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Post by gadget on Apr 13, 2018 7:19:33 GMT -8
Lets say in theory that creating a good draft was not an issue or something to worry about in your heater design, what would you do differently??
I'm in the middle of designing my heater build for this summer and am looking for idea inputs. It is going to be a vertical masonry heater with a ceramic fiber board burn chamber. It will have a hidden drum like a rocket heater with a blower to move heat to the room. There will be a 5 foot long bench off to one side. From there a copper heat exchanger in the garage with a 55 gallon plastic barrel for storing condensots(?). Lastly a blower pulling the flue gases out through 2" PVC exhaust.
Looking for inspirational ideas. If i'm going to the hassle of a blower, what benefits should I add or what am I missing??
-Gadget
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stoker
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Post by stoker on Apr 13, 2018 13:22:50 GMT -8
I would probably make it a downdraft design, where fuel is added from the top.
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Post by gadget on Apr 13, 2018 18:13:12 GMT -8
This is the basic shape I am working with, It is going to have a front loading burn box  ![]() |
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Post by gadget on Apr 13, 2018 18:31:07 GMT -8
I would probably make it a downdraft design, where fuel is added from the top. I have seen down draft front loading wood boilers with a shoe box burn chamber underneath the burn box. Looked like a very efficient design. |
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Post by Vortex on Apr 14, 2018 0:37:30 GMT -8
Lets say in theory that creating a good draft was not an issue or something to worry about in your heater design, what would you do differently?? I'm in the middle of designing my heater build for this summer and am looking for idea inputs. It is going to be a vertical masonry heater with a ceramic fiber board burn chamber. It will have a hidden drum like a rocket heater with a blower to move heat to the room. There will be a 5 foot long bench off to one side. From there a copper heat exchanger in the garage with a 55 gallon plastic barrel for storing condensots(?). Lastly a blower pulling the flue gases out through 2" PVC exhaust. Looking for inspirational ideas. If i'm going to the hassle of a blower, what benefits should I add or what am I missing?? -Gadget If draft wasn't an issue, then theoretically you could have as much mass as you liked and harvest 100% of the heat, as normally the limit is there so there's still enough heat left in the chimney to create the draft necessary to drive the stove. Not that I personally would want a stove whose safe function depended on electronics. |
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Post by gadget on Apr 14, 2018 8:08:14 GMT -8
Lets say in theory that creating a good draft was not an issue or something to worry about in your heater design, what would you do differently?? I'm in the middle of designing my heater build for this summer and am looking for idea inputs. It is going to be a vertical masonry heater with a ceramic fiber board burn chamber. It will have a hidden drum like a rocket heater with a blower to move heat to the room. There will be a 5 foot long bench off to one side. From there a copper heat exchanger in the garage with a 55 gallon plastic barrel for storing condensots(?). Lastly a blower pulling the flue gases out through 2" PVC exhaust. Looking for inspirational ideas. If i'm going to the hassle of a blower, what benefits should I add or what am I missing?? -Gadget If draft wasn't an issue, then theoretically you could have as much mass as you liked and harvest 100% of the heat, as normally the limit is there so there's still enough heat left in the chimney to create the draft necessary to drive the stove. Not that I personally would want a stove whose safe function depended on electronics. I guess that brings up the question if electronics are necessary for an induction blower exhaust? I'm planning on no electronics or at least being able to run with or with out any controllers. A failed blower would be no different then a blocked flue pipe. Major smoke back into the room and everyone freezes their butts off. Could be dangerous if there was an open burn chamber door and no one was there tending the fire. Possible smoke explosion in the stove?  ? I can get all the induction blowers I want for free so spare parts are not a problem. New ones can be had for under $100. If your worried about power, they do not need much and simple solar setup could run it very easily. My 2 speed Fesco blower only draws 60watts on low and 85watts on high. No electronics needed. Just a simple a/c induction motor. One could use a 12v DC motor if they wanted it to be even simpler but the a/c motor is more efficient. |
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Post by gadget on Apr 14, 2018 9:17:39 GMT -8
If draft wasn't an issue, then theoretically you could have as much mass as you liked and harvest 100% of the heat, as normally the limit is there so there's still enough heat left in the chimney to create the draft necessary to drive the stove. Not that I personally would want a stove whose safe function depended on electronics. I guess that brings up the question if electronics are necessary for an induction blower exhaust? I'm planning on no electronics or at least being able to run with or with out any controllers. A failed blower would be no different then a blocked flue pipe. Major smoke back into the room and everyone freezes their butts off. Could be dangerous if there was an open burn chamber door and no one was there tending the fire. Possible smoke explosion in the stove? ? I can get all the induction blowers I want for free so spare parts are not a problem. New ones can be had for under $100. If your worried about power, they do not need much and simple solar setup could run it very easily. My 2 speed Fesco blower only draws 60watts on low and 85watts on high. No electronics needed. Just a simple a/c induction motor. One could use a 12v DC motor if they wanted it to be even simpler but the a/c motor is more efficient. On a side note, I was house sitting once and had a pellet stove with a clogged exhaust. I got it lit and running, closed the door. Started to notice a little bit of smoke coming from random parts of the stove and the flame was not moving like it normal would. This was only my 3rd time using this pellet stove so I wasn't fully familiar with it but I could tell something was wrong. I could hear the blower was running. My friend I was house sitting for latter told me a bird hand worked its way into the 4" flue pipe got stuck and died in there. Poor bird, this is why there needs to be some strong screen around your flue pipe. Moral of the story, have a secondary way to heat your home. |
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alext
New Member
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Post by alext on Apr 14, 2018 10:15:10 GMT -8
Lets say in theory that creating a good draft was not an issue or something to worry about in your heater design, what would you do differently?? I'm in the middle of designing my heater build for this summer and am looking for idea inputs. It is going to be a vertical masonry heater with a ceramic fiber board burn chamber. It will have a hidden drum like a rocket heater with a blower to move heat to the room. There will be a 5 foot long bench off to one side. From there a copper heat exchanger in the garage with a 55 gallon plastic barrel for storing condensots(?). Lastly a blower pulling the flue gases out through 2" PVC exhaust. Looking for inspirational ideas. If i'm going to the hassle of a blower, what benefits should I add or what am I missing?? -Gadget If draft wasn't an issue, then theoretically you could have as much mass as you liked and harvest 100% of the heat and water condensate |
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alext
New Member
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Post by alext on Apr 14, 2018 11:25:57 GMT -8
If draft wasn't an issue, then theoretically you could have as much mass as you liked and harvest 100% of the heat, as normally the limit is there so there's still enough heat left in the chimney to create the draft necessary to drive the stove. Not that I personally would want a stove whose safe function depended on electronics. I guess that brings up the question if electronics are necessary for an induction blower exhaust? I'm planning on no electronics or at least being able to run with or with out any controllers. A failed blower would be no different then a blocked flue pipe. Major smoke back into the room and everyone freezes their butts off. Could be dangerous if there was an open burn chamber door and no one was there tending the fire. Possible smoke explosion in the stove? ? I can get all the induction blowers I want for free so spare parts are not a problem. New ones can be had for under $100. If your worried about power, they do not need much and simple solar setup could run it very easily. My 2 speed Fesco blower only draws 60watts on low and 85watts on high. No electronics needed. Just a simple a/c induction motor. One could use a 12v DC motor if they wanted it to be even simpler but the a/c motor is more efficient. There might be another solution. Place your stove outside the house into small good insulated non combustible shed. Collect heat with thermal mass, and than ventilate house through duct with warm air from the shed. Btw, dont be affraid of electronic. You can find very advanced controllers in a modern gas and wood burning stoves. Combustion optimisation, safety features, ignition, pre purge and post purge procedures typically run by stove microcontroller. Look at this Fireplace Everythind totally controlled by electronics. Plus you can do online diagnostics and control through internet. I am trying to implement some more features to this design to control air consumption and combustion. |
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Post by gadget on Apr 14, 2018 12:40:25 GMT -8
I guess that brings up the question if electronics are necessary for an induction blower exhaust? I'm planning on no electronics or at least being able to run with or with out any controllers. A failed blower would be no different then a blocked flue pipe. Major smoke back into the room and everyone freezes their butts off. Could be dangerous if there was an open burn chamber door and no one was there tending the fire. Possible smoke explosion in the stove? ? I can get all the induction blowers I want for free so spare parts are not a problem. New ones can be had for under $100. If your worried about power, they do not need much and simple solar setup could run it very easily. My 2 speed Fesco blower only draws 60watts on low and 85watts on high. No electronics needed. Just a simple a/c induction motor. One could use a 12v DC motor if they wanted it to be even simpler but the a/c motor is more efficient. There might be another solution. Place your stove outside the house into small good insulated non combustible shed. Collect heat with thermal mass, and than ventilate house through duct with warm air from the shed. Btw, dont be affraid of electronic. You can find very advanced controllers in a modern gas and wood burning stoves. Combustion optimisation, safety features, ignition, pre purge and post purge procedures typically run by stove microcontroller. Look at this Fireplace Everythind totally controlled by electronics. Plus you can do online diagnostics and control through internet. I am trying to implement some more features to this design to control air consumption and combustion. Later, much later...maybe next year I'm going the raspberry pi route. Temp and gas monitoring w/ secondary air regulation. I have a nice working electronic throttle body off a chevy truck that is simple dc motor driven with a simple potentiometer position sensor that would work nice for air inlet regulating. I want it to ride on top of the system and not necessarily be in 100% control, just fine tune. If there is any full control by electronics it will be for safety cutoff....like to high temp at the last heat exchanger or low temp out of the burn chamber....etc.. For now it will be manual controls with a couple of thermocouples and thermometers for seeing temps -Gadget |
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alext
New Member
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Post by alext on Apr 14, 2018 13:13:53 GMT -8
Let's look at the combustion process from another side.
You starting fire. What do you need at this point?
You have to pre-hit your stove and fuel. Thermal mass is working against you. You dont need it as well as significant airflow. You can pre-hit stove and fuel with gas torch, like 100 000 BTU.
After ignition you have to increase airflow gradually to establish combustion process. After that you need to add termal mass to a system and harvest the hit. Than fuel starting to burn out.
You have to decrease airflow for not to loose stored heat.
You need a controller as well as direct vent to optimize burning.
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Post by gadget on Apr 14, 2018 14:34:29 GMT -8
Let's look at the combustion process from another side. You starting fire. What do you need at this point? You have to pre-hit your stove and fuel. Thermal mass is working against you. You dont need it as well as significant airflow. You can pre-hit stove and fuel with gas torch, like 100 000 BTU. After ignition you have to increase airflow gradually to establish combustion process. After that you need to add termal mass to a system and harvest the hit. Than fuel starting to burn out. You have to decrease airflow for not to loose stored heat. You need a controller as well as direct vent to optimize burning. alext you are one sharp thinker. I will tell you that I think you just summed up my biggest challenge. I have been working on this wood heater design over for literally years now. Now that I am a home owner and actually live somewhere that gets real winters I'm building a wood heater. My biggest decision is absolutely do not want a chimney so what to do. Condensing wood burner is my solution. Not because I want that last 10-20% of heat but I just am not going to do a chimney. Maybe if this fails miserably I will modify and put in a chimney but first I will give this a go and document it all. Now back to what you said, I have this idea of heat recycling. Basically, complete burn then all heat is removed and recycled back into the air inlet and the room air/mass. I really should just start a build thread because allot of the pieces work together. Example, I have a 3,500watt/220v heating element out of a dryer that will be infront of the air inlets for preheating. I also have a stainless heat exchanger from the secondary stage of a gas furnace for preheating inlet air..etc... The idea is that of heat trapping. In theory the only looses will be electrical from pumping air through the system and heat exchangers. Great input so far everyone! Thank you!! -Gadget |
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Post by ronyon on Apr 21, 2018 18:48:34 GMT -8
I like you idea. Many rocketeers are dedicated to builds that work on passive principles only.
I think a little bit of electric might be a great way to avoid a chimney,and capture more heat.
Is the heat exchange coil in the bench,feed water from and returning steam to the plastic barrel on the garage,while the exhaust goes out to the blower?
Or does the exhaust go to the plastic barrel and out through the blower, while the heat exchanger coil in the barrel sends heated water inside to a radiator?
Or am I totally confused?
I think a galvanized steel pipe or an aluminum duct would be a better choice than pvc for your vent.
If you send your post-blower exhaust into lengths of buried,corragated,perforated, plastic pipe,you will heat(somewhat) the ground it passes through,and filter the exhaust as well.
If you do this along an exterior wall, you can create a layer of warmth,especially if there are cold frames or a greenhouse above it.
A metal pipe or duct, run through the mass,can provide preheated combustion/make up air,just be sure to include flaps to prevent air from escaping the home.
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Post by gadget on Apr 21, 2018 19:08:44 GMT -8
I like you idea. Many rocketeers are dedicated to builds that work on passive principles only. I think a little bit of electric might be a great way to avoid a chimney,and capture more heat. Is the heat exchange coil in the bench,feed water from and returning steam to the plastic barrel on the garage,while the exhaust goes out to the blower? Or does the exhaust go to the plastic barrel and out through the blower, while the heat exchanger coil in the barrel sends heated water inside to a radiator? Or am I totally confused? I think a galvanized steel pipe or an aluminum duct would be a better choice than pvc for your vent. If you send your post-blower exhaust into lengths of buried,corragated,perforated, plastic pipe,you will heat(somewhat) the ground it passes through,and filter the exhaust as well. If you do this along an exterior wall, you can create a layer of warmth,especially if there are cold frames or a greenhouse above it. A metal pipe or duct, run through the mass,can provide preheated combustion/make up air,just be sure to include flaps to prevent air from escaping the home. So far my design is as follows Its a vertical masonry heater from floor to ceiling. There is a bench to one side. Ceramic Fiber burn chamber with an upper burn path kinda similar to a contra flow masonry heater. From there to a bell for heat extraction similar to a barrel on a rocket mass heater. Then through a stainless steel heat exchanger(salvaged from a condensing gas furnace) to preheat the incoming air. From there to the bench similar to a rocket mass heater (6" ducting) after the bench through the wall into the garage to a copper heat exchanger. basically 120 copper tubes. 5 feet long 1/2 inch ID tubes. They will have about a 15 deg. angle so condenses can drip into a 55 gallon barrel. The end of the tubes and the blower will be above the barrel, all air tight. From there pushed out to the world with the PVC pipe exit. The PVC is nice because it won't rust and it is cheap. Its used in most new condensing furnaces for the flue and is code. I have no doubt that there are going to be challenges with a condensing exhaust setup but I think it is time for some experiments in this area. There are allot of instances where a chimney is not an easy install or governments eyes are prying on your "stack" so to speak..... |
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Post by permaculturebob on Dec 21, 2019 5:15:23 GMT -8
I have been using a forced /assisted draft since my first BB conversion of a j tube.
Just a simple 12 volt fan, gets a little sooty after a while, but cheap enough to replace.
I would make sure that you do have enough mass to keep exhaust temps real low, and a regulator/ potentiometer to control the speed of the fan.
I am also noticing that with my exhaust at ground level, care needs to be taken regarding the carbon dioxide, monoxide , etc. I am extending the exhaust pipe to at least get it farther from the house, and may bury it underground in a loosely sealed chamber of some sort where it may get some biological processing before going into the atmosphere
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