Luís Ricardo Bernardo
Energy and Building Design, Lund Technical University, Lund, Sweden
Henrik Davidsson
Energy and Building Design, Lund Technical University, Lund, Sweden
Björn Karlsson
Mälardalen University, Västerås, Sweden
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http://dx.doi.org/10.3384/ecp110573765Published in: World Renewable Energy Congress - Sweden; 8-13 May; 2011; Linköping; Sweden
Linköping Electronic Conference Proceedings 57:13, p. 3765-3772
Published: 2011-11-03
ISBN: 978-91-7393-070-3
ISSN: 1650-3686 (print), 1650-3740 (online)
One of the most expensive components of a solar thermal system is the storage tank. Retrofitting conventional domestic hot water heaters when installing a new solar hot water system can decrease the total investment cost. In this study; retrofitting of existing water heaters using forced circulation flow was investigated. A comparison with a standard solar thermal system is also presented. Four simulation models of different system configurations were created and tested for the climate in Lund; Sweden. The results from the simulations indicate that the best configuration consists on connecting the collectors to the existing heater throughout an external heat exchanger and adding a small heater storage in series. For this retrofitted system; preliminary results show that an annual solar fraction of 53% is achieved. In addition; a conventional solar thermal system using a standard solar tank achieves a comparable performance for the same storage volume and collector area. Hence; it is worth to further investigate and test in practice this retrofitting. Furthermore; using the same system configuration; solar collectors can also be combined with new standard domestic hot water tanks at new installations; accessing a world-wide developed and spread industry.
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