Question from a friend

[rjdudley]

Matt a friend of mine has three questions for you:
1) Regarding your NY restaurant build: Did you have to get permitting from the city? How hard was it? And if E & E Wisner have built 700+ heaters did they get permits (that you're aware of) for any of those?
2) He has access to A LOT of soapstone dust. What are you thoughts about mixing it into the cob mass? How would it affect the ratios? Is it even a good idea?
3) An interesting twist of use for the RMH: What if someone painted black the piece(s) of exhaust tube that is outside of the house (causing it to attract heat in the summer) and buried another tube into the ground where it's cooler. Then hooked the cooler pipe into the RMH allowing cooler gases in the summer to flow into the bench thus creating a huge cool mass. Oh, the things people think of. Idle minds are …
Ray

[hpmer]

I think mixing the stone dust into the mix for the bench is a great idea. Not so much for the feed tube through the heat riser, obviously. Many people use rocks and other dense objects in the bench for a few reasons. First, they store more heat than cob, and second they take up big chunks of space which means less need for cob (and the work that goes into making it).

Your dust will help with the first objective and depending on how much he has access to might also help with the second.

[4seasons]

I have no ideas on the permit issues but I love the other two ideas.
Soapstone is regarded as one of the best thermal batteries available so if you can't build a bell from soapstone I would think adding the dust to cob would be a very good idea. Having never worked with soapstone myself I am only guessing but I would think that you could add it to your cob as a substitute for sand and get some good results. May want to try it as a small scale experiment first before anyone puts lots of time and materials on the line though.

I am very curious if someone may have tried to use cool underground air to cool their house before. I know that storm cellars and root cellars stay cool all summer long so the idea seems sound. The problem that I can see is more a matter of size, flow, and temperature difference. The underground temperature can very depending on several factors but let's use a 58F temp as an example. If you were trying to cool a house from 82F you would need the same amount of air as in the house to cool to 70F using basic averaging. Your AC unit can cool by recycling the same air back thru after it has been cooled to further cool the air but it is also running much cooler temperatures at the coils. Another way to look at this is the fact that in a RMH you are producing temperatures from the fire above 1000F. You then store the heat to raise your house temps to 70F. That is a temperature difference of 1428% vs trying to cool with an 82% change in temperature. I am not sure I am explaining this very well but hopefully you understand the difference in scale that I am trying to convey. In other words a RMH works because it is so much hotter in a small space than the large space you are trying to heat. Underground air is only slightly cooler than your house so it would take a much larger volume of air to work. I think it would work but unless you have a large cave system or underground silo to tap into my math just doesn't seem like it would be worth the effort.

[rjdudley]

Thanks hpmer and 4seasons! Great answers and I do understand your math 4seasons. It makes sense. The scale does seem to be the answer.
Well, he may just work on the soapstone idea and leave the "cooler" idea alone unless someone else has better physics to bolster the idea.
As for the permits issue, it seems that with more and more heaters being built (along with the ones already built by E&E, Ianto, etc) that either everyone is flying under the radar or perhaps these are becoming more accepted by "the man". There has to over 1000 built by now. I haven't heard of any liability issues. How do E&E, Paul Wheaton, etc get around any liability issues? Waivers? Small print saying they're not liable?
Curious.

[mannytheseacow]

Start here, Ray:

It's an interesting question that you raise. I'm guessing there are thousands under the radar.

Not that I have one or know anything about them ( ) but a "friend" in a similar position heated his home with wood and still is heating his home with wood. For insurance reasons, nothing ever really changed. You could just tell the insurance company that you put a wood burner in, play dumb (uh, I don't know) and leave it at that.

I've been curious about the NY installation too.

[hpmer]

One difference on the cooling vs. heating issue is that the stove is only burned a few hours per day, whereas the cooling system would be 24/7 (I'm assuming it would work in reverse at night) so there would be maybe ten times the air flow (say 24 hours vs. 2 hours).

May not be exactly as efficient, but I bet it would work pretty well. And not much expense or effort to try it and see.

If the bench were built as a bell, he might want to build it so he can raise the exit pipe in the summer so it's the hottest of the gases that exit, which of course is opposite to what you want in the heating season.

Might be some condensation issues to deal with much like cool glass of water "sweats" in a warm room, but an interesting question to be sure.

[matt walker]

Ray, the NYC build was outdoor, so we looked at it like a fire pit. As for installing a RMH in a home, there are a few regulatory agencies to consider in any install. Local building codes, state solid fuel device regulation, etc. Local codes are one thing, state regs are another. Depending on how you classify your heater and where you live, you might be able to pass both or none. My money is on none. As for someone getting one to "meet code", I have serious doubts that there are any legal installs in Oregon, and I know for a fact that there are none in Washington. Meeting local code is only a small part of the process, the bigger one is state regs. Here's an interesting excerpt from Oregon law:

http://www.oregonlaws.org/ors/468A.465

I've been a long way down this road in the last year, and while there is a clear path to getting through this maze, it's going to take a mountain of money to get there.

Now, all that said, there are some states where "masonry heaters" are exempt from a whole lot of the regulations, so in some places it's entirely possible to have a legal install right now, I believe.

I love the soapstone idea! I wish I had access to that stuff, I bet it will work great.

Passive cooling with Earth Tubes is nothing new, and is done all the time in buried homes and even in modern passive house design, as far as I know. If you search around, you'll find all sorts of resources for ideas. Most involve long, buried runs of plastic drain pipe plumbed to cool, shady locations on end and inside the home or the home's mass on the other, with careful attention to slope and elevation, among other things. Lots of details out there, but yeah, I think it would work great. I have zero cooling needs here so it's not something I've put much thought into, but yeah, it seems fun!

http://www.campmackinaw.com/earth_tube_ ... eating.htm

[rjdudley]

As usual a wealth of info. Interesting Oregon info Matt. These state regs could be back breakers. Just listened to Sneaky Heat dvd from Paul Wheaton and he and E&E estimate that 100k RMHs have been built. And I think he said that was LAST year. Momentum is gaining.

[mannytheseacow]

[pa_friendly_guy]

The Insurance requirements were all about clearances to a combustible wall, floor or ceiling. There was no requirement on smoke or pollution from the Companies and no real requirement to meet code, other than the safe clearances to combustible walls etc. They are worried about the house burning down from a poorly installed wood stove, they just don't want to have a claim from your being stupid. They want 18" clearance in front of the door where the stove is loaded so that sparks cant fly out and hit combustible floors, 3' from combustible walls so there is no chance of them over heating and , I think it was 18" clearance from the chimney pipe to the ceiling, but I am not sure any more. The stove should be on a non-combustible floor, or mounted on brick, tile, stone etc. Their requirements make sense from a fire safety point of view, nothing close to the wood stove, so nothing can over heat and catch fire. In an installation like Matt's you see that he has non-combustible brick under the stove , non-combustible brick on the walls behind the stove and he enters an approved chimney through a non-combustible thimble. I don't know how much clearance he has in front of the stove where he feeds in the wood, but if he has at least 18" of non-combustibles on the floor then I would approve his installation if I inspected his home. If he does not have 18" in front they sell non-combustible rugs that are approved and give you the needed clearance.