Reverse your water flow. Cold in at top, flow down, hot out at bottom. This is known as counter current exchange and extracts the most heat from the flue gas. Great build!!
@@BenBrand Same here. This is super important for maximum efficiency. It would be awesome if he could reverse the water flow and compare the different time? Love this!
Even though it would be at the expense of thermal dynamics transfer of heat energy, would it be worth trying sans pump and allowing convection to do its thing in current configuration?
@@EnglishLevy maybe if the water barrel was lifted up so its height was the same as the coil. But with it being down below all of the water in the coil will get hot but there would be no wear for it to flow heat wise up since the top tube goes down so far even below the bottom tube before it gets into the barrel. It only takes a very tiny amount of movement to get an order of magnitude more heat so having a very small pump is worth it for sure
I have no intention of making this contraption but I must compliment the video maker. Clear instructions, no wasted time, no filler, no stupid music. Bravo!
Having done this 40 years ago, I can tell you that if you put the copper coil inside the pipe it will be covered with creosote in a few months which will insulate the coils which will keep the coils from heating properly. I put the coils on the outside of the 6" pipe and slipped that inside a piece of 8" pipe with 6" to 8" reducers on both ends of the coils to keep the coils out of the smoke. That worked the best and still gets the water hot enough to burn you. As far as I know it is still working fine. Keep up the good work. Jerry
copper starts to get soft at around 750f and melts at around 2000f so you probably could get away with it if you really dialed in the fire. I think the only way we'll know for sure is to try it. Maybe after all the testing is done on this first unit I'll have to give it a try...
@Flexsan, I'm sure you could, but it would difficult because you can't easily control the temp and you can't see the coil. One rule I learned later on was, If at all possible what ever you do try to make it Maintenance Free. Jerry
@GreenhillForgecould you stick a bunch of peltier modules on the upper part of the chimney to generate electricity for the pump? That way it could be truly off grid and it would double as a temperature control system to protect the copper.
Wow, very impressive! This video shows about 5% of the actual work you put into this. Hours and hours of planning, sourcing materials, welding, measuring, cutting, grinding, lighting the fire, etc. People like you are what made humanity great. Bravo!
As someone with an imagination , but who struggles to put a shelf up straight, I am continually impressed by the ingenuity and practical ability of folk like yourself. Well done sir.
My folks had a system like this in their house for decades. During the winter, they'd switch to the heat exchanger attached to the woodstove, and use that to heat the house via baseboard hot water heaters. There was a boiler for that system as well, but they'd only use it during shoulder seasons, with the woodstove providing all the house heat during the winter. It was a complicated system, but it really worked great for them.
Ive been heating house, hot water , and cooking on a woodstove for the last 49 years I love your video , and the way you present the materials and instructions on how to DIY one for ones self. Im unqualifyed to build one myself but if a pre made was for sale Id sure consider buying it, its way better then the stainless steel pipe I got in the firebox of my cookstove. thanks for your sharing
This was fun to watch, as I lived for a few years in an entirely wood-heated house in Vermont with a wood cookstove from the 1920’s that had a ‘water jacket’ (pipes in the lining of the firebox). It was attached to a water tank behind it, fed by gravity. Within an hour or so of lighting the stove there would be a supply of hot water for dishes and showers. You could tell how much hot water was left by feeling the tank, which through convection would feel warm to the touch from the top down. You just had to be careful because the hot water could get VERY hot if the stove had been going for a while without using the hot water.
I did a science fair project about efficient energy use and included a hot water heater nearly identical to your design, the teacher said it wouldn’t work so I built a working scale model to prove it. He was an ass so was still sceptical in an ego driven way. I knew he was wrong and I also got me a shinny gold medal for my effort at the fair. So there Mr ………! (No names)
In school I made an ammonia condenser. We generated the ammonia with an ammonia salt and a strong base. The vapor would leave reaction chamber and condense in a stainless steel coil that was immersed in dry ice and acetone. A collection vessel was under the coil that was also immersed in the dry ice solution. Within 15 minutes enough NH3 was collected to add my Li and other necessary ingredients. By lunch the entire science department was in overdrive and eating was the last thing on our minds. Go science!!!
A tip of the cap to you sir!! This is a gem of a how-to video complete with real-world testing in the same vid!! The world needs more like you, great build, great explanations, great lighting, great safety demonstration, beautiful countryside too. Consider swapping the direction of cold return water into the top and out the bottom to oppose flow of gases to water. As an aside I really enjoy your power mullet, keep it up you're doing wonderful work here!
This was the best most comprehensive video on this subject I’ve seen. Particularly like your thinking with the spacers to expose as much of the surface area of the pipe as possible. Bonza!
Nice reminder of a concept that has been around for over a hundred years. It works, my grandfather built one of these over 70 years ago and discussed the concept with me in the 1960's. He used a G cylinder as the sheath and pushed heat into the bottom of the G cylinder from a chip heater and exhausted the smoke through a chimney welded to the top of the G cylinder which was cut away around 200mm from the valve assembly at the top of the G cylinder. Very efficient.
WE had a slow combustion stove on the farm a Carmichael with a wet back,it worked on thermo siphon no pump involved ,if water got to hot had a shepherds type crook vent pipe to let out steam and over flow water to the roof into the guttering and back to the water tanks, the hot water tank was on the roof ,well presented and learned a lot thanks
A couple of things from someone who has done something similar over 25 years: 1. Your water system must be open loop (not pressurized). I have an open loop tank (like yours) with a second coil inside that is pressurized as part of my home's hot water system. Hot water in the tank heats our DHW as it moves through the coil. Works very well. 2. Your stove pipe heat exchanger is going to get fouled from creosote and ash condensing on the relatively cool surface (been there, dealt with that). You'll need to periodically disassemble it and use a wire brush or something to clean your copper coil. Or you can drain the water from the coil and burn it clean. Not as effective. I ended up building a straight pipe grid actually inside the top of my stove for easier access for cleaning the copper pipe. Also, having it inside the stove causes combustion condensation to drip back into the fire to be re-burned meaning cleaner smoke up the chimney. Once I did that, my stove pipe stays much cleaner. 3. I use a differential temperature controller to control my pump. Turns the pump on when the temperature exiting my heat exchanger is 10 degrees higher than the bottom of the tank. Great job! Your fabrication skills exceed mine.
You are simultaneously condensing your smoke by rapidly transferring its heat to the water … thereby collecting the remaining combustible solids contained in the smoke onto your coil and interior of the box….eventually a chimney fire will happen…..I would suggest keeping the smoke off the coils by having the copper wrapped around a stove pipe that would be easy to clean or be kept creosote free with a higher burn temperature.
That's true. There's a balance to be had between how much heat you extract and how much buildup you get. My woodstove is one of those wide ranges and it takes out almost too much heat. 3 years in a row the sweep has not found anything in the pipe but I have to do a cleanout of the stove each year instead or it clogs up!
Yes, and this buildup will happen rapidly in a few hours of burn choking the spacing between the coils and the efficiency will collapse right along with the buildup.
Same came here to look if anyone had mentioned this, and warn about flue fire. Think although a loss of heat conversation for safety a modified design that be slid over a traditional flue, this would allow a couple of things protecting the coils and the ability to disconnect it and reconnect it to a flue on a fire without the need to remove the original flue, but the butterflies top and bottom would have to be put into the permanent flue not the heat converter, but this would allow the system to be moved between multiple fire places.
Love your content mate! One of my favorite subjects paired with your delivery, filming, editing and knowledge all combine to create an awesome clip. Thank you for sharing all the small details. Hopefully one day I'll build myself one of these and will be referring back to your videos. You'll hit 100k+ if you keep this up.
This system is 6.08 kW here's calculations for those interested: to heat 1 kilogram of water 1 Kelvin (or C) you need 0.00116 kWh of energy (or 4.19 kJ/(kg. K)) 40c-7c = 33c temp difference (end v start temp.) 106 liters of water roughly equals 106 kilograms of water, 33*106*0.00116 = 4.06 kWh this was done in 40 minutes though, so: 4.06kWh / (40/60h) = 6.08Kw
This the by far the best build video I've ever seen! Well edited, minimal explaining, fast forwarding of the actual cutting/welding scenes and keeping it as simple as possible. Nice work!!! You've earned my sub!
I can appreciate this greatly! For to heat a wooden hot tub I built a heater very similar to this. For the coil which was of 304 stainless, 5/8” tube, instead of ice, I filled it with salt used 10” and 6” pvc pipe for the mandrel, fabricated a “C” “wrench with a curved pawl at one end of the “C” I fitted with a nylon plastic insert to let it slip and accommodate the radius of the tubing. The wrench had about a 4’ handle welded on, I did my twisting vertically. I put a 6” coil within the 10” coil, with the spring back of the inner coil it also gave me a fairly close clearance. I mounted a “ or 9” Nat.Gas burner under it held vertically spaced with a steel strap frame. For the shroud, again very similar, it was a double “tube” a separated w fiberglass from sheet metal. At the end I found the the greatest efficiency, and the quickest heating time was by flowing maximum volume of water thru the coils. At first I had it plumbed to be one continuous coil but I found it best to separate the bottom and top of both coils and installed a “Y” necked from 5/8” up to 1 1/2” and wound up with a small 1/4 hp transfer pump jst for circulation, then a standard 2 1/2hp swimming pool pump with a strainer basket for heating and to run aeration jets. I regulated the gas valve with a waterbed thermostat (had to tweak that a little). It all worked like a champ for 15 yrs. The 6 1/2’ tub, & heater set up looked great trim with cedar privacy surrounding went with the home when we sold it, heck IT sold the house! Also, instead of a flu, I finally mounted 3/3” discs 6” apart welded to 1/2” rod as a “Heat buffer” and stood it in the center of the inner coil. Very VERY IMPRESSED with you fabricated BREAK !!!
Nice design!! If I may offer a little advice, you may want to change the steel holding the copper tubing in place to a "friendlier" metal like brass, or maybe use copper strapping. Due to a process called Electrolysis, the two metals touching will result in one wearing the other one down over time, causing leaks.
@winksworks No, it isn't. It is a better conductor than almost every other metal, but it will almost always lose the battle when placed too close to other types of material. Especially galvanized pipe.
Super nice work! You can bump the efficiency by reversing the flow in the coil. Inlet at the top and outlet at the bottom. Reverse flow heat exchangers is a more efficient config.
I must admit that the video perfectly present the work, masterful work, without any music, no wasted time, perfectly shown in the most informative way.
Your presentation style is so clear and concise, I really appreciate how effectively you're sharing you idea and the thought process along with it. I don't do any welding and was trying to figure out how you were going to manage those standoffs, but cut to fit and weld in place is the absolute best way to go there. Cheers
Bro. This was a master class in thermal transfer in practice. I've sat down and thought about this exact creation numerous times. I work in the industrial water treatment industry and have seen thousands of heat exchangers. This was very well done. I've never seen a pipe bent with ice. We've always done it with sand. Great, magnificent work. Bravo!
Great video :) . I made one of these, about 30 years ago. While it was only 1% as well built as yours, due to no electricity on my farm, it could easily boil the entire contents of a 180 litre water tank within 3 hours. Yup, the tank was literally vibrating, as the water inside was boiling - - and all without a water pump! Needless to say, I was massively impressed at how well it worked :) .
We live in a travel trailer and do physical labor, we stick framed a bath/sauna house complete w/ a half dozen slider insulated big windows that came our way, w/a wood stove under the clawfoot tub. Your video was top notch! To complete our "rural living in comfort" we use a metal snow shovel to put the coals from the fire in a wheel barrow w/water to make biochar for the garden
This is music to my ears! I have no idea how to do this and now you have shown us all how to do this! Thank you so much! Watching from freezing England at the moment.
Your coil will be thickly covered in creosote (less efficient) in 3 weeks or less, and needs to be cleaned. It has the BTU's of coal and will make a fantastic chimney fire... Allowing for cleaning must be part of the design. if your water tank bottom is 2ft. above the top of the coil you don't need a pump. Ask me how I know...
@ my system produced 4 to 6 litres of creosote every 3 weeks. but It did the job for hot water. easy cleaning must be built into the system.without diligent maintenance it's a chimney fire waiting to happen.
Great video great contraption! One thing I learned having the the copper inside the fire place or flue is that it condenses really quickly and builds a lot of soot and char around it. Which then doesn’t transfer the heat as well. One way to clean it is empty the water out and burn a really hot fire to burn off the carbon buildup.
Try using your heat exchanger without the pump, just free flow pipes. Cold inlet at the bottom of the tank, hot fill at the top. You should find the external kettle still heating up because the hottest water rises to the top and automatically pulls in cooler water from the bottom of the tank.
BUT, ONLY IF THE TANK IS HIGHER THAN THE COIL. If you want a thermosyphon to work, then the receiving tank needs to be HIGHER than the coil, so the hot water can rise to expand into it. The pipe must slope UP The tank's coldest water at its bottom will also then drop to the bottom of the coil. The pipe must slope Down.
@greenwood4020 Not true, most early tractors used thermosyphons, the radiator was at the same height as the cooling jacket. The heat rising and cold return allowed circulation.
@@johnqpublic9074 You are correct. I should have stated the most efficient designs are, as I described. Most model T Fords used the thermosyphon system, but it was susceptible to overheating if worked heavily, but served well for most Model T usage. Many types of water pumps were available as after market accessories.
You're at about 19,600 BTU/ HR based on your start / stop and total time. Awesome. Working on a coil system to feed in floor radiant for an office shed build coming up. Love your video!
It's a pleasure to see a content creator build cool stuff without 50k+ $ of sponsored equipment! you did really well with something almost anyone with a garage could manage to have at home, keep up the good stuff!
I like your build quality and the video was excellent. In Boy Scouts one of our scout masters had a “keg” or a stainless propane tank (not sure which) but it had a coil inside surrounded by water. He heated the water in the tank and the coil water came out the shower head. Metering was just a ball valve. It was awesome!
This is so awesome! I have been pondering this concept for years, so excited to see a version of it in action! You are fantastic, and thank you for sharing with all of us!
I had a similar setup up in a double barrel stove in my basement to heat a 600 gallon water battery, worked incredibly well to provide a bunch of stored heat after the fire went out.
If you added a thin metal pipe in the middle of the coil and fill the coils space with sand. Cleaning would be better and the sand once heated will stay hot long after stove burns out. Might save on fuel
Careful with heating sand, it produces silica at high temps. Should be ok near the pipes with the water running through keeping it at max 100C but the edges of the square may reach dangerous temperatures.
@@Andevinga wood stove only gets to just under 600 degrees the chimney will be way cooler then that and silica is a type of sand and sand doesn’t melt until 1700°c maybe I’m misunderstanding what your saying lol
I'm really impressed by your design and your detailed explanation. I am a fussy machinist of 40+ years and both you and I know the devil is in the details. I have been considering a very similar design for a hybrid stove for hydronic floor heating. My only concern with a stove like yours is creosote build-up due to the cooling of the gases. This is why I am considering a hybrid which tends to burn very clean. I really look forward to more of your stuff. I am a new subscriber. All the best from Canada and thank you so much for your hard work.
thanks! this wouldn't work well as a regular use, long term design. I just wanted to test direct contact with the glue gases to get the high end values of possible heat transfer to compare with further designs down the line.
Dude! That was amazing! Your craftsmanship is outstanding. Your video editing skills are incredible. And to top it all off you own a German Shepherd! Best dogs ever.
Heres an idea, using excess solar energy. Once your battery has reached full charge, diverting the excess into a heating element and filling the contraption with sand. Solar electric water heater.
@beatdrive741 His idea is a good one. Once the batteries are full and you have already paid for the panels, you are best off to find some other use for the energy. The panels are selected for changing the batteries on the worst days of the year so most of the time there is excess. Heating elements come in all wattage levels.
@@kensmith5694 it isn’t efficient in the slightest, there are better approaches that already exist. Sure it could work but you’ll end up with an overly complicated installation that gives you very small amounts of warm water. Lower the wattage, lower the capability. For something as crucial as hot water availability you want simplicity really where possible. If you want to use the excess energy you’d honestly be better off storing it elsewhere as potential energy. Another battery, or pumped water storage or something.
@@kensmith5694 sure thing, you can but it’s simply inefficient in a multitude of ways. Ultimately it boils down to what problem are you trying to solve. Maybe there’s an edge case where it works but I’m not seeing it..
Interesting idea. Won't the copper cause rapid galvanic corrosion of the iron and collect creosote rapidly as the smoke passes over the water cooled copper? Maybe 5/16" stainless brake line or 3/8" stainless wort chiller coil tubing would be safer?
I am about 7:50 in and I see steel touching copper. As a plumber my alarm bells started going off saying dis-similar metals touching, galvanic corrosion. That would worry me for the longevity of this build. So far I am enjoying you video and information. This is the first video of yours I have seen.
I completely agree with the design which you have proposed and you do have a hand in great videography, and I do appreciate the fact that it’s a very short video based on the fact that information without any accompanying music. A better suggestion, even than what your design is would be to convert a single wall, wood stove to become a double wall, wood stove with a water jacket. It’s even the heated with the cold in at the top and the warm out the bottom.
I have experimented with a similar setup in my workshop en learned the following; 1 - Run the water in the coil above 60C to avoid condensation and deposit of creosoot. This is dangerous as it can catch fire. I use a system with a thermostat that regulates the primary circuit to around 65C. Anything over that will be mixed into the secondary circuit with radiators and hot water boiler. 2 - You need draft in your chimney for a good fire; Don't cool down your exhaust gas too much as it will stall the draft. Try to build a waterjacket around the fireplace to keep the chimney temp high. I works fine in the video with sunny weather I don't know if it still works if there is a freezing cold. Alternatively you can use a chimney ventilator that sucks the air through no matter what. 3 - Don't put a valve right after your fire. If the fire is running and you close the valve your room is full of smoke. If I have an over temperature in my water system, fi if the pump stops, then 2 systems get in place: The air intake to the fire shuts off and cold water is purged into the coil. These are spring loaded and don't need electricity to run. Safety first! You are a very creative person! Love the video.
How did you rig it to shut off the stove air intake? Did you use a temperature/pressure relief valve for the water?or how did you do the cold water safety?thanks!
@@edcat6587It is utility drinkwater; That is pressurized at 3 bar and releases a spring loaded piston that pushed the air intake valve. Once triggered you need to manually reset everything. The drinking water is released into the primary circuit that typically has a pressure of 1.5 bar. A pressure release valve in the primary circuit releases the surplus water into the garden.
Great project, impressed by the efficiency! And nice editing too, I predict a steady rise in views and subs in the future! I subbed after watching the stove build video and am looking forward to the next! A solution to have a circulation pump also driven by the heat would be amazing, it's such a critical part of the system and would make it pretty mobile. I guess a stirling engine would be too weak🤔 This is going to affect my sleep tonight I'm afraid😂
Thanks! I didn't get into this in the video but I'll try to remember to touch on it in the follow up video, but these types of systems can actually be run without a pump. Hot water expands and rises just like hot air does, so if you place the barrel vs the heat exchanger properly the hot water will naturally rise through the copper coil by itself. The only issue with this system is that it might be too hot, meaning the water doesn't move quickly enough to keep the copper from overheating. That's why I added the pump. Maybe after the rocket stove test I'll try taking the pump out and see what happens, at least that way if the copper melts I got the tests done first.
@GreenhillForge Yeah, I've seen a few projects without a pump, but it does seem to be very finicky to get to circulate fast enough, and then it could become somewhat of a safety issue. The principle would be the same(opposite) as a fluid cooling system, my knowledge limits to engines and such where there's always a pump, I wonder if systems without pumps are used elsewere🤔
@@malefunctionable Yeah, thermosiphons are passive heat exchanging systems and they're used in at least a few things I can think of. Biggest one being rooftop solar hot water systems. But I can't think of any that come anywhere near the kind of temps in solid fuel burning systems. A lot easier and safer if you're topping out at like 140F instead of 1200F.
Just occured that a simple steam engine could work really well and would also sync up well with the system. The hotter it gets the faster the pump would run. Maybe I'll try building one...
Using a solid fuel fire to heat water was fairly standard in rural UK for most of the last century. Fire places and stoves were specially designed for it.
That was with a back boiler installed into the burning chamber or at the back of the fireplace (hence the name) rather than using the heat from the flue/chimney.
@@Andeving he doesn't have a British accent. Good spot on the Tesco bag though, perhaps he lives in the UK? Or maybe Tesco is a tourist hotspot for the travelling American, and he brought home a souvenir? Either way, it's incredibly useful to provide both imperial and metric. I wish more channels would do so. It amazes me the number of people that use feet and inches in the UK (and farenheit too), and never bother to provide conversion for the viewer/reader. I regularly read articles in the UK press, and on UK TV programs, that state things in feet without conversion. It's bloody annoying, given that anyone that went to school in the UK beyond around 1980 would have been taught in metric. Although, weirdly, I could never fathom (pun intended) a person's height or weight if described in metric, despite weighing food in metric and measuring objects in metric. Kudos to this channel.
Years ago I used a wood stove to heat the small house in the woods where I was living. When the ancient water heater went out, I used the wood stove to heat water by 1) putting water in a large pot and 2) putting the pot on top of the stove. It worked!
I think you should double the chimney and have your heater horizontal. That way you can make the water flow in the opposite direction of the flames, that way the difference in temperature will make it much hotter. Maybe raise your water tank so that the copper is at half height and that way the water moves naturally without the need of a motor. I hope to see a continuation of the project if you make any improvements :)
You made a critical mistake that inhibited the performance This comes from the energy experts in the HVAC industry, it is called Pre-Heating. The cold water inlet should be at the top, closest to the end terminals if the flue. When you look at the Copper tubing, a section of that copper, say 1" length. It will conduct heat at a specific rate, drawing heat away from the flue and transfer that heat through the heat of conduction to the water. Since that Heat Transfer is limited, you are considering Temperature Rise. Since the heat closest to the stove is hotter than it is by the termination of the flue, you want the most heat transfer as possible. If your inlet water is at the farthest point, it absorbs heat, and as it runs through that Copper Pipe, it will be exposed to hotter temps. You are literally Pre-Heating the water before it gets to the Hottest portion of the Flue, where it will absorb the most heat. Additional benefit is that the resistance of the water to the Pump will be reduced, resulting in a more efficient pump operation with less stress on the motor. Your Heat Rise will likely improve by 25-50°. Another improvement to your setup would be to add your heat exchanger as a bypass to a primary flue, with the damper installed above a tee, where the air would go into a tee when primary flue passage is closed off. This would minimize flue gases exposed to the heat exchanger unless needed by simply closing the damper. Basically, close the damper to turn on the hot water heater.
The inlet pipe at the top is best for a pumped system, backwards for a thermal only circulation system. The water rising when heated makes the pump work harder, not less. I like your bypass idea... Mine use-to boil off every once in a while... I plumed for that, and it would have been irrelevant except the standard blow off valves are not rated for repeated use and tend to leak after 2-3 times.
Basically what you described is what is known as a counterflow heat exchanger. What is in the video is a thermosiphon. If you have an adequate pump, then thermosiphon isn't required. Counterflow designs can be very efficient! Would be a simple mod and a great follow-up video.
@@chasbaderwe Pre-Heating the air of 90% condensing gas and oil furnaces. It pulls so much heat out of the flue gases that it condenses the moisture from those gases. Due to the acidity, and the moisture, we can not use a metal flue for them, we have to use PVC, and account for removal of those condensate. Extremely efficient.
With respect to your factually accurate and clearly written description. Your talking like your living on grid and not rationing every watt of solar energy. ie the pump. using a pump when thermal siphoning will do the job is scandalous! not unreasonable or erational mind you. the coil caking up with hard or sticky creosote is a maintenance "nightmare" and a chimney fire waiting to happen. ultimate efficiency must needs take a back seat to maintenance and safety. this guy did a great job on fabricating and thinking of maintenance. that being said I would not be cleaning that design in my house as it would be a terrific mess every 3 weeks. It may end your marriage if you have one. I would not build one fire to heat my house and another to heat the water,extra labour. so that's a problem. In case you sense a extra bit of passion here that would be because I came by it honestly. (long explanation, not relevant to the facts) creosote is an insulator and hostile to energy transfer efficiency. not that that is in any way a problem, up till week 3. then the system works poorly and safety is threatened.then you clean it. a good set up takes 45 minutes to an hour from lighting the fire, after that you risk a boil over an have to deal with the problem of steam. or an explosion take your pick. I know it's counter intuitive but your striving for mediocrity here. the best system is a water jacket around the flue (1/4" of water ) and for the love of all that is holy plumb it so that every last bubble floats to the top and harmlessly blows out the steam rated blow off valve, just like o'll Moby Dick. the water jacket allows you to use a chimney brush in a few minutes.easy. if the water jacket is to efficient the steam rated valve takes care of that. just make sure the steam and water eject in a harmless direction. one more thing there is a magic line 2 feet above the coil were hot water will not go below. make sure the bottom of the tank is above that. or use a pump- be a heretic I don't care. Jared
I love your ingenuity with the coil-forming and i am going to share it with my metal-shapers' forum. While it was unnecessary in this experiment; the storage vessel needs an escape vent, so that boiling water can escape. If it can't escape the vessel becomes a bomb and will explode. Be WARNED people have been killed by homemade-hot-water systems. In Western Australia the vent is a tall piece of 1/2" copper pipe, with the top bent into the shape of a shepherd's crook. Boiling water can then fall onto the roof of the house where it is unlikely to burn anyone. Love your movie and your presentation!
Thanks! Yeah, a closed system definitely needs some kind of pressure relief. I show my off-grid water jacket wood stove shower system in my next video and its a closed system so it has a built in pressure relief valve.
@GreenhillForge I think the disadvantage to this design is the fact that soot and tar will condensate on the copper pipes, slowing down heat transfer and making it a pain to clean. You can also create a thermosiphon to circulate the water without the use of a pump.
I wonder if you could mitigate this issue (AND BOOST EFFICIENCY!) by incorporating a catalytic converter into this build. Combust more pyrolytic by-products and extract more energy simultaneously? Just an idea...
the stove has a secondary burn chamber so it's pretty efficient already but cat stoves are cool too. I've got a video of the stove design and build you can check out if you want
@ Cool! I will check them out! Have you ever looked into thermoelectric generating elements? Perhaps something like the BioLite stoves, where the generated electricity is used to power a fan and a USB power port?
@ Yeah, I've played around with peltier/seebeck modules but you need tons of them to generate substantial amounts of power. I also have a video of building a stirling engine which can be used as a stove fan or for generating energy.
I bet the exchanger would work horizontally so long as the chimney was insulated and tall enough to create draw. As for the combustible buildup everyone is talking about, a complete burn would definitely help, either with high heat + gasifier second stage or a catalyst. And your build is such that you can do a complete disassembly and clean which is amazing. Fantastic job and excellent video editing
A friend of mine used river sand as the insulation it takes a bit to warm up but once hot it stays hot for a long time and he said he just filled the whole thing up with sand around the flue pipe and coil and outer case. It works very nice I have used the hot water from it !
Brilliantly done, very impressed by the efficiency. By my estimations that’s around 5.7kW to heat up that much water and about 85% heat recovery, can’t get much better than that :)
You actually did something I've thought about for years. Nice. The only problem I might see is that as you cool the exhaust, creosote will form on the copper pretty quickly and fill the contraption up.
So I watched this vid and then went and watched the fireplace build vid and I am just amazed at the efficiency and elegance of how well you designed and built both. The issues that I wouldn't of even considered and then when you mentioned them I imagined complex solutions but then you just "Add a couple of holes" and it works beautifully.
We stayed at a off grid place a couple years ago that had a similar setup to heat up water for showering, etc. worked about as quick and if we kept feeding the fire, it would essentially function the same as a 'tankless' boiler. Only downside was having to wait in the morning before any hot water was available.
The house I grew up in was built in the early 1900's. There was a Majestic coal/wood stove that we pretty much only used to take the chill off first thing in the morning or during the occasional power outage, such as the time we finished cooking the Thanksgiving turkey. It had a water tank fastened to the back between the stove and the wall and there were the ends of a pair of pipes sticking out from the wall that must have at one time connected the tank to the house's plumbing system.
To the point with detail. Great design with service access. The difference of temperature from bottom to top is great. I wonder how much more another foot in length would help extract more energy. Great Work!
Ever seen those hot tubs which are a kit made of wood? Into the water they drop an aluminum barrel and have a fire in the barrel. The water protects the aluminum from the heat of the open fire and the fire heats the tub water. I've always wondered if this would work in a pool.
One thing you want is,the colt water coning in from the top and the hot going out the bottom. I don't know the science behind it but when using wood boiler to heat your hot water in the house if you put in and outs going the same direction it's less efficient. Maybe you could do a test reversing the water flow and compare.
Yeah, basically it's preheating the water before it gets to the hottest point. But if you run it from bottom to top you can actually remove the pump and a "thermosiphon" will move the water by itself.
We can't wait for the next video! We have a hot tub heating system that works as follows: Water flows down a 4m tall pipe to maintain pressure, with a T-piece at the top of it to regulate the amount of water entering the pipe and vent steam to the top if needed. The water travels through a tap and a one-way valve, entering the top of the heating chamber(almost the same as yours, but it flows the other way around). By the time it reaches the bottom, it turns into steam. The steam goes out from the stove and passes through another heat exchanger (a coil in water) to condense and is then pushed back up to the T-piece at the top of the system. This creates a closed-loop system with no pump needed-it operates similarly to a ram pump. The one-way valve facilitates the movement of steam and water through the system, ensuring continuous circulation. Because the same water is recirculated, no dirt or chlorine from the outside contaminates the system. You can hear the one-way valve activating as it causes steam pressure to push the steam or water through the condenser coil and back to the top. When the pressure drops, the valve opens again, allowing more water to flow down the pipe. This is a low-pressure steam system, so if the steam pressure becomes too high, it vents at the top of the T-piece for safety. To enhance safety further, we've installed a safety valve just after the one-way valve. We've tested the system thoroughly, including by heavily stoking the fire. The safety valve only opened once when we intentionally blocked the T-piece at the top (something you should never normally do). It takes some adjustment to get the system working perfectly. We use a tap before the one-way valve to control the amount of water that flows through the system.
Oh, yes almost forgot, the one way valve must be positioned level with the ground, so that the little flap hangs downwards, this makes it easy for the steam/water to close it.
@ so the water that is heated is in a closed system and separate to the water in the actual hot tub? And the hot tub water is heated by contact with the condensing coil?
@GreenhillForge I'll only be back at home in about 2 months time, I can draw you a rough sketch of it if you want to try it?, I'll send you a message on your contact form on the website.
It wouldn't be a bad idea to incorporate a temperature/pressure relief valve at the storage tank just in case the pump fails or the temperature in the storage tank gets too high. I scrapped out a gas water heater once and there was a sheet metal baffle (twisted into a spiral) running down the center of the heat exchange tube to direct the heat toward the heat exchange surface. That might help increase the efficiency even more. You did an magnificent job! Well designed and implement. Thank you for sharing.
Great proof of concept project. Next step, dealing with the creosote. Follow up steps, bimetallic issues, smokeless efficiency, automated airflow control. Again great work and presentation, you’ve got my subscription. 👍
Tradesmen are the salt of everyday life. You, sir, are an artist at your craft. Absolutely have a new follower! Wonderful video, well done, great direction and teaching.
I've been running a wood fired bioler at my house for 5 years. It supplies all the hot water we could ever need together with floor heating and radiant heat for house. It burns about 150 pounds of wood a day. Our cold wate line enters the top and hot water comes out the bottom. We love it and for our winters it costs us $300-350 a season. Spring, summerand fall it cost $90 for hot water.
Hard to believe,150 lbs. Of wood a day only costs that much,for a whole season ....you must only pay pennies a cord.....or is the $150 the amount you pay for chainsaw fuel? Thanks
Wow. Nice job. 1100 to 300-something, that's great heat extraction. That work wasn't entirely above what I could do, but I do wish I'd gone to a "trades" high school. I've always been interested in a water heating system with a gravity feed, hot water tank above the heat source with proper control manipulations and safety but without use of any power.
Love how simple you twisted the copper coil, but that metal enclosure looked like one hell of a faff! Especially considering you need a welder to do it your way. I feel it would have been a lot simpler and more effective to get or make a cylinder slightly wider in diameter than the coil, close the bottom off and then fill the cylinder with sand. Sand retains heat very well and gives it off really slowly.
@GreenhillForge Ah alright then. Good to know, because I was only "theorizing" from what I learned about sand recently in another similar video. They used sand as a sort of heat battery. Wicked stuff it is. And sand is cheap as chips too.
@@Johny40Se7en Yeah, sand for something like a rocket mass heater system is great. It all depends on what you want to do with the heat once you've made it.
I did a 6' long, but otherwise similar coil in a stainless tube packed with dry sand. It takes a little while to heat up, but delivers consistent and quick recovery, and isn't really affected by high/low fire.
Brilliant, just brilliant! Had a professor of English lit. say that genius is "doing that which is often thought but never done". Thank you very much!🙏🙏😎👍👍
Reverse your water flow. Cold in at top, flow down, hot out at bottom. This is known as counter current exchange and extracts the most heat from the flue gas. Great build!!
Had to check this out! Thanks for the pro tip! 🙌
I'm so glad this was already the top comment that I could thumbs up on!
@@BenBrand Same here. This is super important for maximum efficiency. It would be awesome if he could reverse the water flow and compare the different time? Love this!
Even though it would be at the expense of thermal dynamics transfer of heat energy, would it be worth trying sans pump and allowing convection to do its thing in current configuration?
@@EnglishLevy maybe if the water barrel was lifted up so its height was the same as the coil. But with it being down below all of the water in the coil will get hot but there would be no wear for it to flow heat wise up since the top tube goes down so far even below the bottom tube before it gets into the barrel. It only takes a very tiny amount of movement to get an order of magnitude more heat so having a very small pump is worth it for sure
I have no intention of making this contraption but I must compliment the video maker. Clear instructions, no wasted time, no filler, no stupid music. Bravo!
Exactly. Editor knew EXACTLY what we didn’t need to see and cut it out or sped it up. 👍 Excellent work.
@@mykidsfuture5582 Nail, head, you know the thing.."Joe By-done" Ret.
Top call!
Yep… awesome!
Perfect presentation.
Best put together video I've seen in ages. Clear and to the point.
Just subscribed to your channel. 👍✌️
Oh man no waisted time, no repeating the same phrase, clear and concise and to the point. A pleasure to watch. Great video thumbs up.
And no bullshit "industrial noise pollution"?! LOL!
This is how videos should be. I definitely get excited when new videos come out. Always top tier.
No doubt. It's really something you learn to appreciate isn't it 😅
@ Good call.
Having done this 40 years ago, I can tell you that if you put the copper coil inside the pipe it will be covered with creosote in a few months which will insulate the coils which will keep the coils from heating properly. I put the coils on the outside of the 6" pipe and slipped that inside a piece of 8" pipe with 6" to 8" reducers on both ends of the coils to keep the coils out of the smoke. That worked the best and still gets the water hot enough to burn you. As far as I know it is still working fine. Keep up the good work. Jerry
Could you burn of the creosote by firing it without any water in the loop?
copper starts to get soft at around 750f and melts at around 2000f so you probably could get away with it if you really dialed in the fire. I think the only way we'll know for sure is to try it. Maybe after all the testing is done on this first unit I'll have to give it a try...
I'll be trying something similar soon so I can test the differences in efficiency of thermal transfer. It's definitely the safer route though.
@Flexsan, I'm sure you could, but it would difficult because you can't easily control the temp and you can't see the coil. One rule I learned later on was, If at all possible what ever you do try to make it Maintenance Free. Jerry
@GreenhillForgecould you stick a bunch of peltier modules on the upper part of the chimney to generate electricity for the pump? That way it could be truly off grid and it would double as a temperature control system to protect the copper.
Wow, very impressive! This video shows about 5% of the actual work you put into this. Hours and hours of planning, sourcing materials, welding, measuring, cutting, grinding, lighting the fire, etc. People like you are what made humanity great. Bravo!
As someone with an imagination , but who struggles to put a shelf up straight, I am continually impressed by the ingenuity and practical ability of folk like yourself.
Well done sir.
My folks had a system like this in their house for decades. During the winter, they'd switch to the heat exchanger attached to the woodstove, and use that to heat the house via baseboard hot water heaters. There was a boiler for that system as well, but they'd only use it during shoulder seasons, with the woodstove providing all the house heat during the winter.
It was a complicated system, but it really worked great for them.
Ive been heating house, hot water
, and cooking on a woodstove for the last 49 years I love your video , and the way you present the materials and instructions on how to DIY one for ones self. Im unqualifyed to build one myself but if a pre made was for sale Id sure consider buying it, its way better then the stainless steel pipe I got in the firebox of my cookstove. thanks for your sharing
Right 👍
This was fun to watch, as I lived for a few years in an entirely wood-heated house in Vermont with a wood cookstove from the 1920’s that had a ‘water jacket’ (pipes in the lining of the firebox). It was attached to a water tank behind it, fed by gravity. Within an hour or so of lighting the stove there would be a supply of hot water for dishes and showers. You could tell how much hot water was left by feeling the tank, which through convection would feel warm to the touch from the top down. You just had to be careful because the hot water could get VERY hot if the stove had been going for a while without using the hot water.
I did a science fair project about efficient energy use and included a hot water heater nearly identical to your design, the teacher said it wouldn’t work so I built a working scale model to prove it. He was an ass so was still sceptical in an ego driven way. I knew he was wrong and I also got me a shinny gold medal for my effort at the fair. So there Mr ………! (No names)
In school I made an ammonia condenser. We generated the ammonia with an ammonia salt and a strong base. The vapor would leave reaction chamber and condense in a stainless steel coil that was immersed in dry ice and acetone. A collection vessel was under the coil that was also immersed in the dry ice solution. Within 15 minutes enough NH3 was collected to add my Li and other necessary ingredients. By lunch the entire science department was in overdrive and eating was the last thing on our minds. Go science!!!
@@HeyGuy213 that’s an amazing story Jesse!!
It’s a water heater. Not a hot water heater.
@ well your not wrong
@@amyspring3891Lol, right. Why would someone need to heat already hot water??
A tip of the cap to you sir!! This is a gem of a how-to video complete with real-world testing in the same vid!! The world needs more like you, great build, great explanations, great lighting, great safety demonstration, beautiful countryside too. Consider swapping the direction of cold return water into the top and out the bottom to oppose flow of gases to water. As an aside I really enjoy your power mullet, keep it up you're doing wonderful work here!
Thanks for the warning about the toxicity of the insulation. Thumbs up for that alone. Good man.
I have no idea why I ended up here but this has been one hell of a video great job on the build and the video
Came for the experiment- stayed for the haircut. You are awesome- wish you were my neighbor! Best of luck to you !!!
This was the best most comprehensive video on this subject I’ve seen. Particularly like your thinking with the spacers to expose as much of the surface area of the pipe as possible. Bonza!
Nice reminder of a concept that has been around for over a hundred years. It works, my grandfather built one of these over 70 years ago and discussed the concept with me in the 1960's. He used a G cylinder as the sheath and pushed heat into the bottom of the G cylinder from a chip heater and exhausted the smoke through a chimney welded to the top of the G cylinder which was cut away around 200mm from the valve assembly at the top of the G cylinder. Very efficient.
WE had a slow combustion stove on the farm a Carmichael with a wet back,it worked on thermo siphon no pump involved ,if water got to hot had a shepherds type crook vent pipe to let out steam and over flow water to the roof into the guttering and back to the water tanks, the hot water tank was on the roof ,well presented and learned a lot thanks
A couple of things from someone who has done something similar over 25 years:
1. Your water system must be open loop (not pressurized). I have an open loop tank (like yours) with a second coil inside that is pressurized as part of my home's hot water system. Hot water in the tank heats our DHW as it moves through the coil. Works very well.
2. Your stove pipe heat exchanger is going to get fouled from creosote and ash condensing on the relatively cool surface (been there, dealt with that). You'll need to periodically disassemble it and use a wire brush or something to clean your copper coil. Or you can drain the water from the coil and burn it clean. Not as effective.
I ended up building a straight pipe grid actually inside the top of my stove for easier access for cleaning the copper pipe. Also, having it inside the stove causes combustion condensation to drip back into the fire to be re-burned meaning cleaner smoke up the chimney. Once I did that, my stove pipe stays much cleaner.
3. I use a differential temperature controller to control my pump. Turns the pump on when the temperature exiting my heat exchanger is 10 degrees higher than the bottom of the tank.
Great job! Your fabrication skills exceed mine.
@@zettaiengineer4202 Look again.
@@TheGhungFu you're right, he wrapped copper around pipe to shape it but its not there in the end.
You are simultaneously condensing your smoke by rapidly transferring its heat to the water … thereby collecting the remaining combustible solids contained in the smoke onto your coil and interior of the box….eventually a chimney fire will happen…..I would suggest keeping the smoke off the coils by having the copper wrapped around a stove pipe that would be easy to clean or be kept creosote free with a higher burn temperature.
That's true. There's a balance to be had between how much heat you extract and how much buildup you get.
My woodstove is one of those wide ranges and it takes out almost too much heat. 3 years in a row the sweep has not found anything in the pipe but I have to do a cleanout of the stove each year instead or it clogs up!
Yes, and this buildup will happen rapidly in a few hours of burn choking the spacing between the coils and the efficiency will collapse right along with the buildup.
Came looking for this comment.
That buildup will also choke the flue, not good for the stove.
Same came here to look if anyone had mentioned this, and warn about flue fire. Think although a loss of heat conversation for safety a modified design that be slid over a traditional flue, this would allow a couple of things protecting the coils and the ability to disconnect it and reconnect it to a flue on a fire without the need to remove the original flue, but the butterflies top and bottom would have to be put into the permanent flue not the heat converter, but this would allow the system to be moved between multiple fire places.
Yes copper outside of the pipe then insulation and outer pipe will still condense however there is additives that helps prevent this
Love your content mate! One of my favorite subjects paired with your delivery, filming, editing and knowledge all combine to create an awesome clip. Thank you for sharing all the small details. Hopefully one day I'll build myself one of these and will be referring back to your videos. You'll hit 100k+ if you keep this up.
This system is 6.08 kW
here's calculations for those interested:
to heat 1 kilogram of water 1 Kelvin (or C) you need 0.00116 kWh of energy (or 4.19 kJ/(kg. K))
40c-7c = 33c temp difference (end v start temp.)
106 liters of water roughly equals 106 kilograms of water,
33*106*0.00116 = 4.06 kWh
this was done in 40 minutes though, so: 4.06kWh / (40/60h) = 6.08Kw
This the by far the best build video I've ever seen! Well edited, minimal explaining, fast forwarding of the actual cutting/welding scenes and keeping it as simple as possible. Nice work!!! You've earned my sub!
I can appreciate this greatly!
For to heat a wooden hot tub I built a heater very similar to this.
For the coil which was of 304 stainless, 5/8” tube, instead of ice, I filled it with salt used 10” and 6” pvc pipe for the mandrel, fabricated a “C” “wrench with a curved pawl at one end of the “C” I fitted with a nylon plastic insert to let it slip and accommodate the radius of the tubing. The wrench had about a 4’ handle welded on, I did my twisting vertically. I put a 6” coil within the 10” coil, with the spring back of the inner coil it also gave me a fairly close clearance. I mounted a “ or 9” Nat.Gas burner under it held vertically spaced with a steel strap frame. For the shroud, again very similar, it was a double “tube” a separated w fiberglass from sheet metal. At the end I found the the greatest efficiency, and the quickest heating time was by flowing maximum volume of water thru the coils. At first I had it plumbed to be one continuous coil but I found it best to separate the bottom and top of both coils and installed a “Y” necked from 5/8” up to 1 1/2” and wound up with a small 1/4 hp transfer pump jst for circulation, then a standard 2 1/2hp swimming pool pump with a strainer basket for heating and to run aeration jets. I regulated the gas valve with a waterbed thermostat (had to tweak that a little). It all worked like a champ for 15 yrs. The 6 1/2’ tub, & heater set up looked great trim with cedar privacy surrounding went with the home when we sold it, heck IT sold the house!
Also, instead of a flu, I finally mounted 3/3” discs 6” apart welded to 1/2” rod as a
“Heat buffer” and stood it in the center of the inner coil.
Very VERY IMPRESSED with you fabricated BREAK !!!
Nice design!!
If I may offer a little advice, you may want to change the steel holding the copper tubing in place to a "friendlier" metal like brass, or maybe use copper strapping. Due to a process called Electrolysis, the two metals touching will result in one wearing the other one down over time, causing leaks.
Isn't the copper higher on the nobility scale than steel?
@winksworks No, it isn't. It is a better conductor than almost every other metal, but it will almost always lose the battle when placed too close to other types of material. Especially galvanized pipe.
@ Well spotted!
just add tefgel to contact points.
@@BOSS_DOG how do I know you're a seafarer 😂
Nice job 👍👍
Super nice work! You can bump the efficiency by reversing the flow in the coil. Inlet at the top and outlet at the bottom. Reverse flow heat exchangers is a more efficient config.
Precisely what I was thinking. Deffinately helped my offset head double helix reflux condenser I use to distill "fuel" with.
Great stuff, as a heating engineer this idea has been living in my head for the past 20 years 🏆
Really nice design, smart way to deal with bending the copper.
I must admit that the video perfectly present the work, masterful work, without any music, no wasted time, perfectly shown in the most informative way.
Your presentation style is so clear and concise, I really appreciate how effectively you're sharing you idea and the thought process along with it. I don't do any welding and was trying to figure out how you were going to manage those standoffs, but cut to fit and weld in place is the absolute best way to go there.
Cheers
I love that there’s essentially no wrong way of doing this as long as it achieves the same outcome , but we’re watching such a innovative method
Bro. This was a master class in thermal transfer in practice. I've sat down and thought about this exact creation numerous times. I work in the industrial water treatment industry and have seen thousands of heat exchangers. This was very well done. I've never seen a pipe bent with ice. We've always done it with sand. Great, magnificent work. Bravo!
But this design can't be cleaned. After a few burns you get serious buildup around your copper tubes, essentially insulating the tubes.
Great video :) .
I made one of these, about 30 years ago.
While it was only 1% as well built as yours, due to no electricity on my farm, it could easily boil the entire contents of a 180 litre water tank within 3 hours.
Yup, the tank was literally vibrating, as the water inside was boiling - - and all without a water pump!
Needless to say, I was massively impressed at how well it worked :) .
19:15 - I love that scientific representation of temperature by touching your face to it lol
figured it was the best way to visually prove how cool it was, lol
face is definitely more sensitive then callused work.hands. the viual is a hug to the devise that takes care of you
Exquisite I have also built one with a beer keg it’s 85% efficient
85% is insanely efficient, what's your secret?
We live in a travel trailer and do physical labor, we stick framed a bath/sauna house complete w/ a half dozen slider insulated big windows that came our way, w/a wood stove under the clawfoot tub. Your video was top notch! To complete our "rural living in comfort" we use a metal snow shovel to put the coals from the fire in a wheel barrow w/water to make biochar for the garden
All that is fascinating. Well done!
This is music to my ears! I have no idea how to do this and now you have shown us all how to do this! Thank you so much! Watching from freezing England at the moment.
Your coil will be thickly covered in creosote (less efficient) in 3 weeks or less, and needs to be cleaned. It has the BTU's of coal and will make a fantastic chimney fire... Allowing for cleaning must be part of the design.
if your water tank bottom is 2ft. above the top of the coil you don't need a pump.
Ask me how I know...
Ok, how…Assuming you tried it w/reverse flow?
Creosote was the problem that I had when I attempted a similar water heater.
@ my system produced 4 to 6 litres of creosote every 3 weeks. but It did the job for hot water. easy cleaning must be built into the system.without diligent maintenance it's a chimney fire waiting to happen.
@ mine had no pump and used thermal circulation. it works just fine.
Great video great contraption! One thing I learned having the the copper inside the fire place or flue is that it condenses really quickly and builds a lot of soot and char around it. Which then doesn’t transfer the heat as well.
One way to clean it is empty the water out and burn a really hot fire to burn off the carbon buildup.
Try using your heat exchanger without the pump, just free flow pipes. Cold inlet at the bottom of the tank, hot fill at the top. You should find the external kettle still heating up because the hottest water rises to the top and automatically pulls in cooler water from the bottom of the tank.
That's coming up soon
BUT, ONLY IF THE TANK IS HIGHER THAN THE COIL.
If you want a thermosyphon to work, then the receiving tank needs to be HIGHER than the coil, so the hot water can rise to expand into it. The pipe must slope UP
The tank's coldest water at its bottom will also then drop to the bottom of the coil. The pipe must slope Down.
@greenwood4020 Not true, most early tractors used thermosyphons, the radiator was at the same height as the cooling jacket. The heat rising and cold return allowed circulation.
@@johnqpublic9074 You are correct.
I should have stated the most efficient designs are, as I described. Most model T Fords used the thermosyphon system, but it was susceptible to overheating if worked heavily, but served well for most Model T usage.
Many types of water pumps were available as after market accessories.
This content is the peak of modern civilisation. Incredible.
I love this type of content.
You're at about 19,600 BTU/ HR based on your start / stop and total time. Awesome. Working on a coil system to feed in floor radiant for an office shed build coming up. Love your video!
Outstanding !!! Clear, to the point, and a pleasure to watch from start to finish.
It's a pleasure to see a content creator build cool stuff without 50k+ $ of sponsored equipment! you did really well with something almost anyone with a garage could manage to have at home, keep up the good stuff!
I like your build quality and the video was excellent.
In Boy Scouts one of our scout masters had a “keg” or a stainless propane tank (not sure which) but it had a coil inside surrounded by water. He heated the water in the tank and the coil water came out the shower head. Metering was just a ball valve.
It was awesome!
lmao they also probably know how to make a moonshine still too!
@ what happens at scout camp..stays at scout camp 😁
This is so awesome! I have been pondering this concept for years, so excited to see a version of it in action! You are fantastic, and thank you for sharing with all of us!
I had a similar setup up in a double barrel stove in my basement to heat a 600 gallon water battery, worked incredibly well to provide a bunch of stored heat after the fire went out.
If you added a thin metal pipe in the middle of the coil and fill the coils space with sand. Cleaning would be better and the sand once heated will stay hot long after stove burns out. Might save on fuel
Careful with heating sand, it produces silica at high temps. Should be ok near the pipes with the water running through keeping it at max 100C but the edges of the square may reach dangerous temperatures.
@@Andevinga wood stove only gets to just under 600 degrees the chimney will be way cooler then that and silica is a type of sand and sand doesn’t melt until 1700°c maybe I’m misunderstanding what your saying lol
I'm really impressed by your design and your detailed explanation. I am a fussy machinist of 40+ years and both you and I know the devil is in the details.
I have been considering a very similar design for a hybrid stove for hydronic floor heating.
My only concern with a stove like yours is creosote build-up due to the cooling of the gases. This is why I am considering a hybrid which tends to burn very clean.
I really look forward to more of your stuff. I am a new subscriber. All the best from Canada and thank you so much for your hard work.
thanks! this wouldn't work well as a regular use, long term design. I just wanted to test direct contact with the glue gases to get the high end values of possible heat transfer to compare with further designs down the line.
@GreenhillForge Ahh...ok...I figured as much. Thanks for your quick reply.
Dude! That was amazing! Your craftsmanship is outstanding. Your video editing skills are incredible. And to top it all off you own a German Shepherd! Best dogs ever.
Thanks! Props to the wife for the editing.
I am very impressed with your build. In fact, you just made me think... in floor off grid heating.
absolutely
Heres an idea, using excess solar energy. Once your battery has reached full charge, diverting the excess into a heating element and filling the contraption with sand. Solar electric water heater.
Heating elements are HEAVYYY loads, wouldn’t work imo. Google Solar PV-T panels mate, a much better solution I think.
@beatdrive741 His idea is a good one. Once the batteries are full and you have already paid for the panels, you are best off to find some other use for the energy. The panels are selected for changing the batteries on the worst days of the year so most of the time there is excess. Heating elements come in all wattage levels.
@@kensmith5694 it isn’t efficient in the slightest, there are better approaches that already exist. Sure it could work but you’ll end up with an overly complicated installation that gives you very small amounts of warm water. Lower the wattage, lower the capability. For something as crucial as hot water availability you want simplicity really where possible. If you want to use the excess energy you’d honestly be better off storing it elsewhere as potential energy. Another battery, or pumped water storage or something.
@beatdrive741 Storing energy as heat is fine. I see no point in further discussion
@@kensmith5694 sure thing, you can but it’s simply inefficient in a multitude of ways. Ultimately it boils down to what problem are you trying to solve. Maybe there’s an edge case where it works but I’m not seeing it..
This coil build is so satisfying, I would do it the same way. Incredible craftsmanship!
Interesting idea. Won't the copper cause rapid galvanic corrosion of the iron and collect creosote rapidly as the smoke passes over the water cooled copper? Maybe 5/16" stainless brake line or 3/8" stainless wort chiller coil tubing would be safer?
For galvanic corrosion to occur, the metallic junction must be in the presence of an electrolyte.
I am about 7:50 in and I see steel touching copper. As a plumber my alarm bells started going off saying dis-similar metals touching, galvanic corrosion. That would worry me for the longevity of this build. So far I am enjoying you video and information. This is the first video of yours I have seen.
it's just a test unit. I'll be on to a new design within a few burns.
Excellent Design and Fabrication!! Very Efficient - Well done!
I completely agree with the design which you have proposed and you do have a hand in great videography, and I do appreciate the fact that it’s a very short video based on the fact that information without any accompanying music. A better suggestion, even than what your design is would be to convert a single wall, wood stove to become a double wall, wood stove with a water jacket. It’s even the heated with the cold in at the top and the warm out the bottom.
thanks! I showed my off grid water jacket shower in the following video. check it out if you'd like
Well thought out and executed project there, thanks.
I have experimented with a similar setup in my workshop en learned the following;
1 - Run the water in the coil above 60C to avoid condensation and deposit of creosoot. This is dangerous as it can catch fire. I use a system with a thermostat that regulates the primary circuit to around 65C. Anything over that will be mixed into the secondary circuit with radiators and hot water boiler.
2 - You need draft in your chimney for a good fire; Don't cool down your exhaust gas too much as it will stall the draft. Try to build a waterjacket around the fireplace to keep the chimney temp high. I works fine in the video with sunny weather I don't know if it still works if there is a freezing cold. Alternatively you can use a chimney ventilator that sucks the air through no matter what.
3 - Don't put a valve right after your fire. If the fire is running and you close the valve your room is full of smoke. If I have an over temperature in my water system, fi if the pump stops, then 2 systems get in place: The air intake to the fire shuts off and cold water is purged into the coil. These are spring loaded and don't need electricity to run. Safety first!
You are a very creative person! Love the video.
How did you rig it to shut off the stove air intake? Did you use a temperature/pressure relief valve for the water?or how did you do the cold water safety?thanks!
@@edcat6587It is utility drinkwater; That is pressurized at 3 bar and releases a spring loaded piston that pushed the air intake valve. Once triggered you need to manually reset everything. The drinking water is released into the primary circuit that typically has a pressure of 1.5 bar. A pressure release valve in the primary circuit releases the surplus water into the garden.
That was awesome. I have no idea how the algorithm delivered me. But I'm glad I watched it. You put a lot of work into that project.
Great project, impressed by the efficiency! And nice editing too, I predict a steady rise in views and subs in the future! I subbed after watching the stove build video and am looking forward to the next! A solution to have a circulation pump also driven by the heat would be amazing, it's such a critical part of the system and would make it pretty mobile. I guess a stirling engine would be too weak🤔 This is going to affect my sleep tonight I'm afraid😂
Thanks! I didn't get into this in the video but I'll try to remember to touch on it in the follow up video, but these types of systems can actually be run without a pump. Hot water expands and rises just like hot air does, so if you place the barrel vs the heat exchanger properly the hot water will naturally rise through the copper coil by itself. The only issue with this system is that it might be too hot, meaning the water doesn't move quickly enough to keep the copper from overheating. That's why I added the pump. Maybe after the rocket stove test I'll try taking the pump out and see what happens, at least that way if the copper melts I got the tests done first.
@GreenhillForge Yeah, I've seen a few projects without a pump, but it does seem to be very finicky to get to circulate fast enough, and then it could become somewhat of a safety issue. The principle would be the same(opposite) as a fluid cooling system, my knowledge limits to engines and such where there's always a pump, I wonder if systems without pumps are used elsewere🤔
@@malefunctionable Yeah, thermosiphons are passive heat exchanging systems and they're used in at least a few things I can think of. Biggest one being rooftop solar hot water systems. But I can't think of any that come anywhere near the kind of temps in solid fuel burning systems. A lot easier and safer if you're topping out at like 140F instead of 1200F.
Just occured that a simple steam engine could work really well and would also sync up well with the system. The hotter it gets the faster the pump would run. Maybe I'll try building one...
@GreenhillForge Do it!
Using a solid fuel fire to heat water was fairly standard in rural UK for most of the last century. Fire places and stoves were specially designed for it.
That was with a back boiler installed into the burning chamber or at the back of the fireplace (hence the name) rather than using the heat from the flue/chimney.
By adding metric measurements instead of just the imperial…you’re a star mate 🎉🎉
Also why is he using Fahrenheit when he lives in UK? (British accent, Tesco bag at 19:07)
@@Andeving power outlets too...
He does not have a British accent though.
Never Never use that 3rd world form of measuring called the metric system
@@Andeving he doesn't have a British accent. Good spot on the Tesco bag though, perhaps he lives in the UK? Or maybe Tesco is a tourist hotspot for the travelling American, and he brought home a souvenir?
Either way, it's incredibly useful to provide both imperial and metric. I wish more channels would do so. It amazes me the number of people that use feet and inches in the UK (and farenheit too), and never bother to provide conversion for the viewer/reader. I regularly read articles in the UK press, and on UK TV programs, that state things in feet without conversion. It's bloody annoying, given that anyone that went to school in the UK beyond around 1980 would have been taught in metric. Although, weirdly, I could never fathom (pun intended) a person's height or weight if described in metric, despite weighing food in metric and measuring objects in metric. Kudos to this channel.
Great stuff!
Nobody needs a hot water heater, we need cold water heaters 😜
It’s because people don’t like going to the ATM. They like going to the ATM machine.
Came to say the same If the water is already hot it doesn't need a heater
@@Reviloj to enter their PIN number
Made me laugh. smile and grin.
Nice job
Years ago I used a wood stove to heat the small house in the woods where I was living. When the ancient water heater went out, I used the wood stove to heat water by 1) putting water in a large pot and 2) putting the pot on top of the stove. It worked!
thanks for using metric and celsius units, not many american youtubers do these days, THANKS
I think you should double the chimney and have your heater horizontal.
That way you can make the water flow in the opposite direction of the flames, that way the difference in temperature will make it much hotter.
Maybe raise your water tank so that the copper is at half height and that way the water moves naturally without the need of a motor.
I hope to see a continuation of the project if you make any improvements :)
You made a critical mistake that inhibited the performance
This comes from the energy experts in the HVAC industry, it is called Pre-Heating.
The cold water inlet should be at the top, closest to the end terminals if the flue. When you look at the Copper tubing, a section of that copper, say 1" length. It will conduct heat at a specific rate, drawing heat away from the flue and transfer that heat through the heat of conduction to the water.
Since that Heat Transfer is limited, you are considering Temperature Rise.
Since the heat closest to the stove is hotter than it is by the termination of the flue, you want the most heat transfer as possible.
If your inlet water is at the farthest point, it absorbs heat, and as it runs through that Copper Pipe, it will be exposed to hotter temps. You are literally Pre-Heating the water before it gets to the Hottest portion of the Flue, where it will absorb the most heat.
Additional benefit is that the resistance of the water to the Pump will be reduced, resulting in a more efficient pump operation with less stress on the motor.
Your Heat Rise will likely improve by 25-50°.
Another improvement to your setup would be to add your heat exchanger as a bypass to a primary flue, with the damper installed above a tee, where the air would go into a tee when primary flue passage is closed off. This would minimize flue gases exposed to the heat exchanger unless needed by simply closing the damper. Basically, close the damper to turn on the hot water heater.
The inlet pipe at the top is best for a pumped system, backwards for a thermal only circulation system.
The water rising when heated makes the pump work harder, not less.
I like your bypass idea... Mine use-to boil off every once in a while... I plumed for that, and it would have been irrelevant except the standard blow off valves are not rated for repeated use and tend to leak after 2-3 times.
Basically what you described is what is known as a counterflow heat exchanger. What is in the video is a thermosiphon. If you have an adequate pump, then thermosiphon isn't required. Counterflow designs can be very efficient! Would be a simple mod and a great follow-up video.
@@chasbaderwe Pre-Heating the air of 90% condensing gas and oil furnaces. It pulls so much heat out of the flue gases that it condenses the moisture from those gases. Due to the acidity, and the moisture, we can not use a metal flue for them, we have to use PVC, and account for removal of those condensate. Extremely efficient.
With respect to your factually accurate and clearly written description.
Your talking like your living on grid and not rationing every watt of solar energy. ie the pump.
using a pump when thermal siphoning will do the job is scandalous! not unreasonable or erational mind you.
the coil caking up with hard or sticky creosote is a maintenance "nightmare" and a chimney fire waiting to happen. ultimate efficiency must needs take a back seat to maintenance and safety. this guy did a great job on fabricating and thinking of maintenance. that being said I would not be cleaning that design in my house as it would be a terrific mess every 3 weeks. It may end your marriage if you have one. I would not build one fire to heat my house and another to heat the water,extra labour. so that's a problem.
In case you sense a extra bit of passion here that would be because I came by it honestly. (long explanation, not relevant to the facts)
creosote is an insulator and hostile to energy transfer efficiency. not that that is in any way a problem, up till week 3. then the system works poorly and safety is threatened.then you clean it.
a good set up takes 45 minutes to an hour from lighting the fire, after that you risk a boil over an have to deal with the problem of steam. or an explosion take your pick.
I know it's counter intuitive but your striving for mediocrity here.
the best system is a water jacket around the flue (1/4" of water ) and for the love of all that is holy plumb it so that every last bubble floats to the top and harmlessly blows out the steam rated blow off valve, just like o'll Moby Dick.
the water jacket allows you to use a chimney brush in a few minutes.easy.
if the water jacket is to efficient the steam rated valve takes care of that. just make sure the steam and water eject in a harmless direction.
one more thing there is a magic line 2 feet above the coil were hot water will not go below. make sure the bottom of the tank is above that. or use a pump- be a heretic I don't care.
Jared
I love your ingenuity with the coil-forming and i am going to share it with my metal-shapers' forum.
While it was unnecessary in this experiment; the storage vessel needs an escape vent, so that boiling water can escape. If it can't escape the vessel becomes a bomb and will explode. Be WARNED people have been killed by homemade-hot-water systems.
In Western Australia the vent is a tall piece of 1/2" copper pipe, with the top bent into the shape of a shepherd's crook. Boiling water can then fall onto the roof of the house where it is unlikely to burn anyone.
Love your movie and your presentation!
Thanks! Yeah, a closed system definitely needs some kind of pressure relief. I show my off-grid water jacket wood stove shower system in my next video and its a closed system so it has a built in pressure relief valve.
Hmmm.. something about this looks very familiar....
Thank you Patrick Remington for inventing this water heater,, truly a leap forward
Had to peek at your channel after a comment like that. Looks like some nice stuff. Is there a design you settled on or a favorite?
@GreenhillForge I think the disadvantage to this design is the fact that soot and tar will condensate on the copper pipes, slowing down heat transfer and making it a pain to clean. You can also create a thermosiphon to circulate the water without the use of a pump.
I wonder if you could mitigate this issue (AND BOOST EFFICIENCY!) by incorporating a catalytic converter into this build. Combust more pyrolytic
by-products and extract more energy simultaneously? Just an idea...
the stove has a secondary burn chamber so it's pretty efficient already but cat stoves are cool too. I've got a video of the stove design and build you can check out if you want
@ Cool! I will check them out! Have you ever looked into thermoelectric generating elements? Perhaps something like the BioLite stoves, where the generated electricity is used to power a fan and a USB power port?
@ Yeah, I've played around with peltier/seebeck modules but you need tons of them to generate substantial amounts of power. I also have a video of building a stirling engine which can be used as a stove fan or for generating energy.
It's a water heater. Not a hot water heater ! 😂
Exactly, why would you need to heat hot water? It's a cold water heater.
I bet the exchanger would work horizontally so long as the chimney was insulated and tall enough to create draw. As for the combustible buildup everyone is talking about, a complete burn would definitely help, either with high heat + gasifier second stage or a catalyst. And your build is such that you can do a complete disassembly and clean which is amazing. Fantastic job and excellent video editing
Putting it inside the flue is a good idea. I've always tried to extract heat from the outside, with varying levels of success.
there's pros and cons. more videos coming with different designs and more tests.
A friend of mine used river sand as the insulation it takes a bit to warm up but once hot it stays hot for a long time and he said he just filled the whole thing up with sand around the flue pipe and coil and outer case. It works very nice I have used the hot water from it !
Brilliantly done, very impressed by the efficiency. By my estimations that’s around 5.7kW to heat up that much water and about 85% heat recovery, can’t get much better than that :)
Always dreamed of same system just didn’t have the skills . Nice work thanks
You actually did something I've thought about for years. Nice. The only problem I might see is that as you cool the exhaust, creosote will form on the copper pretty quickly and fill the contraption up.
So I watched this vid and then went and watched the fireplace build vid and I am just amazed at the efficiency and elegance of how well you designed and built both.
The issues that I wouldn't of even considered and then when you mentioned them I imagined complex solutions but then you just "Add a couple of holes" and it works beautifully.
Honestly, I never ever in my life saw somebody working as fast as you do !😂 Nice !!
We stayed at a off grid place a couple years ago that had a similar setup to heat up water for showering, etc. worked about as quick and if we kept feeding the fire, it would essentially function the same as a 'tankless' boiler. Only downside was having to wait in the morning before any hot water was available.
You are a master mate. Is a shame you don't have more people following you.
The house I grew up in was built in the early 1900's. There was a Majestic coal/wood stove that we pretty much only used to take the chill off first thing in the morning or during the occasional power outage, such as the time we finished cooking the Thanksgiving turkey.
It had a water tank fastened to the back between the stove and the wall and there were the ends of a pair of pipes sticking out from the wall that must have at one time connected the tank to the house's plumbing system.
To the point with detail. Great design with service access.
The difference of temperature from bottom to top is great. I wonder how much more another foot in length would help extract more energy. Great Work!
Great design and craftmanship. Appreciate the quantitative testing at the end. Look forward to your future work!
This kind of set-up would make a great efficient swimming pool heater too!!
Ever seen those hot tubs which are a kit made of wood? Into the water they drop an aluminum barrel and have a fire in the barrel. The water protects the aluminum from the heat of the open fire and the fire heats the tub water. I've always wondered if this would work in a pool.
One thing you want is,the colt water coning in from the top and the hot going out the bottom. I don't know the science behind it but when using wood boiler to heat your hot water in the house if you put in and outs going the same direction it's less efficient. Maybe you could do a test reversing the water flow and compare.
Yeah, basically it's preheating the water before it gets to the hottest point. But if you run it from bottom to top you can actually remove the pump and a "thermosiphon" will move the water by itself.
@GreenhillForge yes but I'm most cases you gdt steam when you do that
You deserve more subscribers. I'll add myself to that list.
Thanks mate!
We can't wait for the next video! We have a hot tub heating system that works as follows:
Water flows down a 4m tall pipe to maintain pressure, with a T-piece at the top of it to regulate the amount of water entering the pipe and vent steam to the top if needed. The water travels through a tap and a one-way valve, entering the top of the heating chamber(almost the same as yours, but it flows the other way around). By the time it reaches the bottom, it turns into steam.
The steam goes out from the stove and passes through another heat exchanger (a coil in water) to condense and is then pushed back up to the T-piece at the top of the system. This creates a closed-loop system with no pump needed-it operates similarly to a ram pump. The one-way valve facilitates the movement of steam and water through the system, ensuring continuous circulation. Because the same water is recirculated, no dirt or chlorine from the outside contaminates the system.
You can hear the one-way valve activating as it causes steam pressure to push the steam or water through the condenser coil and back to the top. When the pressure drops, the valve opens again, allowing more water to flow down the pipe.
This is a low-pressure steam system, so if the steam pressure becomes too high, it vents at the top of the T-piece for safety. To enhance safety further, we've installed a safety valve just after the one-way valve. We've tested the system thoroughly, including by heavily stoking the fire. The safety valve only opened once when we intentionally blocked the T-piece at the top (something you should never normally do).
It takes some adjustment to get the system working perfectly. We use a tap before the one-way valve to control the amount of water that flows through the system.
Wow, that sounds like an awesome system. I'd love to see pictures or better yet videos.
Oh, yes almost forgot, the one way valve must be positioned level with the ground, so that the little flap hangs downwards, this makes it easy for the steam/water to close it.
@ so the water that is heated is in a closed system and separate to the water in the actual hot tub? And the hot tub water is heated by contact with the condensing coil?
@GreenhillForge I'll only be back at home in about 2 months time, I can draw you a rough sketch of it if you want to try it?, I'll send you a message on your contact form on the website.
@GreenhillForge Yes 100%
It wouldn't be a bad idea to incorporate a temperature/pressure relief valve at the storage tank just in case the pump fails or the temperature in the storage tank gets too high. I scrapped out a gas water heater once and there was a sheet metal baffle (twisted into a spiral) running down the center of the heat exchange tube to direct the heat toward the heat exchange surface. That might help increase the efficiency even more. You did an magnificent job! Well designed and implement. Thank you for sharing.
Thanks! It's an open system and the tank is wide open. I like the spiral idea.
Great proof of concept project. Next step, dealing with the creosote. Follow up steps, bimetallic issues, smokeless efficiency, automated airflow control. Again great work and presentation, you’ve got my subscription. 👍
Excellent. Serious amount of energy going up the flue. Always wondered why there is not a commercial unit.
Tradesmen are the salt of everyday life. You, sir, are an artist at your craft. Absolutely have a new follower! Wonderful video, well done, great direction and teaching.
I've been running a wood fired bioler at my house for 5 years. It supplies all the hot water we could ever need together with floor heating and radiant heat for house. It burns about 150 pounds of wood a day. Our cold wate line enters the top and hot water comes out the bottom. We love it and for our winters it costs us $300-350 a season. Spring, summerand fall it cost $90 for hot water.
Hard to believe,150 lbs. Of wood a day only costs that much,for a whole season ....you must only pay pennies a cord.....or is the $150 the amount you pay for chainsaw fuel? Thanks
Wow. Nice job. 1100 to 300-something, that's great heat extraction. That work wasn't entirely above what I could do, but I do wish I'd gone to a "trades" high school. I've always been interested in a water heating system with a gravity feed, hot water tank above the heat source with proper control manipulations and safety but without use of any power.
Love how simple you twisted the copper coil, but that metal enclosure looked like one hell of a faff! Especially considering you need a welder to do it your way. I feel it would have been a lot simpler and more effective to get or make a cylinder slightly wider in diameter than the coil, close the bottom off and then fill the cylinder with sand. Sand retains heat very well and gives it off really slowly.
sand would actually be the opposite of what this system wants. the point is to avoid a thermal mass.
@GreenhillForge ah ok
@ Your idea would be great for an indoor system but this is for an outdoor system that just wants to make hot water asap
@GreenhillForge Ah alright then. Good to know, because I was only "theorizing" from what I learned about sand recently in another similar video. They used sand as a sort of heat battery. Wicked stuff it is. And sand is cheap as chips too.
@@Johny40Se7en Yeah, sand for something like a rocket mass heater system is great. It all depends on what you want to do with the heat once you've made it.
I did a 6' long, but otherwise similar coil in a stainless tube packed with dry sand. It takes a little while to heat up, but delivers consistent and quick recovery, and isn't really affected by high/low fire.
I've got a deisgn coming soon I think you'll like.
Brilliant, just brilliant! Had a professor of English lit. say that genius is "doing that which is often thought but never done". Thank you very much!🙏🙏😎👍👍