Posted by schooner on March 18, 2006, 12:25 pm
Just curious what the pros and cons are for using outside or inside air for
Is there a big disadvantage to using outside air other than the lower temp
that you are starting from since inside air is preheated to some degree.
Looking to see if simplifying an installation to use outside air is a good
move or better to do the extra work to draw from inside the house.
Posted by Morris Dovey on March 18, 2006, 3:19 pm
schooner (in R_SSf.2758$nQ6.1945@clgrps13) said:
| Just curious what the pros and cons are for using outside or inside
| air for the intake.
| Is there a big disadvantage to using outside air other than the
| lower temp that you are starting from since inside air is preheated
| to some degree.
Depends on your locale and what's likely to be blowing in the wind -
there's dust almost everywhere, fine powder snow in the north, ammonia
in farm country...
| Looking to see if simplifying an installation to use outside air is
| a good move or better to do the extra work to draw from inside the
I would think that adding an efficient heat exchange subsystem to
prevent thermal waste might not be very much of a simplification - and
without it the cold outside air will be displacing already warm inside
I'd warm the inside air for efficiency and cleanliness - and ventilate
as needed for health and comfort.
DeSoto, Iowa USA
Posted by SJC on March 18, 2006, 6:03 pm
The house can only contain so much air. If you bring outside air in,
then inside air has to go out. This would lose a lot of heat you already
have in the house.
Morris mentioned heat exchangers. Sometimes these are used to =
heat from the outgoing inside warm air to the incoming colder outside =
but then you would want to put that prewarmed outside air through the =
to heat it up more. That does not sound like a very simple, low cost =
Posted by meow2222 on March 20, 2006, 3:57 am
I guess it depends how you design it, and how much heat you decide to
recover. A sheet of galv corrugated, as used for cheap roofing, is not
an expensive heat exchanger.
Posted by Gary on March 20, 2006, 2:43 pm
Seems to me this is the disadvantage, and it could be quite a large one.
If its really cold out, the collector probably would not even heat the outside
up to room temperature, so the output air would cool the room rather than heat
Basically you would be wasting the heat that is needed to heat the air from
outside ambient up to room temperature. If you don't need the outside air for
ventilation, it seems to me to be a very inefficient way to go.
"Build It Yourself" Solar Projects
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