[Strawbale] Sub Floor Radiant Heating

[Shody Ryon]

--- Ilan Ungar <adrihalut at gmail.com> wrote:

> So heating earth is complicated. In that case, I
> don't think I should have a
> problem insulating the bottom of the slab since we
> use pile (or is it
> Caisson?) foundations and the slab does not transfer
> loads to the soil.

I don't think it is complex, per say, the thermal
storage just should be isolated from the living space,
for seasonal long term thermal storage of renewable
heat, as I understand it.

> I was asking about slab thickness because I imagine
> I would want the heat to
> be smooth with little low and high peaks. This means
> larger heat storage,
> correct? 

This would be storage inside the living space.

With a typical 20 cm slab and 10 cm
> flooring and filling (???), one
> would remain with a cold floor after a single cloudy
> day. So, what would the
> parameters for arriving at a correct
> floor-thickness/heatsink-volume be?

I am not trying to follow this as I think there are
too many variables

> A larger heatsink will require more heat which I

Are you inter-changing heatsink and thermal storage?

> The article also mentions the high cost of this
> system, around $14,000.
> Solar panels and tanks are not that expensive here,
> is it the PEX that makes
> this system so expensive?

$5000 for varible speed on demand water heater. This
might be desireable for someone with a regular
schedule away from the house most of the time; no one
in the house for long regular periods, perhaps with a
low thermal mass floor, so the timer could shut the
system down and turn it back on and save energy.

I think PEX is 50 cents a foot.

The price may include labor.

> 
> Thanks Derek. Wouldn't that require lots of tripple
> glazing at the South
> with heatsinks absorbing sunlight etc? 

The thermal collector should not have low E or tripple
glazing or anything that would reduce energy charging
the collector

> In that case,
> wouldn't that require
> backup heating after a single cloudy day?

in most cases-yes, because they are not designed
correctly.

If good designer with energy efficiency in mind could
design a house to be 100% solar heated even in very
extreme Alaska with -60F. This design would have,
among other things, small windows, accept for southern
(sun facing, that is) sun space windows outside the
insulation envelope. I doubt you would need an extreme
design in this regard where you are.

> In the climate we have here, I am imagining an
> insulated floor slab, with
> solar heating. Seems to me I can even have the house
> ventilated in winter
> with open windows during the daytime. Once the
> windows are shut, within an
> hour or so, I'd get a nice cozy temperature
> throughout the house
?

I think so. some people really like the temps like
this, others not so much so make sure everyone will be happy.


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