Link to poor Man's vent/heat exhanger

[Chuck_Surette]

Hi Guys,

Did a fruitless search last night, for a link I was given a while back here.  

It was for a vent, to be used as kind of a poor man's heat exchanger.  Installed behind the fridge, it would draw outside air in when there was a negative pressure inside the house.  In turn, the cold outside air would be tempered by the warm coils on the back of the fridge.

Ring any bells??

We are finally getting ready to build and I'm kicking myself for losing the link.

Thanks,
Chuck Surette

[Amanda_931]

No, doesn't ring any bells.  Sounds interesting, though.

The ones I know about are the collectors that can run hot air into your house--IIRC Mother Earth News and Home Power have published a few, there's at least one commercial version.

They can be rearranged to pull hot air out, cool air in from some a cooler side (which might be underneath) the building.

The store-boughten kind of heat exchangers can be home-made, there was an article in a very old Popular Science/Mechanics about this, have an internet acquaintence who's done it.  

[bartholomew]

Here ya go...

http://www.jlconline.com/cgi-bin/jlconline.storefront/44d244ce00161bb727177f000001059c/Product/View/0306back

[ShawnaJ]

Sounds something like the system my dad has in his house. It's a heat exchange system in his "super good cents" home, maybe some info under that? I know it involves hot/cold air going down into the ground and the opposite being drawn back into the house.

I am just grateful my heat pump hasn't quit today. It's 97 with a feels like of a whopping 118 at 4:19 PM.....gotta love the South.

[Amanda_931]

Sounds pretty interesting--I wonder if it works as well with the high-efficiency Energy Star refrigerators.

(it's using the Refrigerator instead of the sun to heat the collector--same idea, though)

[Chuck_Surette]

THAT'S IT!!

THANKS BARTHOLEMEW!!

I'll never lose it again.  I should send it to my inspector, before I forget....

[Amanda_931]

This version is "solar"-powered rather than "fridge"-powered in the form of siding, and does use a fan.  And you may sacrifice all your south-facing windows.

No provision for changing what happens to that hot air, either, apparently "the control" is to shut off the fans.

http://www.energyrefuge.com/archives/solar_siding.htm

the dark-colored metal cladding is heated by solar radiation

ventilation fans located at the top of the wall create a negative pressure in the cavity between the cladding and the building

outside air is drawn through tiny holes in the SOLARWALL® and is heated by the metal panels

the air rises in the cavity to a plenum at the top of the wall

the incoming warm air is ducted to the nearest fan

warm, fresh air is distributed throughout the building

operating efficiency of up to 75% (rated by both the Canadian and US governments)

on a sunny day, the temperature in the SOLARWALL® can raise the air temperature by 30° to 76° F (16° to 40° C) depending on flow rate

the cost of a SOLARWALL® solar heating system in new construction is usually less than the cost of a brick wall or even a metal-clad wall; thus, energy savings are realized, with no payback period

even on cloudy days, the SOLARWALL® provides significant energy savings as a preheating system for ventilation air

[ki4hpz]

This looks like a great idea to pull fresh air in the living/dinning room. How would you put fresh air in the bedroom/bathroom too to prevent mold and meldew in a tight house?

[Amanda_931]

Exhaust fan on the side of the house opposite where you want fresh air?


Internet acquaintance with allergies runs his incoming air, IIRC--

a) through a filter.  Maybe (sometimes?) a dehumidifier as well.

b) through an air-to-air heat exchanger.

c) ducted into his closets (and possibly bathroom)

d) I think it's from there into the rest of the house.  But the closets get first dibs on fresh (dry?) air, so that they really really don't mildew.

I think this all sounds wonderful.

(too tired to find his web site--got someone new working with me--she seems much more likely to push me than the last two people did--them I could outwork without half trying.  Not this time!  And because it's been so hot we decided that 6 AM was a good starting time.  Actually it was raining here when she got here, but we still cut wands for a wattle and daub wall, did quite a bit of clearing weeds.  She agreed with me that my red tomatoes, even if they were ripe, tasted like winter hydroponic or greenhouse jobs)

[glenn kangiser]

got someone new working with me--she seems much more likely to push me than the last two people did-

Please stay away from second story openings, stairs - etc., Amanda -- Maybe first floor is best while she is around. :-/

[ki4hpz]

I was thinking about passive no electricity designs for the poor man in orther ares of the house...

[Amanda_931]

You can do it if the rooms you vent are on the equator-wards side of the building.

Vent from the room/closet at the bottom--outside to a small collector that vents at the top.  Same principle as the solar-wall.

And you can do it with PAHS because there you do have a constant movement of air throughout the building.

That does get to be designed into your building from the beginning.  

And while the person I mentioned earlier was trying to do a PAHS house, he, like everyone else, wondered if mold and mildew in the large array of underground tubes were going to give him trouble--and I found his house!

Here's more information on John Hait and PAHS--if anyone gets the 2005 version of the book, let us all know how it is--a bunch of us wondered if the--considerably greater--cost meant a lot more information, or just color photos.

http://www.rmrc.org/pahs/

http://www.rmrc.org/shopping.htm

and here is the house I was looking for earlier:

http://paccs.fugadeideas.org/tom/index.shtml

don't know if this helps, but here's a diagram from a very strange site:



from this site--I really love the phrase "self-comforted house":

http://www.midcoast.com/~bo/PAHSgreenhouse.html

(and thank you Glenn!--fortunately I don't do heights--but she's coming again tomorrow)

[ki4hpz]

Thanks, do you have a simple diagram of how to add passive air flow/ventilation to a room? Like the poor man stuff. I really believe a house should be passive as much as possible. Never know what our government will do to energy cost.

A though, what about an LP gas stove passive vent....

Thanks for the help!

[Amanda_931]

I'd just love to find a passive stove vent.  Something that takes--exhaust products and moisture and scents (I really love carmelized onions--after they're cooked) and especially in the summer, heat--out of the room.

The collector in the system I described can be extremely simple, home-made is good.

Plywood box, with a glass or (especially if you aren't using this for heat) clear plastic top.  Inside painted black.  Better would be a couple of layers of corrugated metal roofing, as dark as possible, on the inside.  Set so it is facing the sun--I've had in mind on the wall, not perfect, but simple--with some sort of through-the wall duct (ducts if you had in mind putting heat into the room) set at the bottom to pull the air from the inside, and a way to send this out into the atmosphere at the top.

I'm pretty sure that Home Power had a free article on the subject (their collector was better, but connected to a basement window with ducts) but what I turned up first was this not too awful .pdf file.   enjoy:

http://www.homepower.com/files/prangektu.pdf?search=passive%20solar%20heat

[Amanda_931]

Starting to find things under "simple solar collector"

This one's close enough.  There's a perfectly lovely diagram in the .pdf.  I can copy his photos, but not the diagram.  He's using black window screen for the black, not black painted plywood with baffles or several layers of dark metal roofing.

From Build-it Solar (site owner joined this forum, didn't he?) and Home Power (not the one I had been looking for, but it's actually better...The list of collector considerations on the first link are pretty interesting)  

http://www.builditsolar.com/Projects/SpaceHeating/solar_barn_project.htm
http://www.builditsolar.com/Projects/SpaceHeating/SolarBarn.pdf

[ki4hpz]

I wounder if you surrounded the cookstove with bricks and have a flue exhause like a fireplace? Would that take the majority of the heat out?

[Amanda_931]

Worth thinking about.  Not even sure you need the surround.  All you really need is to start the heat (etc.) up the chimney.  

With the heated cob bench, if you can't get the chimney to start pulling air out, you are supposed to go down to the vertical part, light a twist of paper (or fatwood) stick it into the chimney there, where you should have a cleanout.  Might be able to do something like that in a pinch.

[glenn-k]

Your PAHS link here --- http://www.rmrc.org/shopping.htm  cost me money, Amanda.

I bought the e-book on making electricity out of scrap metal -- looks like fun -- it can assist in keeping solar power batteries charged and give you a place to dispose of the old Packard.

Nice little book and the author himself sent me a link to the download when somehow I missed getting it.  Well written - slightly humorous and easy to understand.

[Amanda_931]

Oh, dear.  



I didn't really intend to do that.

[jraabe]

Here's the wall ventilator/collector from the Built-it-solar PDF that Amanda linked to earlier. Very clever.



And the Frig HRV diagram from JLC... put them together and you get...

[Amanda_931]

Thank you John.  

You'd have to have your collector lower than where you wanted your air output.

Which is what the Home Power article that I'd originally been looking for did--had the (mostly sheet metal) collector out in the yard, insulated duct going (uphill) into a basement window.  the author used it to heat the basement.  The cold basement air going to the collector could go downhill just fine from another hole in the window.

I'm a lot more comfortable building with wood than sheet metal.