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Post by swoprofessor on Mar 12, 2012 0:13:39 GMT -8
Has anyone tried salts as a heat storage - its the most recent thing with solar heat storage and some are up to 50 to 80 times the heat storage of water per volumne
would be interested in any results
Jim
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Post by Dan (Upstate NY, USA) on Mar 12, 2012 3:57:18 GMT -8
I never heard of this, dry salts or salts in solution?
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Deleted
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Post by Deleted on Mar 12, 2012 5:30:33 GMT -8
I think he means molten salt, which has indeed a very high heat storage capacity. The problem: It may never become cold enough to become a solid.
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Post by Rinchen on Mar 12, 2012 6:07:07 GMT -8
It is indeed used for solar systems, but only for concentrated solar. The salt mixture needs about 626F to fully melt which can only be reached right at the top/middle of the barrel. After that you still need a way to dissipate this heat into the place where you want it. In concentrated solar they use it to generate steam and drive a steam turbine. Seems to give more problems then it solves... Personally I like the simplicity of a RMH. If you want to store more heat in a lower mass, perhaps you could build a water storage, since water stores more heat than rock per Kg. Of course you also need to take into account not just the storage, but also the heat power delivered to the room which depends on temperature difference within your heat storage, distance of heat to travel and the surface area that does the radiating.
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Post by Donkey on Mar 12, 2012 7:57:39 GMT -8
To my knowledge, salts have not been tried. It's a complicated solution that (in analysis) presents more problems than it solves. Water storage HAS been tried with various results. Seems to me that water storage suffers the same, more problems than solutions.
Solids as storage (rock, brick, sand, concrete, cob) is simple, effective and safe. Neither of the above solutions tend to accomplish all three. Not to say it isn't possible, just hasn't been done satisfactorily yet.
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Post by swoprofessor on Mar 12, 2012 9:39:02 GMT -8
I was reseaching evacuated solar tubes for hot water / heat complimentary. I found Rocket stoves by accident following a 'that looks interesting' link. I believe overall the Rocket Stove is a better answer. I always avoided wood do to several factors all of which the Rocket stove concept seems to eliminates them.
You may be correct as to the salt having 'more problems than it solves' . I read some people were trying to make a rocket stove 'sans cob bench'. The ability of molten salt to store heat in a smaller area was already on my mind and seems to be a posible answer to the 'sans bench'. I agree with Donkey that the best thing about the current design is the simplicity. Its like the benefits of a rocket with the simplicity of a hammer. Anyone can follow directions and build one. Well almost anyone :-D
as to Karl and Richen - your comments are also accurate however recently there have been some molten salts combined that lowers the melt / freeze temp to 133C. Would this change your view any?
I was looking at it in two ways - one no different than the cob bench - no distribution at all - just a smaller heat storage and thus no bench. In some phase change heat storage ideas they dont even try to move the heat. It is a harvest / store / release in place concept. Some PCMs melt/ freeze point is about 70-90F so the winter sun heat is absorbed and then released at night - but these would not put up with the higher heat of a RMH but the concept of store / release is similar.
I do have a large house OLD house built around civil war time (1850-1880) I have found hand poured nails while doing remodeling - kinda cool - I know a RMH can produce enough heat but as I understand it it is radiant heat and I not sure it can heat all 3 floors from one RMH in my basement. So moving some heat is a minor concern. Just brainstorming. Thanks for the comments
Jim
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Post by Donkey on Mar 12, 2012 19:17:58 GMT -8
Hmm.. 133C does change the equation somewhat.. Still, there's some head-scratching, hair tugging and elbow grease involved to make that one work. For small footprint solutions, have you explored the bell stove concept? Dunno how that would entirely heat yer old house, but bell stoves are VERY versatile. Definitely worth a look.
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Post by Rinchen on Mar 13, 2012 0:37:28 GMT -8
I would agree with Donkey on the bell concept. You would be able to construct three small bell's, one on each floor. To be honest, with the experience I have gained from building my RMH, I would now build a bell heat exchanger instead and put one bell on the 2nd floor. With my current RMH I am doing the same "head-scratching, hair tugging" to come up with ways of getting more heat upstairs. It does get there through the floors though, just not enough of it ;-)
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Post by Deleted on Mar 13, 2012 2:53:38 GMT -8
133C changes a lot, but still it has to stay allways liquid for smooth operating.
In the house of my grandparents rooms on two floors were heatet from a single fireplace by air chanells moving hot air to the rooms. Germany can be very cold in the winter, sometimes below -20°C and even then the rooms were comfortable warm. The air was heatet by convection from a huge mass of cast iron. This should work with an other kind of mass in the same way. I think a third floor would have been possible too.
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JBW
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Post by JBW on Mar 13, 2012 14:46:02 GMT -8
I do have a large house OLD house built around civil war time (1850-1880) I have found hand poured nails while doing remodeling - kinda cool - I know a RMH can produce enough heat but as I understand it it is radiant heat and I not sure it can heat all 3 floors from one RMH in my basement. So moving some heat is a minor concern. Just brainstorming. Thanks for the comments Jim Jim, I remember a visit to Shirley Plantation a few years ago. They had original (early 1700's) brass floor registers for the passing of air to the upper stories. It was heated in the basement by the massive fireplace and I was told it worked pretty well for the time. The registers were round with spiral spokes that would cover or expose the matching holes in the secondary plate. This might be a "period correct" way to move the heat upstairs in your house. Joel www.shirleyplantation.com
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Post by Rinchen on Mar 14, 2012 0:17:47 GMT -8
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