mirrors used to concentrate the solar radiation on absorber tubes like in PTCs. It uses line focus technique similar to PTCs with lower capital costs due to the presence of light structural members without moving joints and lower optical efficiency due to: higher cosine losses because of blocking of reflected solar radiation by adjacent mirrors and shading of incoming solar radiation at low sun positions,mirrors on horizontal plane cannot reach ideal parabola andshading by the fixed receiver.
A comprehensive review on small-scale passive solar stills for desalination
Published in Environmental Technology Reviews, 2021
Zhi Yong Ho, Rubina Bahar, Chai Hoon Koo
Similar to the Fresnel lens, the concept of linear Fresnel reflector is to concentrate solar irradiance to a focal point or a focal line through a huge number of fragments. However, the Fresnel lens achieved the objective using refraction, while the linear Fresnel reflector uses long and narrow mirrors. The flat mirror fragments reflect the solar ray toward a fixed solar receiver. Fresnel reflector are often used on heat transfer fluid heating and water heating as it could generate temperature ranged from 150°C to 520°C [82]. Linear Fresnel reflector is usually used in large scale power plant and desalination plants [83].