Colector parabolico

Desalination 220 (2008) 612–618

Parabolic trough collector testing in the frame of the REACt project
Dirk Krüger*, Yuvaraj Pandian, Klaus Hennecke, Mark Schmitz
Deutsches Zentrum für Luft- und Raumfahrt e.V., in der Helmholtz-Gemeinschaft (DLR), Institut für Technische Thermodynamik, Solarforschung, Linder Höhe, 51147 Köln Tel. +49-2203/601-2661; Fax +49-2203/601-4141; email:dirk.krueger@dlr.de
Received 23 March 2007; accepted 21 April 2007

Abstract Solar thermal parabolic trough collectors can be used to provide heat for desalination, cooling and electricity generation. The set-up and some intermediate results of a measurement campaign for the evaluation of a parabolic trough collector — the Solitem PTC1800 — are presented. Optical tests of the concentrator were used todetermine the intercept factor, allowing to give recommendations for optical improvements. Thermal testing up to 200°C with pressurised water showed low radiative and convective losses. Keywords: Parabolic trough collector; Solar thermal; Concentrating; Optical losses; Thermal losses; Cooling

1. Introduction In the frame of the project REACt (selfsufficient renewable energy air-conditioning system forMediterranean countries) a row of four parabolic trough collector modules of the type Solitem PTC1800 has been tested at the DLR’s test facilities in Cologne, Germany. Especially their efficiency at temperatures between 150°C and 190°C is of interest for combining them with absorption chillers, which is foreseen for the project. REACt is a project on the subject of concentrated solar energy forcooling funded by the EU
*Corresponding author.

aiming at joint research between European and Mediterranean partner countries. The project partners are: • Centro Interdipartimentale per la Ricerca sulle Energie Alternative e Rinnovabili – CREAR • Solar Heat And Power — SHAP • Deutsches Zentrum für Luft- und Raumfahrt e.V. — DLR • Solitem Gunes Enerjisi Tek. Ltd. Sti. — SOLITEM • AssociationLibanaise pour la maitrise de l’Energie et l’Environnement — ALMEE • National Energy Research Center — NERC • Centre de Développement des Énergies Renouvelables – CDER

Presented at the conference on Desalination and the Environment. Sponsored by the European Desalination Society and Center for Research and Technology Hellas (CERTH), Sani Resort, Halkidiki, Greece, April 22–25, 2007.0011-9164/08/$– See front matter © 2008 Published by Elsevier B.V. doi:10.1016/j.desal.2007.04.062

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Fig. 1. Left: Mounting of foundations, Right: Tracking row foundations.

After developments and adaptations of the solar system and absorption chillers, the system is being tested in European laboratories. In parallel demonstration plants inJordan and Morocco are being planned. Erection of the solar cooling systems is planned for 2008. 2. Foundations Commonly concrete foundations are being used for the installation of parabolic trough collector fields on ground. Concrete foundations have two disadvantages: high costs of construction and the great expense for removal. Additionally it is difficult to place the anchors protruding from theconcrete for fixing the pylons exactly in place. Ground screws, which are new on the market, offer a less expensive and comparatively easily removable solution. They are drilled into the ground by a hydraulic machine (Fig. 1). On their upper side a flange can take up bolts for connecting the pylons (Fig. 2).

It took only a few hours to put all the ground screws. The precision of mounting theground screws depends strongly on the procedure. It is necessary to specify the tolerance of their position according to the necessities of the collector. The pylons can be inclined slightly, so that their heads even reaches the right position, if the

Fig. 2. Flange of ground screw.

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Fig. 3. Red pipe mounted for absorber reflection...