[Greenbuilding] Chase Fan and Differential Thermostat

[Steven Tjiang]

Great that somebody is trying this approach finally here,
where you pull in heated air from the attic and store in
thermal mass under the floor which radiates it back.

There is a japanese outfit called omsolar which has been
doing this in Japan.  They tried to market the same design
in california several years ago but it didn't get any traction.
They built a couple of houses with their under floor storage
system but that was the extent of it.

Would be interested in how it works out for you and how
you get it together

On 10/3/07, Eli <elitalking at hughes.net> wrote:
>
> I am looking for information on a reversible fan to go into a 26"x26"
> chase
> that takes hot air from solar gains that stratify in the attic (heat
> chamber
> I call it) and pulls it to the crawl space, where Main Level Floor is a
> composite concrete slab for thermal mass.  I would like the fan to be
> reversible so I can also pull cool air in during the summer night to vent
> out the cupola and cool the slab.  For my solar clients, I am using a
> composite slab for floor instead of framing, because it is very affective
> as
> a thermal mass with air on both sides.  Hot air delivered then spills up
> to
> bottom of slab looking for opening through floor across from where air is
> delivered to allow air to rise into the house.  However, I need a strong
> reversible fan that is fairly quiet.  I also need an air differential
> thermostat to turn fan on when crawl space is 15 degrees +- less than heat
> chamber.  It would also open an automated vent that would close when fan
> cuts off, when a low heat difference is reached, thereby preventing the
> heat
> from rising back into the heat chamber.
>
> The slab works without the active components.  However, it will work much
> better when those features are operating.  If you have any suggestions, I
> would appreciate it.
>
> This is on a new addition.  However, I see potential to apply this to
> retrofits with redesigned attic (foam insulation along sloped sheathing to
> create a heat chamber) and created chase to go to basement or crawl space.
> On retrofits, I would be looking for ways of adding thermal mass.  Perhaps
> in a crawl space this could be racks of water jugs supported by ground.  I
> want to determine the appropriate amount of thermal mass to avoid
> overheating from solar components added.
>
> Eli Fishpaw Architect
> Lexington, VA
>
>
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-- 
(LSD) Steve; KI6LQC