Air Handling

[DavidLeBlanc]

In the not so tiny house I'm currently living in, a 22' x 30' flat roofed shack of a place (in inner urban Seattle!), the air handling in the house is very bad: no opening windows in the LR and no kitchen stove exhaust!

Since I want to super-insulate to save on heating/cooling when I build my Builder's Cottage, I'm wondering how to provide for air handling, hopefully with some sort of heat exchanger to scavenge the conditioning out of the stale outbound air. There will be a kitchen stove hood exhaust for starters (and I realize I can't scavenge that air!). My current thinking are those small 2-3" dia a/c conduits distrubuted throughout the house and connected to a heat exchanger and fan in the machine room. Heating will be either hydronic or 1 or more propane stoves/fireplaces (like Victoria's Cottage) here and there. I'd prefer something a bit simpler though! Any suggestions?

Speaking of kitchen stove hood exhausts, aside from loosing a small amount of cabinet space (the stove will be in a corner with one side on an outer wall), would it be OK to run it out horizontally? Otherwise, going vertical, it would crimp the loft area above.

[Amanda_931]

Air-to-air heat exchangers help--seen them a couple of times on ebay.  Otherwise they tend to be violently expensive

And one of the OLD popular mechanics or science or something had plans that didn't look too bad.

If you had some corrugated aluminum around apparently they don't cost that much to make.  Blowers move the air.

I've got the information, but it's in three HUGE files.  Person who sent it to me scanned photo quality, I'm afraid.

There are a bunch of things called "solar chimneys" but if you have a fair amount of sun--and a suitable south-facing wall--the simplest, a tall black box with a glass south front and openings front and rear, top and bottom can work.  

Open the outside bottom and inside top to bring warm air from the outside.

Inside bottom outside top will vent from somewhere else in your house.  etc.

I'm trying to figure out how to do this easily on a second floor.

The principle is the same as stringing a black plastic trash bag across a south-facing window, sealed at the sides (duct tape of course?), leaving space at bottom and top for air movement--I heard this recommended once.  

And sometimes these things really look like chimneys, sticking up out of the roof.

Might look at Ianto Evans' heated horizontal flue rocket stove.  The horizontal flue can be up to 40' long, reputedly one of the cleanest burning wood stove designs (but since it's a DYI deal, might not work if you've need wood-stove certification).  And since it's a wood stove, it does take quite a bit of tending, even if it does radiate heat for a couple of days.

http://www.cobcottage.com/rocket.html

[DavidLeBlanc]

Thanks Amanda!

the stove exhaust I'm talking about is to vent cooking odors and humidity, not carry combustion gases. Run would be 3' or less to the outside.

[glenn-k]

They also have ductless vent that run through a charcoal filter but here is a link that explains all.  Horizontal should not be a problem.

http://www.kitchensource.com/range-hoods/rangehoodtypes.htm

[Amanda_931]

Some air-to-air heat exchangers ARE for room air.   It helps keep the inside air at whatever room temperature you have, heating or cooling the outside air as it comes in.

This kind of thing.

I know nothing at all about either of these guys.

http://www.americanaldes.com/PDFfiles/HRVRes.pdf

picture, order form, and no .pdf file for one here:

http://www.smarthome.com/3033.html

[Amanda_931]

You can get air moving throughout your whole house (not going to be cheap!) including the closets, maybe even under beds to keep mold from growing.

Good for the allergic.

[DavidLeBlanc]

Yeah, sorry if I'm being confusing. I am talking about both exterior/interior air exchange with energy scavenging through an air handler (heat exchanger) and also talking about removing cooking odors and water vapour from cooking through a kitchen exhaust ("stove") hood. Also humidty from the bathrom through a bathroom vent fan.

[glenn-k]

Seems you would then need a heat exchanger that was common from all the things you want to exchange heat from to your heating unit hopefully rigged somehow so as not to require more energy input to make it work than you get from it.  The Monitor stove scavenges heat from the exhaust and uses it in the intake air in the double wall exhaust pipe.  Their application requires a controlled amount of intake air though - yours would require something capable of handling varying amounts of air depending on what was running.  I don't know what's available commercially- maybe you could build a home brew one

[DavidLeBlanc]

My idea is not at all sophisticated - in fact it's the commonest (that I know of) form of energy scavenging on modern forced air heating systems: a galvanized "ziggy-zaggy" box with 2 interleaved air paths. one path sucks fresh, unconditioned air in past the other path that's blowing stale, conditioned air out. Add a basic furnace filter and, if so inspired, a humidfier (which complicates the system and substantially increases operating costs due to higher pressures needed to get past the filter and humidifer "choke points").

I recall reading, years ago, about a similar system that heated a 2,000+ sq. ft. house in a N. tier state off of the hot water heater exhaust! It wan't much bigger than a section of standard hot air duct mounted in a hallway ceiling!

[Amanda_931]

"a galvanized "ziggy-zaggy" box with 2 interleaved air paths."

Yep, that's what you want, although I'm told that aluminum will work a whole lot better than galvanized steel--better heat transfer.

Since they have to be enclosed and therefore difficult to clean, filters are pretty important.  Don't have to be the really heavy duty ones, good quality AC or furnace filters are fine.  And at least one blower.

Kitchen and maybe bathroom ones need to be on a different circuit, I'd think.   (air duct circuit, not electrical--in the interests of having the thing stay clean)

[DavidLeBlanc]

Kitchen and bathroom are direct vent to the outside.