R. Herrero Martín
Technical University of Cartagena, Cartagena, Spain
García A. Pinar
Technical University of Cartagena, Cartagena, Spain
J. Pérez García
Technical University of Cartagena, Cartagena, Spain
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http://dx.doi.org/10.3384/ecp110573844Published in: World Renewable Energy Congress - Sweden; 8-13 May; 2011; Linköping; Sweden
Linköping Electronic Conference Proceedings 57:23, p. 3844-3851
Published: 2011-11-03
ISBN: 978-91-7393-070-3
ISSN: 1650-3686 (print), 1650-3740 (online)
Enhancement techniques can be applied to flat-plate liquid solar collectors towards more compact and efficient designs. Tube-side enhancement passive techniques can consist of adding additional devices which are incorporated into a smooth round tube (twisted tapes; wire coils); modifying the surface of a smooth tube (corrugated and dimpled tubes) or making special tube geometries (internally finned tubes). For the typical operating flow rates in flat-plate solar collectors; the most suitable technique is inserted devices. Based on previous studies from the authors; wire coils were selected for enhancing heat transfer. This type of inserted device provides better results in laminar; transitional and low turbulence fluid flow regimes.
To test the enhanced solar collector and compare with a standard one; an experimental side-by-side solar collector test bed was designed and constructed. The testing set up was fully designed following the requirements of EN12975-2 and allow us to accomplish performance tests under the same operating conditions (mass flow rate; inlet fluid temperature and weather conditions). In this work the preliminary results obtained are presented and the standardized efficiency curve is shown for both tested solar collectors. A relevant improvement of the efficiency has been reported and quantified through the useful power ratio between enhanced and standard solar collectors.
