[Strawbale] [strawbale] (was) Blower Door test set up

[David Neeley]

At this point, I still plan on building with a geothermal heat pump
and, consequently, not being off grid. Since I live in Texas, getting
by without air conditioning in our summers would be rather brutal.

That said, it seems that an energy recovery ventilator (not a *heat*
recovery vent, since we are mostly a cooling climate!) would seem to
reduce the load on the ground source unit even more. I would think
that building it into the air system might be somewhat ideal--probably
at the air return and intake point.

For what I am planning, a primary concern has been getting a unit
small enough--the smallest size forced air units I can find are 2.5
tons. I plan on a house only about 900 (probably--maximum of 1200
surely) square feet, with strawbale walls and about R60 plus radiant
barrier in the attic. The saving grace will be that the ground source
unit has a two-speed scroll fan and multi-speed fan. Thus, it can run
at a very low speed most of the time when in cooling mode.

(I happen to love porches, so for now I am planning a porch around the
house. With our climate, that should be a rather practical living
space as well as shielding the house proper from the sun.)

Should I wind up building rurally, though, I would be very tempted to
do one of Don's AGS houses and dispense with the mechanical HVAC
system. Our average ground temperature year round is within the
comfort envelope all by itself, so I am not even sure how much heat
I'd need to gain to put underground for winter use.

Another practical problem will be finding a place to build, should I
build within the DFW Metroplex (the local name for the complex of
cities including Dallas and Fort Worth and innumerable suburbs), that
is in an acceptable area and in which I can build that small. Too many
of the newer suburbs have minimum house sizes that are way more than I
intend to build.

I have not yet begun to study the ERV systems available, nor to figure
out how they would be best integrated into a geothermal system.

David

On 4/9/07, Frank Tettemer <frankt at webhart.net> wrote:
>
> David wrote:
>  > As far as constructing a near net-zero energy house, it seems to me
>  > that the best method might be to make one as tightly sealed as
>  > possible while incorporating an energy recovery ventilator for the
>  > needed air exchanges inside. That is exactly what I contemplate doing,
>  > at this point anyway. Would this strategy be wrong?
>
> I like what you're contemplating, David!
> In our province of Ontario,
> the "Chief Building Official" would certainly require an HRV installation,
> (whether an SB wall assembly is "naturally aspirating" or "not".)
>
> So the strategy is to determine how many amp/hours (or Watt/hrs) are
> required per day,
> for the operation of the HRV system.  Then, the design can include that
> particular electrical consumption,
> in amongst the other daily loads, in order to size the PV array and/or
> battery bank.
>
> Naturally, that brings up the following question:
> Where does one source an efficient HRV system?
> Do the Danes or the Germans have any more efficient systems
> than the energy-suckers that we have
> on this side of The Pond?
> It's a problem.
> What's a poor boy to do?
>
> Frank Tettemer
>
>
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