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ROI Of my investment for the unit I'm building for myself.

I would like to give the plans and stuff away after I perfect it. Then again a little money to have to live and for other projects plus maybe a little to leave my girls would be nice.

Sadly I will likely give this one away as well as I did the others....... I've built several things that went commercial but others took credit and made the money. One was in the late 80's the other two were mid and late 90's.

Actually only two of those were products the other was more of a method.
 
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So I'm starting to get back on my feet a little again. A little more / better balance would be nice before I actually start trying to work on stuff again. But I did go cruse my junk / scrap piles with a tape measure. This would be for rocket mass heater / TEG version 2.0. I have options in the junk department. 3 unused woodstoves that I saved from the landfill and 5 old heating oil tanks. Plus some 8" schedule 40 or 80 (wall looks to be about 3/8 thick) steel or iron pipe and a few options for a bell. Two of the three stoves have 8" outlets and the third is unknown. I'm most likely to use one of the two 8" units because they are larger. One is brand unknown the other is a double walled with passive air circulation Glacier Bay fireplace insert stove. I'm thinking for a house size build the glacier bay would be the ticket but since this is not going to be but a 1kw cabin / cottage size build. AKA A larger proof of concept. I'm thinking the other 8" outlet one. But before any of that happens I'll finish testing what I have now once I get the rest of the parts and get to it / feeling a little better. No point in going further if this much doesn't work!

Two questions come immediately to mind. First what size bell height & width for an 8" outlet from a batch box? Second how much mass to pull from for 3.5 days minimum? I'll likely be using granite for the mass again. Smaller in size if I can afford it. I have plenty of #57's but this calls for something that will really pack in tight. Not quite dust and maybe not even crush & run but one step up from there I think.

While I will finish the one I'm working on now the rest is simply me thinking out loud wondering if you guys have any thoughts ideas opinions?
 
To further the last post a little more. The idea would be to mate a pipe and bell to an existing woodstove. Then fitting that inside an oil tank or two-three welded together and fill with mass. Then wrap the thing in insulation and run 2) 6" lateral pipes at ground level or just below ground inside the lean-to the stove is in along the walls on both sides where wood will be stacked above it and then to the outside. That way the whole structure becomes a heated mass and insulator for the heat pump / generator. Plus the wood will be dry. lol
 
Biggkidd said:
@Tirediron
Thanks I'll have to check in to it.

Not having a very good day here, so goes life with MS. Not looking like any progress will be made today unless the wind chills out. While it's not all that cold or cold at all to many, I'm freezing, it's 48f with a strong breeze and I just can't get warm even inside where it's 72.
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Sounds a lot like my problem, only my wife has to tell me that it's way to hot as she is reading the thermometer which is one foot below the ceiling and I'm cold and am sitting on the raised stove platform with my back to the stove, just another issue with getting older, being cold all the time and feeling the effects of gravity, all being the downside of being 81.
 
My daughter is bringing me another pack of 80 grit belts later today if the store has them. The rest of the parts are supposed to be in by end of week so I should be able to get back to testing. Provided of course the rain ever stops so I can get back to work on it and cut & split more firewood. When the moisture is way up like this my body reminds me of everything I've done to beat the crap out of it over the years and that's even worse when it's cool / cold and wet. So not really moving right now anyway.....
 
Have the belts in hand to attempt to finish flattening the steel plate. A super surprise came in the early arrival of some of the parts from Amazon. First time in a long time ANYTHING has shown up early!
Since last week when she brought me the first pack of belts they went from $10.99 to $11.99. Looks like things are picking up speed!
Now I just need some decent weather to work in and to feel half decent plus some dry wood nice then testing can resume.
 
Biggkidd said:
Have the belts in hand to attempt to finish flattening the steel plate. A super surprise came in the early arrival of some of the parts from Amazon. First time in a long time ANYTHING has shown up early!
Since last week when she brought me the first pack of belts they went from $10.99 to $11.99. Looks like things are picking up speed!
Now I just need some decent weather to work in and to feel half decent plus some dry wood nice then testing can resume.
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Waiting for the Youtube ;)

Re: the fill

Every transition between aggregate and air is a barrier. Aggregate to aggregate contact can move heat via conduction. Aggregate to air to aggregate requires convection or radiation to transfer heat.

I forget the gravel rating but there is a grade of gravel with a high dust content that can be impacted to near solid.

Ben
 
Neb said:
Waiting for the Youtube ;)

Re: the fill

Every transition between aggregate and air is a barrier. Aggregate to aggregate contact can move heat via conduction. Aggregate to air to aggregate requires convection or radiation to transfer heat.

I forget the gravel rating but there is a grade of gravel with a high dust content that can be impacted to near solid.

Ben
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Crush and run is what we call it here and I wasn't sure if it or tiny washed gravel would transfer better? If you damp it a little and tamp it it's almost as solid as concrete. I've finished a LOT of parking areas this way.

@Neb BONUS POINTS It's also probably the cheapest thing at the quarry! It's easy to work with too. Lots of good reasons to use it.
 
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Biggkidd said:
Crush and run is what we call it here and I wasn't sure if it or tiny washed gravel would transfer better? If you damp it a little and tamp it it's almost as solid as concrete. I've finished a LOT of parking areas this way.

@Neb BONUS POINTS It's also probably the cheapest thing at the quarry! It's easy to work with too. Lots of good reasons to use it.
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Hey @Neb I've been thinking about this and it brings to mind a point and a question. Solid rock is of course more dense than powdered rock which is the point. The question is would crush and run which is really small gravel and a lot of powder / dust or a larger gravel with rock dust packed in the voids be best? It seems to me the larger the rocks / gravel with the most surface to surface contact and dust just packing the voids might be better. It could be vibrated or watered in.
 
Switched out most of the river rock for smaller granite gravel and started a fire. I got the steel plate down to where MOST of the aluminum plate makes contact. Didn't realize I blew out the plate temperature lifters last time I ran it until a few minutes ago. They were designed for 250f not 350-375f , going to have to rethink that one. Anyway on with testing for now. As it is if I can run it up to 375 and let it cool back to 325 it might be alright. This version just needs to last a minimum of 12 hours before dropping back below 325f, not sure I have enough mass for that which is why I was working the lifter angle so I could run the heat up higher.
 
Biggkidd said:
Hey @Neb I've been thinking about this and it brings to mind a point and a question. Solid rock is of course more dense than powdered rock which is the point. The question is would crush and run which is really small gravel and a lot of powder / dust or a larger gravel with rock dust packed in the voids be best? It seems to me the larger the rocks / gravel with the most surface to surface contact and dust just packing the voids might be better. It could be vibrated or watered in.
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There are two material properties that you have to consider.

Specific heat
maxresdefault (1).jpg

And thermal conductivity

Thermal-Conductivity-700x327.png


Specific heat is the amount of heat energy that is required or raise a unit of mass 1 degree. Water is pretty high but not useful for your temperature range. ( energy per pound)

Thermal conductivity describes a materials ability to move heat through a surface area. (Is it a conductor or an insulator?)

Google those properties of the materials you are considering. Find your best balances.

Hope you are having fun.

Still waiting for the Youtube video.

Ben
 
Water under pressure may end up being the best bet. I believe every pound of pressure raises the boiling point about 3f . So water under 50psi would raise the boiling point to just about 362f IIRC...

Back when I was playing with steam I had my boiler up to about 150psi.
 
A little baffled. The mass is up between 100 and 200f but there's a ton of cold condensation or coolant under the insulation on the coolant lines and puddling on the steel plate. The coolant level may be a hair low, maybe a quarter inch across a 5 gallon bucket. But this feels and smells like nothing / water not like antifreeze. Guess I'll have to wait and see...
 
Had to be condensation. I opened up one end and marked the level on the bucket. The bucket hasn't changed and the condensate is gone with the end open. It must have gotten moist. I did notice a darker area when I was changing the rock on top. Plus some of what I put in was damp but I thought I had given it time enough to dry, it looked dry.
 
That's interesting, when the stove is already up 175f or so it will light and draw well enough to burn without the fan. Not burn well mind you but burn none the less. It doesn't burn well even when the fan is on. I screwed the pooch on that one! lol But hey now I know something else that doesn't work. Boy that's a long list! hahahaha
 
Tirediron said:
Wouldn't pressurizing the intake air be more effective than drawing the exhaust air,
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Yeah I had a few little problems with that approach. One the cobbled together firebox isn't exactly airtight, the door doesn't seal. Two the fans just can't take the heat and melt even from a couple feet away in a piece of duct work. It just wasn't intended to be pressurized. Love the learning curve.
 
Biggkidd said:
Yeah I had a few little problems with that approach. One the cobbled together firebox isn't exactly airtight, the door doesn't seal. Two the fans just can't take the heat and melt even from a couple feet away in a piece of duct work. It just wasn't intended to be pressurized. Love the learning curve.
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At least I can say the heat is pretty much all pulled into the mass considering the fan hasn't melted in the exhaust / chimney pipe! AKA a piece of old 6in ductwork pipe.
 
Man this thing takes forever to heat up. Then again it also takes a long time to cool off. Anyway I've had it going several hours again and it's just around 200f. While that's been going on I put the siding on the other side of the lean-to it's under. Then I went and drug out an old damaged panel type 7x8 garage door. Trying to figure if there's some way I can use it to close in the last side. Maybe lock the panels with 2x and hinge it from the top? IDK yet but I have been using up some of the junk around here. lol
 
Not sure if I'm going to make it as tired as I am but my goal for tonight is to get the stove & module plate up around 375f . Considering what a friend told me about these modules that's about as high as I want to take them. If I can get them that high and everything goes okay then, well actually I'm not sure what then. lol I'll either work on the lifter plate modification or go ahead and mount all the modules and try it as is just taking care not to overheat the modules and work more on the lifter mods later once I'm making power...
 
Biggkidd said:
Man this thing takes forever to heat up. Then again it also takes a long time to cool off. Anyway I've had it going several hours again and it's just around 200f. While that's been going on I put the siding on the other side of the lean-to it's under. Then I went and drug out an old damaged panel type 7x8 garage door. Trying to figure if there's some way I can use it to close in the last side. Maybe lock the panels with 2x and hinge it from the top? IDK yet but I have been using up some of the junk around here. lol
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...Well there goes Neb's chance of ever seeing a photo of it :(.
 
5:10am 350f 2 modules in series 7.85 volts 2 amps! I pulled the fan and capped the chimney. I know the temp will rise quite a bit yet but once it hits 375-385f I'll manually lift the plate and toss a couple spacers under it and crash!
 
Based on what you are presenting, I would bet that 5 modules would make a reasonable (18 volt, 35 watts) 12V battery charger, I would add a diode to that circuit so they didn't drain the battery when the heat was off....
 
UrbanHunter said:
Based on what you are presenting, I would bet that 5 modules would make a reasonable (18 volt, 35 watts) 12V battery charger, I would add a diode to that circuit so they didn't drain the battery when the heat was off....
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Going in a slightly different direction. 36 modules in series through a MPPT charge controller for a 48 volt system. Looking for 200 watts nominal in the working range of 300-350f.
 
The temp isn't rising as quickly as I expected, still barely over 350f. 8.08 volts 2.05 amps. I know it's going to go up I just wonder how long it's going to take. The really hot firebox heat soaks up into the mass I've learned but it must take several hours...
 
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