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  1. Awesome! Can you rig up some kind of system that will slow the pellet burning when the greenhouse is at target temperature? Something that will constrict pellet flow so there is essentially just enough burning to start it up again if need be?

  2. That is a beautiful burn. If it is too hot I assume you will just narrow down the passageways and/or pellet feed tube. Can you get expanded steel and stainless?

  3. yes, 12 pounds. That's around 96000 BTU's/hour. I'm taking around 34,000 into the water, the rest goes into the air and thermal mass, and some goes out the chimney! Pellets cost 4.18 for a 40 pound bag.

  4. Try fuel oil instead of gas. It won't exsplode if you use too much. I do that or use a little used motor oil.

    When I was 14 I put about a tuna fish can worth of gas on a fire I though had gone out. Was going to wet the 'fuel' and let it soak up the gas and try lighting again. Blew everythng out of the 55 gal drum… burned my eye brows off and some of my hail. The lit gas and crap I was trying to burn covered the lawn… Fire was going good but so was the yard
    After that I never use gas

  5. Awesome update on the rocket stove. You have some great ideas that work. I really enjoy your videos and the detail to explanation on them. Keep up the great work!

  6. From experience using pellet fuel…moisture is your enemy. Clogging is usually caused by moisture. Good luck with this experiment.

  7. Solid update! We plan on heating our cob house with a rocket mass that utilizes both radiant and mass heating techniques. Your videos are really helping me wrap my brain around some of the engineering issues. This is awesome stuff.

  8. hey love the vid man always using that grey matter and that's what we need…Ceramic is also good and cheap it'll with stand the temps… cam across this guy vid and I think you would love it the name is (wood stove run's a generator, produces gasoline, runs a fridge and heats hot water at the same time ) keep up the great work and buy a Electric eel to help with energy cost πŸ™‚

  9. Hey Rob.. in a previous post you said that you had Koi…

    i was wondering what the water temp in the tank is.. The reason being if the water temp was to warm, if the fish are mature enough, they could go into spawn'n mode which could cause damage to the fish and cause a Spike in Ammonia in the system..

    Was wondering how big the Fish are at this stage and number's of fish..


  10. The rocket mass heater is the part of your greenhouse project that interests me most. Thanks posting the very interesting videos.

  11. I can't answer for this stove's operator, but in my experience you get the most efficient burn by burning hot and fast. The thermal mass stores the lion's share of heat energy like a giant battery and releases it slowly. Depending on the weather and how much fuel you put through it, you may not need to burn but every few days.

  12. There is a book by Leslie Jackson and Ianto Evans about rocket mass heaters that explains all the physics and design principles. It will save you a lot of trial and error, it's a great book. As far a pellet feed, seems like this dude is cutting edge.

  13. Awesome! Thanks for making all your research open source. I wonder if there's not a way for you to use free wood chips instead of having to buy pellets. My city gives me all the wood chips I can haul away. I've thought of making a cartridge of sorts to fill with the free wood chips and arrange it to where the fire can heat, gasify, burn it, and leave me with charcoal to make biochar for potting mix or aquaponic substrate. Looking forward to your future discoveries, good work.

  14. You know, if you made char and rinsed it, you could charge it with nutrients by using it to filter your aquaponic water and recycle those nutrients into your potting mixes. Hook a urinal up to your water tank and you'd never need to buy nutes again once you had enough vegetable scraps going to keep your fish fed. Use azomite and sea90, recycle all your nutes, eat raw vegan off your crops, you'd look and feel like Bruce Lee in no time.

  15. The entire floor of the greenhouse acts as a thermal battery! You should watch some of my other videos about building the dome. πŸ˜‰

  16. my sample slats that I showed in the video are 304. I have 304 expanded steel on order and should be here for this weekend.

  17. Not really, the drafting keeps the flames going up the chimney. There's no air in there so it would just smolder.

  18. the building is roughly 30,000 cu. ft. when it's below freezing outside, I'll usually burn 2 bags (80 pounds). When I'm working in there, it may be 3 because I don't like to be cold. πŸ˜‰

  19. I've done some work with a second grate. It was hard to access and the ash would build up on it because there wasn't a lot of movement to keep things clear. πŸ™

  20. the water is around 60 degrees and will go up to a max of 78 or so during the summer. I'm sure they'll start breeding this spring. My larger ones are about a foot long now.

  21. I have piles of wood chips here that we just spread around on the ground. I've been trying to figure out a way to pelletize them without having to run them through a hammer mill first. Some day, I'll come up with something!

  22. You rock!!! I just put my first RMH in my small 12×28 foot hoop house. I am using standard fire wood which is a bit wet and am getting incredible amounts of smokeback. I still need to bury my 8" pipe with sand but my supplier stored his sand outside and it is frozen solid. I need to wait for a thaw. I am going to duct the intake outside the hoop house so that if i do get smokeback it will go outside. What do you think?

  23. usually, the hotter the burn, the more efficient it is….but….it's heating up the greenhouse too fast now. πŸ˜‰

  24. Do you know what is the temperature in the combustion chamber ?

    Ss304 will handle temp higher than 1400 Β°F bug will spall or flake (oxidation) after the cycling condition hot-cold.

    SS409 is the best choice but does not exist on round running. 409 does very well in the 800 to 1300 F. Over this temp, it will be catastrophic for 409

    Types 309S and 410S are heat resistant that resist even higher than 1500 F but it expensive

    So you need to know the temp in you combustion chamber

  25. I haven't purchased a thermocouple (yet) to check that temp but most people say it burns around 1200-1500. I have some ss304 in there now and it's holding up fine so far…..much better than the carbon steel!

  26. Great work Rob. You definitely add a great deal to the projects you share but showing hard data about them as well as showing how/why certain parts may not work over time.

  27. Thanks, I'm hoping to add some thermocouples and other sensing equipment into the system for next year. I'd like to get some real numbers on how well it works.

  28. Good video! Use kerosene or diesel instead of gasoline. Much safer. Have you done any cost analysis of a RMH with wood pellets versus using a conventional heater (maybe propane)? Twelve lbs/hr rate for wood pellets sounds like it could be costly.

  29. I usually use diesel but was out. πŸ˜‰ I haven't compared other fuels. Pellets cost $4.18 for 40 pounds so that's about 1.25 per hour. A standard oil furnace burns about 1 gallon per hour at about $4.00+ per gallon. When it's really cold out, I usually burn about 80 pounds ($8.36) per day.

  30. I know, but i think at the temps you are at, there should be only marginal improvement in efficiency, but you can loose significant durability. I think i read on permies that even stainless will disintegrate after a year or two if the stove is "over optimized" for efficiency.
    But it will be useful either way, if you actually test this. πŸ™‚

  31. You were talking about restricting the pellets led to a less "rockety" burn. is that due to less air from a lower draw? Would adding a fan allow a variable stove to operate at better efficiency?

  32. It's not about restricting the pellets, the laminar flow is because the gasified air mixes with the fresh air that comes through the "ash slot" in the grate so the air flow isn't very turbulent. With a regular RMH, the fresh air is getting sucked through the wood and mixing in there….very turbulent. I don't have any proof that it's a better burn, but I do know it's hotter since it's melting my rock wool and that's rated for 2000F.

  33. I am wanting to heat my 28' x 40' barn which i don't have enough electricity to put in an electric boiler, so i am thinking of trying wood. I have come across your videos and found them very helpful. However, i would like to capture most of my heat into water so i can heat the floor. Would there be a way to build it so that most of the heat could be captured in the water? could i build the heater of steel and use a water jacket? what would your thoughts be? Thanks for all the info so far.

  34. You should be able to build a water jacket around it. When I rebuild this one over the summer, I'm planning on doing a similar thing.

  35. Wow, you have done some impressive work. It looks to me like you may have something you can patent. Have you considered that?

  36. Patents are expensive and a huge pain in the butt to do. I rather just share this with the general public. πŸ˜‰

  37. You are basicly building a micro blast furnece i suggest you read up on blast furnece's that may hrlp you achive your desired goals. And may i suggest titanium 6-ALV its cost a little more and is a pain to bend (dont go under 1/4 Radius) but you aint gonna melt it.

  38. I have much admiration for people willing to take the unbeaten path and experiment. Its trailblazers like you that make other peoples lives much easier. Thank you

  39. 12 lbs per hour? Thats alot of btu's. A 40,000 BTU pellet stove only uses about 6.6 lbs per hour. Wouldnt it be more efficient to fab up some hydro to a pellet stove?

  40. Why not use a heavy guage ni-chrome mesh rotating barrel as a fire grate, so that the barrel can be rotated slowly to churn the coals and allow the pellets to crumble and drop the fine ash thru the mesh, down onto a ceramic (fireproof) ash pit. the rotating barrel could be geared to the pellet auger so that they both rotate during operation. (manually, or use some sort of spring wound, or gravity/pendulum escapement, etc. ; )Thanks for sharing some good engineering thoughts, and experience!

  41. Protecting them even more expensive… Simple fact is patents are for the 1% to fuck over the rest. What you need to do is put it in the Creative Commons and specify how one can use your IP. Just a thought. That way if someone tries to patent your work it is already in the Creative Commons.

  42. I have a heater for my greenhouse but can't get the suction you are getting and I get smoke puff backs… Is my burn tower too short…. Too much barrel space… Thoughts?

  43. Have you experimented with a thicker Drilled metal plate for your top cover? Pretty much every rocket that i have seen using expanded metal fails due to the high temps.

  44. The expanded stainless steel is working fairly well so far. Most of the combustion occurs after the gas leaves the area. It's still hot, but not as hot as the combustion chamber!

  45. You probably answered this already, but, did you get a secondary temp reading of the expelled air out of the dome? You only show the 101F @ 5:21…Too bad you couldn't extract more heat out of that air.

  46. When I'm running it with the pellets, it's about 150F at the exhaust. Considering it's over 2000 inside, getting it down to 150 is pretty good! πŸ˜‰

  47. According to sales in this area, people are selling their pellet stoves because of the cost of pellets and corn they burn and are switching to the EPA rated woodstoves instead. I've noticed this more lately and am glad I didn't invest in the high cost of a pellet stove, over my wood furnace. The research you've done is interesting however and I wish you well with its development.

  48. Thanks. I choose to burn pellets over wood even though I can get unlimited wood for free. I'll spend around $800 for this season in pellets. The time I save buy not having to cut, split, stack, season, move, and stack again is well worth the investment. Plus, my back thanks me!

  49. Yup, I understand, and I'm not saying pellets are not a good idea. I however, like to process my wood (good exercise) that's all. I'm old school yet, but who knows, some day maybe pellets will be the answer.

  50. hey just a thought, instead of you using the expanded steel for the lid why dont you make another grate to position over it. im sure it will hold up far better. πŸ™‚

  51. It's restricts the gas flow just a bit too much. The new stainless grate I'm using is holding out fairly well.

  52. I'm with you 12# a hour is alot, a 40# bag, 4 bags a day. 16 dollars a day. Awesome presentation though young man.

  53. Hey web, awesome video's. Quick question, are you heating day and night? or just at night? I read that greenhouses with tripple pane polycarb can get up to 70's during the day if properly insulated. When i build, i would only want to have to heat at night. And if you do, why would you want to double your burn rate? Wouldn't that mean you'd have to get up in the middle of the night to refill the pellet hopper?

    Sorry for the slew of questions

  54. I usually only burn one or 2 bags (40-80 pounds) at a time. There's enough mass in the building to maintain the heat throughout the night.

  55. Have you thought of substituting some ceramic in for the steal parts. I imagine they'ed last longer. You should look into to.

  56. And with longer chimney, fire will be more hotter, because draft is bigger. chimney could be 3-5 feets longer, or use the old good rule: make the chimney as long as the top of the building. Then smoke goes far from the building and the risk of the fire is smaller, because dmoke isn't so close to wall. without longer chimney, wall may become black, too. In Finland, chimney MUST be as high as the building. the law says so. AND can you close the air flow after burning?. continues…

  57. It's been a full year now since you published this. I'm tinkering with pellets now too and wondering what refinements you've made on your system since then? I really need to come by for a visit. πŸ™‚

  58. Seems your biggest issue is crappy pellets, The local made pellets where I live leave no ash or clinker when used in a mass produced heater, the cheaper imported pellets used in the same heater will clog it up as you experienced.

  59. Man that is a nice heater! I like this it sure burns hot. If you are wanting to make any replacement parts to last longer than the 304 stainless you have some good options Inconel will withstand a lot of heat. Titanium and tungsten are also very heat durable. 304 stainless is very common and is a work horse but as you go higher in the 300 series the stainless has higher alloy content and will be more durable like 309, 316, 321. 316 is a good upgrade from 304. I bought some incoloy 925 a while back I like it a lot it is very burn out resistant at 2000 degrees F.

  60. How expensive heating with RMH like this comparing to other methods or central heating? Wont it be more than potential commercial profit from yield on that same area?

  61. I heat my house with 40 pounds of pellets per day. The amount of heat you're getting vs how much you're burning is a joke. It would be cheaper to heat my house with electric heaters than burn as many pounds of pellets as you do.

  62. Nice research and design progress. Consider reviewing Korean gravity-fed pellet hoppers. They have made some very efficient pellet feeders/ burners.

  63. 12 pounds an hour is an awful lot of pellets. You're only getting a little over three hours on a bag?
    And using gasoline to start this fire is so dangerous.

  64. I have a question and hope someone will see this who knows the answer. Have you tried to burn wood chips- and by that I mean the tree services now put lots of the wood they cut down through a chipper. I have a heater made like yours out of a old water heater and I also have the 22 degree feed tube. I don't have the dump pan but mine is a lot like yours and I had thought if I had a bucket of chips and wood start the heater going with some sticks/ limbs and then take a small ice scoop and drop them down the throat of the feed tube they would burn ok. I am thinking I would need a little grate or stand at the bottom so air would flow but other than that I am thinking this should work. I would have to feed it often but my heater is only supplemental ti cut down on fuel cost while burning up basically trash. Anyone else had or done this idea

  65. Nice explanation and so as the work.. Can you try to push cold air flow whit any turbine and what can happened..?

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