[Greenbuilding] please rant: thar she blows

[Corwyn]

On Apr 10, 2007, at 15:31, Nick Pine wrote:

> Corwyn writes:
> The simple whole house conductance would be 48x48ft^2/R24
> = 96 Btu/h-F for the ceiling + 4x48x8/24 = 64 for walls,
> totaling 160. Each room would be at most 24^2/24 = 24 for
> the ceiling + 4x24x8/24 = 32, totaling 56... 56/160 = 35%,
> for a 65% savings.

Nope, for this simplistic analysis:
whole house: 192 for ceiling and _floor_, 64 for walls = 256
by room 48 for ceiling and _floor_, 32 for walls = 80
= 31%

>> Significantly less than 75%.  First, all those other rooms can't be .
>> outside temperature or 1) your pipes will freeze, and 2) they won't
>> heat up fast enough when you enter them.
>
> Honeywell makes thermostats that measure both wall and air temps and
> can raise the air temp to compensate for initially cooler walls,
> making the rooms perfectly comfortable :-)

How does this address my points at all?
>
>> low mass is not no mass. everything in the room is going to heat up
>> and then cool down again,
>
> Got any numbers at all? What are the assumptions in your simulation 
> program?
> What's the time constant of rooms with 0.5 Btu/F-ft^2 varnished SIP 
> walls
> and R24 insulation? Suppose people change rooms every 4 hours...

Tons.  Which is why I wanted to know the assumptions you used to get 
your 75%.  Since you did it by dividing a house in quarters, never 
mind.

>> I stick by my finding of a maximum of 37% savings, BEFORE heating the
>> individuals.
>
> The individuals are heat sources, no? Why would they need heating?

Well gee, if all this isn't to keep people warm, just let them live 
outside, and save the world.

>
>> You also need to consider the embodied energy in the additional
>> insulation...
>
> Well no. I don't have to do that.

No, you don't; but don't expect anyone to give your advice any value.

Thank You Kindly,

Corwyn
-- 
Corwyn
Kermit didn't know the half of it...
http://www.greenfret.com/
corwyn at greenfret.com