Hot Water Heating Idea

The use of a compressor tank is not a good idea either, unless you like rusty water. The tank is not coated on the inside like a hot water heater. KD

You guys are really trying to squeeze every possible BTU out of your wood, I just decided to replace our old water heater with a On Demand unit. Costs a little more at first but was told it would last twice as long and use a fraction of the gas.

deck2 said:

You guys are really trying to squeeze every possible BTU out of your wood, I just decided to replace our old water heater with a On Demand unit. Costs a little more at first but was told it would last twice as long and use a fraction of the gas.

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I wouldn't get all warm and fuzzy about those critters either. From all my research they have a hell of a time with hard water and have a lot of other issues. I saw some computations some plumbers did and you would be lucky to ever recover your expenses in the long run. You really have to dig through a mountain of hype to find it though.

Check-out what could happen if you don't get your system correct...
http://www.youtube.com/watch?v=68p4ngS-yME

I looked into the on-demand domestic hot water last year and came to the same conclusion as Driz. At our usage the payback didn't exist.

kd460 said:

The use of a compressor tank is not a good idea either, unless you like rusty water. The tank is not coated on the inside like a hot water heater. KD

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Neither are well casings or bladder tanks.Don't see any rust in my water now .

LEES WOOD-CO said:

kd460 said:

The use of a compressor tank is not a good idea either, unless you like rusty water. The tank is not coated on the inside like a hot water heater. KD

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Neither are well casings or bladder tanks.Don't see any rust in my water now .

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You may be correct but I know when I drain my air compressor the water is rusty. I suppose that it would clear but still could taste funny. Just a thought.
Ed

Years ago, I met a guy that put some kind of heat exchanger on his wood stove, with a circulator and everything. I asked him if he had ever been through a power failure and he said, yes, the water began to boil out of the coil and the solder melted on a few connections and the entire thing self vented. He soldered the connections back together and thought they made great safety relief valves.

I don't advocate anyone doing this, however. :roll:

I think the A/C coils are going to be a disappointment as they are generally finer tubes without much internal volume but a lot of pressure drop. The mineral oil in the system can be cleaned out, but may be noxious if the system compressor had a burnout. I don't think you can ever get the smell of a burned out compressor out of things.

You ARE recovering that refrigerant per the EPA, aren't you? :bug:

Chris

I think I'm giving up on the idea of doing anything with the hot water at least for another year. From what I've read about the on demand systems, they may never pay for themselves in savings (much like solar panels). Some people have actually reported using MORE nat gas with an on-demand system. And you STILL have the problem of 40F degree water coming into the house during the winter. I still kind of like the idea of keeping it simple - a basic small holding tank behind the stove, no heat exchangers, just to warm up the incoming water, is probably a good idea... if I find a good deal on a suitable tank, I'll probably do that at some point.

One idea, if you can get one that is, a copper tankless coil from an old boiler. Some of them are small enough to fit in a pot of water that can sit on a corner of the stove. Just keep the pot filled and submerge the tankless right in there. The only downside I can think of is you could cool the flue gas down too much and there would be some heat loss to the room if the pot is too big. You may have to add a small relief valve in the line just in case and possibly a mixing valve so no one could get scortched if this works too efficiantly.

I was trying to get one of these when I was running my old steel plate stove. The problem is most boiler guys keep the coils and turn them into scrap metal yards for $$$. Copper ain't cheap anymore.

Adios Pantalones said:

VTZJ said:

Adios Pantalones said:

I'd also add that heating hot water is an inefficient way to recover heat.

Anyone know how long it takes to freeze ice?

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If you are having trouble freezing your ice, try unthawing it first.

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Unthawing is just freezing... How long does that take for ice?

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"How long to freeze ice" is like "where do they bury the survivors". Ice is already frozen and survivors don't get planted.

But this thread brought an interesting bit of trivia to mind. Freezing water to ice is a not just a matter of time, it is a matter of refrigeration capacity. Freezing a ton of water into ice takes 288,000 BTU's, or 12,000 BTU/hr for 24 hours. So a convention emerged - a "ton" of air conditioning is 12,000 BTU/hr. So if you needed to freeze a ton of water into ice you could use a one ton chiller for 24 hours, or a two ton chiller for 12 hours, etc. Usually window A/C units are rated in BTU's/hr. But even now central A/C is sold in tons of capacity.

""How long to freeze ice" is like "where do they bury the survivors". Ice is already frozen and survivors don't get planted."

umm- that was the joke... look at the earlier posts

Adios Pantalones said:

""How long to freeze ice" is like "where do they bury the survivors". Ice is already frozen and survivors don't get planted."

umm- that was the joke... look at the earlier posts

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I know it was a joke... I was giving another example of the same kind of joke....

Well it is not funny anymore.

d.n.f. said:

Well it is not funny anymore.

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And your snide comment added huge value!

Look, the point of my post was to state the derivation of the term "ton" in air conditioning. If some people find it interesting - fine.

Hi Engine guy,

Thanks for the origin of a ton. I knew of the 12K BTU, but not the detail background of it.

Cheers.

And you STILL have the problem of 40F degree water coming into the house during the winter. I still kind of like the idea of keeping it simple - a basic small holding tank behind the stove, no heat exchangers, just to warm up the incoming water, is probably a good idea... if I find a good deal on a suitable tank, I'll probably do that at some point.[/quote]


the price of propane is making me think of a new energy efficent electric hot water heater,we are thinking that using pre heated water will allow us to use a smaller heater . My sons have a house in Puerto Rico and supply hot water for as many as 6 people with a 20 gal electric water heater,the water coming in to the house is about room temp In fact before the water heater installation I was able to shower comfortably with the incoming water temp. We were thinking let the cold incoming water go into an old water heater tank,there it gets to room temp in the basement--say 60-65, then it moves to another hot water heater tank positionede above the pellet stove , heating the water to -i dont know maby 100 degrees plus from there it goes to the electric HWH which should be able too make hot water quickly and cheaply We built our log cabin,son is restoring an old boat and we built a ratrod from scratch last winter5 we have welders tools metal fab experience Etc but do not want to blow our selves up Any comments please LFE

I think that should work okay. Just note that sometimes when water is stored at ~ 100 F or so, bacteria can grow in the water causing a rotten smell. Clorinated city water is far less prone to this than well water. This is why the recomended min temp setting on a water heater is 140 F.

how about a pan on the stove top? You could wash dishes, your socks, make soup, maybe even all with the same water...
But seriously, too much trouble. A pan on the stove is probably as efficient. Insulate your water heater, or its room.

Here's an old thread that we did last winter. I basically heated water with my wood stove. I now have solar up and running to the same tank. I don't see a big issue with that. https://www.hearth.com/econtent/index.php/forums/viewthread/13691/

Mike

Jimbob said:

I think that should work okay. Just note that sometimes when water is stored at ~ 100 F or so, bacteria can grow in the water causing a rotten smell. Clorinated city water is far less prone to this than well water. This is why the recomended min temp setting on a water heater is 140 F.

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Good point. Another great reason to never use hot water to cook or drink. I have seen recommendations to set it at 120. That's where we set ours and we don't need to add cold water when showering. I would say try it if you can keep the cost down and let us know the results.
Ed