On Aug 24, 7:10 pm, Sunworshipper Sunworshipper wrote:
I've been trying to design my buildings up north so I don't totally
freeze and ran into a lot of aluminum mylar. I'm having trouble
understanding how, what I hear of light speed radiation is going to go
through plywood and reflect back any kind of substantial energy. Or
through concrete. Can anyone explain how radiant barriers are
effective on buildings or maybe suggest another group to ask? Or
should I just keep it for solar experiments?

I'm also lost on how I can design a system to feed the wood stove,
without opening a window to -20 degrees. I'm thinking of having a vent
to the attic to draw from.

Put your hand under or beside (not over) a bright incandescent bulb.
You can feel the heat. Now place a piece of aluminum foil over your
hand. Aluminum is a very good heat conductor so if it heated up you'd
notice fast, but it doesn't. It reflects the infrared heat radiation.

It's a little more difficult to show that emissivity works both ways,
that surfaces which don't absorb heat also don't radiate it. If you
heat black iron or a stove element you can feel the heat radiating off
it with the back of your hand. I just tried and can detect an iron
frypan at 120 F from a few inches away. Do the same with polished
stainless steel or glass and you can't feel it. In fact once the red
glow fades freshly blown lab glassware is a serious burn hazard for a
long time. Since it doesn't radiate it stays hot much longer than you
expect and doesn't warn your hand.

My wood stove is in the basement and the air to feed it comes in
through normal building leaks, especially around the garage door.
Upstairs is better sealed to keep the warm air in. It's like a hot air
balloon which doesn't leak out the top even though the bottom is wide
open.

Some of the cold air feeds the stove and some of it is warmed and
replaces indoor air. I controlled it by watching the humidity while
weatherstripping the upstairs. When it rose to a comfortable level in
winter I stopped tightening the house. I've never measured the air
change or infiltration rate but cooking smells disappear in a few
hours. The heat loss rate is 2~3% of the difference between indoors
and out per hour. You have to find your own acceptable balance between
ventilation and heat loss, those are simple indicators. Thank you
Jimmy Carter for paying for it.

You can easily check draft and airflow by lighting a wadded sheet of
newspaper in the top of the stove, assuming you don't have a catalytic
converter or a badly creosoted, combustible chimney. For mine only a
whisp of smoke will leak out before the chimney begins to draw. That's
a good way to light a fire cleanly, too. If you open a vent into the
attic you may have smoke-flavored cold air rushing down the chimney
when the fire dies out.

Because the living space doesn't leak much air the temperature
difference between floors and rooms is lower than my neighbors'
similar but less well sealed houses. They have to run their stoves
hotter to keep upstairs comfortable. The disadvantage of a stove in
the basement is that the upstairs warms up very slowly, but it does
keep ashes and firewood debris off the rug. Also my wood stove
accessories include a rusty old anvil on a stump that doesn't match
the living room decor.

In summer I vent the bathroom outdoors after a shower and do steamy
cooking outside. I watch the humidity and open windows on nice
evenings. The window seals are wood frames double-glazed with
polyester film and with a few of them out in summer the house breathes
normally.

I live in southern NH which is humid and reaches 100F and with those
few precautions a single window A/C is enough to keep the house
reasonably comfortable and protect the machine tools from rust. Your
results and especially your temperature tolerance may vary.

Jim Wilkins