Greenhouse Rocket stove

I am currently building a rocket stove for my greenhouse. The fire bricks i used are 4.5" by 3.5". When I place the small barrel 16" over the chimney it leaves very little space for the
flu gasses to escape. Will the design shown work where I would attach the 16" barrel to a 24" barrel as shown on the attached diagram. Will I still get the draw I need?

Fred : I've only helped on the build of 2 ' rockets' and 2 rocket stove mass heaters - but they worked ! I tried to listen to the Instructors carefully ( Ernie and Erica Wisner , who are moderators on these forums ). I want a R.S.M.Heater in my Yurt by next spring ! Having said that, The Golden Rule seems to be Feed Tube no higher than 1/3rd the height of the Heat Riser/Chimney, and Burn Tunnel length 2/3rds the height of the Heat Riser, - - so, I ask, why do you have your Rocket Stove belpw grade in your picture, this may add height to your Feed Tube , changing your scale ! Here are my thoughts, 1) The higher you raise your thermal mass to be just below your seedling bed , the less distance you will have to bend over to work on your plants ! 2) if you have your Feed Tube outside your greenhouse you will not be meeting yourself coming and going in and out thru your Green House Door losing heat to outdoors with every trip ! And you want to use your Green house for greens, Not wood storage * ! Remember that the rocket stove needs a lot of attention to feed it, tho the pumping of heat into the thermal mass is Automatic ! Every time I visit these forums I find that I gain new understanding of how my future R.S.M.Heater will be set up ! Pyro-maticly yours Allen L. * - I guess the wood could be considered Thermal Mass ! A.L.

Fred : I've only helped on the build of 2 ' rockets' and 2 rocket stove mass heaters - but they worked ! I tried to listen to the Instructors carefully ( Ernie and Erica Wisner , who are moderators on these forums ). I want a R.S.M.Heater in my Yurt by next spring ! Having said that, The Golden Rule seems to be Feed Tube no higher than 1/3rd the height of the Heat Riser/Chimney, and Burn Tunnel length 2/3rds the height of the Heat Riser, - - so, I ask, why do you have your Rocket Stove belpw grade in your picture, this may add height to your Feed Tube , changing your scale ! Here are my thoughts, 1) The higher you raise your thermal mass to be just below your seedling bed , the less distance you will have to bend over to work on your plants ! 2) if you have your Feed Tube outside your greenhouse you will not be meeting yourself coming and going in and out thru your Green House Door losing heat to outdoors with every trip ! And you want to use your Green house for greens, Not wood storage * ! Remember that the rocket stove needs a lot of attention to feed it, tho the pumping of heat into the thermal mass is Automatic ! Every time I visit these forums I find that I gain new understanding of how my future R.S.M.Heater will be set up ! Pyro-maticly yours Allen L. * - I guess the wood could be considered Thermal Mass ! A.L.

Hello Allen,

Thank you for your reply and input. All the dimensions I have used were calculated using "Rocket MassHeaters" by Ianto Evans and Leslie Jackson. The 24" barrel piece that I added is 13" tall, so I was wondering if this extra capacity at the bottom would affect the flu gas flow? All dimensions, as previously mentioned have been followed. At the north end I built on a potting shed / wood storage area. You will see on the attached sketch that the exhaust pipe will run beneath the beds which are 2' in height (less bending). The beds will have rock in the first 8" to act as a heat sink below the beds.

The rocket stove was built inside the greenhouse so I can also benefit from the radiant heat. I live in the heart of the Rockies where 20' feet of snow is average for winter. Our winter temperatures can vary wildly - and be anywhere from -31 to +15 degrees F.

Again, thanks for your input - and after you review the latest attachment, if you have any ideas, I'd love to hear about them.

Fred.