"Thermal mass" - Storing heat...

[Billy_Bob]

As I discussed in another thread (topic), I installed my two 50 gallon water heater tanks next to my wood stove...

Well I have discovered something interesting. In the past I would put wood on the fire before going to bed and the living room would be cold in the morning like 60 degrees.

With the two water heater tanks there, it is now around 70 degrees in the morning!

I searched around on the internet to learn more about this. Seems there is a thing called "Thermal mass". This is where a material stores heat, then later releases that heat. Seems water is quite good for this!

So in addition to having my wood stove hot water, I also now have a heat storage unit or "rechargeable heat battery". Evens out the temperature during the night and into the morning...

 

[JackD_ME]

If you look into it more you'll also find the original "thermal mass" was the russian fireplace consisting of a huge mass of rock built around a firebox with chimney sliders. They would burn a screaming hot fire for several hours, reload the fire box then close down the chimney sliders forcing more heat into the rock mass.
A guy I know here in Maine burns his 8 to 10 hours twice a week and keeps his house at 75* all winter.

 

[gink595]

I found that out with putting in a stone floor and walls around my wood stove. I stays warmer in the mornings or when I leave for long peroids of time.

 

[Metals406]

Thermal mass is awesome.

I know a lot of old-timer welders that made their own wood stoves. They would line the outside with remnant pipe, and that would drastically increase their thermal mass, but not the overall area the stove took up. Let's say you have a piece of 3" sch. 40--12" long... It makes a piece of 3/16" steel plate, 9-7/16" wide, and 12" long. A lot of thermal mass, for a piece that only takes up 3.5" of room.

 

[lwalper]

Yeah, that's the principle behind the Hearthstone soapstone stoves. I think they're BTU ratings are a bit exagerated -- probably based on the thermal mass idea -- but mine (a Mansfield) burns well and continues to contribute heat to the room for some time even after the fire dies down. The weather this time of year makes it hard to heat to a comfortable temperature (40s at night, overcast 60s in the daytime) but a hot blazer for a couple of hours heats the stone mass (and about 6 feet of exposed flue), then it's fairly comfy throughtout the rest of the day and evening without getting things too hot.

I've burned this stove for a couple of years now and have really gotten to like it. Heat output is good (nowhere near advertised) and stable, even when there's not a blazing fire -- ran around in my T-shirt all winter.

 

[The Lorax]

I looked at one of these, but it was quite expensive.
I don't need a lot of heat anyway, a 5kw woodburner heats the whole house.

 

[Metals406]

I looked at one of these, but it was quite expensive.
I don't need a lot of heat anyway, a 5kw woodburner heats the whole house.

You burn peat moss though right?

 

[The Lorax]

You burn peat moss though right?

No way! That requires you to either buy it or go and dig it out of a bog and dry it.
NO chance for chainsaw use means no fun.
I only burn wood, mostly pine but some ash as well.
Peat also is poor value for heat vs ash.

 

[Metals406]

No way! That requires you to either buy it or go and dig it out of a bog and dry it.
NO chance for chainsaw use means no fun.
I only burn wood, mostly pine but some ash as well.
Peat also is poor value for heat vs ash.

I've never been to Ireland (Yet), and I've watched a lot of shows about cutting and drying peat for burning... I was under the impression that wood was rather precious there.

 

[The Lorax]

Wood might be precious if you live in Connemara but where I am in the SW there are lots of trees, plenty of forestry as well, mostly Sitka, Lodgepole pines.
The west coast is pretty barren mostly bog and rock, not very attractive for me.
But tourists seem to enjoy it.

 

[Metals406]

Wood might be precious if you live in Connemara but where I am in the SW there are lots of trees, plenty of forestry as well, mostly Sitka, Lodgepole pines.
The west coast is pretty barren mostly bog and rock, not very attractive for me.
But tourists seem to enjoy it.

Lodgepole?? Thats awesome!!! Only a few U.S. states have Lodgepole Pine in abundance... Mine being one of them. Lodgepole is great firewood.

 

[The Lorax]

Yeah, I burn anything I can get my hands on and cut.
As long as it is dry and gives off some heat, it'll do.
I had a friend tell ask me to cut a load of logs that had washed up on their campsite, I cut a good trailerload 8'x5' of wood all types, Alder, pine etc.
I don't really need lots of heat in my house, I have tripleglazed windows and a Heat recovery system so a small input is all thats needed.
If I cook a roast dinner the whole house heats up!
A storm came through and blew down two cypress trees which are pretty lightweight, but split and dried they heat the house just fine.
I am of the opinion that Insulation and reducing heatloss is the key to haveing an efficient home, I also have solar panels for hot water in the summer, they work really well from now to november, If I had an older house I would look at one of those biofires, they were around €6000 euro if I recall.

 

[Metals406]

Yeah, I burn anything I can get my hands on and cut.
As long as it is dry and gives off some heat, it'll do.
I had a friend tell ask me to cut a load of logs that had washed up on their campsite, I cut a good trailerload 8'x5' of wood all types, Alder, pine etc.
I don't really need lots of heat in my house, I have tripleglazed windows and a Heat recovery system so a small input is all thats needed.
If I cook a roast dinner the whole house heats up!
A storm came through and blew down two cypress trees which are pretty lightweight, but split and dried they heat the house just fine.
I am of the opinion that Insulation and reducing heatloss is the key to haveing an efficient home, I also have solar panels for hot water in the summer, they work really well from now to november, If I had an older house I would look at one of those biofires, they were around €6000 euro if I recall.

I build homes... And you're right. Insulation is key to a comfy, easy to heat/cool home. What kind of construction is your place? Brick? Heat recovery systems are also really nice.

 

[The Lorax]

I have a scanhome, they are built offsite, in Sweden.
The construction is 6x2" stud with 10mm masonite racking on the outside, then a 20mm batten and your choice of timber cladding or a fibre cement board called blu-clad.
On the inside there is 150mm of high density rockwool, a vapour barrier and the plasterboard.
I don't really like concrete construction it is kind of cold and hard to get the coldbridging details right.
Saying that it is probably the most common form of house construction at present.
Wood/timberframe is around 30-40% and climbing.
The HRV makes a huge difference to the living environment,fresh dry air is a really nice feeling.
Most of the timber houses that they build here are called timberframe, and are a hybrid of concrete block outer skin and a timberframe inside.
I don't think that the two systems work well together but for some reason they are what is built here.
I think longterm there will be problems with these kind of houses.

 

[Metals406]

I have a scanhome, they are built offsite, in Sweden.
The construction is 6x2" stud with 10mm masonite racking on the outside, then a 20mm batten and your choice of timber cladding or a fibre cement board called blu-clad.
On the inside there is 150mm of high density rockwool, a vapour barrier and the plasterboard.
I don't really like concrete construction it is kind of cold and hard to get the coldbridging details right.
Saying that it is probably the most common form of house construction at present.
Wood/timberframe is around 30-40% and climbing.
The HRV makes a huge difference to the living environment,fresh dry air is a really nice feeling.
Most of the timber houses that they build here are called timberframe, and are a hybrid of concrete block outer skin and a timberframe inside.
I don't think that the two systems work well together but for some reason they are what is built here.
I think longterm there will be problems with these kind of houses.

I see they're modular construction. The Japanese have really nailed down the pre-fab concept... And we're starting to see a lot more here in the U.S. We have SIP, and companies that make everything in a shop, and erect it on site. It's commonly called 'panelized' here.

Another thing I noticed right away, is the simplicity of the exterior elevations, and floor plans. I've built a lot of huge, overcomplicated, monstrosities... Usually the rich trying to show off.

Which package did you pick? The 'passive'?

 

[Wood Scrounge]

I see they're modular construction. The Japanese have really nailed down the pre-fab concept... And we're starting to see a lot more here in the U.S. We have SIP, and companies that make everything in a shop, and erect it on site. It's commonly called 'panelized' here.

Another thing I noticed right away, is the simplicity of the exterior elevations, and floor plans. I've built a lot of huge, overcomplicated, monstrosities... Usually the rich trying to show off.

Which package did you pick? The 'passive'?

My brother IN-law just bought a modular (cape Cod style) that is the tightest house I have ever been in. th little VC stove he had installed heats that thing pretty well. If I am in the market for a new house I will defiantly consider modular.

 

[Metals406]

SIP (Structural Insulated Panel) construction is a good alternative too. Fly it all on the foundy with a crane... Pretty fast, and hi-E efficient.

 

[The Lorax]

Another thing I noticed right away, is the simplicity of the exterior elevations, and floor plans. I've built a lot of huge, overcomplicated, monstrosities... Usually the rich trying to show off.

Which package did you pick? The 'passive'?

The passive was only just starting when we built in 05.
We didn't go for the full passive house, we used a lot of the design elements of a passive house but in a conventional low energy build.
Our gable width is the Baltica, we were not allowed by the planners to build a Nordica, so we fel that the extra insulation on the North side would affect the room size adversely.
Our south side has lots of glass to help with passive solar heating and it is very effective, thats one reason why we didn't go for the biofire as we felt it would be easy to overheat the house.
Plus the other reason is that the part of Ireland we live in has a microclimate that is a lot warmer than the rest of Ireland.
We rarely see frosts and snow is a rarity.
I know the builder quite well, his reasonings regarding simplicity of design is primarily energy efficiency , He calcuates that one poorly constructed bay window will lose more heat than an average scanhome.

 

[Metals406]

That's a real nice lookin' place ya got there!

 

[The Lorax]

That's a real nice lookin' place ya got there!

Thank you.
That pic is a couple of years ago, we had just moved in and were still getting setup, I have some more from more recently but haven't upp'ed em yet.
There wasn't even a flue back then....