scholarly journals Optical Raytracing Analysis of a Scheffler Type Concentrator

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 260
Author(s):  
Daniela Fontani ◽  
Paola Sansoni ◽  
Franco Francini ◽  
Francesco Toni ◽  
David Jafrancesco

The Scheffler type concentrator is a curved metal reflector particularly suitable for solar thermal systems with a receiver fixed to the ground. Its operating principle is to deform the reflector throughout the year to optimize its performance in collecting sunlight. This study analyses the optical performance of a Scheffler reflector during the year. A CAD software tool is utilized to reproduce the mechanical deformations of a real Scheffler concentrator and the shape of the light spot on the receiver is analyzed by means of raytracing simulations. The starting configuration is the equinoctial paraboloid, which produces a point-like spot on the two equinox days only. On all other days of the year, this paraboloid is deformed in a suitable way in order to keep the spot as small as possible, but, even so, it is no longer a point-like spot. In the present work the simulated light distributions on the receiver, generated by the paraboloids (deformed or original), are compared. The results confirm the working principle of the Scheffler type concentrator and allow correctly sizing the receiver.

2018 ◽  
Vol 176 ◽  
pp. 99-109 ◽  
Author(s):  
Angeliki Kylili ◽  
Paris A. Fokaides ◽  
Andreas Ioannides ◽  
Soteris Kalogirou

2021 ◽  
pp. 60-71
Author(s):  
Tshewang Darjay ◽  
Cheku Dorji ◽  
Tshewang Lhendup ◽  
Martin Elborg

The Royal Government of Bhutan has accorded the highest priority towards diversifying the energy-mix through the promotion of renewable energy technologies. There is a national target to generate 3 MW equivalent of energy from the installation of solar thermal systems alone. However, little investment and priority are given for development of solar thermal applications. Some of the present existing solar water heating (SWH) systems are exhibiting faults which leads to low consumer confidence in SWH technology due to the non-functioning of previous installations which is very detrimental in this introductory stage. This study aims to identify problems of existing SWH systems through field surveys and develop a draft guideline to avoid faults in the future. To analyse the problems with existing SWH systems in Bhutan, the first phase of the study consists of collecting secondary information and opinion from the relevant government sector, local installing companies and end-users. The information on the manufacturer’s products, policy barriers, markets and consumer challenges is also collected. Base on this information, findings on the limitation of existing policy instrument and gap in demand and supply side is described. The second phase of the study comprises field visits to existing SWH system sites. The field surveys of twelve representative existing SWH systems are analyzed. Out of twelve sites, eight SWH systems had critical faults which causes major failure of the system and the other four sites had minor faults. To analyse the faults of existing SWH systems, faults are classified into design faults, plumbing circuit faults, solar collector faults, absorber faults, installation faults and user behavior faults. The major faults which lead to the failure of the existing SWH system are plumbing failure, condensation inside the collector and absorber tube leakage. The causes and solutions of the faults are discussed.


2012 ◽  
Vol 30 ◽  
pp. 134-143 ◽  
Author(s):  
Christian Holter ◽  
Bernhard Gerardts ◽  
Philip Ohnewein ◽  
Angela Dröscher ◽  
Franz Feichtner ◽  
...  

Energies ◽  
2015 ◽  
Vol 8 (6) ◽  
pp. 5725-5737 ◽  
Author(s):  
Rokas Valančius ◽  
Andrius Jurelionis ◽  
Rolandas Jonynas ◽  
Vladislovas Katinas ◽  
Eugenijus Perednis

2018 ◽  
Vol 4 (3) ◽  
pp. 25 ◽  
Author(s):  
Daniel Ferrández ◽  
Carlos Moron ◽  
Jorge Pablo Díaz ◽  
Pablo Saiz

ResumenEl actual Código Técnico de la Edificación (CTE) pone de manifiesto la necesidad de cubrir parte de la demanda energética requerida para el abastecimiento de agua caliente sanitaria y climatización de piscinas cubiertas mediante sistemas de aprovechamiento de la energía solar térmica. En este artículo se presenta una comparativa entre las dos principales tipologías de captadores solares térmicos que existen en el mercado: el captador de placa plana y el captador de tubo de vacío, atendiendo a criterios de fracción solar, diseño e integración arquitectónica. Todo ello a fin de discernir en qué circunstancias es más favorable el uso de uno u otro sistema, comparando los resultados obtenidos mediante programas de simulación con la toma de medidas in situ.AbstractThe current Technical Building Code (CTE) highlights the need to cover part of the energy demand required for the supply of hot water and heating of indoor swimming pools using solar thermal systems. This article presents a comparison between the two main types of solar thermal collectors that exist in the market: the flat plate solar collector and the vacuum tube solar collector, according to criteria of solar fraction, design and architectural integration. All of this in order to discern in what circumstances the use of one or the other system is more favourable, comparing the results obtained through simulation programs with the taking of measurements in situ.


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