Hey there brother! This series has gotten you a new subscriber. I enjoy your fabrication tips and I am looking forward to more. Anyway something I noted on your last video was you could capture more heat by placing an inverted cone baffle in the center of the flue. This would drive the heat out to the coil.and it could be achieved by welding a 1/2" rod in a C shape at the top and bottom. I would love to show you additional ideas I have. Anyways keep up the good work
Guess I’m glad I didn’t comment on the original vid, you definitely covered all of it here. Only thing else was I was going to recommend having a bypass for when you started up the fire, that would cut the creosote down. Maybe you could do a 3-4 inch in the middle and it could be the bypass and the plug to block the center. Ether way was a great build.
First of all i love these videos, very informative and well made. It would be cool to measure the thermal power given to the water. If you measure the water temperature before the pump and at the exit of the heater, knowing the water flow, it is very easy to calculate the power. If you record the temperatures with some kind of data logger you should see also how the power changes in time. By doing so you can compare the power to the water to the theoretical thermal energy contained in wood.
Fascinating topic. When I saw the first video last night I was surprised that you put the coil inside the chimney instead of around the outside of a chimney. I like the design with the square outer portion for the insulation though. If you put a round pipe in the middle of the copper for the gases and creosote to go up and then filled the copper coil side with sand it might have a longer lifespan. It may not be as fully efficient but the sand would help hold the heat a bit.
Some of my good friends did exactly this at their cliff cabin in Peterson Bay, across from Homer, AK. The shower was attached to their sauna. The problem with wrapping copper tubing around the outside of the flue is that very little heat is transferred. It wasn't insulated, either. There was no water storage tank or mixing so you got a short burst of hot water in between cold. I don't think soot or creosote is much of a problem if you have complete combustion, which is the big challenge.
Love these series and look forward to the next one! Really keen to understand the benefits of having a insulated firebox to have the combustion temp as high as possible, and then extracting the heat. Opposed to having water jackets around the fire and therefore potentially loosing alot of that potential by cooling the fire.
Can you try sending the water the other way trought and compare the results to just letting it flow naturally, love your videos man, and your wife is a superhero with the editing
I got an interesting one for you, surround the stove in a sand battery, provides longer lasting heat, you can add coils inside, which would make a great way to heat floors/water/(the room it is in) more efficiently and longer. Just thought of it as I was thinking of your experiment, if you keep the work you've already done but add the sand battery you'll have quick AND lasting heat with less waste of fuel. Just a thought.
What I'm getting from this is get a large metal tub on a platform, have removable raised wooden slats inside, light a fire underneath the tub, when the temperature is hot enough put the wooden floor in and turn the fire off. Job's a good 'un.
Great follow up! Hopefully you can manage to make a design that can be suited for permanent use with cleaning every 6 months or so. Then I would build one too :P
Thanks! Could always be wrong but I'm pretty sure the explanation is dead on, this is from the first result from googling "galvanic corrosion between copper and steel" just now - "Let’s consider a case where a copper water tube is connected to a steel pipe through an adapter, and the water inside is an electrolyte. As steel is electro-negative to copper, electrons will flow from steel to copper, and the steel pipe will corrode. For economic reasons, making an all-copper system can be difficult in most cases. Breaking the electrical contact through a thick six-inch coupling made of insulating material is an easier way to avoid galvanic corrosion."
Take the Copper out of the flue gases and create a constant contact to the flue, use a solder to make a permanent contact allowing for great heat transfer. Perhaps use aluminum tubing instead of copper. Adding an outer sheath with tubing sandwiched between the outer sheath and actual flue would allow you to use the spacing between the tubing to channel the air from the bottom to the top, could even add a bypass channel so the air, once it reaches the top, can be channeled back to the bottom. Since the majority of hot air is going to be next to the flue, this will still allow for a vacuum to suck the hot air back down the bypass channel and create a constant airflow. It will eventually preheat the air and increase to match comparable flue gas temperatures. So you would benefit from heat of convection and conduction.
I don't know what you have available to you .. but if you can get your hands on an old "propane hot water heater" .. it already has a flue up the middle .. and you can build the firebox under it. From there you can also run a line into a house then through a larger tank where hot water is kept in reserve .. then with thermostat control send the hot water through a radiator .. with a fan behind it to heat your house. With the fire box on the outside .. you keep your ash etc. outside .. and bring your heat inside in the form of water. Always interesting stuff to think about!
Maybe this has already been suggested, but... What if you did the opposite, multiple less "spirally" spiraled pipes from bottom to top where you have the hot gases pass through the pipes and inside a water jacket? Multiple pipes creates a lot of surface area for the heat exchange and the multitude of pipes combine to get enough area for the gasses to pass. The upside would be that the side of the pipes that is exposed to the gases can easily be cleaned given that a reasonable spiral is used (think huge pipe/barrel cleaner).
Could you try adding sand by filling the inner chamber where the coil and steel pipe are, would the sand create chemical insulation and yet transfer the heat ?
I've tried a bunch of things to heat water - they all work....kinda, but all have weak points. I am presenlty building a rocket mass heater with a cast iron bath on the top of the riser. then, inside the bath water will be a 22mm copper coil which will thermosypon through my geyser. This will take longer to heat up than direct to copper, but I have zero chance of it steaming and blowing up my house.
especially if it's cold and wet from condensation at first. I suspect 90% of that soot is from the first 10 minutes while the fire is still relatively cold and condensation is forming on the outside of the copper.
I build the fire and light it and go do other things for an hour. when I come back the water is hot and the fire is out so it's not an issue. otherwise I'd agree, good eye though
@GreenhillForge Hey, thanks for getting back! I really enjoy what you are demonstrating. I am looking for land to build a 500 Sq ft small house here in Washington state. I plan to be totally off grid.
As stated in my comment on the other video, did you show that to your local chimney sweeper? I personally know that they love stuff like this, so maybe ask them.
I realize that I'm commenting a little late in the project but... there's really no need to extract any greater amount of heat by putting a diffuser in the middle. You're already on the verge of boiling and it would only cause more of a creosote problem.
About the steel about what about stainless steel pipe or those that has acid resistant ones? Wouldn't those work better than galvanic ones or black steel pipes? I am currently designing one waaaay bigger for floor heating but nobody else in the family knows about :D
I wish I could get statistics on a set up with the coil wrapped around the outside of the flue then insulated and a metal protector around all that. not because it is the most efficient set up, but it's easier to make than a water jacket and cleans quick and no mess. Kris Harbour did it, without insulation. but his analysis and statistics were like "it works" ... very sad :(
Just my opinion, but thermosyphon is stupid, haha. It's something that people get romantic about, or really attached to but it just doesn't make sense in most applications. If you are using solar to heat your water slowly, perhaps, but if you are transferring a few thousand BTUs the wate ris going to boil unless you have a decent flow rate.. Using a pump that uses 20 watts or so will give you way better results. Edit: People are also really attached to vortexes, haha. That swirl is always what the answer is, regardless of the question.
I disagree. It depends on your intended use. My in-house woodstove which ran all day and most of the night could easily heat the entire 40-gal water tank in a few hours with a hot fire. My added solar hw heater also thermosyphoned into the same tank. No pumps.
@@Shmerpy I should have added ... "if you don't care about efficiency". If your heat exchanger is not efficient (not good at absorbing energy) then you don't need to worry about boiling water. If you are paying for your heat source (paying for wood or oil) then you don't want to just throw away that heat energy. You can't beat physics. If the exchanger absorbs a large amount of energy into a small volume of water it will boil it, and if you increase the volume, it won't boil. To not boil the water you can either reduce exchanger efficiency and waste energy, produce a smaller amount of heat, or increase the flow. PS, you're not disagreeing. If it takes hours to heat 40 gallons then you're either wasting a lot of heat or not making a lot of heat.
Good points. I'm only talking about heating water hot enough for household use. If the woodstove is on all day then efficiency is not an issue for me. The woodstove also heats the house. My house was out in the boonies so I could do things like move the HW tank upstairs so it could thermosyphon, something most people would not be able to do. Hope that makes sense.
@@Shmerpy I totally get what you are saying. In some situations it works well. If you need to transfer more BTUs, you can use more than one run. If a single run can transfer 5000 btu/h then two runs can transfer 10,000. I'm also not sure how much of an effect larger lines come into play... but I'm sure it has an effect on flow rates. Cheers.
@@loweredexpectations4927 Any pump is subject to failure, either in the pump or the power supply. Then you have a bomb. As all that heat will overwhelm any normal safety valve. Thermosyphon fed radiators have been used for over a hundred years and many of the older hotels in Europe use them, and they are multi story and many rooms ALL on thermosyphon. It all about good boiler and piping design and SIMPLICITY. The less moving parts, the less failures. KISS
Thanks for the update, looking forward to the rocket stove vid!
Awesome. Pumped up to see the Rocket version. Forge on !
Thanks for the update, I’m looking forward to see the design get better over time
Great video, super informative!
Great update can't wait to see your next design
Hey there brother! This series has gotten you a new subscriber. I enjoy your fabrication tips and I am looking forward to more.
Anyway something I noted on your last video was you could capture more heat by placing an inverted cone baffle in the center of the flue. This would drive the heat out to the coil.and it could be achieved by welding a 1/2" rod in a C shape at the top and bottom. I would love to show you additional ideas I have. Anyways keep up the good work
I love this, always wanted to experiment with heating water like this and all the info you have on the subject is awesome.
Thanks for the updates!
Looking forward to the rocket stove video, looks super interesting!
Excellent. Looking forward to seeing your rocket version.
Guess I’m glad I didn’t comment on the original vid, you definitely covered all of it here.
Only thing else was I was going to recommend having a bypass for when you started up the fire, that would cut the creosote down. Maybe you could do a 3-4 inch in the middle and it could be the bypass and the plug to block the center.
Ether way was a great build.
It's a good idea, might do something like that in the final design?
First of all i love these videos, very informative and well made.
It would be cool to measure the thermal power given to the water. If you measure the water temperature before the pump and at the exit of the heater, knowing the water flow, it is very easy to calculate the power. If you record the temperatures with some kind of data logger you should see also how the power changes in time. By doing so you can compare the power to the water to the theoretical thermal energy contained in wood.
All of this is coming in the next video. Hoping to get it up later today.
Fascinating topic. When I saw the first video last night I was surprised that you put the coil inside the chimney instead of around the outside of a chimney. I like the design with the square outer portion for the insulation though. If you put a round pipe in the middle of the copper for the gases and creosote to go up and then filled the copper coil side with sand it might have a longer lifespan. It may not be as fully efficient but the sand would help hold the heat a bit.
I've got a design coming that I think you'll like..
Some of my good friends did exactly this at their cliff cabin in Peterson Bay, across from Homer, AK. The shower was attached to their sauna. The problem with wrapping copper tubing around the outside of the flue is that very little heat is transferred. It wasn't insulated, either. There was no water storage tank or mixing so you got a short burst of hot water in between cold. I don't think soot or creosote is much of a problem if you have complete combustion, which is the big challenge.
Incredible work, really love your videos. Thanks for sharing!
Loved you in the new gladiator movie
You are awesome! Thank you!
Thanks again for the information. I appreciate that you are taking the time and effort to share this.
THIS IS COOL! Thank you.
Love these series and look forward to the next one! Really keen to understand the benefits of having a insulated firebox to have the combustion temp as high as possible, and then extracting the heat. Opposed to having water jackets around the fire and therefore potentially loosing alot of that potential by cooling the fire.
I just wanted to take a minute of my own and say these vids are great, and so is the doggo. Keep up the good work 👍
Can you try sending the water the other way trought and compare the results to just letting it flow naturally, love your videos man, and your wife is a superhero with the editing
Sure, when I settle on a design that works safely with thermosiphon, I'll do a test with countflow and report the results.👍
I got an interesting one for you, surround the stove in a sand battery, provides longer lasting heat, you can add coils inside, which would make a great way to heat floors/water/(the room it is in) more efficiently and longer. Just thought of it as I was thinking of your experiment, if you keep the work you've already done but add the sand battery you'll have quick AND lasting heat with less waste of fuel. Just a thought.
Ooo you opened up the insulation without gloves on!
What I'm getting from this is get a large metal tub on a platform, have removable raised wooden slats inside, light a fire underneath the tub, when the temperature is hot enough put the wooden floor in and turn the fire off. Job's a good 'un.
Awaiting your next model!
Water heaters use that sort of "auger bit" baffle for similar reasons I think. Might be worth looking into.
Great follow up! Hopefully you can manage to make a design that can be suited for permanent use with cleaning every 6 months or so. Then I would build one too :P
I've got a design coming that I think you'll like. We'll see if it works soon.
@GreenhillForge Fantastic, looking forward to it :)
I think the galvanic explanation might be off, but otherwise, I love the videos!
Thanks! Could always be wrong but I'm pretty sure the explanation is dead on, this is from the first result from googling "galvanic corrosion between copper and steel" just now - "Let’s consider a case where a copper water tube is connected to a steel pipe through an adapter, and the water inside is an electrolyte. As steel is electro-negative to copper, electrons will flow from steel to copper, and the steel pipe will corrode. For economic reasons, making an all-copper system can be difficult in most cases. Breaking the electrical contact through a thick six-inch coupling made of insulating material is an easier way to avoid galvanic corrosion."
Take the Copper out of the flue gases and create a constant contact to the flue, use a solder to make a permanent contact allowing for great heat transfer. Perhaps use aluminum tubing instead of copper.
Adding an outer sheath with tubing sandwiched between the outer sheath and actual flue would allow you to use the spacing between the tubing to channel the air from the bottom to the top, could even add a bypass channel so the air, once it reaches the top, can be channeled back to the bottom. Since the majority of hot air is going to be next to the flue, this will still allow for a vacuum to suck the hot air back down the bypass channel and create a constant airflow. It will eventually preheat the air and increase to match comparable flue gas temperatures. So you would benefit from heat of convection and conduction.
I've got a design coming that you might like
Craigs idea PLUS baffles in the venting to slow down the gases (heat).
Keep it up man. Your going to be massive. Also please high 5 your wife for the really good editing
Honestly with all the soot buildup I don’t think it would be a problem 3:59
I don't know what you have available to you .. but if you can get your hands on an old "propane hot water heater" .. it already has a flue up the middle .. and you can build the firebox under it. From there you can also run a line into a house then through a larger tank where hot water is kept in reserve .. then with thermostat control send the hot water through a radiator .. with a fan behind it to heat your house. With the fire box on the outside .. you keep your ash etc. outside .. and bring your heat inside in the form of water. Always interesting stuff to think about!
It's not wood fired but aside from wood stoves my house is heated with radiators and an outdoor boiler. cool stuff.
Maybe this has already been suggested, but... What if you did the opposite, multiple less "spirally" spiraled pipes from bottom to top where you have the hot gases pass through the pipes and inside a water jacket? Multiple pipes creates a lot of surface area for the heat exchange and the multitude of pipes combine to get enough area for the gasses to pass. The upside would be that the side of the pipes that is exposed to the gases can easily be cleaned given that a reasonable spiral is used (think huge pipe/barrel cleaner).
Chances are, your mullet is far superior to theirs. Therefore, their opinions on your work are moot.
He needs to shave his chinwhiskers first, it's not a man's mullet till the tash is attached.
Could you try adding sand by filling the inner chamber where the coil and steel pipe are, would the sand create chemical insulation and yet transfer the heat ?
I've got a video coming soon I think you'll like
I've tried a bunch of things to heat water - they all work....kinda, but all have weak points. I am presenlty building a rocket mass heater with a cast iron bath on the top of the riser. then, inside the bath water will be a 22mm copper coil which will thermosypon through my geyser. This will take longer to heat up than direct to copper, but I have zero chance of it steaming and blowing up my house.
But could you imagine the number of new subscribers you'd get if you captured your house blowing up?
Oh wow, sooth builds up fast on copper pipe.
especially if it's cold and wet from condensation at first. I suspect 90% of that soot is from the first 10 minutes while the fire is still relatively cold and condensation is forming on the outside of the copper.
I did notice that the stack for the shower hot water heater is below the open roof peak. Probably should extend above the roof line?🤔
I build the fire and light it and go do other things for an hour. when I come back the water is hot and the fire is out so it's not an issue. otherwise I'd agree, good eye though
@GreenhillForge Hey, thanks for getting back! I really enjoy what you are demonstrating. I am looking for land to build a 500 Sq ft small house here in Washington state. I plan to be totally off grid.
As stated in my comment on the other video, did you show that to your local chimney sweeper? I personally know that they love stuff like this, so maybe ask them.
Didn't see that. That's a great idea. Or the local boiler guy.
I realize that I'm commenting a little late in the project but... there's really no need to extract any greater amount of heat by putting a diffuser in the middle. You're already on the verge of boiling and it would only cause more of a creosote problem.
To clean the coil, just use the hot water spray !
About the steel about what about stainless steel pipe or those that has acid resistant ones? Wouldn't those work better than galvanic ones or black steel pipes? I am currently designing one waaaay bigger for floor heating but nobody else in the family knows about :D
A dampened 2nd flue would allow you to regulate water outlet temperature
Like a bypass to divert hot gasses away from the heat exchanger?
i am waiting on the rocket stove video :)
very soon
I wish I could get statistics on a set up with the coil wrapped around the outside of the flue then insulated and a metal protector around all that.
not because it is the most efficient set up, but it's easier to make than a water jacket and cleans quick and no mess.
Kris Harbour did it, without insulation. but his analysis and statistics were like "it works" ... very sad :(
If you are worried about corrosion from salt you could use sugar.🤷♂
Where do you live? it's beautiful
RUclips comments is like brainstorm mining
All the off-the-grid water heater haters 😅
Just my opinion, but thermosyphon is stupid, haha. It's something that people get romantic about, or really attached to but it just doesn't make sense in most applications. If you are using solar to heat your water slowly, perhaps, but if you are transferring a few thousand BTUs the wate ris going to boil unless you have a decent flow rate.. Using a pump that uses 20 watts or so will give you way better results.
Edit: People are also really attached to vortexes, haha. That swirl is always what the answer is, regardless of the question.
I disagree. It depends on your intended use. My in-house woodstove which ran all day and most of the night could easily heat the entire 40-gal water tank in a few hours with a hot fire. My added solar hw heater also thermosyphoned into the same tank. No pumps.
@@Shmerpy I should have added ... "if you don't care about efficiency". If your heat exchanger is not efficient (not good at absorbing energy) then you don't need to worry about boiling water. If you are paying for your heat source (paying for wood or oil) then you don't want to just throw away that heat energy.
You can't beat physics. If the exchanger absorbs a large amount of energy into a small volume of water it will boil it, and if you increase the volume, it won't boil. To not boil the water you can either reduce exchanger efficiency and waste energy, produce a smaller amount of heat, or increase the flow.
PS, you're not disagreeing. If it takes hours to heat 40 gallons then you're either wasting a lot of heat or not making a lot of heat.
Good points. I'm only talking about heating water hot enough for household use. If the woodstove is on all day then efficiency is not an issue for me. The woodstove also heats the house. My house was out in the boonies so I could do things like move the HW tank upstairs so it could thermosyphon, something most people would not be able to do. Hope that makes sense.
@@Shmerpy I totally get what you are saying. In some situations it works well. If you need to transfer more BTUs, you can use more than one run. If a single run can transfer 5000 btu/h then two runs can transfer 10,000. I'm also not sure how much of an effect larger lines come into play... but I'm sure it has an effect on flow rates.
Cheers.
@@loweredexpectations4927
Any pump is subject to failure, either in the pump or the power supply. Then you have a bomb. As all that heat will overwhelm any normal safety valve.
Thermosyphon fed radiators have been used for over a hundred years and many of the older hotels in Europe use them, and they are multi story and many rooms ALL on thermosyphon. It all about good boiler and piping design and SIMPLICITY. The less moving parts, the less failures.
KISS
The accent doesn't match the outlet.
RUclips comments is like brainstorm mining