First data is coming in from the larger pellet basket I made for Critter, "Works TOO well!" "Kick Shock" Kevin MacLeod (incompetech.com) Licensed under Creative Commons: By Attribution 3.0 creativecommons...
I built a 55 gallon version of your stove (6" flue) and your pellet basket. The stove is on my page, although I say nothing during the vid, I do believe I credited you in the notes. My burn chamber and riser is of insulated firebrick. My basket is made out of quarter inch stainless tubing, hammered flat. I incorporated a height adjustment so I can control the burn. I was getting the sides of the barrel up to 800°. Given the size of the area I was heating, it was wonderful but, like Critter, I went through a lot of pellets.... easily a 40lb bag a day, probably more. Also like him, I hand fed the basket.... which wasn't too bad since my workshop is in the next room, where intake air is drawn from. Being financially challenged, I could not afford to feed it pellets. I began experimenting. Chainsaw sawdust works almost as good as pellets. I also shredded up bark, sifted it to 1/4 inch... it works but burns worse than cheap softwood pellets. The basket needed to be cleared of ash every 10 minutes... The bark is now being used as mulch. Not recommended. So far, my best fuel has been chopped branches, about 1 to 2 1/2 inches in diameter, cut to about 3 inches long. I got surface temps over 1000 with well cured wood. I will be retiring this stove next season, having seen tons of other innovations in YT. I want to incorporate innovations that I see as compatable. I also want to burn cord wood, but still have the option to burn pellets. I tried attaching a steel box to the Zero rocket to burn cord wood... BIG mistake.... however, HUGE lesson was learned. The fire MUST be as close to the riser as possible. Also T2H made a comment on another vid about how a larger fire needs a larger flue, proportionally. So, I may be making another huge error. . but I have to try. I'd like to stick to the 6 inch flue. Oh, I'm also using a crushed stone mass... so.... If mass is used, it is in one's best interest to have the exhaust as hot as possible. More ideas are flowing. My next build will begin in September. Thank you again for the inspiration. I send everyone who is interested in their first build your way. Your build is very basic, AND highly functional. Peace
Many top fed pellet stoves suffer from the burn creeping towards the pellet hopper. I have a commercial pellet stove from Harmon. It eliminates the creeping burn problem by feeding in the pellets from the bottom with a screw and a 1.5 inch auger. Only the pellets on the end of the auger get ignited. The pellets push upwards into the bottom of the coals in the burn chamber. Ash and any unburned pellet material get pushed to the front of the burn chamber and fall off into an ash tray. Initially the pellets are gravity fed into a sliding 1/4 " steel flat plate with an oblong slot in it that oscillates on top of a similar oblong feed hole to the auger. When it's open, the pellets fall thru. When it's closed no pellets fall thru to the auger. The faster the motor runs, the faster it feeds pellets to the system. Control the fuel rate, and control the temperature. The same motor runs both the auger and slides the plate. Food for your thought!
Hi Mark, I have an idea that might throttle back the rocket. Could you set a loose fire brick up against one side of the burn tunnel/feed tube, then make a pellet basket that is 1 1/4 inch narrower? That should keep the dynamics of your current setup the same, just provide less surface area for combustion. It might also be a good way to switch between heavy winter use and lighter spring/fall use. Great job on all of this!
Question : When at a somewhat optimal temperature what is the depth of the basket in the burn chamber . I am implementing your design using a 100 lb propane tank . And have optimized a lot of things, but do not want to build this piece 3x if possible
The bottom of my pellet basket sits about only 3/8" off the floor of the burn chamber. It is positioned all the way forward (toward the tank) for lighting. As it warms up I gradually move it back away from the tank maybe 40% of the way at full tilt boogie, allowing more air to enter in front of the burning pellets, thereby adjusting the air fuel mixture. Think of it as a carburetor. Choke on when starting, lean out when warmed up.
My configuration differs from yours, but the same 'burn through' happens at about the 3 hour mark. I believe the rise in brick temp is partly to blame, plus the lack of a sleeve. That will be my next modification.
You can easily regulate the amount of BTU's by regulating the primary air coming in. To create a certain amount of heat you need a certain amount of fuel and a certain amount of air. If you lower the amount of air coming in, less fuel will burn and therefore less heat will be produced.
You're speculating. We have actual data. While what you say is true, it did nothing to alleviate the primary concern of burn creep up the basket toward the feeder tube. In fact, it made it worse. The solution is to keep air velocities high and restrict the basket size. I describe only one method. There are others.
If you won't provide enough air, it will still burn but unefficent, will create much soot, ash and smoke. More efficent way is to limit how much pellets are burning at the time. To keep balance between choking and blowing off the flames.
is it possible to make another updated vid of the inside of the stove to see how it's held up ...i have bought your plans but still yet to build it and just wondered how it's surviving after a few years of burning thanks
Hi I'm busy toying with a few ideas for my workshop in the UK. I'm a joiner and have a tons of wood shavings from the thicknesser. Do you think there is a way I could make this work with them? Btw great videos! James
Hey Z. Love the ongoing data I've been seeing from you. 1. What can you tell me from critters findings and yours with regards to the best air gap from the burn tunnels floor and the bottom of the burn basket. I know that critters basket was possibly going to examine it through different burn heights of the feeder to see potential of different pellet pound burn rate as well as possible heat output control. I'm trying to figure out my baskets air gap underneath bottom surface of the basket. 2. I noticed I don't have an air gap in front of the basket while burning in the latest videos of your newest basket. Have you stopped doing that due to better burn or is it still applicable. I'm asking because I wonder what you think about air feed from the burn tunnel level instead of through the fuel feed. I was gonna supply air from the start of the burn tunnel sideways and allow some air supply flow down one of the side of the pellet basket to give another point of air supply mixture. Thoughts?
Glad you're enjoying this series. Here's your answers. 1. It's still all about ratios. My fuel inlet is roughly 3.5" square. My optimum height above the floor just over 3/4". Critters is roughly 5.5" square and his optimum height is close to 1". That said, his "optimum" also runs too hot. His biggest problem now is throttling it down. A combination of height adjustment and fuel restriction in the basket will be necessary. 2. Now that my new basket design burns even hotter than the last, and I run it a little higher (>3/4" vs 5/8"), I find that too much air entering in front of the basket (ie bypassing the fuel) creates way too much "thump-thump", to the point that the pressure waves coming back puff some of the smoke back up the fuel inlet and out. Best way for me to control it was to leave the front of the basket sealed off against the fuel inlet as best as possible. Every stove will be a little different. Small changes make a big difference. Work slowly, test, test again, then test some more before making more changes.
so I just fabed up a cage thingy like yours, my stove is bigger , it burns awesome , but wow I could easy burn 40# of pellets in a day , if I left it burning how much does yours burn??
@@zerolabs Ok I may be 6 so I guess I may not be outta line... I do have a chute from the Cage 5"x4" x18 " and I was thinking maybe the large volume was forcing more pellets through before the burning ones were 100% gone but maybe not... I am in the process of making a smaller feed tube setup like yours to see if it burns less..
Do the pellets make more heat than using regular wood for fuel? Just curious. By the way, I used your J-tube design for my stove and it works great! Thanks!
Pavel Zajec pellets have a moister content of+- 10% and are Small it has more surface area -> faster offgassing of the wood =faster burn = more heat . finer feul Burns faster, a woodblock Burns long and gives heat of slowly wooddust suspended in aire can explode ,oilburners spray a mist of oil witch egnites with a mere spark oil in a puddle meeds more heat to egnite .
always better to limit fuel supply, messing with air supply or exhaust can cause cold fire which makes too much creosote, smoke. Unfriendly to neighbors, bad for maintenance of your system.
how. much does he want to burn ? if he has a good insulated inners he can reduce to a certain Point the feed ,if you are sure he has the same feedstock all time ,he can reduce to make tha entance like a 6inch rocket ,i don't know what Mass is behind or if it is straks up throu the roof ,you drain the most out of it some send out 200 °c /400°fso that is different to sending out 90°/210°f at the end of a burn (sory for my englich ,hengel greeting from belgium )
wow! got her running hot! cant wait to see how the mod works out!! also i found a old wood stove with 4 removable plates for cooking. ( if needed) and it cross burns like a rocket stove across the top or around a oven. been thinking of making it burn pellets so the burn time can last more then 2 hours on fire wood. any one have any suggestions? I can send detailed pic's.. it is heating my bus well at this time just don't give much time for sleep, between loads.. note this thing is small burns best on 2×2 size wood or one larger and one smaller.. temp out side is 23 and it's 96 in my bus.. that's 96 square ft..
have you seen the www.rocketheater.com stove. just like yours but without the brick. what do you think? i asked about the cleaning of the main tank and they said "The heat exchanger seldom needs to be cleaned, once every few years or so. Remove the pipe from the back and use a vacuum cleaner. Daily and weekly maintenance is ash removal of the combustion chamber, which takes less than 10 seconds."
Maintenance cycle is about the same for mine. I pull the top off for full cleaning inside once a season. Burn tunnel gets cleaned out once every 3-4 burn cycles. What I will say is his exhaust temps are WAY higher than mine meaning much less efficient. I have never exceeded 200*F even with the stove glowing orange at the top measuring over 1000*F. So, is his design better? You decide.
@@zerolabs yours has fins that probably make all the difference. I just see how much simpler his design is and cheaper it is, but with no plans. I wonder if either stove would benefit from secondary air. If secondary air was added, would the temps on top go up or less soot build up?
Technically, my primary air intake enters behind the basket and secondary air enters ahead of the basket. I adjust the A/F ratio by the front to back position of the basket in the main opening. Very simple. Very effective. Very easy to throttle it up and down.
@@zerolabs i see what your saying, but that secondary air cools the hot flame , the very reason for the fire brick . i personally think it would be better to add it half way up the column then test to confirm it helps. well thats my 2 cents. thanks for your replies.
I think his best options is to reduce the feeding to his rocket heater by putting something on the sides of his basket reduceing it to a 6" feeder 1/2 inch of Rockwool on both sides for testing is the fastes way to do that .
Thanx Z! I found a stainless shopping cart in the woods I'm thinking of turning into a pellet basket experiment for my Rocket Stove heater. The novelty of cutting wood has turned into a chore, must be great to just load pellets!. BTW, have you heard of MagneGas? I've been using MagneGas for about 3 years as a green replacement to Acetylene and it's awesome. I figure you probably already know about it but if not check out my vids and MagneGas.com, I'm obsessed w the MagneGas story lol. Keep it Up your are awesome!
did he try to limit the aireflow behind the basket Just by setting in a Fire brick ,i know these stoves like to run like a jet propulsion engine ,smaller stock tends to burn hotter ,long live Rockets ,, i already thought that a 8" systems would give a runaway ,look at deb for4web (here on RU-vid) he Burns 20 pounds or was it kg /hour he burned a foot of stainless pipe (Inox for the rest of us )away in a Rocketstove heating his Dome ,so jes we are working on the Edge of technology
Greetings, Belgium. BOY! You ask a lot of questions! :P Okay, he has tried a damper on the inlet side and on the exhaust side. Both cause more rapid creep of the burning pellets upward through the basket. That is undesirable. He is shooting for about 40,000-50,000BTU/hr or roughly 5lb of pellets/hr. He has a thermal mass attached to his rocket and his flue temps are about 175°F, even when it was glowing cherry red.
