Copper water coils - Why not ??

Re: Copper water coils - Why not ??

PostBy: Lightning On: Wed Aug 29, 2012 3:47 pm

Berlin wrote:The problem with copper and especially soldered joints in the firebox isn't that they will melt or corrode if everything is working properly and you have proper flow and cooling capacity, the problem is that IF something doesn't work right, if the circulation fails or your water temp through the coil gets too high or the pressure is removed from the domestic water system, then you will have a rapid failure with serious consequences. Stainless will maintain its strength and integrity well over twice the temperature copper will, and many times that of a soldered joint; if there is a problem, with stainless (or even other steels), and a steam bubble forms, the rapid heating that will occur won't lead to a catastrophic and potentially deadly failure of the system.


Ah yes, warning heeded! I would be very nervous having a solder joint in the firebox. But seems like a heavy piece of copper 3/4 inch bent into a U would be ok.. I wish someone would post that has done it. I'm not confident being the ginnea pig with it :lol:

And for making something that would attach to the outside? :yearight: I'm interested in heating the water, not lifting it from 50 degrees up to 54.. It only makes sense to me that a coil in the box where its 500 - 600 degrees would be much more efficient at making hot water.
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Copper water coils - Why not ??

PostBy: carlherrnstein On: Wed Aug 29, 2012 3:56 pm

I aggree that a tube in the firebox would heat your water faster but i just cant think of a good reason as to why you would put copper in that type of environment when stainless steel can be had.

See here for a external copper heating coil set up Making a external DHW Coil
carlherrnstein
 
Hot Air Coal Stoker Stove: combustioneer model 77B
Coal Size/Type: pea stoker/Ohio bituminous

Re: Copper water coils - Why not ??

PostBy: Lightning On: Wed Aug 29, 2012 4:07 pm

carlherrnstein wrote:I aggree that a tube in the firebox would heat your water faster but i just cant think of a good reason as to why you would put copper in that type of environment when stainless steel can be had.

See here for a external copper heating coil set up Making a external DHW Coil


My reasoning for using copper is that I was hoping to find a more economical way to make a DHW coil instead of Stainless Steel..
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix


Re: Copper water coils - Why not ??

PostBy: Yanche On: Wed Aug 29, 2012 10:51 pm

I grew up in a home heated with a hand fired Burnham Anthracite coal boiler. Domestic hot water was heated with a "hand". It was a cast iron lump suspended above the fire by the iron supply and return flow pipes. It looked like a four finger hand or fist. The "hand" heated a riveted plate galvanized water tank via thermal gravity flow.

For you skilled tinkers, craftsman, welders, shade tree mechanics, etc. I suggest trying cast iron. Perhaps one or two sections of a very small cast iron radiator or perhaps a shortened section of a cast iron baseboard radiator.
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

Re: Copper water coils - Why not ??

PostBy: SMITTY On: Wed Aug 29, 2012 11:10 pm

GREAT idea, as usual once again! 8-)

My beloved air-cooled 2-stroke BW80 cylinders are made from cast iron. It's heavy & can be brittle (none of which matters for home heating) ... but NOTHING beats it in heat transfer. Haven't melted a BW down yet! :D

Oh, and it's also CHEAP - free all over Craigslist too. 8-)
SMITTY
 
Stoker Coal Boiler: Patriot Coal - custom built by Jim Dorsey
Hand Fed Coal Stove: Harman Mark III (not currently in use)
Coal Size/Type: Rice / Blaschak anthracite
Other Heating: Oil fired Burnham boiler

Re: Copper water coils - Why not ??

PostBy: franco b On: Wed Aug 29, 2012 11:47 pm

Lightning wrote:And for making something that would attach to the outside? I'm interested in heating the water, not lifting it from 50 degrees up to 54.. It only makes sense to me that a coil in the box where its 500 - 600 degrees would be much more efficient at making hot water.

What you say is true, but on the outside you would have far more heat transfer surface in square inches than with pipe inside. Against a 400 degree stove it would heat a lot of water very hot. Just put a pot of water on the stove top and see how fast it boils. Time it and measure the water quantity and the square inches in contact with the stove to get an idea.
franco b
 
Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea

Re: Copper water coils - Why not ??

PostBy: Lightning On: Thu Aug 30, 2012 6:04 pm

franco b wrote:
Lightning wrote:And for making something that would attach to the outside? I'm interested in heating the water, not lifting it from 50 degrees up to 54.. It only makes sense to me that a coil in the box where its 500 - 600 degrees would be much more efficient at making hot water.

What you say is true, but on the outside you would have far more heat transfer surface in square inches than with pipe inside. Against a 400 degree stove it would heat a lot of water very hot. Just put a pot of water on the stove top and see how fast it boils. Time it and measure the water quantity and the square inches in contact with the stove to get an idea.


You have a point franco. I agree that would be applicable for like a free standing stove that heats radiantly. Trouble is that my furnace has a forced air jacket around it, where air is forced between the firebox and the jacket and sent into my duct work. The exterior of the jacket doesn't get very hot. Placing somekind of external coil isn't really an option. At least I wouldn't think so :D
Lightning
 
Hand Fed Coal Furnace: Clayton 1537G
Coal Size/Type: Nut/Stove Size Mix

Re: Copper water coils - Why not ??

PostBy: franco b On: Thu Aug 30, 2012 6:43 pm

Under those conditions I agree.
franco b
 
Hand Fed Coal Stove: V ermont Castings 2310, Franco Belge 262
Baseburners & Antiques: Glenwood Modern Oak 114
Coal Size/Type: nut and pea

Re: Copper water coils - Why not ??

PostBy: Earnhardt On: Sun Sep 09, 2012 9:40 pm

I have had great success with copper pipe in wood fires; I made a pool heater and burn wood it works great. It is very important to have plenty of flow. I have about 250 feet of 3/4 pipe with soldered 90 degree fittings. I had a problem a couple times because of a lack of flow. I was splitting the return water from the pool filter and the water would actually boil in the pipes and the joints separated. I cleaned the joints and soldered them. Once I had a dedicated pump I had no more problems. The reason I am interested in installing copper in my coal stove is because of the superior heat transfer compared to stainless steel. If one considers the heat inside the firebox as opposed to the outside I think some efficiency could be gained in terms of getting the heat out of the firebox and not going up the chimney or power vent in my case. Once a firebox gets up to temperature the heat doesn't transfer well into the metal because there is less potential or thermal differential. This energy or a great deal of it is likely destined to be lost to the chimney / vent. If the ability exists to introduce cooler material (water in this case) into the fire box, it could provide a mechanism to transfer this heat outside the firebox where it could be utilized.
Earnhardt
 
Stove/Furnace Make: Alaska
Stove/Furnace Model: Stoker

Re: Copper water coils - Why not ??

PostBy: steamup On: Wed Sep 12, 2012 4:41 pm

Lightning wrote:
carlherrnstein wrote:I aggree that a tube in the firebox would heat your water faster but i just cant think of a good reason as to why you would put copper in that type of environment when stainless steel can be had.

See here for a external copper heating coil set up Making a external DHW Coil


My reasoning for using copper is that I was hoping to find a more economical way to make a DHW coil instead of Stainless Steel..



For the "What it's worth" deparatment-

I had a plumber tell me on a job where I specified stainless tubing in lieu of copper, the stainless was cheaper than the copper.

Stainless pipe on the other hand may be a little more expensive but much thicker wall. Personally, I have had some experience with copper in fire box conditions in model steam loco's as water preheaters. With an oil fire, they didn't last very long. With propane, they lasted ok. Temperature, corrosion, pressure, flow are all variable factors.

The additional heat transfer due to the thinner wall of tubing will be insignificant.
steamup
 
Stoker Coal Boiler: Axeman-Anderson AA-130, Keystoker K-6
Hand Fed Coal Boiler: HS Tarm 502 Wood/Coal/Oil
Coal Size/Type: pea, buck, rice

Re: Copper water coils - Why not ??

PostBy: mcrchap On: Mon Sep 17, 2012 12:35 pm

Yes, copper would definitely melt. If you don't want to use stainless, then you would have to use cast iron. Steel would warp and twist eventually.
mcrchap
 
Hot Air Coal Stoker Furnace: Keystoker A 90
Coal Size/Type: rice
Other Heating: New Yorker Oil boiler
Stove/Furnace Make: keystoker
Stove/Furnace Model: Econo

Re: Copper water coils - Why not ??

PostBy: SMITTY On: Mon Sep 17, 2012 12:42 pm

Won't melt with water inside it. It just gets pitted, warped, & corroded from the heat & gasses.
SMITTY
 
Stoker Coal Boiler: Patriot Coal - custom built by Jim Dorsey
Hand Fed Coal Stove: Harman Mark III (not currently in use)
Coal Size/Type: Rice / Blaschak anthracite
Other Heating: Oil fired Burnham boiler

Re: Copper water coils - Why not ??

PostBy: Short Bus On: Mon Sep 17, 2012 8:17 pm

We had an old fashioned coal cook stove, with a copper coil, no sodder just bent tube, worked good, always conected to full water tank, gravity circulation.
Short Bus
 
Stoker Coal Boiler: Kewanee boiler with Anchor stoker
Coal Size/Type: Chestnut / Sub-bituminous C
Other Heating: Propane wall furnace back up only

Re: Copper water coils - Why not ??

PostBy: marsoviy On: Thu Oct 11, 2012 12:04 pm

JJLL wrote:

My question is, why aren't they made out of copper?


I think ,because the water after a copper coil
has an unpleasant smell and tasty and green from copper oxides.
This easily leads to liver tserozu
marsoviy
 

Re: Copper water coils - Why not ??

PostBy: NoSmoke On: Wed Oct 24, 2012 6:50 am

I had two options when it came to deciding if I wanted to go with a coil in my firebox, or on the outside of the stove, and I think it may be interesting to people to see why I chose the latter...going with an outside coil rather then the inside.

As someone else said, it is easier and gives you more square inches in which to capture the radiant heat. As is, in order to protect my walls from excess radiant heat I had to put up a tin heat shield, so my thoughts were, if I am going to put something up to protect my walls, why not install a device to help capture that radiant and heat and put it to good use? As is, I cannot hold my hand on my current heat shield without severly burning my hand...I believe there is plenty of radiant heat available to do what I want.

For me, that good use is plumbing my pre-heated water to my main heater...my propane boiler. Because I have radiant floor heat in a concrete slab, and a state of the art heating system, I only need to run water that is between 75-100 degrees in temperature. This water temperature is controlled by my computer system that monitors the heat I am losing in the floor, the heat returning from my heating zones and the temperature outside. It constantly changes according to how warm or cold it is outside. If the temperature outside goes down, the water must be warmer in order to make up for a concrete slab that is losing more heat; if the temperature goes up, the water flowing through my concrete slab goes down. In this way I have very even heat within my home and my boiler is only heating water a slight amount, thus saving btu's. It is because of this rather low water temperature that I don't want super hot water, I only want warm water, but lots more of it. An external coil will enable me to have that.

So what I want to do is, install a radiant shield with copper coils applied to the front of it, pump the water through a circulator pump hooked in conjunction with my boiler, and routed through a flow control valve, and supply my main propane boiler loop with hot water. After that my boiler system will take over and meter the hot water to my floors as needed.

In this way, I should have greater control over the heat emanating from my stove. My greatest fear is actually getting the water too hot and flashing to steam, this is another reason I chose to go with outside coils because I can more easily adjust the distance between the stove and the coil allowing me to fine tune a heat range.

Will this collected heat be enough to heat my 3200 square foot home? I severely doubt it, but by capturing wasted btu's in the form of errant radiant heat, I should be able to contain it, and pump it to where it is better used (my back bedrooms) and thus give me greater living comfort and spend less on propane.
NoSmoke
 
Hand Fed Coal Boiler: New Yoker WC90
Hand Fed Coal Stove: Vogelzang Pot Bellied Stove
Coal Size/Type: Stove/Nut/Pea Anthracite
Other Heating: Munchkin LP Boiler (Back-up)