Adding thermal mass?

[MagraAdam]

Hi guys, I've got a free standing slow combustion wood heater in my house. Air is taken in from the room and it has a 6 inch flue and a baffle plate to aid in burning the gasses. It's in a corner of the lounge room and it was designed to not need fire bricks and is made out of 8mm plate. I added fire bricks to the sides and back to direct more heat out the front and too as I didn't need it heating the walls. I was wondering about adding bricks to the sides (just normal solid house bricks) and maybe the back to add thermal mass to it. Maybe even a few bricks thick to make like a table on each side. The theory being that it'll all heat up and keep the house warmer for longer. Kind of like a rocket mass heater, but not quite.

Has anyone had experience doing this or have any reasons why I shouldn't do it?

Thanks heaps,

Adam

 

[Ronaldo]

I sure think it would work. That's basically what a soapstone stove is doing and is designed to do, store heat and release it slowly.

Sent from my SM-G930VL using Tapatalk

 

[MagraAdam]

I sure think it would work. That's basically what a soapstone stove is doing and is designed to do, store heat and release it slowly.

Sent from my SM-G930VL using Tapatalk

Thanks mate, those soapstone heaters look very cool!

I think this is more like what I'm thinking of making, but not the top bit.. just the sides and back..

https://www.heavenlyheat.com.au/

 

[MagraAdam]

Well, I've done this. I'll see how it goes..

 

[MagraAdam]

Well, the fire got extremely hot, pushing a ton of heat out the top plate and flue. I have moved the bricks off the fire box walls by about half an inch and now hot air is convecting in the gap and the bricks are absorbing the heat and I don't think the fire will over heat now..

 

[Ronaldo]

Looks like that should work just fine.


Sent from my SM-G930VL using Tapatalk

 

[sb47]

Yes adding bricks will add thermal mass. The more you add the more it will store. But it comes at a cost of fast heat as it will take much longer to get things up to temp. I found by adding a fan along with bricks will far exceed what a heater will do without the added parts. A few years ago I replaced the fire bricks in my stove and I had enough left over to cover the top with 2 layers of fire brick. The bricks are about 1'' thick. It works great when cooking on the stove and helps to keep me from burning and scorching the pan. It cooks better and heats more evenly. I used paver bricks on the back and sides because they look better and are denser then house bricks.
People have used thermal mass in Earth ships and green houses for ever.
In my shop I keep a bunch of plate steel stacked on and around the stove to catch and hold heat. I've got about 6'' worth of plate steel on the stove and it will hold heat all day long.
It's also a great way to keep excessive heat away from walls and gives a great thermal barrier to protect anything that sits close to the heater.

 

[Piotr Pakula]

Adds heat shields for plastic saw parts

 

[Sandhill Crane]

A consideration is what's under the floor to support the weight.

 

[MagraAdam]

A consideration is what's under the floor to support the weight.

Yep, I'm aware of this. Thanks though.

 

[MagraAdam]

Adds heat shields for plastic saw parts

I don't understand how this fits here?

 

[Piotr Pakula]

This is the humorous element

 

[tomalophicon]

I built a big black hearth out of slate with mine and that mofo gets extremely hot. When the fire is dying the kids all lie down on the hearth to suck up the last of the heat.
You could lay more bricks out below the firebox too.
Cheers,
Tom.

 

[Ted Jenkins]

Yes adding bricks will add thermal mass. The more you add the more it will store. But it comes at a cost of fast heat as it will take much longer to get things up to temp. I found by adding a fan along with bricks will far exceed what a heater will do without the added parts. A few years ago I replaced the fire bricks in my stove and I had enough left over to cover the top with 2 layers of fire brick. The bricks are about 1'' thick. It works great when cooking on the stove and helps to keep me from burning and scorching the pan. It cooks better and heats more evenly. I used paver bricks on the back and sides because they look better and are denser then house bricks.
People have used thermal mass in Earth ships and green houses for ever.
In my shop I keep a bunch of plate steel stacked on and around the stove to catch and hold heat. I've got about 6'' worth of plate steel on the stove and it will hold heat all day long.
It's also a great way to keep excessive heat away from walls and gives a great thermal barrier to protect anything that sits close to the heater.

Yes I concur. When I first built my house I had a standard subfloor which made the house pretty controllable as far as heating was concerned. Start the fire maybe run the fan for a few hours and the inside temps jumped up to 70 F. Then I added close to a 1000 SF of ceramic tile. It now takes close to a 24 hour day to bring temperature up to comfortable. However it also takes about 48 hours to get down to 50 F. So yes the more mass the the more buffering one will see. Thanks

 

[Del_]

All through the eighties and half way through the nineties until I moved I used a cast iron radiator turned upside down beside my wood stove to heat domestic hot water using a totally passive system. Worked out great. I also had a one gallon stainless steel tank inside the wood stove. Multiple radiators could probably do it without the internal tank. 3/4" copper for the plumbing with pressure relief and an air bleeding device. Thermosiphoning works great and automatically comes to a stop as the radiator cools preventing DHW heat loss.

 

[Ted Jenkins]

All through the eighties and half way through the nineties until I moved I used a cast iron radiator turned upside down beside my wood stove to heat domestic hot water using a totally passive system. Worked out great. I also had a one gallon stainless steel tank inside the wood stove. Multiple radiators could probably do it without the internal tank. 3/4" copper for the plumbing with pressure relief and an air bleeding device. Thermosiphoning works great and automatically comes to a stop as the radiator cools preventing DHW heat loss.

If some one could store a 1000 gallons or more of heated water which would have to be insulated they could regulate their home for quite some time. A problem for people that live in the colder climates is antifreeze if the system was not running. Copper pipe would have very little corrosion. Thanks

 

[cumminstinkerer]

If some one could store a 1000 gallons or more of heated water which would have to be insulated they could regulate their home for quite some time. A problem for people that live in the colder climates is antifreeze if the system was not running. Copper pipe would have very little corrosion. Thanks

I have 1500 gallons of storage on a boiler, here in central Iowa in the coldest times I have a fire for 4ish hours a night then run off the storage until the next night, this heats my crappy insulated house and domestic hot water.

 

[muddstopper]

If some one could store a 1000 gallons or more of heated water which would have to be insulated they could regulate their home for quite some time. A problem for people that live in the colder climates is antifreeze if the system was not running. Copper pipe would have very little corrosion. Thanks

If you have 1000 gal or more of water storage, you are crazy to not include some sort of solar heater.

 

[Gobtool02]

Your fire is probably burning more efficiently and hotter now. I had a homemade wood stove that I later built a plenum around it and a gravity feed system to get the heat upstairs, 1 10-in return and 1 10 in duct to upstairs. The sheet metal plenum held more heat in the stove, I didn't have fire brick except in the bottom, warped the back and eventually developed a crack with a hole I could stick my fingers through about a foot long. Mine I believe was out of 7/32 steel. You may want to put some fire brick inside at the back, they make some thin ones if you can figure out how to keep them in place. Just a thought I'm sure it's hotter in there now than it was.

 

[Gobtool02]

Make sure it's not turning red at the back probably in the middle a third to half the way up. 1300 f and up will burn the carbon out of the steel and cause it to degrade and crack.