RE: [GBlist] foundation insulation boards

["Paul" <webmaster@globalcircle.net>]

Nice when it all comes together, huh. That's how it works. Esp the point
about needing a certain amount of thermal mass to absorb the solar and
avoid overheating. Of course if the sunspace is not a living area, it CAN
overheat without a problem, and they say you can have an efficient
greenhouse sunspace or an efficient living sunspace, but not both. A
growing space needs all its stored heat to get through a cold night, and
ideally that would be too hot for a comfortable living space.

--paul, webmaster http://globalcircle.net
peace and liberty, sustainability and justice
*********** REPLY SEPARATOR  ***********

On 2/26/02 at 9:31 AM Ralph Bicknese wrote:

>Mass exposed to the interior of a building envelope helps moderate
>temperature swings even if it is not directly exposed to sunlight.  But it
>is only 1/6 to 1/10 as effective at absorbing differences in temperature
if
>not directly exposed.  Mass neither creates energy or uses energy. It
>simply
>stores it for release later.  So it is not realistic to call basement
walls
>or slabs energy hogs (unless perhaps one is referring to the embodied
>energy
>in the production of concrete.  Even then there is debate about the life
>cycle implications verses other options).  Once the energy is in the
>building skin mass only helps moderate temperature swings.  In other
words,
>it helps minimize high and low swings and keeps the temperature closer to
>an
>average temperature. If a building includes a high percentage of south
>facing window it can have a great deal of solar heat input.  Without
>sufficient mass a space with a high ratio of solar collector (south
window)
>will be heated to an uncomfortable level.  And rather than bask in 80 or
85
>degree F temperature people are more likely to open a window and dump
solar
>heat.  With sufficient mass more of the "excess" heat will be absorbed and
>stored for use later when the sun goes down.  By varying the quantity,
>type,
>thickness, and location of mass one can "tune" the mass to either absorb
>heat or coolth slowly or quickly.
>
>Cheers,
>Ralph
>



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