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Thermal mass for multi-story house. - Page 2

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Posted by charles bash on January 25, 2005, 6:52 pm
It looks like aultiere is going to spend Big Money on building a house
to take advantage of "passive solar heating ".

I am not at all a big fan of "passive heating". You need at least one
"temperature control" for the comfort of any heating system, and then it
is no longer "passive" but "active".

I strongly advise you to seek the services of an Experienced engineer
who is a member of the A.S.H.R.A.E.,, (( American Society of Heating,,
Refrigeration and Air Conditioning Engineers ))

Probably find them in the Yellow Pages. Ask if your prospective
consultant has ever designed any solar heated buildings. He should be
familiar with the modist ASHRAE "hand book" references on solar design.
There are other engineering solar design books out there, as well.

 And he  should preferably be a member of the International Solar Energy
Society and American Solar Energy Society also..

He might wish to "moonlight" from his engineering employer, to give you
a reduced "fee" so he can gain the experience of working on your

I wouldn't spend a lot of money on "by gosh" hearsay or Rules of Thumb
construction without some professional guidance.

Charles Bash,,  member ASHRAE



Posted by John Smith on January 25, 2005, 7:17 pm
auteiri@fastmail.fm wrote:

Extra thermal mass can be added on 2nd/3rd floors - see www.maxxon.com and
www.usg.com (search for Levelrock).
Works fine on current residential TJI + plywood floor decks.

You have already had a suggestion of a thermal water column. Viessmann and
others make solar water heaters (see
ish ).

You can use devices like these to sufficiently heat water for radiant floor
heating in your climate & domestic h/w purposes.

You can also consider SIP wall panels ( www.thermocore.com ) with high
insulation values and smaller wall thicknesses using polyurethane insulation
(higher R-values than EPS).

Posted by lelson on January 25, 2005, 7:32 pm
 One possibility is a rock or concrete slab "solar" floor. This and
other useful thermal mass suggestions are in Chiras' book "The Solar
House" http://www.dirtcheapbuilder.com/solhouspashe.html

Chiras and others (e.g. Mazria) talk about quantifying the required
amount of thermal mass in terms of floor space. Maybe you will have

Lee Elson

auteiri@fastmail.fm wrote:




Posted by Nehmo Sergheyev on January 25, 2005, 9:06 pm
 - auteiri -

- Nehmo -
Assuming thermal mass were desirable in your situation, and that's
debatable, having it anywhere in the house would work as long as you
circulated a fluid, air perhaps, between where the mass is to where it

Tridipanel doesn't appear to have much thermal mass. It's really isn't
made for that characteristic.
 "...polystyrene sandwiched between two-engineered sheets of
eleven-gauge steel welded wire fabric mesh."

     *  Nehmo Sergheyev  *

Posted by nicksanspam on January 28, 2005, 1:59 pm

Sounds like you don't much space heating or cooling at all.

And airtightness, altho I tried to help one Californian figure out
how to solar heat a new house with the windows open :-)

And not much insulation.

A slab can help cool the house, with ceiling fans. A low-e massy ceiling
can help warm it, with thermosyphoning air heaters. You might look into
"the Barra system," which is popular in Europe, or put some fin-tube pipe
under a low-e ceiling, with a stratified heat storage tank on the ground.
This can also preheat water for showers.

A whole-house fan with a smart controller may also be useful, letting you
bring in cooler outdoor air when the house needs cooling and warmer dry
outdoor air when the house needs heat.

Indoor thermal mass is good, but these panels look heavy and expensive.

It wants to have lots of surface, with short internal and long external
time constants RCi and RCe. A thermal capacitance C Btu/F with A ft^2 of
surface in slow-moving air has an internal time constant RCi = C/(1.5A)
in hours. With a G Btu/h-F house conductance, RCe = C/G hours.

For instance, a 30'x40'x8' house with an R40 attic and R30 walls and G8
Btu/h-F and 2400 ft^2 of 1" drywall (2 layers) with 2400 Btu/F plus 2400
Btu/F of possessions with A = 4800 ft^2 would have RCi = 4800/(1.5x4800)
= 0.67 hours (40 minutes) and RCe = 4800/128 = 37.5 h.

Concrete also has internal and airfilm thermal resistance...

Or tuck some 4" PVC water pipes between the basement ceiling joists.

Water stores about 6X more heat per pound than masonry. You might
"pug" the floors with EPDM or poly film water ducts between joists.

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