Heat Sink

[fubar2]

Ive had an idea rattleing around my small brain for some time now. I have a Clayton add on furnace plumbed into my fuel oil furnace and got an idea to lay up block walls and a top over the add on. Then fill the space around it with rubble and stone to use as a heat sink or saver. Is this a good idea or no? I cant think of many negatives can you?

 

[laynes69]

I wouldn't do it. You need that heat to go through the ducts, not around the unit. Plus, The unit will put out some radiant heat as it sits.

 

[Geez]

What he is describing is a HAHSA (Heat And Heat Storarage Area. ) Generally speaking, a woodburner is surrounded on all sides by large rock, rubble, or broken concrete blocks. Supply and return ducting is passed through the block walls and the air is drawn through the rock where it picks up the heat stored in the stone.
The advantage is supposed to be that as the wood is burned, the rock stores the heat, much as the water in an OWB does. It's also supposed to distribute a more even heat.

 

[laynes69]

Yeah a stone mass of heat, like a masonary heater. But if it was a gravity stove I would say try it. Its forced air for a reason. If it was a little woodstove, it would be different.

 

[Geez]

Yeah a stone mass of heat, like a masonary heater. But if it was a gravity stove I would say try it. Its forced air for a reason. If it was a little woodstove, it would be different.

A HAHSA is still forced air. It's just that the air is forced though the air spaces of the rock storage area during it's circuit, where it picks up more heat from the rock.
Think of it like this, the rock is really just an extension of the metal shell of the woodstove. When the house is not calling for heat, the fire still burns, and the rock is still being heated.
The units I've seen have been very effective.
I don't know exactly what a Clayton add on furnace is or if a HAHSA would work with it. I'm just stating that the OP is describing a HAHSA and I'm attempting to explain what one is.

 

[cityevader]

What I'm picturing is you're trying to capture radiant heat that would otherwise not be going through exchanger/ducting anyway, correct?

If so, go for it!

 

[fubar2]

What I'm picturing is you're trying to capture radiant heat that would otherwise not be going through exchanger/ducting anyway, correct?

If so, go for it!

Pretty much so yes. My main goal is to stretch the length of time of produced heat between stove loadings. Save a bit of it for later in a way. It would be like a HASHA more or less.

 

[fubar2]

I wouldn't do it. You need that heat to go through the ducts, not around the unit. Plus, The unit will put out some radiant heat as it sits.

There is a twelve inch duct in the top of the Clayton and it is forced air drawn in the front of the stove and out through the duct. The duct is tied into my oil furnace plenum. Actually forced air would have nothing to do with what Im thinking of.

 

[lobsta1]

Back in the 1970s, I installed a wood fired boiler in my basement. Had a smiliar idea. I made up a pipe loop about 10 rungs high on the side going into the boiler. Then I built a brick enclosure around it & filled it with sand. Worked great to preheat the water, BUT it turned out to be a stupid idea. It held in so much heat that the side of the stove severely buckled.
Al

 

[fubar2]

Back in the 1970s, I installed a wood fired boiler in my basement. Had a smiliar idea. I made up a pipe loop about 10 rungs high on the side going into the boiler. Then I built a brick enclosure around it & filled it with sand. Worked great to preheat the water, BUT it turned out to be a stupid idea. It held in so much heat that the side of the stove severely buckled.
Al

Hmmm theres one I didnt think of. Mabe it aint such a good idea after all.

 

[Geez]

That's one reason a HAHSA is usually designed with large rock (hence large air spaces too) and pulls the air through the air spaces. Sand would simply sit and get hotter and hotter.

 

[woodbooga]

off topic but I had to share.

We have a heat sink. It has four legs, black curly hair, and answers to the name Monty.

Our little cocker spaniel loves to conk out next to the stove and I swear he soaks up a good chunk of the btus. I've thought that as part of our heating strategy we should chase him around the other living areas where we spend the most time to ensure that the heat is disbursed better.

 

[fubar2]

off topic but I had to share.

We have a heat sink. It has four legs, black curly hair, and answers to the name Monty.

Our little cocker spaniel loves to conk out next to the stove and I swear he soaks up a good chunk of the btus. I've thought that as part of our heating strategy we should chase him around the other living areas where we spend the most time to ensure that the heat is disbursed better.

Get an electronic collar with a remote controll. Whenever you feel chilled give him a zzzzzzzzttttttt and you wont even have to leave your chair.