How to build a Rocket Stove Water Heater!! 

It would’ve been way better if you just made it like this instead of that. Next time try changing that piece to this piece and it’ll be much better, trust me

The round one used less wood and didn’t use a pump. One could argue that it was most efficient.

I was a pipe welder and an insulator. Wrap that in a removable blanket. It will be way more efficient

In boilers, there is the phrase "Hot to hot, cold to cold". This refers to the optimum flow direction of water relative to combustion gasses. The coldest water should enter the stack and the hot water (or steam) should be withdrawn from a place alongside the fire. This makes sense, we can measure boiler effectiveness by exhaust gas temperature -- the cooler the exhaust, the more efficient the boiler. Obviously, cold water entering the stack will remove more heat from the gases than hot water will. The technical term is "counterflow circulation".

Patrick just nonchalantly called us all weak 😂

"He's strong... and blows good" You got the job

Nice builds!! I probably would have used a pump on both to get a fair comparison. great for a small hot tub or clawfoot bathtub with a view!

From the Pacific Northwest, Can't wait to have Hot water to take a shower while camping this year. My family thanks you, without any idea how hot H2O came to camp this summer!!! lol

I’ve seen a number of rocket stoves come out in the last few years and my biggest thought has been application. Appreciate the idea.

+1 for weighing the wood for the test.

Excellent workmanship , simplicity of design, and 100% on functionality in off-the-grid living.

One thing I noticed after building several wood burning water heater is when you put the copper coil inside the stove it will get charred on the outside skin of the coil in turn insulating the water from the heat enough to be frustrating as the water can escape the heat enough to stay Luke warm! When using propane burner inside with inside coil the results were much better as it doesn't accumulate the black crust when using wood!

I'm so glad to find this video to test which is more efficient. I knew the square one with a built-in coil inside would heat up faster. That was my first initial guess before you started the stoves. I would pass it on to my friends who want to heat up the outdoor tub. This would do it! Thanks!

I would DEFINITELY have shoved the hose from my air compressor into the pipe to clear the sand XD That sounds like fun lol. Such a cool project!

If you add a plain loose metal sheet into the flue, it'll help with efficiency. The metal sheet/plate heats up, and radiates the energy from the gasses in the middle of the flow onto the the coils. Might not be a ton, but I've heard that gas water heaters do that to get a few more percent efficiency. Also, if you're using a pump, you might do cross-flow on the coils. Cold water into the top and warm water out of the bottom. The thermal gradient is more efficient that way. Kind of interesting - the same principle is used in some fish gills - the unoxygenated blood is fed into the last gills first, where the water has already had some of the oxygen pulled out. The result is that the fish can "breathe" a lot more efficiently and even to lower concentrations of oxygen where they might not survive otherwise.

Great little project!! TYVM

Awesome build, here are some suggestions for a version 3.0: - smaller copper pipe diameter, but a way longer pipe, may help with faster heating, since smaller volume of water inside per surface area of coil touching the stove wall. Ideally the copper would be wound all the way up the chimney, to maximize surface contact and therefore heat exchange. In a theoretical perfectly efficient system, this would mean that the stove exhaust gases and the water exiting the coil would be at the same temperature. - Some kind of heat transfer substance (similar to thermal paste between computer chips and heat sinks) between the copper coil and the stove wall would be great, since the contact of the round tubing on the flat wall is basically minimized by the geometry of the round tube (only tangentially touching). Building an additional outer wall around the copper tubing and filling it up with fine sand (or maybe even filling it with lead?) should work. This will increase warm-up time for the stove itself, because it's just more mass to heat up, but should increase overall efficiency. - square copper tubing may also work, since it would increase contact surface with the stove wall.

07:50 I like the pop sound of the welder in these time-lapses. Kind of soothing. 🤙🏽

Love to see this kind of ingenuity, I use this same principle in refrigerant recovery. A 1/2” copper coil covered w/3/4” clear tubing submerged into a 5 gallon bucket of water, 3/4” tube attached to a submersible pump (pump circulates water through clear tubing over copper tubing) the other end near the top of bucket. Copper line used as refrigerant in/out. For faster recovery fill bucket w/ice. Refrigerant likes to migrate to the coldest area, by circulating cold water over the copper tubing, thus rejecting heat to the ice water you have created a condenser, and can quickly move refrigerant.

This is a great project Pat. Really clever. I live off grid in a tent here in the outer suburbs of Melbourne Australia and i dont have any heating apart from a small fire and a butane gas stove to cook on so showers aint happening. I just either use bottled water and shower gel and chux wipes to lather up or make a solution of household disinfectant and water then use a spray bottle and paper to wash myself down. Definitely the shower gel is a better option rather than poisonous disinfectant on my body but your rocket stove is awesome and very clever. My other problem is carrying bittled water is not easy. Ive done myself injury and had a mild heart attack in February 2024 on an extremely hot day. It was around 38- 39 degrees Celsius so thats above 100 degrees fahrenheit. Your stove is awesome, you got my subscription 👍👌

Great job, love the round tubing variation on this concept!

Kudos to you sir, for working so well with that 'tricky to work', but neat looking round tubing. Bravo! 🔥🚀

Some pipe wrap on the outlet (hot) hose would help retain some of that heat. Those open hoses are acting like radiators. In fact, leave enough copper to run all the way to the storage tank, and wrap that. Honestly, I'm waiting for the video where you get the water hot enough the hose melts. Great videos man, thank you!

I like that you experiment and improve designs

Great idea to have a water heater.

Great video! Yes the first one will perform faster with that pump since you're creating a recirculating pump essentially so less energy to heat up the water because the warm water is moving more through out the system faster as utilizing less energy.

Awesome stove I will be making one!

sed the same exhaust tape on my still's coils! Love this Idea!

Great stuff....thanks!

Love it! 👍🏼

Thats amazing!

Awesome Build!

Fascinating work... keep making the content for us to enjoy...

Very cool, I would build one of these for sure...

great idea

I can confirm. This is working. Been messing around with it around 4 months ago. Managed to warm up the water by 60C.

Nice work!

Cool stuff. If you mess with this a lot, you can buy a combustion analyzer and make an intake that you can meter to get the burn as efficient as possible, maybe some baffles in the chimney or a cap, to slow the draft and use a small pump like you did on the square stove. I would bet you could get the ice water to 120 In half the time! Thanks for the content!

subscribing and adding your project to my apocalypse survival skills.

Pump works best because heat conduction is best when temperature difference is greatest and pump ensures this difference by replacing hot with cold quickly. Nice build.

Great work

Good stuff.

Nice build!

i love big magnets for welding pipe on a table

Thanks for sharing

Been waiting for this one

You have convinced me to buy a welder.

Very interesting!

Its been around for years had one as a bath and shower heater in the 50s and it had been in the house from the 20s

Nice build.

Prettiest rocket stove, them there are fighting words 👍

A couple of observations I'd like to offer: The square tubing one has a shorter flue than the cylinder one, so it wasn't an exact comparison. Also, you would have a more efficient burn if you had a longer flue, and the copper on the upper part of the flue. I think the reason that you were getting an inefficient burn (as seen from the smoke) was because the temperature of the burn chamber was being cooled down with water. You could also try introducing secondary air, but that's a separate experiment

Love it

The first stove has roughly twice the air intake. And an electric pump. It runs lean and has electric assistance. It's awesome. I like the other slow burning stove that doesn't need any outside help. I see you opened the bottom vent, and it worked better. I want to see a rematch.

That's the smartest looking design I've seen extent!!!! Outstanding young🌱 man 👏!!!!! Mine heat's a 150 gallon hot 🥵 tub in an hour maybe 70 minutes except a little taller and it's a six inch diameter version but one could easily say the look like twins!!!! No pump nessesary water 💧💦 in at the bottom and the heat rise's it up in the top!!!!

Epic video!!

Thx

If you ran the test again, could you run the pump with the new stove as I think that it probably reduced the time needed to heat the water by a fair emount. I'd be really interested in the results 🤔 Thanks for another cool project 😊👍👍👍👍

Nice! You always make the best stuff. By the way; stable ice water that is completely mixed and the ice is only slowly melting, the water is at 32°F (0°C) with only adjustments for how far your pressure altitude is away from standard sea level pressure of 29.92" Hg. Any remaining ice that remains in the bucket is negative thermal mass that has to be heated. You should have added ice to each bucket, let it stabilize and then remove all the ice, and had the same volume/weight of water, and it would have been at the same temperature and thermal mass for adding heat energy. Good test otherwise.

"I'm really strong" Internet arm wrestle challenge if i ever heard one. 😅 Awesome video, I'll be using this for my outdoor shower! Cheers!

Great video. Going to watch the other square tube one now.

Damn great job!🧐👍👍👍👍👍👍👍👍

Hi from Croatia! Good job!

Awesome build

I’m sure there are already tons of comments but if your pumping one through the heat exchanger and the other relying on thermal flow , the pumped one will work way better and because it’s using absorbing more heat faster you’ll have to feed it more. Cool video though.

Built a pool heater like this using one of my older forges.

thanks good video

wow, first american to say soldering instead of the generic sawdering, worthy of me subscribing

good looking stove. both worked well . the square one is for the impatient...

you got a steampunk-esque rocket stove/water heater. I like it

Hi Patrick, My design uses the coil as the lower part of chimney. Just solder the gaps, or put it inside the tube.

Great video, really enjoy your work!

thats a nice stove. you should also flip it around and test the round one with the pump to see the actual increase in speed.

nice work

I like build 1 most. Round pipe is not to bad .

Cool !!!

I suggest you try swagelok style compression fittings, I've had great results with them.

Nicelydone

Nice stove ... I'd like to build one of those for a pool heater. BTW ... Nice bucket ... My aunt went to M.S.U. to get her Bachelor's and Master's in Agriculture.

Can also wrap the copper tubing around a section of pipe a hair smaller than the pipe in your finished rocket stove. The copper will then have a tighter fit around your permanent stove.

Very. Cool😊😊😊

Ferrule not feral my friend. It's a good idea for you to be doing this and to have made this video because if the grid collapses we have to have clean water but having hot water to wash things and to bathe with it's almost a necessity in itself

Patrick , você é um gênio. 🇧🇷🇧🇷🌹 São Luís do Ma.

Next step is definitely a round tube, same size, with internal copper piping. if it's a 4" pipe, I would wrap your tubing around a 2.5" pipe to form it, suspend it in the center of the vent chamber, then weld the pipe sections together. But I do agree with the tripod build. With 3 legs, you can't have one leg off the ground.

I have always wondered why people put the inlet and outlet of the bucket of a thermosiphon at different levels. You could put both at the bottom or send the hot water into the bottom of the bucket. As long as the hot water coming out of the rocket stove continues upwards it will cycle. The pressure in the whole system is the same as it acts as one column of water.

4 inch Angle magbets work wonders to hold your work while tack welding..harbor fr

Good show

Nice

Ok... You got my attention. ... 😁 That's a brilliant simple design that looks great. What more could ya ask for?

Love the design, i would love to see a very portable version of this. Perhaps in the future I will experiment with a back packing collapsible rocket stove with the coil inside. But if you beat me too it I would thoroughly enjoy that video. Cool work!

VERY cool, will try one for my hot-tub-curently with snorkel stove- I think this will be better. I think your front leg is really weak and a potential hazard. No reason not to make it more or less straight down!

Cool 😎 video

You should also try the new pipe model using the pump just for a fairer comparison, since faster circulation could mean quicker temp increase (possibly more efficient), so might find along with the change in venting the contest could be a lot closer.

thaks❤❤

I would recommend putting a cover lid on the wood port to overcome its thirst to go out quicker.

LOL ...re inventing the WHEEL ... good job

Square tube gives you more volume for the same size as well. But yeah, it's a lot easier to build with.

It would be interesting to try this to do auto feed with wood pellets. It would also be interesting to see where the stall point is.

This guy is a genius 👌🏼

"He saw the Foam, and was in his zone" that one shoe guy