Author Topic: Forced air heating with a Lister  (Read 20323 times)

Procrustes

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Re: Forced air heating with a Lister
« Reply #15 on: February 21, 2006, 07:11:09 PM »
Dear Procrustes,

You are correct in your analysis.  No water ever leaves the 1,300 gallon storage tank.  It's just a heat bank.  The advantage is the tank doesn't have to be pressurized.  I can build it out of plywood and 2x4's with cheap EPS foam for insulation.  It will be lined with cheap durable EPDM pond liner. The cost to build one of these is very very reasonable compared to commercial stuff that size.  So I must use copper heat exchangers to move the heat in and out.  A pressurized tank that size costs a fortune and won't fit through a regular door.

My present heat exchanger is tiny by comparison, just a retrofitted 30 gal gas water heater.  What used to be the flue now carries 3 gallons of 50/50 antifreeze.  Since it was originally a water heater, it has the over temp/over pressure safety valve in case the SHTF, but it takes very little supervison.  A shower and a load of laundry is plenty for 5-8 hours of further operation. 

The mongo tank would take weeks to over heat I think, if ever.

Finest regards,

troy

So you're going to build the water tank into the crawlspace of the new house.  That's a good idea.  You're going to bury it right?  I figured on two days with a backhoe (about $600 around here) to dig mine.  I have to dig outside of the house obviously, which will mean a few pricey insulated lines.  As I mentioned elsewhere I'm looking into a geothermal heat pump as well.  It would be totally swank to pump heat out of my house into the heat tank during the summer.  I don't see why you couldn't do this with the PEX that you otherwise use for hydronic heating (this wouldn't be geothermal, obviously).

kyradawg

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Re: Forced air heating with a Lister
« Reply #16 on: February 21, 2006, 08:42:46 PM »


Peace&Love :D, Darren
« Last Edit: August 03, 2006, 05:38:17 AM by kyradawg »

solarguy

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Re: Forced air heating with a Lister
« Reply #17 on: February 21, 2006, 09:00:46 PM »

Quote

So you're going to build the water tank into the crawlspace of the new house.  That's a good idea.  You're going to bury it right?  I figured on two days with a backhoe (about $600 around here) to dig mine.  I have to dig outside of the house obviously, which will mean a few pricey insulated lines.  As I mentioned elsewhere I'm looking into a geothermal heat pump as well.  It would be totally swank to pump heat out of my house into the heat tank during the summer.  I don't see why you couldn't do this with the PEX that you otherwise use for hydronic heating (this wouldn't be geothermal, obviously).

Quote

No, not in the crawlspace, in the basement along with the Lister.  No parasitic heat loss fall/winter/spring.  That's why it's so important for the tank (or the materials for the tank) to be able to pass through a regular door. 

I suppose you could do a summer tank outside and a winter tank inside, but with 4" of foam insulation all around, the unwanted heat transfer from the tank to the house in the summer will be minimal.

Finest regards,

troy

Finest regards,

troy

hotater

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Re: Forced air heating with a Lister
« Reply #18 on: February 28, 2006, 03:34:43 PM »
A friend and 'neighbor' (3 miles away) in Western Colorado built a solar house with a 4,000 gallon insulated concrete tank built as part of the foundation.  Into that 'heat bank' of water he fed solar hot water panels, wood stove heat exchanger fluids and water that trickled through a Trombe wall when the thermostat said it was warm enough.  Some water replenished the tank but most of the heat was gathered by heated fluids going through heat exchangers.
 At a time I was burning 12 cords of wood a year and had cold feet he maintained three times more house on next to nothing and had heat to spare.
  The house is still there and used as a dude ranch now. I don't think it's used in winter anymore....I wonder if something went wrong?....  I'll have to find out.

Just up the road from there is Marble Retreat. At the time it was built it was the largest solar forced air heated building in the world.  It used a huge chamber of washed gravel with perforated pipes running through it as a solar heated heat sink from which heat could be drawn later.

I've lived for the last twenty years in houses with natural hot water flowing through the floors....NOTHING beats that for comfort and economy!!
7200 hrs on 6-1/5Kw, FuKing Listeroid,
Currently running PS-Kit 6-1/5Kw...and some MPs and Chanfas and diesel snowplows and trucks and stuff.

hotater

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Re: Forced air heating with a Lister
« Reply #19 on: February 28, 2006, 05:52:48 PM »
I bought an old 12.5JC Onan genset for $50 at an auction.  It's a four cylinder, air cooled, propane engine running at 1800 rpm.  The entire cylinder head area is behind sheet metal shrouds that pull air through the head fins and out a 12 x 12 inch squirrel cage fan. 

THAT is a forced air heater!!
7200 hrs on 6-1/5Kw, FuKing Listeroid,
Currently running PS-Kit 6-1/5Kw...and some MPs and Chanfas and diesel snowplows and trucks and stuff.

BruceM

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Re: Forced air heating with a Lister
« Reply #20 on: February 28, 2006, 07:02:01 PM »
Troy, I've very interested in your insulated tank design.  I'm working on plans for an off grid homesite and also plan to use a 1000 -1500 gallon tank for heat storage.  I was going to use a galvanized steel water storage tank (about $1000/1000 gal) inside my insulated shop building for the home in floor heat and domestic hot water use but your approach sounds intriguing, since the liner could be replaced fairly easily every 20 years.  With the steel tank I'd put 4" of blue board under it, and R30 of fiberglass around it in a framed in space.  One wall would be hinged for access so it could be serviced or replaced.

The forces on the bottom  side walls of a square box are significant- have you some details on the structure?

Best Wishes,
Bruce

solarguy

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Re: Forced air heating with a Lister
« Reply #21 on: March 01, 2006, 03:50:49 AM »
Dear Bruce,

I will crunch the numbers before I build one, but I have also been pretty successful with the TLAR engineering method, as popularized by Burt Rutan.  That's:

That
Looks
About
Right.

Your mileage may vary.

The stress will be mostly dependent on the head, or height of the stored water.  Thus a low tank is much cheaper to build than a tall one of the same volume.  Plywood pretty much dictates side walls of 4 feet, with water about 3ft deep.  EPDM liners come in pretty standard widths if you want the cheap price.  A sheet of epdm 10ft x 25ft folded up like a chinese take out box makes a good sized water tank.  I envision a body of water approx 3' x 3' x 18'.  An exterior frame with 2x6's every foot is probably strong enough.  But, as mentioned, I haven't crunched the numbers yet.  I think my estimate for the whole thing came in about four hundred bucks.  Make certain the floor can take the weight.

Hope that helps!

Finest regards,

troy

ps, each framing station will need a board on all 4 sides, bolted/screwed/glued at all four corners to form a complete square and resist all that outward thrust.

tr
« Last Edit: March 01, 2006, 04:27:38 PM by solarguy »

Procrustes

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Re: Forced air heating with a Lister
« Reply #22 on: March 01, 2006, 05:41:52 AM »
Here's some technical information about thermal flywheels: http://europa.eu.int/comm/energy_transport/atlas/htmlu/thermdtech.html

pigseye

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Re: Forced air heating with a Lister
« Reply #23 on: April 12, 2006, 03:33:55 AM »
Well, we've gone off topic of the original post but I wanted to expand on this thinking.

My idea is to build a listeroid genset and house it in the detached garage, you could use the genset to heat a home built tank when your electricity load is low (nightime) and simultaneously use the exhaust heat to heat the tank non-stop when the lister is running. 

The tank could be built in the garage and could be built into benches or cabinets to minimize lost floor space.   Any lost heat in the winter, when temperature differential is greatest would heat the garage.  You would obviously want to minimze heat loss as much as possible in the summer.  But here in WI, summer's not that long.

In the winter I would augment the tank heating with outdoor wood furnace.  You could burn all your paper,  scrap wood, firewood, or WVO to provide heating assistance to the mass when demand on it is greatest.

A few questions,

Would you have lower heat loss in the tank if you built more in a cube shape?

How large would the heat exchanger have to be for each device that adds or takes heat away from the heat storage mass?  Would 25 feet of coiled copper generally be adequate?  Maybe someone with more smarts could crunch the numbers for domestic water heat with temps like 45F in with a demand for 120F out.

Are there any risks with large tanks of water with mold or other things that could grow in real warm water?

Any other links out there for such design ideas?

Thanks
Pigseye



solarguy

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Re: Forced air heating with a Lister
« Reply #24 on: April 12, 2006, 04:01:12 AM »
Here's my opinion.  I'm not an engineer and don't even play one on tv.

The exhaust heat exchange is trickier than the coolant heat recovery.  If you cool the exhaust too much, you will get condensation of some fairly nasty and corrosive stuff.  The presence of that moisture will cause soot to stick like mad to the inside of your exhaust pipe, rapidly clogging it.  Thus, some means is necessary to monitor and clean out said exhaust pipe.  Other wise, lovely.  You could also just have a longish (not too long of course) exposed steel pipe and heat the garage directly.

Commercial outdoor wood furnaces are, as a rule, pretty inefficient.  If you actually capture 35% of the heat in the fuel as useful heat indoors, you're doing a marvelous job.  By comparison, EPA rated wood stoves may approach 80% efficiency.  The commercial ones are also pretty expensive and can smoke like a bandit.  No way you could run one in town IMHO.  Smoke = pollution too.

If they say "efficient" but don't mention a % or real data from an independent testing agency, it's just hype.  That doesn't mean you can't have one, or shouldn't have one, I just don't want you to be dissappointed.  If you google search for outdoor wood furnace efficiency you'll learn lots of interesting stuff.

All other things being equal, you will have lower heat loss from a water storage tank that's cube shaped vs shaped like a shoe box because it presents less surface area per gallon for heat loss to occur through.  The best would be sperical, which is not a trivial task for a homebuilt tank.  The taller the tank, the stouter it will have to be constructed.  Don't even think about pressurizing such a tank.

Heat exchanger sizing gets messy.  Depends on the material, size, flow rate, construction and some other stuff.  Temp in and Temp out don't give quite enough information either.  We'd also have to know the flow rate, which would give us BTU/hr.  That's really outside of my specialty though.

Yes, things can grow in warm water tanks.  My particular design is also bad because the water in the tank is stagnant, serving only to store and release heat.  There are biocides you can add to forstall that and it really depends on temperature.  You can also get epdm liners with built in algaecide.  Better be sure you're not drinking that stuff though.

Good luck, have fun, be careful!

troy

Doug

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Re: Forced air heating with a Lister
« Reply #25 on: April 12, 2006, 04:14:40 AM »
Outdoor wood furnaces are real pigs ( no pun intended ) on wood.
Here's a good example of a well designed clean burning fire but without a good heat exchange the value goes up the stack.

http://www.inetlink.ca/a31ford/cgcmb/Updraft-Gasifying.mpg

Doug

I've kicked around and puttered at this for a bit. Everything needs to be thought out and planned carefuly.
I plan so far in advance that I'll probly heat with gas for another decade......

Jackpine Savage

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Re: Forced air heating with a Lister
« Reply #26 on: April 12, 2006, 01:36:16 PM »
I love radiant floor heat and had planned on getting an outdoor wood burner, until I did more research! Unless you have access to a steady stream of waste wood, I wouldn't want to feed one.

I'd love to get one of these but they are not cheap: http://www.woodboilers.com/ .

Doug

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Re: Forced air heating with a Lister
« Reply #27 on: April 12, 2006, 07:38:03 PM »
Somebody needs to come up with some sort of clean burning high eff self stoking outdoor boil system.
A wife makes a lousy stoker....

GuyFawkes

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Re: Forced air heating with a Lister
« Reply #28 on: April 12, 2006, 08:01:15 PM »
Somebody needs to come up with some sort of clean burning high eff self stoking outdoor boil system.
A wife makes a lousy stoker....


use and old turbo to make a gas turbine, small as you can, then inject sawdust into the exhaust for afterburn.
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Original Lister CS 6/1 Start-o-matic 2.5 Kw (radiator conversion)
3Kw 130 VDC Dynamo to be added. (compressor + hyd pump)
Original Lister D, megasquirt multifuel project, compressor and truck alternator.
Current status - project / standby, Fuel, good old pump diesel.

Doug

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Re: Forced air heating with a Lister
« Reply #29 on: April 13, 2006, 03:19:51 AM »
Nice idea, but I don't haver any saw dust, plenty of rocks and trees....

Doug