Heat storing in wood stove

[upny]

   Hi all

We have an old wood stove in the kitchen. It´s in use a lot but we rarely use the oven for making food.  My idea was to fill the oven with tile bricks or something to store some heat. Is there something better than tile bricks for this? Since the stove is old, close to antique i don´t want to do something that can´t be undone later.

Happy new year!

Upny

[whatsnext]

steel plate if the stove can handle the weight.

John......

[skravlinge]

It depends on how hot it will be. If it is real hot it must be something stands the heat without  changing in a way it is not restored going cold. A cheap stuff will be sand.

[Ungrounded Lightning Rod]

I understand soapstone is the classic thing to put in a stove to hold heat for a while after the fire is out.  Some stoves and fireplaces are built with chunks of it for just that purpose.

[Chagrin]

Water has a higher heat capacity than stone (sand, cement, soapstone, whatever) by a factor of 5.

[wooferhound]

if you use water

watch out for those explosions

[LEXX]

If you were to use some of those porcelan bricks that you can get for barbecues it would be a good combination of durability, safety, and efficiency.  The only problem i can see is that when you fire up the stove the heat won't come quite as quickly but you'll probably not even notice the difference.

LEXX

[jimjjnn]

Fire brick would be much better. The are very dense thus holding a great deal of heat. They also dont crack very easilt like tiles or bricks woud doe to expansion and contration. Just open the ovn door when fire is low or out and you should get lots of heat. A small fan could move the heat around the room. You could also open the oven while fire brick is warming up thus getting heat at a more gradual rate and then may not need a fan at all.

[nothing to lose]

If you got the money, old pennies!

Kinda silly in post in away, but sort of serious too.

I figure scrap copper would suck up heat well, hold it till the stove starts cooling off, then release the heat fast also as needed. Aluminum or copper either one may work well. I am thinking as an oven it would not be exposed to direct flames or laying in the hot coals. Either will heat faster than sand or bricks, get hotter than water, and release the heat back to the stove or room when the fire goes out.

Actually not sure of any reason they would not work well. So if you have alot of scrap aluminum or copper laying around I would give it a try. I have the scrap, but all my wood burners would exposed it to the flame and coals and I figure that would eat it away fast or I would try it here.

[upny]

Hej

jimjjnn suggested fire brick.

After some digging in the back of my head i remembered having some fire brick deep back in my old shed. So after some digging in the shed i found just enough fire brick to fill the oven. After some packing and turning of bricks the oven is now filled. While writing this the bricks are heating up for the first time. Haven´t got time for any scientific measuring at the moment but i will report later.

Thank You all for good ideas.

Ulf

[jimjjnn]

Most metals especially aluminum and copper will give off heat rapidly and may not hold enough heat because of their density. Water is great but as stated, you risk steam explosion. very bad.

Iron is good as it absorbs slower and gives up heat slower. Weight might be a problem. All dense ceramics are close to iron. Take a regular brick and a firebrick in one hand and feel the difference.aaaaaaaaaaafirebrick may be like iron weightwise as it is heavy.

[jimjjnn]

The reason I remembered the firebrick was because as a kid I had to help reline 2 two story steam boilers for 2 steam double acting steam engines. At that time we had no labor laws Per Se.

It took us 2 weeks for one boiler. I noticed that the firebricks were syill hot after the boiler was sut down for two weeks. Your idea brought back the memory. Hard work as we were kids of 10-15 yrs old at the timeThose firebricks ain't light weight either. As I recall about 12-15 lbs each. Working inside a hot boiler is no fun.

[nothing to lose]

Yep fire brick is good.

I was thinking more of this being a cook stove where you would want the mass heated fast in a limited time, 30-60 minutes of cooking, then get that extra heat back out before the next meal is cooked for another 60-90 minutes or whatever. More of a fast heat, fast cool setup to even the temps in the room between meals. Also I figured the cast iron stove being hot to begin with will only cool at a set rate, enternal mass like copper should not cool faster than the surrounding cast iron. Well, provided it does not have a draft of cold air flowing over it

I am thinking of heating something in a wood burner I mentioned earlier I think, that I can carry upstairs in a rock house to hold/move heat. Not sure what I could use for that. Thinking again on the aluminum scrap, heat it fast and hot at the fire then sit it in a tank of water upstairs to heat the water which will slowly release heat over night. Maybe about a 20lb hot block would heat the water pretty well in 2 trips?

I'll use a heat exchanger and water tanks downstairs probably, but can't upstairs since I won't be able to run the pipes

Something that gets real hot, is light to carry, won't spill, and will heat the water fast that I store upstairs is what I'll need for this. Water will be solar heated durring the day, so I mostly need to top it off at night before bed with extra heat to last till 6am.

[upny]

  First test results:

After fireing up the stove to make some food and warm the house a bit yesterday I kept the fire for about four hours. After the fire was compleatly burned out i opened the oven a little and good heat came out for about an hour. This is more or less what i expected and this is good enough considering the oven only has a volume of about 30 Litres

Greetings

Upny

 

[jimjjnn]

I forgot one thing with the fire brick.

They should have a little air space between each brick so that heat can be absorbed more fully into the brick. Not a large space, but 1/4 inch or more. Cross stacking the brck will help support the whole stack.