Rocket Stoves and all things pertaining there to!

Dirtdevil
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Re: Rocket Stoves and all things pertaining there to!

Unread post by Dirtdevil » Fri May 10, 2019 8:17 am

Well, I need to get started building this heater. It is going in a greenhouse with a large aquaponic fishtank. The thing that concerns me is that the ducting for the heat sink will have to be directly below the 500 gallon tank and I'm thinking that the tank and water will suck so much heat out of the ducting as it leaves the heater that it will effect the draw on the combustion gasses. Not only does the ducting run under the tank when it leaves the heater but it also comes back under the tank before it is vented outside. What are your thoughts on this. I would like to use the heat beneath the tank to help warm the water but could also install rigid foam over the top of the ducting before I poured the bottom of the fish tank on top of it. If all else fails I would consider installing a fan in the exhaust stack. Have you seen anything on line that addressed these concerns?

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Farmfresh
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Re: Rocket Stoves and all things pertaining there to!

Unread post by Farmfresh » Fri May 10, 2019 9:12 am

OOOOOh.... Aquaponics too?! We need another thread. I have always wanted to do something in that area.
Matthew 19:26 Jesus looked at them and said, "With man this is impossible, but with God all things are possible."
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Dirtdevil
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Re: Rocket Stoves and all things pertaining there to!

Unread post by Dirtdevil » Fri Jun 28, 2019 7:40 am

Well I have started building the Rocket mass Heater for my greenhouse. I have to wait for a little cash to get more components to continue. I signed up for a forum that deals with such things. http://donkey32.proboards.com/ You can read the posts without signing up but can't ask questions.
This information would probably only matter to ICU but the consensus of the builders there is that the best way to build a heat riser is by lining a piece of metal duct or some metal tube with ceramic fiber blanket. Quick, easy and cost effective.
https://www.ebay.com/bhp/ceramic-fiber-insulation

It also seems that the preference for new heaters is a batch box design

http://www.batchrocket.eu/en/

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Icu4dzs
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Re: Rocket Stoves and all things pertaining there to!

Unread post by Icu4dzs » Mon Jul 01, 2019 4:15 pm

I agree. The research that has been done clearly identifies these changes as beneficial. In days gone by, everyone (especially Satamax) always said, "Metal is doomed" but then after discovering the ceramic blanket, that appears to have changed. As for the batch style, I have the materials but have not built one for several reasons the most important of which is location, location, location.
That is a really good forum for the subject. You will find several very good folks there eg. Peter Berg, Matt Walker for starters. If you study their methods you will be very satisfied.

Of note is the "P" channel devised by (of course) Peter Berg. It seems to improve the burn at the combustion chamber.

Keep working on it. I think you will be very happy with the results.
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Dirtdevil
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Re: Rocket Stoves and all things pertaining there to!

Unread post by Dirtdevil » Tue Sep 03, 2019 8:03 am

It was my understanding that that two inch gap between the top of the bell and the top of the heat riser was crucial as well but I posed the question on the Donkey site. One of the experts there said that it was all right to increase that gap to lessen the effect of the heat on that particular spot in the bell. I'm probably going to maintain that 2 inch gap but I'm going to cut down another barrel lid and bolt it underneath the top of the barrel as a sacrificial lid.

http://donkey32.proboards.com/thread/35 ... -drum-bell

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Icu4dzs
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Re: Rocket Stoves and all things pertaining there to!

Unread post by Icu4dzs » Tue Sep 03, 2019 3:59 pm

Why not just add a layer of ceramic fiber cloth to the top of the bell on the inside to mitigate the extreme heat coming up the heat riser? That would be much easier than adding another barrel and it would prevent having to rebuild it after any length of time? I noticed that Peter Berg said to increase the space from 2" to more than that.
I imagine that the ceramic fiber cloth and a bit more space will both take care of the problem but the ceramic fiber has to be INSIDE the top, not out on top of the bell...
Just my $0.02
Your believing it is not required for it to be true. TMM
I'd rather have it and not need it, than need it and NOT have it!
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Dirtdevil
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Re: Rocket Stoves and all things pertaining there to!

Unread post by Dirtdevil » Tue Sep 03, 2019 5:07 pm

Well I posted the question expecting folks who had been using them for a number of years to respond with their experience. Except for the guy with the stainless steel bell no one did. The idea about the ceramic fiber sounds right. I'm going to buy a roll to make the heat riser out of anyway.

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Icu4dzs
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Re: Rocket Stoves and all things pertaining there to!

Unread post by Icu4dzs » Tue Sep 03, 2019 6:53 pm

Yep, that’s how I’d approach it. I should have put that suggestion on that forum.
Your believing it is not required for it to be true. TMM
I'd rather have it and not need it, than need it and NOT have it!
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Dirtdevil
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Re: Rocket Stoves and all things pertaining there to!

Unread post by Dirtdevil » Sun Jan 12, 2020 7:45 am

The Rocket Mass Heater in my greenhouse has been done for a few weeks. It has had it's problems. It is a six inch system with thirty lineal feet of horizontal duct in a two foot by seventeen by eighteen inch high bed filled with cob and capped by three inches of concrete. After getting the bed finished I let it sit and didn't get the heat riser and bell finished until just before Christmas. In the mean time it got real cold here and the cob in the bed froze. The heater would not draw because it the hot air could not push through the length of the frigid bed. It created what they call a cold dam. I bought a six inch duct fan and attached it to the top of the flue. With that running the system works very well and temps on the surface of the bell exceed 500 degrees F. Still it has taken hours of run time to even get the bed up to forty degrees closest to where the ductwork starts. It will now run with out the fan, but not well. I'm sure it will take many more hours of run time before this system starts to preform as intended, to heat the greenhouse and allow for year round growing.

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Farmfresh
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Re: Rocket Stoves and all things pertaining there to!

Unread post by Farmfresh » Sun Jan 12, 2020 8:39 am

So does this mean in the future that you will have to get the fires going BEFORE things freeze? How cold can the system get before you have the cold dam problem again?
Matthew 19:26 Jesus looked at them and said, "With man this is impossible, but with God all things are possible."
"Stop Dreaming About the Good Life and Start Living IT !"
Every little bit ... is a little bit.

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