Rocket mass heater

[Bennyweed1]

So I discovered when looking into solar furnaces.

Anyone ever use one?

I am thinking of creating a outdoor mass heater and using it to boil water which I'll store in a 250 gallon insulated reservoir.

I have all these old hydronic wall radiators i removed from the walls of my house when I converted to forced air. Kinda regretting it, high efficiency or not, i feel like a sucka dependent on the monopolized utility man.

I want to generate some hydronic heat again and try to reduce my stupid high gas bill. I have abundant wood and fuel sources around my which are pretty regular and sustainable.

Rocket mass heaters are supposedly ultra efficient in their simply design and emit virtually no exhaust aside from co2 And steam.

Anyone familiar?

 

[stoned-trout]

yes I have ...gassifier setups kick ass too.. also converting to hydronic heating kicks ass ..but startup costs are a bit high initially..heres my old one ..it heated house,water and floors,greenhouses and fishpond...yeehaw

 

[Wayzer]

Nice stonedTrout!

I also looked into these recently.
lots of good how to videos on utube
curious to see what others may have to say on this aswell

 

[Bennyweed1]

I decided to place the thing outside because there are no code issues doing it that way.

So the heater will be outside and the tank will be inside and insulated where it will store the heat. Ill have to play around with where I want to put the heat exchanger in the rocket mass because I read in the main burn tube, temps can reach 1200 degrees F, which is also the reason it emits virtually not exhaust.

Everything is burnt up by intense heat similar to how a catalytic converter works on a car.

Its stupid fascinating in my head being that I can run cheap ass experiments until I find a method that works and then buy some good build materials.

I dont know the mathematics involved in figuring out how many BTUs ill need to heat 250 gallons of water up to 180 degrees.

 

[Wayzer]

from some site.
seems like that should def give u an idea

"Incoming potable water temperature is assumed to be 50°F (10°C). For most uses, the water heater temperature setting is 120°F (49°C), but can be as high as 140°F (60°C). For an end use such as a shower, a typical temperature of 105°F (41°C) is achieved with a combination of hot and cold water. To determine how much of a temperature rise is needed, subtract the incoming water temperature from the desired output temperature. Note that this same methodology can be applied to process water requirements for commercial or industrial applications.
Calculating BTU Requirements

A BTU is defined as the amount of heat required to raise the temperature of one pound of water one degree Fahrenheit. Since a gallon of water weighs 8.34 pounds, the gallon per minute flow rate can be converted to pounds for the specified time use, and then converted back to BTU. As an example, the BTU use of a 15-minute shower with a 2.5 GPM showerhead can be calculated as follows:

The amount of heat required = Water Volume (lb) x Temperature rise (°F) x 1 Btu/lb°F

Water Volume (lb) = 2.5 gal/min x 15 min x 8.34 lb/gal = 313 lb

Temperature rise from 50°F to 105°F = 55°F (assuming an average shower temperature of 105°F)

The amount of heat required = 313 lb x 55°F = 17,215 BTU required to raise 313lb of 50°F water up to 105°F

If the gas water heater efficiency is 68%, then there would be 25,316 BTU (17,215/0.68) required from the heating source to supply the thermal energy for this 15-minute shower. At a cost of $1.10 per ccf (103,000 BTU), the water heating cost for this 15-minute shower is approximately $0.27.

Line losses are not considered in this calculation, but will add to the BTU requirements. Line losses can be significant for heated water that is transported through uninsulated piping where the end use application is a considerable distance from the water heater.

The same methodology can be applied to calculating BTU requirements for heating process water in industrial applications once the flow rate, water heater (or boiler) efficiency, and line losses are known."

 

[stoned-trout]

I buried my pipes 4 ft deep in an insulated trench...yeehaw..if I remember right my water tank was 330 gal...made by the amish in pa and picked up by my friend from em..

 

[Bennyweed1]

Thanks for that detailed poost

Is the conversions different for a closed loop recirculating system used for hydronic heating though?

 

[igrowone]

subbing on this one
i had looked at the rocket designs
lost interest when it looked unlikely to get by home insurance issues
but didn't think about the outside setup, hmm, that has possibilities

 

[Mikell]

https://www.icmag.com/ic/picture.php?albumid=56595&pictureid=1322182View Image yes I have ...gassifier setups kick ass too.. also converting to hydronic heating kicks ass ..but startup costs are a bit high initially..heres my old one ..it heated house,water and floors,greenhouses and fishpond...yeehaw

It's exactly how I imagined it

 

[Bennyweed1]

I played around with my first experimental rocket heater and am sold on the design.

I have all this 6" galvanized duct and a hand full of 90 degree elbows so I decided why not just throw something together and see what happens.

The thing looked like some hardcore red neck apparatus. It kinda looked like a 4' tall saxophone made out of 6" duct but the bastarded worked.

It was actually pretty awesome. I played around for a while changing the length of different sections and trying to see what combo made the best fire stream. It really does sound like a rocket, I mean, not like standing next to apollo nine watching it blast off, but the way the current from flame sucks through the duct.

It was incredibly hot, not like camp fire hot, much much hotter. I had the main burn tube glowing red. I had some extra fiber glass insulation so I wadded it around the main tube, and it melted it into glass.

The craziest part was the exhaust for sure. It really does work like you read online. Virtually no smoke was coming out and thats with the ghetto rigged experimental setup.

Im impressed. I am for sure going to pursue this idea, it has some massive potential.

I have a video of the first test run, but I changed it around probably 7 times after I started. I dont really have a way of up loading it though.

 

[DoubleTripleOG]

I read about these a couple years ago. Sounded super awesome!!! When the day comes that I can have a greenhouse, this is what I will heat it with. Super efficient, and all ya need to provide fuel is a chainsaw and splitting maul.

 

[Guest]

I am a big fan of rocket stoves and their modern counterparts!
OC

 

[igrowone]

the tech really is f'ing awesome, geeky sounding but true
i'm pondering pellet stoves, rocket stoves, ... for my house upgrade(hopefully)
pellet isn't bad but hate the lock in to the fuel
now an autofeed rocket stove, that's what i'd like
and for insulation, i've read perlite is pretty kickass for rockets
and growers often have a bag of perlite around

 

[Bennyweed1]

I picked up some stove pipe to start building a rocket mass heater.

I am a far way from figuring out what work best but intend to keep switching things around until I get something I like.

Here is my rough design. Far from complete but enough to test it out. First run was some what of a bust.

My primary burn tube is 6" and the secondary around the 6" is a 10" chimney pipe. I dont think there is enough volume between the two to get the draft I wanted. At the bottom of the 10" secondary pipe I put a 4" exhaust. Ill start with increasing the exhaust port to 6" and see if that does the trick. Will report back later.

I know most people use 55 gallon drums but I dont want to go that route. I want this heater to be portable and easy to move.

pics below

I took the cover off the 10" secondary because I had no draft with it capped and exhausting done to the 4" exhaust port.

Without the secondary, not all of the smoke and gasses are burnt up. None the less, I find this very fascinating.

Im still blown away by the amount of heat it makes.

 

[DTFuqua]

If you look into the way homes were heated way back when in places like Korea, it was a mass heat sink under the house that was also a stove/heater. A fire was built to warm the floors and, I suppose, lasted all night. I think some of the upper classed people had servants/slaves to stay up and keep the fires going during real cold weather. The most efficient I've come across was a small "green house" beside the cabin (smallish) and the mass that the exhaust travels through, to save all the heat before escaping out the flue built against the wall of the cabin. The main door was open in the morning and evening when the burns made everything comfy and breakfast and supper were cooked on the top of the rocket part where the gas is burnt. It's been a long time and a couple of computers ago so I don't have a link. Sorry.

 

[stoned-trout]

with that rocket you got to be there filling it with fuel... my old hydronic ran all night with one full load wood...mine sounded a bit like a rocket when it was packed full and cranking out the heat..i could shoot flames 3 ft out the top stack lol... not ideal but cool lookin

 

[Corpsey]

i have seen one of these smaller dragon heater units working and was impressed with it. their site has some info and plans of other rocket mass heaters and such.

http://www.dragonheaters.com/rocket-mass-heater-products/

 

[Bennyweed1]

The wood last about 2 hours a burn and its a small amount so deciving a hopper would not be difficult.

It know typically these heaters are built around a mass to absorb the radiant heat but I'm not doing that.

My mass is going to be the water tank inside my basement but for right now, I'm trying to refine my rocket heater.

It's a little more difficult because all the plans online are tailored around a mass of sand, clay, perlite, packed around the heat riser and secondary chamber.

 

[Bennyweed1]

progress is being made with different modifications.

Before I was running a 6" heat riser inside of a 8" secondary burn chamber. I did not work well because I had to insulate the primary heat riser.

So I left the 8" secondary wrapped around the 6" heat riser and packed it full of insulation and the results were pretty awesome.

From there I wrapped a 10" duct around the 8" (now being used as a insulation barrier) to be used as the secondary burn tube with the exhaust leading out the back bottom side.

In the pictures I dont have a cap on the 10" secondary because the store was out of them, but you can clrealy see the flames rising out of the primary heat riser which closely resembles a rocket. All the flame and heat is being generated off a few pieces of end cut from some 2x4s and a couple scrap 1x2s.

 

[igrowone]

with that rocket you got to be there filling it with fuel... my old hydronic ran all night with one full load wood...mine sounded a bit like a rocket when it was packed full and cranking out the heat..i could shoot flames 3 ft out the top stack lol... not ideal but cool lookin

that sounds pretty good
my experience with standard type wood stoves is that 4 hours is about the best you can do
but 8-10 hours would be excellent with no active control