Sand battery can it heat my home? 

ITS NOT A WASTE OF EFFORT! It’s an effort. Thank you for attempting something and providing the results so others can learn and be inspired to continue the efforts. I thank you. P.S. I look forward to your results.

Great vid. Would be better if you turned the phone to landscape.

Thank you for this video, you've probably saved people a lot of experimentation. Yours was a completely different take on the idea, I never thought of making the storage moveable.

Love it, brilliant. I also watch the TNT guy. Necessity is the mother of all invention as they say. I have one of those gas canisters lying about, will have to think about how we can use sand more. Thank you for sharing this, look forward to further development.

You might try adding metal fins to both the outside and the inside of the pipe through the tank. I'd put the fins at an angle on the inside of the tank so the flue gasses are slightly deflected by the fins causing them to absorb more heat. While storing heat, the fins in the tube will collect more heat and the fins on the outside of the tube will allow the heat to penetrate into the sand. When releasing the heat, the fins inside the tube will warm the air better and the fins outside the tube will allow for better heat extraction.

Great vid. Robert (TnT) is the man of ideas. My suggestion would be to heat slower over a longer time. Insulate the outside as per the next vid. If you rebuild adding fins or multiply tubes (heat exchanger) would see a better heat transfer. Also try inserting a cooking thermometer into the sand, this will give internal temp. I cannot weld or have enough free time to do this myself. So I admire you for giving it a go. As mentioned in another thread try using smaller containers so you can heat quicker, but also allows you to heat more than one unit from a single wood burn. Or try to use Roberts endless wicks to use waste oil. Well done for giving it a go.

Great video, and timely. I have been heating my home for years with Trombe Walls. They work great. It is best to allow them to capture as much heat as possible throughout the day. Try something before adding rockwool. Paint it black and set it in a sunny window. It will get screaming hot without ANY fire. You can also use Heat Transfer Fluids like Antifreeze and Paraffin. They are nearly as good as sand. Paraffin (oil) has a near linear heat release rate. Sand is used because of the uniformity of the particle moves (transfers) heat evenly. There is worry of Hot Spots, so use an even medium like sand. Lot's of work has been done on heat release rates in industry, but no one uses then to heat your home. My God, that would lower your electric bill to near nothing and we can't have that. Anyway, I have used them for years. I put pans of sand on top of my rolling radiator heaters that have oil in them. I have even talked about it and shown a small version in one of my latest videos. Have a look. There is a solid bottom line on heat...BTU's, you got to make them to be warm. Which is why you would never be able to heat your home with a tealight candle as shown on TV. Welcome to RU-vid. A new subscriber.

That's a great idea... pleased you spent the effort getting behind the idea.

what you want to do is drill holes into the base of the top piece. it will increase your temps. The bottom is pyrolysis and the increase of oxygen will help burn the volatile fumes in the flue as it goes up which will generate more heat rather than just from the wood. It would be interesting to know the airflow through the center. the CFPM airflow to calculate how long it would take to heat up a certain size room. I was looking at using Salt. The melting point and boiling point of salt is much higher so can store more of the heat or you can use wax for lower temps which I think will still be in your range. There is a lot of energy storage when the wax/salt goes between solid to liquid phase change. But I think yours is an easy no fuss solution.

It is very close to a mass heating rocket stove. If you put a barrel over what you made there and force the exhaust gasses back down around the sand, the sand will collect more heat from the exhaust. Then tap into the barrel at the back bottom so the the gases have to go all the way down around the burn chamber and out the back, then send the exhaust thru pipes into more mass, like a cob and clay bench with cement laminated cloth on the outside, etc... and then finally run the exhaust outside. Smart of you to install a relief valve. nice work.

This is the first example I've seen put together after hearing about sand batteries. Well done Sir. As was mentioned by others steel rebar is a cheap easy solution for conducting heat. To get the heat out effectively: use a copper distillation coil / refrigerant coil type layout. Turn that into a heat pipe which can be done using copper wire as condensing material. Search water copper heat pipe. Using a small multi fuel rocket stove in addition to this sand battery would be the most efficient as far as fuel consumption and burn quality. Thank you for sharing your results Sir!

Have a look at the Nansen stove. It has been used on countless Arctic and Antarctic expeditions because it is extremely efficient - it was found to transfer up to 90% of the chemical energy in the fuel source to the water/food being cooked. You may be able to adapt it to heat sand instead. It is a much more complicated construction though.

Great video & I am just about to work on my sand battery idea, thanks for the test which was good results, well done 👍

So I read all the comments... I wish I hadn't but, I'm shocked nobody suggested or referenced a boiler (*like on a steam locomotive - but filled with sand)... as several people have stated this is basically a rocket stove, which leaves little time for the heat to transfer into the sand, which in this case does so through a single large flu that really does have very little surface area to volume ratio (lose/lose). A more efficient system would have a series of smaller pipes (*say 1 1/2" exhaust pipe), ending up much longer in order to hold the same weight in sand in the same size tank. On top you would use a long flu-pipe to help create a flow to get it started, but you would put a damper either inside of the flu or on top (a cap that swivels to cover part or all of the flu - like a BBQ grill). Being able to "damp it down" tighter will make your wood last longer, and hold the heat inside a little longer too, transferring more heat into and back out of the sand (win/win). For those of you looking to "build in" a heat sink system the benchmark is the Russian masonry heater. ;)

Absolutely amazing. I found this video recommended to me under one of TNT's sand battery videos I was watchin

Well done looking great for your first attempt. i am really impressed.

The IR thermometers are much more accurate when aimed at dark surfaces. Just a quick spot of black paint to aim at will help immensely. I’m from the US so my brain only works in Fahrenheit unfortunately, but I noticed that you said you could barely hold your hand on it and the immediately took the temp and it only registered 87. The most you can comfortably touch in Fahrenheit is approx 130 so I think it was indicating quite a bit lower than actual temp

Looking forward to seeing how this progresses. Thank you.

We had these in the army 50+ years ago, we called them Bengazis but they were called other things. We put a baked bean tin full of sand soaked in petrol into the earth then dropped a match down the centre. It boiled nine gallons of water in minutes. Once on exercise in Lower Saxony West Germany the temperature was -27c and the petrol would only ignite with a very small flame, we gave up. Many thanks for your video.

Good on ya for sharing this idea. Brilliant!

Absolute legendary idea, funny how the solution for a lot of things are right in our faces ! (been stepping over a broken kelly kettle at my front door wondering everytime, what can be done with it?) god does certainly work through people ! thanks for being a messenger ! lol 😂💪gb

What if you keep it outside permanently like a boiler and transferred the heat to a radiator inside your house? Then you can burn a fire when you need and don’t have the safety risk of moving something so hot and heavy back and forth? I am looking forward to seeing your progress!

Combine this with a rocket stove to charge it. Its a bit heavy but if you could make this part of the riser for the a rocket stove, you would be able to heat this up pretty fast and then use the fans to force air over it. This is basically a rocket mass heater but in modular form. Most rocket heater use a large built in place thermal mass, but something like this, scale it back to about 35 kilos total mass and you could build a rocket stove to heat multiples up and put several smaller heater in different rooms. I would reccomend doing a rather low flow fan through the middle for heating and having a higher flow fan blowing across it or down from the top.

Ir thermometers are pretty unreliable on shiny surfaces. Worth adding some black spots to read from if you can.

I would leave the furnace outside . build insulated exterior shield around it and a hot air pipe going into the house. the sand is a good idea since wood fires would go out after a hour.

Doing an experiment like this is always interesting. To make it more accurate consider putting a pencil mark where you do your readings. Thanks for the information.

Thank you Lee, it's really interesying. Subscribed, waiting for the next step, insulation, rocket stove base...

Thoughts: (edited after watching part 2) 1) Weld some plates inside the chimney OR make a removeable basket that they can attach to , like slanted baffles that will not only absorb and transmit heat through themselves into the walls, but also force the flow against the chimney sides. | / | | \ | | / | | \ | ... not to scale, 45 degrees? and... 2) Pipe(s) crossing the base of the sand unit above the fire, leading from outside inward because, as others already said, some extra air injection at the base of the chimney would allow secondary burn and raise temps while reducing smoke. You'll want to avoid the air injection being offset though because while a spiral tornado flow burns more efficiently and completely it does unfortunately concentrate the heat in the centre - not what you want if the chimney sides are your target!

Lee. Try making a sheet metal cone for the top exhaust. Like a jet engine would have. Full size on one end and at the top reduce the exhaust end to somewhere between 70 and 80 percent of the size of the pipe itself. This might make it look like the heat is going out faster, and it will be, but before it leaves it will have to stay in the pipe a bit longer and should keep it in the pipe long enough to have an effect on the upper part of the battery.

Fantastic. Keep modifying and experimenting. Could make many smaller ones for separate rooms The ghillie kettle would make a good tent heater.

I have been watching Roberts's channel too, and nicely done so far. First, that temp gun works poorly on that silver paint, paint some of it black and you will see what I mean, also, you need to drill some air holes around the bottom just below the fire grate, this will feed the fire more oxygen which will give you much more heat, maybe a sliding vent cover? and I think much of the time the heat readings you were getting were from the heat moving around the steel case, as it's more conductive than sand, but I really liked this and am planning of building a sand battery too, but heated with excess electricity from my solar, thinking of using hi-tempter PTC heater elements inside of the sand battery etc, as I can't light a fire as I live in a flat, but I do have a garden, which is where I have my DIY solar setup. I'm subbed to see how you get on.

Insulation will really help. I think making stack 2 to 3 feet higher will improve draft. Great job.

So cool dude! Don't see the glass half full, that stove will put a huge dent in the electric bill. Great inspiration to all of us.

You may want to insulate with a removable blanket style(like the ones for water heaters). That way you can have the blanket on outside and take it off inside. That way you can draw down the battery faster for a quick warm up and then if warm enough you can always put the blanket back on if it gets too warm.

Not finished watching yet, but found this video when I was searching for sand battery stuff. I had the idea to make smaller sand batteries around a chimney that could be moved but didn't consider making such a huge one. In regards to the weight, you could always split the battery up like you did with the original tank and have a few smaller ones stacked. This would not only make it easier to move singlehanded, but allow you to have one heating while the other is 'discharging' or even use them to heat multiple rooms.

Great job. Looks like a success to me.

Well done, I like this. I would think having the insulation on the inside between wall and sand would help lower the weight and limit heat transfer to a conductive material and might also allow you to make it look better. If you could connect it up to a solar thermal system and then create a controller to adjust heat inputs and outputs via electro mechanical valves would be a permanent solution without burning and gases.

I thought about this kind of solution and whether it would work. Sand in the ground can retain heat for months at a time If you could route the exhaust through the tank, even have 3 or 4 smaller flues through the tank would provide more surface area for heat transfer for both heating and releasing For anyone with a property that cannot have or cannot afford a stove install this could be a very viable solution Kudos for the experimentation!

Fantastic! Sand battery is the future and with pioneers like you ideas will keep coming and get better. Your fire is not able to get hot enough due to your ventalation slots in the door. If you drill 2 x 20mm holes 1 on either side at the bottom of the base (Under grill height) this will allow the fire to draw in oxegen fater than the door being fully open, also you will need to close up the vents on the door as this is having a negative effect with the fire drawing in oxegen all around is not good for the fire. You can then make some 25mm square pads to close the 20mm vent holes slightly when the fire is in full swing. You want to see the fire coming out the top ie a rocket stove. Its all abount the vents. I will be making a 100lt sand battery here with solar when I know how to in the near future. Well done to you sir

I'm only 11 minutes in, but I think you could get a bit more heat absorption with a baffle hanging down the flue pipe. Gas fired water heaters use them to slow down the upward draft of combustion air and push it outwards to the sand battery (water jacket) to extract a little more BTU's. Ours are a flat piece of steel twisted back and forth (not in a single spiral, as that would just accelerate the exit of flue gas) which hangs down the flue, fully removeable. Great video so far.

Great idea. The temp on the out side will be cooler because it's warming the sand in the middle first.

Great effort Lee.

WW2 soldiers fashioned a 'Benghazi brew can' from a paint tin sized can and a sawn-off artillery cartridge. Moving army columns had very time-limited breaks, so time-to-boil was vital.

I’m working on a similar project and sand is good to 3000 degrees F. A rocket stove at the barrel will reach around 2800. For your setup, I’d recommend using a small fan to basically build a forge. That will speed up the charging time and use less fuel.

I'm no scientist I can only speak as someone who heats their house with wood stoves. If you have a flap type device in the very top of the pipe when the fire is properly going and is almost smokeless you can close down the top to a smaller diameter and slow down the escaping fumes, this will also slow down the escaping heat giving it more time to heat your sand. You can then also use the flap to regulate how much heat you allow out of the pipe when it is placed in the house.

The TYT guy is awesome. Maybe think about 2 holes in your wall with a vent into a sand battery and out. They wouldn't need to be large vent just spiral through the battery with a small fan. And have a large battery outside with a chimney in the middle and a rocket stove as the heat generator.

It would be interesting to see how long the heat takes to travel through the sand from bottom to top. Then design the system that you can control the temperature it radiates from start to finish by how much you put in til how much you get out long term for 24 hours.

If you listen to the creators of the Finnish Sand battery, they explain why their system isn't suitable for a single dwelling. Its more for combined housing developments, district heating etc. It needs Tons of sand, and fairly complex engineering to extract the heat. For single houses, storing heat in water, is a better prospect...

IR thermometers have problems reading off shiney surfaces accurately. Keep it up 👍

I used a cylinder like that to make a drip feed waste oil heater, worked well but adding a small fan REALLY increased the heat, so easy to make, just light a small fire (old rag) in the bottom and drip oil when burning.

I think you were talking about Robert Murray Smith. He is the tnt guy. Super thought provoking bloke.

Attach a grate on the top so you could do some cooking while it heats up. Then when you bring it in the house you could place a smooth rock on the grate about the size of a softball. Then when that heats up you could wrap a towel around it and use it to keep your feet warm in bed. (It'll last for hours if it's heated to 212° f.)

Usually sand batteries for home heating and cooling take the form of a large earth mounds passively warmed by the sun and structure of the home during the day, then releasing their stored heat during the night. TnT sand battery is a cool concept, but to heat a house it would need to be much bigger.

I wondered about using just a metal bucket of sand placed on top of a multi fuel stove. I wondered if it would store enough heat while the fire is on to keep my mountain apartment warm until the next evening. Another option was to use a bucket of paraffin wax as the state change from solid to liquid would hold a lot more energy. What put me of a little was the fire risk.

This is a great idea with the prices of electricity here in the uk looks like your on to a winner here with a bit more experimenting it should do really well. I have sub great work.

We used to put a twelve inch pipe under five tons of sand and put a burner on one end and heat it so brick layers could work in winter heating it in the morning would last all day .

How about a more "cone shaped" flue. Surface area and trap more of that heat escaping. This is a great idea for a wood burning stove to absorb all the heat. Fantastic video bud.

If you have ever been to the beach on a very hot day, the sand may be too hot to walk upon barefoot, however, if you kick the sand just half an inch deep, you'll find cold sand, because sand (silica) is an INSULATOR !! Try your setup using a core of metal rebate welded side to side instead. Metal transfers (conducts) heat well. Thick metal will conduct and hold heat for future use.

I got an idea. What about building big brick box about 2'x2'x5' with a place inside for wood fire box, fresh air intake, exhaust pipe up and fill the rest of the void with sand (I guess a clean out too)? This will be a simple radiating heater that could emit heat from a wood fire for hours after the fire is out. Don't need to do complicated and time-consuming brickwork to create channels in a masonry heater, which purpose is no more than transfer heat from the fire via air in the channels to bricks. With this, heat goes directly to sand to bricks and radiate out. Better yet, bury lower section of the exhaust pipe in the sand box to max heat extraction.

I thought the same,about how you could do this at home. I even contacted the finish company to ask them,I got no reply. My idea was an oil barrel filled with sand, electric heating element in and coiled copper pipe for water inside.Use heating element with solar or off peak electricity? I suppose you could put heating element in this that you made( makes it cleaner for wife?). Basically,it's a DIY storage heater.

It depends on everything. But yes. Same principle behind steam heating used in New York and other various northern cities. Except you maintain a heated volume of sand. You run lines through the entire assembly and move air/water through it to transfer the heat across the system. If you run the lines through your house, it can be made to control the temperature of your house by transferring whatever heat you put the sand at, through the lines, throughout the house.

Love it. I'm lookin for a gas bottle now. I have been distilling ethanol, no flu required when burnt and it burns very well. Cleanest burning fuel known to man, gives off water and a tiny bit of co2. A sand battery is perfect. if you run a copper coil through the battery, hot water on demand. Genius. If you had a jacket on that bottle, you would have doubled your temps easy.

I took a 3 gallon canning pot I filled it up with sand stuck it in the oven..heated it up to 400°..,for an hr..put it in the bedroom 1 hr before bed time. Turn the house temp down to 62° f. Time for bed and The bedroom warmer and cools down slower. You sleep so much better in a cold room.

It's really smart to use these things

Almost 50 years ago I was camping along the Copper Creek in Alaska. As a teenager I had bought an old woodsmen book dated 1914 or something like that. It showed how to dig a fire pit and put large rocks in it. When the fire was done you backfill it and sleep on it. So we did it and put our tent over it. Nothing for 1/2 hour but then it started to get warm. So warm we had to move the tent. It was still warm the next morning. I've thought about it every since, then I start hearing of sand batteries. I'm wondering about building a serious one built into the yard or lawn like 10'x10'x7' deep and using parabolic reflectors in the summer to heat it up? Or maybe I'm crazy.

About your situation I came up with this idea: Build a WALL-fireplace outside that consists of masonry/sand filled or ceramic components. The trick would be that it would have HVAC pipes weaving a time or two through the wall structure until it reaches the top chimney (Or do a dual fireplace wall with two straight chimneys). As I see it you would slowly be heating your "wall" to heat your inside, and when/if the fire dies you will have the residual heat of the sand/ceramics lasting a fair bit. [ Insulate the exterior to maximize retention ]

Drill holes into the flue add bolts going into the sand.This would carry heat deeper into the sand heating faster and more even. Turn the bolt where the head is in the sand just weld the bolt to the flue.

Use baffles in the flue and you will find that the top should be hotter, your loseing about 80% of heat up the flue . I am a retired heating engineer and I used to be involved with the solid fuel advisory board. Also look at putting heat exchanger pipes through it a bit like a steam boiler, you could run just air or water and pump it through radiators? But with water it gets complicated. Don’t get discouraged,you’re on the right path .

You need to put a flat flanged top on the center tube with small legs so it pushes the heat driven out in all directions with your pc fan being enough to get it circulating but no so hard and fast to prematurely cool it too fast. Your on to a good ideal my friend. God bless

Interesting. Greetings from Yorkshire

In one of my hunting cabins down south I built small brick fireplace used a 20 gallon steel drum as chute ran copper pipe coiled around it to rubber hoses to a car radiator closed boiler system radiator has pressure relief. 8 sat 55 gallon over 20 gallon so smoke and heat fills 55 and flows out pipe towards bottom thanks to your vide I might try filling 55 with large rock or sand to hold heat longer to keep water hot. Thanks if want more details let me know I'll be interested in seeing what you come up with in future. I constantly upgrade and adapt mine as I am learning

I love this! You’ve inspired me. I have two old tanks, same size, that I can use. I have a question. Can you not attach chimney pipe to the top and run it out the house through a window? Then you can keep it inside and not have to move it and benefit from the heating up process as well. It reminds me of those vertical iron wood stoves.

You basically built the core of a rocket stove thermal mass heater. If you made a few changes to use the rocket stove to as the heat source it would save you wood..or whatever you decide to burn. And produce no smoke.

Great video, very interesting. Lighting a fire is great, but our use of that heat is so poor

Would adding water to the sand increase thermal conductivity & storage density? I remember a video someone did where they had a huge heat battery out in a shed. I forget what the name of the product is, it's commercially made, but essentially it was a huge drum laying sideways, probably 5-6ft in dia and maybe 10ft long (going on memory). It had an internal chamber full of water, and, as I understand it, a flue system wrapped around that internal chamber. At the one end was the burn box and a powered blower. The burn box was large enough for a proper blaze and decent sized logs. The blower turned that into a super hot blaze that burned near everything, including outgassing from the wood. The super heated air would travel through the flue network around the internal water bottle that would suck up all the heat. There was a thermometer so you could see what the temperature was of the water battery inside and know when to turn off the blower. What was amazing: The exhaust at the opposite end was the fun part of the demonstration. They went outside the shed to the exhaust tube, and it was NOT blowing any smoke at all, and the air coming out was cool/ambient. Not hot, not even warm. Nearly all the BTU's of heat burned off ended up in the water bottle battery. And that heat storage lasted a good, long time (I seem to recall weeks) before they'd need to run the burner again for a few hours to charge back up. Anyway, that was the motivation for the question. Is the sand in your sand battery dry? is there an argument for water to be added . . . assuming it was engineered to be safe (e.g. no bursting/explosions from steam/hot water? Hmmm, I think you said a "sand battery" can get REALLY hot. I may not be thinking this through, because water would turn into super hot steam, and a lot of pressure, at those temperatures. The device I described above was charged to, hmmm, I want to say 250 degrees-ish (memory), and that's a huge tank.

I thought you were a fellow RMS watcher! Lol. If you didn't need to move it around you could encased it in styropaperaircrete with a chicken wire reinforcement, with a spot in the middle that is left uncovered where the heat is allowed to escape towards the room it's in. This would be good for a greenhouse as well.

old gas water heaters have a corkscrew piece in the center pipe exhaust. to slow down & deflect heat to the sides as it rises. this would help heat faster & raise the temperature as you wanted. one of my 40 jobs in my life was oil burner service deliveries as well as gas. newer ones use a recirculating fan from top to bottom to draw in hot exhaust to help heat bottom so some combination may help? or make more efficient? but depending on fuel to heat can cause soot buildup and condensation rust issues which can degrade heat transfer & life of the unit as leaks will eventually happen.. or use stainless steel. its a nice build you have there.

A 15kg bottle of butane is 205kwh of energy. At £60 that is about 30p per kwh. Mains gas is at least 3 times cheaper even at this ridiculous level we are at. Good job on the sand battery, it makes sense if you have free wood. Anyone buying wood is going to be wasting there money though as wood costs more than gas per kwh.

I am joining your channel so I can watch your next video. Is it possible to run a pipe into your house so you get to use most of the heat you genertate from your sand battery? Put the pipe at the top above your heater and insulate the pipe and put a small fan at the end of the pipe and you will get more free heat blowing inside your house. I'm looking forward to watching your next video. Good luck mate.

Insulated steel chimneys can easily be fitted as wall mount to any buildings. Besides, having an outdoor garden boiler stove and insulated waterborne circulation to indoors distribution is also viable if there´s a garden, that is. Opens for wood, coal, turf, oil, waste oils. All easily automated for an even fire run, or shock doctrined by intense fire and thermal batteried by as ex sand. Water circulation pumps can be bought cheap these days and they draw very little juice unless there´s big elevations..

I’ve seen the idea from Finland and yours is a great experiment along the same lines. I wonder if slowing down the flue gasses would help the sand absorb heat.

i was going to something similar with water but sand gets way hotter so cool. one problem i see is the heat from the fire is just going straight up unto the sky it needs a bend or twist in the pipe so the heat has time to warm the sand. i love the idea

Nice job. A 5 gallon TLUD stove underneath, sitting on an air kettle, would dramatically increase btu"s and decrease fuel consumption.

Cool thing! Just wondering if having some kind of coiled flue wound help save some of the heat going directly up. I guess that’s just way to fiddly to build. Just my gut feel is there’s a lot of heat going out the top that “could” (I don’t fully know how) be reused for the battery change. Our stove has a soapstone top that soaks up excess heat - and I guess that’s a similar (low temp) principle.

Nice build pal. Are you losing heat where the sand section meets the wood burning section ? Hard to tell but looks like there's a bit of a gap around at some points on the circumference. Would a narrower flue help ? I read about the industrial ones a while back and i think they melt the sand (or salt in some) but i may have misremembered that. Where do you put the sand in, through the screw hole ?

If you have a fireplace you could burn it in the room out from the fire place and pipe it up to vent out the chimney so you get the heat from the fire and the battery without losing heat up the chimney. You could also put metal mesh inside the pipe area to get extra heat from the flame that goes up the pipe in the center of your battery.

Zero heating past week absolute numb in sunny Scotland Been looking at all different ideas the gas prices are far to much even though we get 10% for outside this sand battery looking like best idea apart from Revolution with pitchforks and torches because this is so wrong. P.s awsome video dude 👌

Really good job bro, maybe next time you make one run a copper pipe inside the sand for hot water....

What about cutting slots through the inner pipe and inserting steel plate through the inner pipe and into the sand. it would act as a heat sink and transfer the heat to the sand better. Also act as baffles for the chimney. best of luck. PS You've given Me an idea for My solar air heater, to incorporate a sand battery using the same principle. Mmmmm : - )

Have you thought about heating the sand with a fresnel lens? Maybe you could create electricity by adding a Stirling engine to a motor? That would be interesting

Insulating will hold the heat in. Vermuculite is a common wood burner insulation . Sealing off the bottom with some sort of plug will stop the flue from conducting heat away after the highest temps achieved and a heat proof cabinet that the cylinder could be sat inside the home with adjustable grills to moderate the heat flow. If you wwanted to maximise the convection then a ring placed around the cylinder with fins possibly of aluminium would increase surface area think of the shape some led lamps use to convect heat away.

I wouldn't insulate the bottom since heat rises for the most part. The hottest will be up at the top. This is a great idea!!!

Once you bring the heater into the house, would it not be better to put a fan at the top and blow the heat out of the bottom? That way, you are heating the air at the bottom of the room, which is where you need it. If you blow the warm air upwards, it's going straight up to the ceiling, where it's not going to warm your feet.

First if all, thankyou for trying to help us all, little suggestion, Chinese hat/flue cap ie vented plate which could also be used to cook on, might not only help with heating times but help re fan with 380 degree heat circulation, just a thought, oh and remember, heat raises which means the heat will eventually spread though out the cylinder

Hi Lee, great video mate. Also a Rob Smith viewer TNT channel 😉👍. Love the simplicity of this mate and have had something similar on my mind for a while. I was looking for something more portable and building more than one. Any chance you could let me know the diameter and height of the sand battery upto the base of the chimney. Also the diameter of the chimney would be good. Once again well done you should be proud mate.

The wood constant supply is the problem as it burns down so does the temp and so the sand temp reacts heat proof insulation on the sand battery while heating and a steady even heat over the experimental time is required .

This is brilliant. It is the tinkering and refining process that gets you something that works for you. For me, I'd want a sand battery that has compartments that I can heat as a whole, then remove those small parts and place them in something in each room to provide central heating. Another thing is convection currents and damp, and the heat generated from a small sand battery will provide hot air that absorbs moisture from the air so opening top windows and trickle vents allows that hot moist air to escape and be replaced by drier colder air.

The thermometer doesn't like shiny objects I put black duct tape on the side for test points

I like the idea, but the problem seems to be the weight. It occurred to me that if you cut it into 3 sections and put in partitions it would be more practical and also allow for use in three rooms potentially.

Insulate with perlite slurry, then put entire unit inside a fireproof cinderblock shed. That'll probably keep it insulated well