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Old 11-06-11, 10:50 PM   #146
Lex Parsimoniae
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Join Date: Feb 2009
Location: Woburn, MA
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I was reading about applications for my new controller board,
and I saw a very interesting idea..

A poster was looking for a Smart attic fan for summer use.
Another poster told him about using a cheap controller that could be configured
to monitor both the inside and outdoor air temperature.
Then program it to only turn on the fan when two conditions exist.
1. It was above a certain temperature outdoors (like 75F).
2. AND, when the attic (or garage) inside temperature was greater than, 10F warmer.
(Those numbers could be tweaked for best efficiency).

Then, he said one could also write a winter program, to turn on the fan,
when the attic(or garage) temperature was colder than the outdoor air temperature!
(Like when a warm front moves in during the night)..

That got me thinking about this thread. It's a way of moving some warmer
air into your attic (or garage), if the solar input isn't there yet.

Think about it. If your attic is really cold before sun up, the only heat around,
is your rooms below. A warmer attic means less heat loss from below.

I hate going out in the morning when it's 35 or 40F and finding my car is still at 20 or 30F..
The instant I leave the garage, every square inch of glass fogs, up on the outside!
Sometimes, it actually forms a layer of ice!

Anyways, it seems like this kind of programmable device could be useful,
not only in using your attic fan to bring in warm air, but to use as a controller
to bring down warmed attic air, as needed.

A programmable thermostat (with a real-time-clock) that could help you
hoard warm air in the attic and then bring it down to warm the house, on demand,
when the attic air was warmer than downstairs..?.
(You would likely need 4 DS18B20 temperature sensors and 2 SSRs)..
Cost maybe $60 for the whole rig..
My hobby is installing & trying to repair mini-splits
EPA 608 Type 1 Technician Certification ~ 5 lbs or less..
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