Heat sink to absorb heat from asphalt shingles (sealed attic)?
greenhouse437
| Posted in Green Building Techniques on
Creating sealed attic would prefer to avoid a vented nailed assembly etc. above deck and at same time find a way to use all that heat that the asphalt shingles absorb which shortens their life even more with a sealed attic.
So supposed there was some kind of thin mesh (or foil?) to put between the shingles and underlayment that would connect to one or two conduits that could divert heat away and maybe even be somehow connected to the domestic hot water system. Seems like those 170 degree summer peak shingle temps could be harnessed. (??)
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Search and download construction details
Replies
David,
At least two companies have developed systems that try to collect heat from a roof by circulating heat through fluid in tubes installed directly under the roofing; the best known of these companies is Dawn Solar.
These systems have several disadvantages, including a high cost (unjustified by the low level of thermal or energy benefits) and the fact that the warm water produced by these systems isn't as hot as the water that comes out of a solar thermal collector.
You end up paying a high price for a lot of equipment that produces lukewarm water; in other words, all of the disadvantages of a solar thermal system, at a higher cost, and with worse performance.
Thanks Martin. I guess more than gaining hot water was the idea of lowering the temperature of the asphalt shingles even if the captured heat went unused, perhaps as I think they use heat sinks in some electronic components. I was hoping that some kind of metal mesh could do the absorption....Thanks again.