The present paper reports the experimental results and the potential performance of the investigation on flat solar thermal collectors using nanofluids as innovative heat transfer fluids for solar energy applications. The straight use of heat-transfer nanofluids in traditional solar flat panel revealed some technical issues, due to the nanoparticles sedimentation. Therefore, sedimentation has been investigated both in standard solar flat panels and modified ones made from transparent tubes. The results of the first tests showed that the main sedimentation parameter is the flow velocity and to better control it a standard flat panel was modified changing the cross-section of the lower and top header of the panel, that have been tapered to keep constant the fluid axial velocity. The modification of the panel shape (patent pending) enabled a negligible particles deposit. After different nanofluids were tested on the panel prototype, water–Al2O3 was chosen as heat transfer fluid. All tested nanofluids were prepared in batch and their thermal conductivity and convective heat transfer coefficient were measured prior of their use as heat transfer fluid in the solar panel. A thermal conductivity enhancement up to 6.7% at a concentration of 3 vol% was observed, while the convective heat transfer coefficient increased up to 25%.

A new solution for reduced sedimentation flat panel solar thermal collector using nanofluids

COLANGELO, Gianpiero;FAVALE, ERNANI;DE RISI, Arturo;LAFORGIA, Domenico
2013-01-01

Abstract

The present paper reports the experimental results and the potential performance of the investigation on flat solar thermal collectors using nanofluids as innovative heat transfer fluids for solar energy applications. The straight use of heat-transfer nanofluids in traditional solar flat panel revealed some technical issues, due to the nanoparticles sedimentation. Therefore, sedimentation has been investigated both in standard solar flat panels and modified ones made from transparent tubes. The results of the first tests showed that the main sedimentation parameter is the flow velocity and to better control it a standard flat panel was modified changing the cross-section of the lower and top header of the panel, that have been tapered to keep constant the fluid axial velocity. The modification of the panel shape (patent pending) enabled a negligible particles deposit. After different nanofluids were tested on the panel prototype, water–Al2O3 was chosen as heat transfer fluid. All tested nanofluids were prepared in batch and their thermal conductivity and convective heat transfer coefficient were measured prior of their use as heat transfer fluid in the solar panel. A thermal conductivity enhancement up to 6.7% at a concentration of 3 vol% was observed, while the convective heat transfer coefficient increased up to 25%.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11587/378158
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 190
  • ???jsp.display-item.citation.isi??? 167
social impact