Hi I'm new to this site and forum. I would like to build a 8" Thermal mass heater and have been looking on Youtube and any other place I can get information which has led me to you . My question is; The exhaust from the barrel, should it be at the bottom of the barrel facing down or at the bottom of the barrel at a 90 degree angle to the side? My idea is to install this in the green house and warm the soil.

thanks

FredinWeston

Fred Lake : Usually, for compactness, The barrel exhausts down into the base where it turns at right angles to enter the Horizontal thermal mass!

Using the Rocket mass heater in a Greenhouse has problem areas to overcome, and this is a little out of my area!

1) Artificially high moisture content in the soil and in the air, combining with lye in the wood ashes deposited within the Barrel, Rocket core and in the thermal bench potentially causing the mortar and the horizontal stove pipe to degrade esp. when the thermal material is buried down in the green house floor

2) The high levels of moisture making the Cob Bench spongy, and causing it to sag .

3) The dragon that lives in your rocket needs frequent feedings of DRY Small Wood, Over 3-4 hrs to give you 20-24 hrs of thermal mass heated green house, while you are working in your green house!
The wood will need its own storage area outside the green house to keep it perfectly dry ! which means you will meet your self coming and going thru the outside door exactly when you are trying to conserve heat!

I have asked the 'powers that be' here at permies to create a Rocket stove in a Greenhouse Forum page so that like minded people can get together and figure how to deal with these issues !

Hopefully we will get that soon, hope this helps Pyro-maticly yours Allen L.

Hi Allen,
Thank you for wanting to put the green house people into their own area. I stumbled into the Rocket heaters a few weeks ago and have become fascinated. We had a green house free standing about 200 feet from the house 20 X 40 and it did well. We have a 120+ mph wind come through here and some folks lost their buildings, the green house survived but damaged. So I moved it to the side of the our house.
We have one long bed 60' X 6' or so we brought up soil from the valley and mixed it in with a load of sand. Our problem is not going to be moisture as we live at almost 9000 feet in Colorado. With the climate change we have intense sunshine and as soon as the sun goes down its cold to very cold maybe 2 percent humidity. I bought plastic conduit and made the hoops with heavy mill plastic and made a green house inside a green house. All working well.

Because of where we live spring comes late, and my wife is thinks we should use a propane heater to keep the green house warm...But really we need to heat the soil. I am refusing to pay the propane guy anymore than I have too ( we also have wood heat in the house with propane as a back up). So when I found the rocket stoves and thermal mass heaters you can bet I sat up straight. What I do know is the fire department has spotters and they will send someone to come check if they think I am burning in the open . The smoke is a problem when I first get up in the am as I stoke the fire and I know they can see it. Mind you I can see miles and miles around me and there are no more than 50 people living within 8 miles around me. No smoke to speak of with a good working rocket stove. That means to me I might get away from any extra carbon tax.

Anyway I am a expert welder and steel fabricator. My plan is to make the whole thing out of metal. When it burns out I will gut it and replace it. I have firewood as I am surrounded by pine trees as far as the eye can see. Because if the altitude was not able to split the wood by hand so we invested in a log splitter some years ago. There would be some room in the green house to stack wood. My concern is the heat coming off the top of the barrel, as we are using the polycarbonate as the covering in the green house, really don't want to come in to melting plastic.

My plan it to dig a trench down the middle of the growing bed and put the pipe in it and vent it out....My unknown right now is...with a 8" system how much pipe can I run? it would be straight no bends and out to the leeward side of the green house. I understand the clean outs and such. Not thinking Cob is going into this build. Most youtube videos show the outlet coming down out of the barrel, I asked because the original design show it coming out the side.

thank you so much Allen

Fred Lake : seems like you've got most of the problems solved, most commercial greenhouse owners treat their Greenhouses as though they were saunas, to the point that every thing is constantly wet -every work bench and table has mud balls under them from the workers scraping mud off of shoes, you should get lots of solar ! Sounds like you could have a gently warmed waist hi seedling starter bed if you wanted to please continue to post here and let us know how your Rocket works for you in your Greenhouse, and watch for the new forum site where we put you people in your place :p ! Pyro-maticly Yours , - Allen L.

Grrrr please get a set of plans or read the book before you build the stove.

DO NOT TRY THE ALL METAL FAIL!!!

there is a reason for the masonry in the burn tunnel and heat riser and steel will not handle the heat. build the damn system as designed before you go and try to change things.

Hi Fred, I have started a new forum topic under the title '' our own forum topic ''! please make a note of it and make any Rocket Stove / Greenhouse topic there !

Hi Ernie, if you could pass the word on a little it would be a blessing,