@@kittyhatescrap3500 yeah but tat would be a downgrade for the audience and Rob. This is his how, channel and he is the decision makers and we are his audience.... Nothing about TV makes that better. All we need to do is make sure Rob receives value for the value he brings to his viewers/customers. Robs product(s) are awesome. Hope he never has to accept a TV deal.
I've been dealing with this topic for a long time and see some potential for improvement As you said, a separate air supply is a definite improvement, I add that this air should already be preheated if possible I would design the combustion chamber like an inverted cyclone separator, so you get a circulating combustion chamber, which means that the heat is very centered and can also have an effect on the ash so that it can really burn completely and it would also ensure that the combustion chamber can clean itself or. you can collect the ashes and before anyone my this is way too complex, i'm german what do you expect ...
The more I think about it the more I like it's design. What the company could do is make and sell add-ons, for example a heat exchanger that easily just pops on or a place to put a mass to hold that heat. They could do this easily as a side hussle so to speak. Not sure if it has a baffle on the air intake to control the heat and fuel burn more efficiently, if not it would be cheap and easy to do so.
Before you modify the Liberator itself, see if you can make a waste oil kit for it that people who own Liberator's could buy and drop in without modification. ideally the waste oil kit would have an external "tank" that holds about 8hrs worth of oil and a way to see how much is in the "tank".
It all makes sense. If you are using steel to make a heater, the insulated riser just goes too far and will destroy a metal riser (and get too dam hot) My pellet fired stove gets up to 600 which is perfect for heat without destroying itself.
I accomplished the extra oxygen that your holes give by running 2 1/2 inch by 1/2 inch square tubes in the upper corners of inside the bottom section . So it leaves all the ash in the bottom of the lower unit and just cleaned by dragging out the ash door as normal. I should add that the tubes also act as a ledge wich holds my burn basket for use of wood pellets . It can be removed to burn long wood.
@@ThinkingandTinkering The builders in the videos say it's to keep the outer shell from getting really hot. None of the wood gasifier stoves have an outer insulating shell...
Now That is a stove and a half! Now I do think you need to be careful what you wish for, especially when asking a guy like me for ideas! My head is full of ideas and bumfluf. So I'll let you decide if it is bumfluf or idea, and if idea weather it is useful or not! :o) As I understand it the insulation in the riser is primarily to stop oxidation of the steel at too high a temp ... so is a good thing. It has the advantage of letting the gasses get hotter and therefore increasing the draught, which if you are going to suck the heat out later in the process is a great thing! I have seen ceramics used for the riser because of this reason. A possibility might be to ship with a ceramic duct? Obviously this could be a problem in regards to damage so might need a good coat of looking at (possibly removable foam inserts?) Also this could be a good revenue stream it terms of replacements a few years down the line? You did not show it but is there a separate air intake to the post burn flame section from th front? If so your extra holes might not be needed. One aspect not talked about too much is external venting. By this I mean having an air source taken from outside so you are not burning the room air and chucking that warmed up air out of the chimney. This can be via an air brick and duct but would need an alteration to the stove to accept this! This might go a long way to making larger stoves UK compliant with regs (I think over 5Kw needs an external vent) The exhaust point is from the bottom of the heater? This could go to a flue or to a thermal mass heater? Maybe a sand box with a solid flue going the length of it (and back) If it were made of an existing flue materiel it should be compliant rather than the homemade versions! It might be possible to construct the body of the stove larger but thinner and have masonry on the inside to at as thermal mass? It might also be possable to construct the stove with a water jacket over part of it to act as a secondary circuit water heater (like those coal back boilers we all used to have in grandad's age! Final idea (for now) How about running a pipe through the body of the stove. Connected to a cheap low volume silent fan this would force air through to be heated and blown out from the heater without being contaminated by fumes. The fan may need to be fitted on the end of a pipe to keep it remote for noise and cooling.
Hi Robert, these guys are in Bourbon Missouri and a lot of us have put dampers on the intake air to slow the burn for pellet heating. Otherwise, the unit is a blast furnace and will cook you out of your own house. Adding a thermal mass is indeed the most efficient use of this heater if you can afford the space for the mass. I have been to the factory and the fellows that work there are genuinely ingenious.
I've had the older model Liberator for a few years now running mostly pellets. It does exactly as advertised. Heats up very quick, burns hot and efficiently. I have nothing negative to say about it.
Your shouty voice and crazy laughing are one of the most endearing I have heard. You remind me of my late engineering profs who was just about the best teacher I ever had. Keep going- its wonderful
Thank you for making me remember Professor Julius Sumner Miller. He was another outstanding gentleman with nary a dull moment as he performed his wonderful experiments.
Hello Robert! We're glad to see the heater found its way to you. If there is anything else we can help you with, please feel free to let us know. We may or may not be developing a stirling engine for these heaters in the future. And dont feel bad about taking a grinder to it. We will have a 3rd generation heater coming out in the future, and we'll be sure to send one your way. I can't give away too much, but its going to be absolutely nuts!
In Ukrainian villages, they build massive rocket-style stoves/ovens, which take up a good chunk of the wall. I think people even sleep on the very top of it, as it stays warm all night. For the country people, the oven/stove isn't just an appliance, it's a viable part of the home to dry wet clothes, to cook, to bake, to sleep on after the day is done. It's amazing how much thermal mass those things have...
Improvement suggestions. Instead of drilling extra holes, run a tube from the front to the back. The air will also be heated by the combustion part. Improve heat convection by increasing the surface by welding on extra pipes or flanges on the outside.
Yes, a 1/2" or 3/8 ss tube running from air inlet, through burn chamber, and up chimney. With small air holes up chimney to inject hot air and add turbulence to mix o2 and combustible gas more thorough. Add an exterior graphine coating or water jacket to help pass off radient heat before it escapes the flue. Add a mass heater along the flue exit. Efficiency isn't only the burn, but the release of the energy for desired effect also.
I like this idea for the air tube. I think about 3/4 to an inch, judging by the number of holes he drilled. Turn the end of the tube upwards so it's not blocked by ash. Weld the tube to the centre of the ash pan. The tube is the long handle of the ash pan, just extract the pan from the front to empty it. No drilling holes, ash falling out, no trapdoor.
Hi Bob. One improvement I can think of is a Sand Battery . One can make it as a buy on for the Liberator. Just a box that encapsulates the chimney, and the client can then fill it with sand... Or water and heat it....
This is a pretty good idea. As long as any diversion of exhaust flow does not reduce the airflow too much. Quite a bit of the unused heat can be recovered. Just in case anyone is thinking of passing the exhaust gas through sand, don't even try it. The restriction in the flow will screw up the whole combustion process.
For those of us who are ladies having a trivet on the top of the lid to be able to put a dutch oven on to cook. Also maybe make accessories such as a off-grid food dehydrator that can go on the trivet, reflector for the back that could be far enough away from the back that there would be a shelf to put a bread loaf pan and possibly bake bread or meatloaf. The reflector shield would have to have a hinge to openba side to put in and take out the liaf pan. Lol Yes, I am a female and a foodie. Lol Women love accessories that can be purchased with or after.
@@chrisallen2005 No where did I say that I would be the one cooking. Women will gladly step aside and let the man cook so long as we still get the accessories to make it look pretty. Lol
Birds eye view on the drum, put a full height half divider and in the front section you can fill it with sand. Will still act like a rocket stove giving instant heat but will also charge the sand as a battery!
I am in the process right now of doing just that although I am using an L shaped exhaust pipe inside the drum and filling it with sand to just below the exhaust pipe.
@@ThinkingandTinkering Variant add on - 'quadrant' shaped drums filled with sand that bolt to put side of burn drum. Other thing often missing from rocket stoves is higher capacity fuel feed so that it can be left longer between refueling - pellet hopper?? Also when I was thinking about rocket stoves my 'design' got (on paper) as far as something like the liberator but half the height but the rear drum had fresh air pipes coming in from the base and running up to near the 'lid' to bring heated fresh air into the drum to give more efficient secondary burn.
Would have been nice to see the Liberator lit up and working, and some results from the test. Maybe another video? Thank you though for doing such wonderfully informative videos.
the only way you lose the heat is venting exhaust gasses while they are still hot enough to capture and redirect to the heating location. the improvement like you mentioned could be an easy cleaning feature, also a coolant loop in the cavity space would be good to help with either heat storage, second room heat or domestic hot water use.
To allow the point for air entry and easy cleaning, try a 50x100mm (2x4inch) pipe under the bottom of the ‘J’, coming to the ‘front’ of the unit, with an removable ash drawer. The drawer can then also be opened and closed by varying amounts to regulate the air then entering the bottom of the flue. That way all three intakes (main air intake, fuel hopper and ‘bypass’ air intake with the ash collector drawer) are at the ‘front’ of the heater.
@@ThinkingandTinkering I have seen a few variations of "afterburner" and so far one was very appealing to me. You just drilled some holes in the bottom of the chimney. Air that is drawn this way is at room temperature, so about 20 degrees C. As you obviously know that, in all substances it will try to reach thermal equilibrium, so you are wasting energy here, cooling that part which should be the hottest. In a few designs i saw that this air was supplied by a square profile, cut off one side then welded along the hearth. One guy even made holes along the chimney pipe and just drilled them on an angle, which gave the exhaust gasses a vortex effect. Anyways, that's my two cents on this topic :) P.S. I really love that someone reached out to you with such request. It means you are doing a wonderful job and it's getting noticed :)
I agree that drilling holes at the chimney base for secondary air intake is not the best idea. The air should come via a tube from the front "mouth" of the stove, so it's preheated in the fire section. Turn the chimney end of the tube upwards and weld it positioned in the middle of the ash pan. Then the air intake tube (maybe 3/4 to an inch?) is also the long handle of the ash pan. Pull it out & empty
This is the basis for a rocket stove mass heater. The exhaust would be piped through a long horizontal pipe embedded in a thick piece of masonry inside the home. Then to the outside into a fairly tall chimney pipe. When done correctly it produces no smoke at all. People often use the inside masonry, with cushions of course, as a couch.
People are willing to pay for convenience and no one likes to spend time cleaning the rig day after day. So, one suggestion to expand on what you have, look at the bottom of the riser and burn chamber. In a drawing it looks like a rectangle connected with a circle on one end which I'll call the BASE. Change the mount system so that the entire BASE becomes a hatch which will swing open on the long side so all the ash will fall to the ground or in a larger container. Then you can easily sweep it clean with a broom if it's not hot 🔥. Close the BASE and your done, less than a minute! People like easy clean and are willing to pay for it! If you like my idea, give me a good price on your new build. :). GL!
Wrap the heat exchanger with corrugated metal. You want more surface area to better couple the hot metal to the air. Look up heat exchangers for camp cooking to get an idea.
Absolutely! I was thinking to maybe weld round or square tubing vertically around outside, to increase surface area and create a convective air flow. But your idea of using corregated metal (like roofing panels) would be of lower cost I think. Nice one! 👍
Instead of an ash pan, provide an ash hoe with which to reach in through the fire chamber & rake the ashes out. In order to introduce secondary oxygen to the vertical rocket tube, drill a 1" hole through the vertical fire tube about 5" up from the bottom & tap it for 1" pipe thread, drill a second hole through the outside barrel to correspond with the first, making it just large enough to slide a piece of threaded 1" black iron pipe through the outer barrel & screw it into the fire tube. At the end of the 1" pipe sticking out of the barrel, drill a series of holes (1/2" dia). 1" schedule 40 steel should have an inside diameter of 1.049 in., and the outside diameter of 3/4" sch 40 steel pipe should be about 1,050 in,. Take a short length of 3/4 " pipe and drill holes corresponding to those in the 1" pipe and then turn it on a lath until it just fits into the 1" pipe, & stop one end. To adjust the secondary air flow, rotate & slide the inner tube to expose more or fewer holes through the outer pipe.
Hi, yes I can think of a few suggestions.. you covered two in your vid with a secondary air inlet and an ash pan.. but the only issue you need to ensure is that after the initial burn phase that no air will escape from where its not supposed to.. being as it is meant for internal use you don't want any form of carbon monoxide to leak.. My suggestion includes a secondary burn feed from the main air inlet (Shared inlet) this will negate any blowback if it were to occur as it would be dragged back in via the initial burn inlet. Ash extraction could be done by installing a service hatch on the side or bottom as you suggest, but this will need to be sealed using fire rope or caulking.. Air flow is like water and electricity, it always follows the path of least resistance, so although the heat is pumping out of the top of the rocket stove and hitting the top plate (which can suffer from heat damage over long term) most of the heat also flows down the side of the exhaust port. My suggestion would be to insert some baffle plates to force the air in circular motion around the radiant heater section before it gets to the exhaust port. Yes this might slow the air flow down a bit. But it would also make it more efficient in using the available heat produced to come into contact with the outer edge. Also on that note, utilising the available heat on the outer edge .. my biggest suggestion is to add fins to the internal and external surfaces of the radian heat drum.. this will give a larger surface area for heat transfer and also increase the rate at which the heat is dissipated out of the system.. Only problem is.. now I've made these suggestions on a public forum they cannot be used in a patent and are open to the public.. that sort of thing really sucks if your trying to make the ideas novel and unique.. to improve your own patent applications. Anyhow good luck to them on developing their product 😎 👍
Interesting, I built a rocket stove the size of that large stove and it got the back of my pizza oven red hot! I couldn't believe it, I thought my BakerStone pizza oven was going to explode, the temperature dial went all the way around! I had to remove the pizza oven and it was OK. After that incident, I added a vent door to control the temperature and I can now keep it steady at 350F to bake bread etc. Very powerful those rocket stoves. I use the wood from falling branches at my Farm.
The ventilator holes shouldn't leak ash, since they are drawing air. But the easiest fix is just a short angled up tube on the outside. More on those holes, if you put one near each of the three available corners, they would add oxygen while starting the vortex. You don't need a lot to start that, just a hint (also keeps the temp from dropping), which three maybe 3/8 inch holes would do.
The up-angled tubing is a great idea! The bypass air could be "throttled", and if my thinking is correct, the ash would become concentrated in the center.
@@mikebond6328 I'm not sure what you're saying. Are you expecting a deep pool of ashes in the chimney that will flow over to the holes and pour out? Then make your holes a little higher up the pipe.
The idea behind Insulating the Rocket Stove is not to do anything in the way of heat radiation. It's 2 purposes are to First get the burn box area up to temperature ASAP. Second is insulating the Inner wall is to Protect the steel from being destroyed by the excessive heat & keeping enough heat in the riser tube is to make sure the wood gas ignites before it leaves said tube. This is where the secondary air comes into play right at the vertical turn of the riser tube.
I like the exhaust consideration already. The right angle is great. Of the wall thought, could the tube become a sand battery? MO is Missouri, Montana is MT.
Essentially what a "rocket mass heater" is. A large earthen mass which the stove pipe exits through. Usually a long, low couch sized lump of cobb which the stove pipe is embedded in the bottom of. You run the rocket hard for a couple hours, which heats the cobb, which after the fire is out and the air intake blocked off and dampers closed, continues to radiate heat.
So grateful for all you share with us. I am planning out three Rocket stoves, one for house, one for shop and one for my bus to tv conversion. Love all the ideas, plans and explanations. Have to check out the boys up north, awesome that we have folks here in the states. From AZ thank you kindly!
It would be adding more cost, but I think add two runners on the bottom that run the length of the base to the chimney for the secondary air intakes, and a flappy panel on a hinge could be used as a damper to control the amount of air intake
Yeah, an air intake could improve its efficiency, but it seems pretty efficient already. For me, what that stove is missing is a water heater, using a copper coil wound around that internal chimney. A fairly simple plumbing job, with cold in/hot out, and maybe even a small hot water tank in there, though that would probably need some kind of pressure release valve. Seriously, with a constant feed hopper and hot water on tap, it would be a really useful piece of kit! Never mind replacing the AGA or Rayburn, you could build your own steam turbine generator or locomotive with a few of those!!!
Joe: with the extreme heat inside the internal chimney the possibility of a steam explosion exists. Wrapping around the exterior drum and utilizing a thermosyphoning arrangement should be safer provided you have enough storage capacity in the water tank or an arrangement to dump excess water heat say thru a radiator and possibly a programmable hot water pump which are fairly cheap and used for hydronic heating. In new home or home upgrade could be pumped thru pex pipe into concrete or underfloor heating and with the large increase in mass could fully utilize the stoves potential and greatly increase the time between stove burns.
This would pair very well with a Tesla Turbine from TesTur Energy. We've just run our first steam tests. Previously we've achieved 4 kW+ with just compressed air alone. In fact, at one point, we were working with Sky Huddleston of Liberator to apply for a grant to pursue pairing the two together, which didn't materialize.
if you fitted iron pipe(s) where the holes are drilled you could then use those pipes, when cold, to vacuum out the ash, the change would add little cost. You could also add fans to increase the flow. The neatest solution I have seen however was the Aussie rockets site where he created a vortex.
Depending on the application or combination thereof if they were to fill the heating chamber with sand but have hollow pipes running through it the sand would heat up and draw air from the bottom, through the pipes, and then out. It can capture the heat quickly and use natural convection currents to slowly (passively) radiate the heat.
Can’t wait for some of your ideas for improvement! Mine is rocking away on pellets, thinking about wrapping exhaust with copper pipe for thermal battery of 55 gallon barrels.
@@ThinkingandTinkering I’d love to see if you have any clogging issues. I think my pellets have a bit too much softwood. Mine will burp smoke too when it runs out of pellets, but I’m working through those issues. Maybe we can come up with fixes.
@@nghermit4922 Try loosening the set screw in the collar of the pellet hopper, dropping the pellet feed tube 1/4" - 1/2", and/or opening the damper when you get low on pellets.
@@nghermit4922 Its "standard starting point" should be around 19" of pipe coming out of the bottom of the hopper; but we make it so that it can be adjusted either way.
Add an ash pan that seals the space effectively so that when you can adjust the amount of venting by sliding it in and out., that way you sort two issues with one simple alteration.
Jeez I love this channel! I can't wait to see what you do with the Liberator! From what I've already read in the comments, you're going to have plenty of ideas for improvement with this, can't wait!
In the past I’ve worked on a vortex rocket stove which made the gravity fed flame concentrate into a swirl coming out from the stack which generate more heat while burning less fuel . The idea is to have the gravity fed material drop down into a circular burn chamber slanted slightly upward to the round stack while positioning the air intake at just the right placement to control the adjustable draft or air intake .Burnt material or ash from pellets would drop down through a grate into a collection box . When built right and depending on the controlling of the air intake , you will actually have a very strong swirl of flame which is very interesting to see .
Hi Robert, not my own idea, but seen in a video of something very similar - wood gasifiers - for vehicles, they added (or injected?) water or steam into the unit, which took care of ash/ soot/ creosote problems and hugely (+/- 40% ??) improved clean heat output. Overlapping technologies & sharing refinements seems like a good idea to me. Have fun! I think it was a you tube video which covered WW2 and included Germany, also London, amongst others, also later, showing more modern use of gasifiers mounted on the backs of pick-up trucks, which looked unusual, but still, a great, portable concept!
Have you considered whether to employ a venturi style air input which may replace the need for the air holes at the base of the stove? Just a thought. Keep up the good work Rob, always interesting and certainly beneficial for us off gridders.
Have a look in the horizontal burn chamber of the liberator and I think you will see insulation on the inside that is detachable and the burn chamber width is wider than the feed tube so the insulation doesn't obstruct the gravity feed.
can we not add an internal lining of say 100mm from the existing external drum wall i.e a drum in the drum like the can in the can heaters whereas it still allows chimney exhaust but the 100mm gap can be filled with kiln dried sand so it retains heat and radiates for longer yes it ads weight but it looks like an item that stays put when sited
Robert: Rather than an ash pan under the amplifier elbow where you have a row of holes drilled, try an angled slot ground into the elbow on a 45° angle where the bottom of this air intake slot is 30mm from the bottom, no ash will roll out here and the relocation of the intake of the air jet air intake will enhance the draw toward through and up the flue. Holes across the bottom will tend to create a burn there and not enhance the draw where it is needed. I would like to see this in oil burner with an automatic light system for a thermostat and flame sensor, etc. I also don't see a circulation blower on the hot air plenum, as a unit this size should have a better way to utilize flow to the space it is intended to heat. And for thoughts and giggles, I am starting a build of a soybean (aka rapeseed oil) forced air furnace to replace my wood burning stove because the price of cut wood deliveries has gone out of sight in my are, and I assume it has gone up drastically in most places.
Dear Robert, please design and sell basic starter kits, with the option to modify and collaborate, using common plumbing fixtures to produce an efficient stove for any individual purpose...
Consider testing the air flow of the air intake holes you suggested adding to the Liberator stove by having the ability to control the amount of air entering. Looking forward to the results. Thanks for the video. (JF)
mr. murray-smith, i follow the development of the rocket stove since years. there is something what i want to say: why is there only one rocket-pipe? why is there not a lager, more broad fire-place with more than one rocket-pipes above it? the 2 or 3 rocket-pipes will pick up the gasses from the larger fire place, without loss of any efficiency, i think, and the bigger rocket stove could be more easily filled with bigger and more pieces of wood in one filling AND be able to feed a waterboiler or heating system. and secondly, the covering with fire-stone of the rocket pipe is a very good idea and will make a better burning proces.
I can suggest a two chamber sliding ash tray. With one chamber in the stove under a grate to keep the wood above and let the ash fall down into the chamber. While the stove is still burning the sliding ash tray can be moved to place the empty chamber into the stove while the chamber that just slid out can be emptied of ash. The ash tray would just need to slide back and forth from left to right in order to empty one of the chambers. The stove never has to be shut down to empty the ash and no efficiency should be lost.
You could use an access door at the bottom of the chimney side, that hinges out from the backside, for a clean out. If you just want airflow then cut some conduit straws to lay inside at the bottom. The conduit can be perforated or have perpindicular slits for airflow, and it will pull from the cold side. That way you aren't making holes in your chimney bottom.
That looks a lot like a gasifier! Looks like it could be easily modified into a gasifier pyrolysis/stove, use the rocket to break the wood down to be distilled into fuels ,using saw dust, shavings, what ever, maybe use the wood gas to fuel a cook stove, catch the methanol to fuel a car or generator, this is what I. Been thinking about building, only a tiny version, built a lot like the liberator, maybe use oil to gasify the wood!
Weld pipe fitting at bottom 2nd burn chamber to port in outside fresh cold air to burn in 900c plus chamber. Dual use at clean time vacuum hose could adapt to air supply for clean out or plug it shut.
i disagree with you Robert. i do believe the entire burn chamber and chimney should be insulated to keep in as much heat as possible. where people go wrong is having exposed steel in the burn chamber. so if the inside is lined with ceramic sheet or if the burn chamber is not made of steel at all but rather clay/cement, then you can easily contain ~2k c. especially if you can surround this chamber with some mass. where this high temperature in the burn chamber becomes useful is that you can burn less than substantial (almost green) wood. the inner tube is not the heater, you do not want to extract heat from it.. the heat is extracted from the outer barrel and any subsequent flue or mass. the awesome thing about the heat extraction barrel is that because the gasses flow downwards, and on the outside the convection causes an up flow of air, you get maximum heat transfer to the air. (just like the blood flow in the leg of a seagull)
Surely you mean a Marvel movie! 😎 Great suggestions for improvements. How about a hot plate on top for cooking? I’ve just bought a log burner for heating and cooking when the power cuts hit. 😬
@3:08 I think those fasteners securing the insulation will prove to be a design flaw. Those may corrode from hot exhaust gases. Also possibly cause the insulation to crack and fall apart due to expansion. I would suggest; instead of bolts, score a rough texture onto the steel walls, and secure the insulation with a thermosetting epoxy.
My Dunsley Yorkshire stove could almost be described as a kind of rocket stove, it has a large fire box for logs, at the back and at the bottom of the chamber is a slot maybe 11/2" high, it is there where I have to light it. The firebox merely undergoes Pyrolysis, once the flames exit through the slot in the back they go through what would be best described has a venturi chamber, this is firebrick insulated and a special brick with I think about 8 holes in it which line up with holes in the back of the steel. The flames drag in more air, and the afterburn chamber goes to about 1500 degrees where it burns off all the smoke, this is then sent around a boiler jacket before heading for the chimney at the same time it passes over the top of the fire box fire brick which provides more heat for pyrolysis. It burns very clean provides hot water and central heating in the worst of winter, it has just not been cold enough yet to use it. But the design could be used in a rocket stove and you may be able to get a diagram online. Another thing I once read about was a professor hills boiler, these involve a down burn feed and a super insulated refractory channel with a air blower.
If your enthusiastic knowledge is combined with these manufacturers the i can only say that the sky is the limit in rocket stove technology from now on . Great video and a wealth of extremely helpful information as always. Thank you.
I like the round exterior housing, it looks like it would lend itself, quite easily to adding a water coil for hot water or distribute heat to other areas.
I think it's great Rob, that someone with your noggin caliber is getting right into this. Thanks for explaining the finer points of effective burn temperature and the whole principle behind an effective rocket stove. The only thing that I can think of to modify this stove is to have a smaller version. Maybe one that could be dismantled ? But we dont want to sacrifice simplicity. The focus on these stoves is evolving and it will be very interesting to see where it goes. Some method of chimney insulation for the DIYer would be good.
I love this!! I was thinking moving the location of the holes around a little bit might be good to help find where they work best! (If they aren't already in the best spot) I was thinking including your oxygen slightly closer to your primary wood burn might be a good idea! Of course too far could be bad but maybe only a couple of inches?
Allowing the fresh air from the holes to mingle with your freshly generated flammable gases a little sooner might allow for an easier burn? They can get roaring a little sooner and have more time spent in the exhaust tube to do their thing?!
Looks great. Maybe one or two of those stove fans on top would help circulate the heat quicker. Speaking as a non-techie, does it make sense to add more thermal mass if the rate of burn and temperature can be regulated by air intake and the amount of fuel being fed in by the hopper? Perhaps a couple of temperature guages would be helpful?
it depends what you want to do with time the heat is released mate - you can think of thermal mass as a battery - the first bit of heat goes to heating the mass - then the room then the fire dies and the heat absorbed by the mass is given out - with out the mass the heating is felt straight away
Steel spalls at 1600F. And we are looking for temps over 1350F which means we could hit 2000F. The liberator is perfect for a home - especially when running on pellets with a bit of a mass. A bit underpowered for quickly heating a shop. Bigger rocket "engines" hit the higher temps easier/faster for cleaner burns. More wood also means more heat per filling - so less need to fill. Which is why the liberator really shines when using pellets.
Howdy. Love the videos, many thanks. I have been working with rocket heaters for many years and, Pls don't take offense at this but you are kind of missing the point. The J tube/burn chamber is only half of the equation. You have mastered this part wonderfully but there is so much more to the story. The liberator is closer to a true rocket stove as it includes the outer shell. The insulation in the riser is not just there to allow the temperature to remain at flash point, it is there to create a temperature difference between the riser and the space between the riser and the outer shell thus creating a huge push /suction/draw propelling the heat out of the system and, ideally, through an exhaust which, because of the power of the draw, can even be horizontal rather than vertical and be channelled through a heat sink like, for instance in my old greenhouse rocket stove underfloor heating ( 20m of horizontal metal ducting underneath the grow-beds), or heated cob benches. but keep up the good work!
Suggest: change lid at top to inverted drum so you can get down to bottom for cleaning. Put outer sleeve (open at bottom and top) over gas chamber to create convection current, include fins b/w inner and outer walls for better heat exchange, which will remove more heat from exhaust gases, it will also keep the outer gas chamber temperature lower and safer
Interesting explanation. I understood that in masonry stove they burned to about 1200C and captured the high temp in a ceramic mass via a convoluted flu system. Is the difference that the flu is not metal and the ceramic can sustain the higher temp, which then acts as a temperature "transformer"....
99.5% efficient - that means you won't improve the burn. Only improvements left are to improve feeding and improve radiation/convection. Would be interested to know what the exhaust temperature is as 60'C is about minimum to prevent condensation and any more than that is waste heat.
I suppose a reduction is size for the same power output would be another improvement which could be done with better conductors, i.e. using cast iron where possible.
It could be possible to extend the bottom square pipe and cover the open end with a hinged cover with air valve. This way you can easily clean out the whole pipe by pushing through a simple piece of wood into the ash bin underneath. A simple folded metal tray sliding on fixed bars could serve as low dust ash holder. On top of the extended pipe a cooking plate can be mounted.
How about a stack of removable or angle adjustable overlapping steel plates to be placed inside the smoke chamber in order to slow down the exit of the hot smoke, which will allow more heat to be generated and used via radiator fins on the outside of the smoke chamber, (these could actually be clamp on so as to be removable as well). More steel carries more heat to the outside air. One could also add heat driven, heat sink type fans to the out side to disperse the heat throughout the room.
You non-stop enthusiasm combined with your knowledge is always entertaining and enlightening.👍
This man deserves his own TV series
Oh wow - cheers mate
@@kittyhatescrap3500 We already have a "MacGuyver" TV series... ;)
@@kittyhatescrap3500 yeah but tat would be a downgrade for the audience and Rob. This is his how, channel and he is the decision makers and we are his audience.... Nothing about TV makes that better. All we need to do is make sure Rob receives value for the value he brings to his viewers/customers.
Robs product(s) are awesome. Hope he never has to accept a TV deal.
Wow nice one Liberator looks like a great product !!
I've been dealing with this topic for a long time and see some potential for improvement
As you said, a separate air supply is a definite improvement, I add that this air should already be preheated if possible
I would design the combustion chamber like an inverted cyclone separator, so you get a circulating combustion chamber, which means that the heat is very centered and can also have an effect on the ash so that it can really burn completely and it would also ensure that the combustion chamber can clean itself or. you can collect the ashes
and before anyone my this is way too complex, i'm german what do you expect ...
German engineering is world famous for good reason.
The more I think about it the more I like it's design. What the company could do is make and sell add-ons, for example a heat exchanger that easily just pops on or a place to put a mass to hold that heat. They could do this easily as a side hussle so to speak. Not sure if it has a baffle on the air intake to control the heat and fuel burn more efficiently, if not it would be cheap and easy to do so.
Before you modify the Liberator itself, see if you can make a waste oil kit for it that people who own Liberator's could buy and drop in without modification. ideally the waste oil kit would have an external "tank" that holds about 8hrs worth of oil and a way to see how much is in the "tank".
It all makes sense. If you are using steel to make a heater, the insulated riser just goes too far and will destroy a metal riser (and get too dam hot) My pellet fired stove gets up to 600 which is perfect for heat without destroying itself.
I accomplished the extra oxygen that your holes give by running 2 1/2 inch by 1/2 inch square tubes in the upper corners of inside the bottom section .
So it leaves all the ash in the bottom of the lower unit and just cleaned by dragging out the ash door as normal.
I should add that the tubes also act as a ledge wich holds my burn basket for use of wood pellets . It can be removed to burn long wood.
Instead of full insulation can you use some of the intake air to pre-heat and cool the burn chimney.
If you’re going to drill holes at the bottom it may help to have a air preheats duct
That's why the can-style rocket stoves are usually filled with dirt, sand, vermiculite, ash, etc., between the chimney and the outer can.
sorry mate - why is that?
@@ThinkingandTinkering The builders in the videos say it's to keep the outer shell from getting really hot. None of the wood gasifier stoves have an outer insulating shell...
A cook top or oven box on top of the round gas director. ❤
Now That is a stove and a half!
Now I do think you need to be careful what you wish for, especially when asking a guy like me for ideas!
My head is full of ideas and bumfluf. So I'll let you decide if it is bumfluf or idea, and if idea weather it is useful or not! :o)
As I understand it the insulation in the riser is primarily to stop oxidation of the steel at too high a temp ... so is a good thing. It has the advantage of letting the gasses get hotter and therefore increasing the draught, which if you are going to suck the heat out later in the process is a great thing! I have seen ceramics used for the riser because of this reason. A possibility might be to ship with a ceramic duct? Obviously this could be a problem in regards to damage so might need a good coat of looking at (possibly removable foam inserts?) Also this could be a good revenue stream it terms of replacements a few years down the line?
You did not show it but is there a separate air intake to the post burn flame section from th front? If so your extra holes might not be needed. One aspect not talked about too much is external venting. By this I mean having an air source taken from outside so you are not burning the room air and chucking that warmed up air out of the chimney. This can be via an air brick and duct but would need an alteration to the stove to accept this! This might go a long way to making larger stoves UK compliant with regs (I think over 5Kw needs an external vent)
The exhaust point is from the bottom of the heater? This could go to a flue or to a thermal mass heater? Maybe a sand box with a solid flue going the length of it (and back) If it were made of an existing flue materiel it should be compliant rather than the homemade
versions!
It might be possible to construct the body of the stove larger but thinner and have masonry on the inside to at as thermal mass?
It might also be possable to construct the stove with a water jacket over part of it to act as a secondary circuit water heater (like those coal back boilers we all used to have in grandad's age!
Final idea (for now) How about running a pipe through the body of the stove. Connected to a cheap low volume silent fan this would force air through to be heated and blown out from the heater without being contaminated by fumes. The fan may need to be fitted on the end of a pipe to keep it remote for noise and cooling.
Perhaps some vent that were kind of like exhaust pipes that went up a couple inches to prevent ash from spelling out?
cheers mate
Hi Robert, these guys are in Bourbon Missouri and a lot of us have put dampers on the intake air to slow the burn for pellet heating. Otherwise, the unit is a blast furnace and will cook you out of your own house. Adding a thermal mass is indeed the most efficient use of this heater if you can afford the space for the mass. I have been to the factory and the fellows that work there are genuinely ingenious.
I've had the older model Liberator for a few years now running mostly pellets. It does exactly as advertised. Heats up very quick, burns hot and efficiently. I have nothing negative to say about it.
awesome mate - thank you for sharing
What about some thermal mass. Like masonry stoves. To hold on to some heat when the stove burns out. Fantastic stuff. Thanks.
@@juliancripps1580 Sand?
@@dengle2001 Robert has a video with a sand-filled thermal mass.
@@juliancripps1580 soapstone
When a man laughs while saying "I'm very reluctant to take an angle grinder to it" I'm all in 😂👌
8:39
Your shouty voice and crazy laughing are one of the most endearing I have heard. You remind me of my late engineering profs who was just about the best teacher I ever had. Keep going- its wonderful
lol - cheers mate
Thank you for making me remember Professor Julius Sumner Miller. He was another outstanding gentleman with nary a dull moment as he performed his wonderful experiments.
Mr gamble my science teacher was similar very inspiring, had a wacky moustache to match
Hello Robert! We're glad to see the heater found its way to you. If there is anything else we can help you with, please feel free to let us know. We may or may not be developing a stirling engine for these heaters in the future. And dont feel bad about taking a grinder to it. We will have a 3rd generation heater coming out in the future, and we'll be sure to send one your way. I can't give away too much, but its going to be absolutely nuts!
In Ukrainian villages, they build massive rocket-style stoves/ovens, which take up a good chunk of the wall. I think people even sleep on the very top of it, as it stays warm all night. For the country people, the oven/stove isn't just an appliance, it's a viable part of the home to dry wet clothes, to cook, to bake, to sleep on after the day is done. It's amazing how much thermal mass those things have...
Russians also
They're all over Europe.
Thermal mass stoves/fires
@@lsmith992 brilliant idea
In Romania as well. We call them teracota
@@danielbuse3639 I think perhaps Eastern Europeans are ahead of the globalists games
Improvement suggestions. Instead of drilling extra holes, run a tube from the front to the back. The air will also be heated by the combustion part. Improve heat convection by increasing the surface by welding on extra pipes or flanges on the outside.
cheers mate
Yes, a 1/2" or 3/8 ss tube running from air inlet, through burn chamber, and up chimney. With small air holes up chimney to inject hot air and add turbulence to mix o2 and combustible gas more thorough. Add an exterior graphine coating or water jacket to help pass off radient heat before it escapes the flue. Add a mass heater along the flue exit. Efficiency isn't only the burn, but the release of the energy for desired effect also.
Welding on extra pipes or flanges on the outside is a absolutely brilliant idea. Good thinking H P. Rocket stove's rock!
I like this idea for the air tube. I think about 3/4 to an inch, judging by the number of holes he drilled.
Turn the end of the tube upwards so it's not blocked by ash. Weld the tube to the centre of the ash pan. The tube is the long handle of the ash pan, just extract the pan from the front to empty it. No drilling holes, ash falling out, no trapdoor.
Maybe, just add a control valve (ball or gate) to this intake pipe, like a damper. Will allow for fine tuning of the air intake.
Hi Bob.
One improvement I can think of is a Sand Battery . One can make it as a buy on for the Liberator. Just a box that encapsulates the chimney, and the client can then fill it with sand... Or water and heat it....
Spot on. I was thinking copper coil midway and surrounded by sand or other material that will hold heat.
@@rocklover7437 I would like to think 2 coils. One for hot water, the other to circulate through another heat-sink and then a radiator.
I like that - good thinking mate - cheers
This is a pretty good idea. As long as any diversion of exhaust flow does not reduce the airflow too much. Quite a bit of the unused heat can be recovered. Just in case anyone is thinking of passing the exhaust gas through sand, don't even try it. The restriction in the flow will screw up the whole combustion process.
I was thinking of heat bricks like the old storage heaters use to have, similar to the sand idea but maybe more tunable.
For those of us who are ladies having a trivet on the top of the lid to be able to put a dutch oven on to cook. Also maybe make accessories such as a off-grid food dehydrator that can go on the trivet, reflector for the back that could be far enough away from the back that there would be a shelf to put a bread loaf pan and possibly bake bread or meatloaf. The reflector shield would have to have a hinge to openba side to put in and take out the liaf pan. Lol Yes, I am a female and a foodie. Lol Women love accessories that can be purchased with or after.
I am offended. Since when did cooking become the sole domain of women?
@@chrisallen2005 No where did I say that I would be the one cooking. Women will gladly step aside and let the man cook so long as we still get the accessories to make it look pretty. Lol
Birds eye view on the drum, put a full height half divider and in the front section you can fill it with sand. Will still act like a rocket stove giving instant heat but will also charge the sand as a battery!
ahhh - now then - that's clever - cheers mate
I am in the process right now of doing just that although I am using an L shaped exhaust pipe inside the drum and filling it with sand to just below the exhaust pipe.
@@ThinkingandTinkering Variant add on - 'quadrant' shaped drums filled with sand that bolt to put side of burn drum.
Other thing often missing from rocket stoves is higher capacity fuel feed so that it can be left longer between refueling - pellet hopper??
Also when I was thinking about rocket stoves my 'design' got (on paper) as far as something like the liberator but half the height but the rear drum had fresh air pipes coming in from the base and running up to near the 'lid' to bring heated fresh air into the drum to give more efficient secondary burn.
Clay might hold onto the heat for longer from some research papers (bentonite based cat litter has been mentioned as a useful substance)
@@markhedger6378 I wonder how well rock wool would work in this application...?
Would have been nice to see the Liberator lit up and working, and some results from the test. Maybe another video? Thank you though for doing such wonderfully informative videos.
You really have a way of imparting knowledge and enthusiasm at the same time, whish I had you as my teacher when I was growing up.
oh wow - cheers mate
You have to be careful with adding additional vents. You will run into back drafting issues.
the only way you lose the heat is venting exhaust gasses while they are still hot enough to capture and redirect to the heating location. the improvement like you mentioned could be an easy cleaning feature, also a coolant loop in the cavity space would be good to help with either heat storage, second room heat or domestic hot water use.
To allow the point for air entry and easy cleaning, try a 50x100mm (2x4inch) pipe under the bottom of the ‘J’, coming to the ‘front’ of the unit, with an removable ash drawer. The drawer can then also be opened and closed by varying amounts to regulate the air then entering the bottom of the flue. That way all three intakes (main air intake, fuel hopper and ‘bypass’ air intake with the ash collector drawer) are at the ‘front’ of the heater.
got it - this is one I may well do myself - cheers mate
@@ThinkingandTinkering I have seen a few variations of "afterburner" and so far one was very appealing to me. You just drilled some holes in the bottom of the chimney. Air that is drawn this way is at room temperature, so about 20 degrees C. As you obviously know that, in all substances it will try to reach thermal equilibrium, so you are wasting energy here, cooling that part which should be the hottest.
In a few designs i saw that this air was supplied by a square profile, cut off one side then welded along the hearth. One guy even made holes along the chimney pipe and just drilled them on an angle, which gave the exhaust gasses a vortex effect.
Anyways, that's my two cents on this topic :)
P.S. I really love that someone reached out to you with such request. It means you are doing a wonderful job and it's getting noticed :)
I agree that drilling holes at the chimney base for secondary air intake is not the best idea. The air should come via a tube from the front "mouth" of the stove, so it's preheated in the fire section. Turn the chimney end of the tube upwards and weld it positioned in the middle of the ash pan.
Then the air intake tube (maybe 3/4 to an inch?) is also the long handle of the ash pan. Pull it out & empty
Great series on rocket stoves Bob. An improvement suggestion, a hot plate for cooking and boiling a kettle seems essential imo.
Isn't that what the flat top of the big barrel section already provides? I was considering that basically a stove top.
I thought the same. Heat goes right away through a chimney.
This is the basis for a rocket stove mass heater. The exhaust would be piped through a long horizontal pipe embedded in a thick piece of masonry inside the home. Then to the outside into a fairly tall chimney pipe. When done correctly it produces no smoke at all. People often use the inside masonry, with cushions of course, as a couch.
People are willing to pay for convenience and no one likes to spend time cleaning the rig day after day. So, one suggestion to expand on what you have, look at the bottom of the riser and burn chamber. In a drawing it looks like a rectangle connected with a circle on one end which I'll call the BASE. Change the mount system so that the entire BASE becomes a hatch which will swing open on the long side so all the ash will fall to the ground or in a larger container. Then you can easily sweep it clean with a broom if it's not hot 🔥. Close the BASE and your done, less than a minute!
People like easy clean and are willing to pay for it! If you like my idea, give me a good price on your new build. :). GL!
MO is still Missouri. 😀 MT is Montana.
A lot of Americans get that wrong, too. There are a lot of states that start with “M”.
cheers mate
Wrap the heat exchanger with corrugated metal. You want more surface area to better couple the hot metal to the air. Look up heat exchangers for camp cooking to get an idea.
Absolutely! I was thinking to maybe weld round or square tubing vertically around outside, to increase surface area and create a convective air flow. But your idea of using corregated metal (like roofing panels) would be of lower cost I think. Nice one! 👍
Ely cathedral has old cast iron (?) stoves with vanes jutting out from the sides to increase the heat exchange surface area
Instead of an ash pan, provide an ash hoe with which to reach in through the fire chamber & rake the ashes out. In order to introduce secondary oxygen to the vertical rocket tube, drill a 1" hole through the vertical fire tube about 5" up from the bottom & tap it for 1" pipe thread, drill a second hole through the outside barrel to correspond with the first, making it just large enough to slide a piece of threaded 1" black iron pipe through the outer barrel & screw it into the fire tube. At the end of the 1" pipe sticking out of the barrel, drill a series of holes (1/2" dia). 1" schedule 40 steel should have an inside diameter of 1.049 in., and the outside diameter of 3/4" sch 40 steel pipe should be about 1,050 in,. Take a short length of 3/4 " pipe and drill holes corresponding to those in the 1" pipe and then turn it on a lath until it just fits into the 1" pipe, & stop one end. To adjust the secondary air flow, rotate & slide the inner tube to expose more or fewer holes through the outer pipe.
Hi,
yes I can think of a few suggestions.. you covered two in your vid with a secondary air inlet and an ash pan.. but the only issue you need to ensure is that after the initial burn phase that no air will escape from where its not supposed to.. being as it is meant for internal use you don't want any form of carbon monoxide to leak..
My suggestion includes a secondary burn feed from the main air inlet (Shared inlet) this will negate any blowback if it were to occur as it would be dragged back in via the initial burn inlet.
Ash extraction could be done by installing a service hatch on the side or bottom as you suggest, but this will need to be sealed using fire rope or caulking..
Air flow is like water and electricity, it always follows the path of least resistance, so although the heat is pumping out of the top of the rocket stove and hitting the top plate (which can suffer from heat damage over long term) most of the heat also flows down the side of the exhaust port. My suggestion would be to insert some baffle plates to force the air in circular motion around the radiant heater section before it gets to the exhaust port. Yes this might slow the air flow down a bit. But it would also make it more efficient in using the available heat produced to come into contact with the outer edge.
Also on that note, utilising the available heat on the outer edge .. my biggest suggestion is to add fins to the internal and external surfaces of the radian heat drum.. this will give a larger surface area for heat transfer and also increase the rate at which the heat is dissipated out of the system..
Only problem is.. now I've made these suggestions on a public forum they cannot be used in a patent and are open to the public.. that sort of thing really sucks if your trying to make the ideas novel and unique.. to improve your own patent applications.
Anyhow good luck to them on developing their product 😎 👍
Interesting, I built a rocket stove the size of that large stove and it got the back of my pizza oven red hot! I couldn't believe it, I thought my BakerStone pizza oven was going to explode, the temperature dial went all the way around! I had to remove the pizza oven and it was OK. After that incident, I added a vent door to control the temperature and I can now keep it steady at 350F to bake bread etc. Very powerful those rocket stoves. I use the wood from falling branches at my Farm.
The ventilator holes shouldn't leak ash, since they are drawing air. But the easiest fix is just a short angled up tube on the outside.
More on those holes, if you put one near each of the three available corners, they would add oxygen while starting the vortex. You don't need a lot to start that, just a hint (also keeps the temp from dropping), which three maybe 3/8 inch holes would do.
The up-angled tubing is a great idea! The bypass air could be "throttled", and if my thinking is correct, the ash would become concentrated in the center.
cheers mate
When the fire goes out gravity wins.
@@mikebond6328 I'm not sure what you're saying. Are you expecting a deep pool of ashes in the chimney that will flow over to the holes and pour out? Then make your holes a little higher up the pipe.
How about drilling air holes in the bottom? An ash pan could cover the holes and catch extra ash. Great video! Thanks!
The idea behind Insulating the Rocket Stove is not to do anything in the way of heat radiation. It's 2 purposes are to First get the burn box area up to temperature ASAP. Second is insulating the Inner wall is to Protect the steel from being destroyed by the excessive heat & keeping enough heat in the riser tube is to make sure the wood gas ignites before it leaves said tube. This is where the secondary air comes into play right at the vertical turn of the riser tube.
I like the exhaust consideration already. The right angle is great. Of the wall thought, could the tube become a sand battery?
MO is Missouri, Montana is MT.
Great idea!
Essentially what a "rocket mass heater" is. A large earthen mass which the stove pipe exits through. Usually a long, low couch sized lump of cobb which the stove pipe is embedded in the bottom of. You run the rocket hard for a couple hours, which heats the cobb, which after the fire is out and the air intake blocked off and dampers closed, continues to radiate heat.
yeah they could and thanks for the correction mate
At least Robert knew about Montana. I bet many people in the U.S. couldn't tell you what MO stood for or what the abbreviation for Montana is, sadly.
@@thisorthat7626 I am not hopeful.
So grateful for all you share with us. I am planning out three Rocket stoves, one for house, one for shop and one for my bus to tv conversion. Love all the ideas, plans and explanations. Have to check out the boys up north, awesome that we have folks here in the states. From AZ thank you kindly!
It would be adding more cost, but I think add two runners on the bottom that run the length of the base to the chimney for the secondary air intakes, and a flappy panel on a hinge could be used as a damper to control the amount of air intake
Yeah, an air intake could improve its efficiency, but it seems pretty efficient already. For me, what that stove is missing is a water heater, using a copper coil wound around that internal chimney. A fairly simple plumbing job, with cold in/hot out, and maybe even a small hot water tank in there, though that would probably need some kind of pressure release valve. Seriously, with a constant feed hopper and hot water on tap, it would be a really useful piece of kit! Never mind replacing the AGA or Rayburn, you could build your own steam turbine generator or locomotive with a few of those!!!
Those 4" holes at the top of the feed tube are for an outside-air intake pipe.
Joe: with the extreme heat inside the internal chimney the possibility of a steam explosion exists. Wrapping around the exterior drum and utilizing a thermosyphoning arrangement should be safer provided you have enough storage capacity in the water tank or an arrangement to dump excess water heat say thru a radiator and possibly a programmable hot water pump which are fairly cheap and used for hydronic heating. In new home or home upgrade could be pumped thru pex pipe into concrete or underfloor heating and with the large increase in mass could fully utilize the stoves potential and greatly increase the time between stove burns.
That is fantastic! I have watched this for years! Great to see your review!!
So glad they sent you their heater to look over. Wonder if a sliding ash pan on the bottom would be hard to add to it?
An extra inlet, to take oxygen from the outside (of the house etc). The inlet may wrap around the outlet to preheat the air intake.
This would pair very well with a Tesla Turbine from TesTur Energy. We've just run our first steam tests. Previously we've achieved 4 kW+ with just compressed air alone.
In fact, at one point, we were working with Sky Huddleston of Liberator to apply for a grant to pursue pairing the two together, which didn't materialize.
Yeah, that grant went to Approvecho Research Labs.
I heard it was only barely, but nevertheless, it's still being considered.
@@bli3366 Thanks for the heads up!
if you fitted iron pipe(s) where the holes are drilled you could then use those pipes, when cold, to vacuum out the ash, the change would add little cost. You could also add fans to increase the flow.
The neatest solution I have seen however was the Aussie rockets site where he created a vortex.
cheers mate - a vortex does seem interesting for sure
Depending on the application or combination thereof if they were to fill the heating chamber with sand but have hollow pipes running through it the sand would heat up and draw air from the bottom, through the pipes, and then out. It can capture the heat quickly and use natural convection currents to slowly (passively) radiate the heat.
Can’t wait for some of your ideas for improvement! Mine is rocking away on pellets, thinking about wrapping exhaust with copper pipe for thermal battery of 55 gallon barrels.
that is one of the things I am thinking about mate for sure
@@ThinkingandTinkering I’d love to see if you have any clogging issues. I think my pellets have a bit too much softwood. Mine will burp smoke too when it runs out of pellets, but I’m working through those issues. Maybe we can come up with fixes.
@@nghermit4922 Try loosening the set screw in the collar of the pellet hopper, dropping the pellet feed tube 1/4" - 1/2", and/or opening the damper when you get low on pellets.
@@bli3366 Thanks! I will set that pipe down a bit! Appreciate it!
@@nghermit4922 Its "standard starting point" should be around 19" of pipe coming out of the bottom of the hopper; but we make it so that it can be adjusted either way.
Add an ash pan that seals the space effectively so that when you can adjust the amount of venting by sliding it in and out., that way you sort two issues with one simple alteration.
Jeez I love this channel! I can't wait to see what you do with the Liberator! From what I've already read in the comments, you're going to have plenty of ideas for improvement with this, can't wait!
Fantastic Rob, wonderful application of enthusiasm, knowledge and passion buddy, thanks for sharing
In the past I’ve worked on a vortex rocket stove which made the gravity fed flame concentrate into a swirl coming out from the stack which generate more heat while burning less fuel .
The idea is to have the gravity fed material drop down into a circular burn chamber slanted slightly upward to the round stack while positioning the air intake at just the right placement to control the adjustable draft or air intake .Burnt material or ash from pellets would drop down through a grate into a collection box . When built right and depending on the controlling of the air intake , you will actually have a very strong swirl of flame which is very interesting to see .
Perhaps Boeing should contact Rob. Their rockets need improvements.
Their planes do as well!
lolol
Hi Robert, not my own idea, but seen in a video of something very similar - wood gasifiers - for vehicles, they added (or injected?) water or steam into the unit, which took care of ash/ soot/ creosote problems and hugely (+/- 40% ??) improved clean heat output.
Overlapping technologies & sharing refinements seems like a good idea to me.
Have fun!
I think it was a you tube video which covered WW2 and included Germany, also London, amongst others, also later, showing more modern use of gasifiers mounted on the backs of pick-up trucks, which looked unusual, but still, a great, portable concept!
Have you considered whether to employ a venturi style air input which may replace the need for the air holes at the base of the stove? Just a thought. Keep up the good work Rob, always interesting and certainly beneficial for us off gridders.
Have a look in the horizontal burn chamber of the liberator and I think you will see insulation on the inside that is detachable and the burn chamber width is wider than the feed tube so the insulation doesn't obstruct the gravity feed.
can we not add an internal lining of say 100mm from the existing external drum wall i.e a drum in the drum like the can in the can heaters whereas it still allows chimney exhaust but the 100mm gap can be filled with kiln dried sand so it retains heat and radiates for longer yes it ads weight but it looks like an item that stays put when sited
I like it - kind of like a combined rocket stove sand battery?
@@ThinkingandTinkering exactly i think it would be awesome
Robert: Rather than an ash pan under the amplifier elbow where you have a row of holes drilled, try an angled slot ground into the elbow on a 45° angle where the bottom of this air intake slot is 30mm from the bottom, no ash will roll out here and the relocation of the intake of the air jet air intake will enhance the draw toward through and up the flue. Holes across the bottom will tend to create a burn there and not enhance the draw where it is needed.
I would like to see this in oil burner with an automatic light system for a thermostat and flame sensor, etc. I also don't see a circulation blower on the hot air plenum, as a unit this size should have a better way to utilize flow to the space it is intended to heat.
And for thoughts and giggles, I am starting a build of a soybean (aka rapeseed oil) forced air furnace to replace my wood burning stove because the price of cut wood deliveries has gone out of sight in my are, and I assume it has gone up drastically in most places.
Dear Robert, please design and sell basic starter kits, with the option to modify and collaborate, using common plumbing fixtures to produce an efficient stove for any individual purpose...
MT is Montana, MO is Missouri, just information, Love your channel, I’m the same way you are in improving things. Thanks
Im waiting to see a heat collector to put on some of these stoves to see what works best.
Consider testing the air flow of the air intake holes you suggested adding to the Liberator stove by having the ability to control the amount of air entering.
Looking forward to the results.
Thanks for the video.
(JF)
Would welding some vertical fins up towards the top help radiate more heat/faster? 🤔 Just posing the question, I'm no expert ✌️
mr. murray-smith, i follow the development of the rocket stove since years. there is something what i want to say: why is there only one rocket-pipe? why is there not a lager, more broad fire-place with more than one rocket-pipes above it? the 2 or 3 rocket-pipes will pick up the gasses from the larger fire place, without loss of any efficiency, i think, and the bigger rocket stove could be more easily filled with bigger and more pieces of wood in one filling AND be able to feed a waterboiler or heating system. and secondly, the covering with fire-stone of the rocket pipe is a very good idea and will make a better burning proces.
I can suggest a two chamber sliding ash tray. With one chamber in the stove under a grate to keep the wood above and let the ash fall down into the chamber. While the stove is still burning the sliding ash tray can be moved to place the empty chamber into the stove while the chamber that just slid out can be emptied of ash. The ash tray would just need to slide back and forth from left to right in order to empty one of the chambers. The stove never has to be shut down to empty the ash and no efficiency should be lost.
You could use an access door at the bottom of the chimney side, that hinges out from the backside, for a clean out. If you just want airflow then cut some conduit straws to lay inside at the bottom. The conduit can be perforated or have perpindicular slits for airflow, and it will pull from the cold side. That way you aren't making holes in your chimney bottom.
That looks a lot like a gasifier! Looks like it could be easily modified into a gasifier pyrolysis/stove, use the rocket to break the wood down to be distilled into fuels ,using saw dust, shavings, what ever, maybe use the wood gas to fuel a cook stove, catch the methanol to fuel a car or generator, this is what I. Been thinking about building, only a tiny version, built a lot like the liberator, maybe use oil to gasify the wood!
Well done to the guys at Liberator. If Robert likes it, well what can I say?
Weld pipe fitting at bottom 2nd burn chamber to port in outside fresh cold air to burn in 900c plus chamber.
Dual use at clean time vacuum hose could adapt to air supply for clean out or plug it shut.
It's nice and all, but a rocket stove for $2500 is a bit much. Maybe I'm just cheap lol
i disagree with you Robert. i do believe the entire burn chamber and chimney should be insulated to keep in as much heat as possible.
where people go wrong is having exposed steel in the burn chamber.
so if the inside is lined with ceramic sheet or if the burn chamber is not made of steel at all but rather clay/cement, then you can easily contain ~2k c. especially if you can surround this chamber with some mass.
where this high temperature in the burn chamber becomes useful is that you can burn less than substantial (almost green) wood.
the inner tube is not the heater, you do not want to extract heat from it.. the heat is extracted from the outer barrel and any subsequent flue or mass.
the awesome thing about the heat extraction barrel is that because the gasses flow downwards, and on the outside the convection causes an up flow of air, you get maximum heat transfer to the air. (just like the blood flow in the leg of a seagull)
Let me ask you a question if I can where the hell can you find carbon 100% carbon felt any ideas
Watch Liberator Rocket Stove videos on UA-cam , SWEET :)
Surely you mean a Marvel movie! 😎
Great suggestions for improvements.
How about a hot plate on top for cooking?
I’ve just bought a log burner for heating and cooking when the power cuts hit. 😬
That top is going to get red hot. 90% of the heat is going to hit it.
lol - absolutely - lol - I like the hotplate idea
@3:08 I think those fasteners securing the insulation will prove to be a design flaw. Those may corrode from hot exhaust gases. Also possibly cause the insulation to crack and fall apart due to expansion. I would suggest; instead of bolts, score a rough texture onto the steel walls, and secure the insulation with a thermosetting epoxy.
Removable sand battery that can be taken into the house escaping uk building restrictions.
My Dunsley Yorkshire stove could almost be described as a kind of rocket stove, it has a large fire box for logs, at the back and at the bottom of the chamber is a slot maybe 11/2" high, it is there where I have to light it. The firebox merely undergoes Pyrolysis, once the flames exit through the slot in the back they go through what would be best described has a venturi chamber, this is firebrick insulated and a special brick with I think about 8 holes in it which line up with holes in the back of the steel. The flames drag in more air, and the afterburn chamber goes to about 1500 degrees where it burns off all the smoke, this is then sent around a boiler jacket before heading for the chimney at the same time it passes over the top of the fire box fire brick which provides more heat for pyrolysis. It burns very clean provides hot water and central heating in the worst of winter, it has just not been cold enough yet to use it. But the design could be used in a rocket stove and you may be able to get a diagram online. Another thing I once read about was a professor hills boiler, these involve a down burn feed and a super insulated refractory channel with a air blower.
1 minute 30 seconds in and I gotta hit the like button just for the humor ! Can’t wait to see any improvements.
I just found your channel yesterday. I wish you lived in my neighborhood. I would have a blast in your shop learning. The wisdom is so enjoyable!
If your enthusiastic knowledge is combined with these manufacturers the i can only say that the sky is the limit in rocket stove technology from now on . Great video and a wealth of extremely helpful information as always. Thank you.
Is it just me or is RMS blowing up a bit now (rightly so)? Marvelous vid, very uplifting
I like the round exterior housing, it looks like it would lend itself, quite easily to adding a water coil for hot water or distribute heat to other areas.
It's brilliant to see you get the respect from the wider community 👏. Keep making the world a better place mr Murray Smith
I think it's great Rob, that someone with your noggin caliber is getting right into this.
Thanks for explaining the finer points of effective burn temperature and the whole principle behind an effective rocket stove.
The only thing that I can think of to modify this stove is to have a smaller version. Maybe one that could be dismantled ? But we dont want to sacrifice simplicity.
The focus on these stoves is evolving and it will be very interesting to see where it goes. Some method of chimney insulation for the DIYer would be good.
Hey Rob, thinking back to your kiln build and then looking at their barrel... any thoughts if the rocket could be used as a makeshift kiln?
I also was going to suggest incorporating a sand battery into that but it looks like it's already been suggested. Great video thanks.
Looking forward to 1753 already. That's a lovely looking bit of kit!
I love this!! I was thinking moving the location of the holes around a little bit might be good to help find where they work best! (If they aren't already in the best spot) I was thinking including your oxygen slightly closer to your primary wood burn might be a good idea! Of course too far could be bad but maybe only a couple of inches?
Allowing the fresh air from the holes to mingle with your freshly generated flammable gases a little sooner might allow for an easier burn? They can get roaring a little sooner and have more time spent in the exhaust tube to do their thing?!
Looks great. Maybe one or two of those stove fans on top would help circulate the heat quicker. Speaking as a non-techie, does it make sense to add more thermal mass if the rate of burn and temperature can be regulated by air intake and the amount of fuel being fed in by the hopper? Perhaps a couple of temperature guages would be helpful?
it depends what you want to do with time the heat is released mate - you can think of thermal mass as a battery - the first bit of heat goes to heating the mass - then the room then the fire dies and the heat absorbed by the mass is given out - with out the mass the heating is felt straight away
I have seen heat powered fans on stoves. Not very powerful but a big help circulating the air.
how about burning it then give an opinion or ideas is it just me ? wtf
Steel spalls at 1600F. And we are looking for temps over 1350F which means we could hit 2000F. The liberator is perfect for a home - especially when running on pellets with a bit of a mass. A bit underpowered for quickly heating a shop. Bigger rocket "engines" hit the higher temps easier/faster for cleaner burns. More wood also means more heat per filling - so less need to fill. Which is why the liberator really shines when using pellets.
Howdy. Love the videos, many thanks. I have been working with rocket heaters for many years and, Pls don't take offense at this but you are kind of missing the point. The J tube/burn chamber is only half of the equation. You have mastered this part wonderfully but there is so much more to the story. The liberator is closer to a true rocket stove as it includes the outer shell. The insulation in the riser is not just there to allow the temperature to remain at flash point, it is there to create a temperature difference between the riser and the space between the riser and the outer shell thus creating a huge push /suction/draw propelling the heat out of the system and, ideally, through an exhaust which, because of the power of the draw, can even be horizontal rather than vertical and be channelled through a heat sink like, for instance in my old greenhouse rocket stove underfloor heating ( 20m of horizontal metal ducting underneath the grow-beds), or heated cob benches. but keep up the good work!
I would watch a channel of you just reviewing other people's work like this. It's like shark tank with a conscience.
Suggest: change lid at top to inverted drum so you can get down to bottom for cleaning. Put outer sleeve (open at bottom and top) over gas chamber to create convection current, include fins b/w inner and outer walls for better heat exchange, which will remove more heat from exhaust gases, it will also keep the outer gas chamber temperature lower and safer
Interesting explanation. I understood that in masonry stove they burned to about 1200C and captured the high temp in a ceramic mass via a convoluted flu system. Is the difference that the flu is not metal and the ceramic can sustain the higher temp, which then acts as a temperature "transformer"....
99.5% efficient - that means you won't improve the burn. Only improvements left are to improve feeding and improve radiation/convection. Would be interested to know what the exhaust temperature is as 60'C is about minimum to prevent condensation and any more than that is waste heat.
I suppose a reduction is size for the same power output would be another improvement which could be done with better conductors, i.e. using cast iron where possible.
It could be possible to extend the bottom square pipe and cover the open end with a hinged cover with air valve. This way you can easily clean out the whole pipe by pushing through a simple piece of wood into the ash bin underneath. A simple folded metal tray sliding on fixed bars could serve as low dust ash holder.
On top of the extended pipe a cooking plate can be mounted.
I just really like you Robert, you seem so genuine. Keep up the good work.
How about a stack of removable or angle adjustable overlapping steel plates to be placed inside the smoke chamber in order to slow down the exit of the hot smoke, which will allow more heat to be generated and used via radiator fins on the outside of the smoke chamber, (these could actually be clamp on so as to be removable as well). More steel carries more heat to the outside air. One could also add heat driven, heat sink type fans to the out side to disperse the heat throughout the room.