The easiest sand battery you can make? Is with an old electric oven. All you need to ensure is that the bottom element is still functioning. Put 3-4 solar panels wired in series and then just take the positive and negative from either side of the array and hook that to the bottom element in the stove directly. Use some self tapping screws and washers to close the front up permanently. Remove the top element that has the oven vent under it, and fill the oven with dry sand.

Had you blocked off the Rocket stove pipe you would have increased the length of time the sand would remain hot. As it was, you had a major thermosyphon going on after the fire was out.

Robert, I've been building Rocket stoves/mass heaters for close to 20 years, the second build (2006) was using a sand battery under a queen size bed. Even when outdoor temps fell to 17deg F, -8deg C, the 350sq ft off grid cabin stayed toasty through the night, and didn't need a blanket.

If you use round river rocks instead of sand, you will not need a heat exchange device to harvest the heat. Simply blow air in and remove hot air as necessary. The round rocks will store the same amount of heat per pound as sand, but it enables air flow with minimal back pressure.

I am by no means a professional welder or never will I pick on anyones welding but one trick i learnt by trial and error is to put the stick into the stick welder and bend it at about a 30 degree angle and It makes striking an arc easier and stops your metal looking like a porcupine with stuck welding rods all over It 😂. Hope that helps anyone starting out.

Interestingly enough, a bit about cooling and heating. In 1934 Oscar Payne drilled a 16” hole 450 feet into the ground. The hole filled with water naturally since there was an aquifer down around 305 feet. He then lowered 3/4” pipe worked into a coil about 40 feet in length down the hole to near the bottom. He was able to pump antifreeze (ethylene glycol) through the assembly and back to the surface where it then passed through a condensing coil with a fan blowing across it. The air temperature cooled to around 68° F but even better was when winter came, the assembly continued to blow air heated to 68°. His total heating and cooling energy involved pumping the ethylene glycol and powering the fan. Later he added a windmill to pump the ethylene glycol and dropped his energy use even more. In the 1950’s he added a device to the system that used the falling of ethylene glycol, thinking he could power the fan from the energy being created. He had to add an alternate power supply the the fan since his device was not constant. All of this took place at “The Tower Motel” on Highway 199 in Sampson Park Texas. Oscar passed away in the late 1990’s, he was known in life as having been the Mayor of Sampson Park and the owner of the first Air Conditioned Motel in Texas. He was a great man and a great friend. I have yet to hear of anyone using a deep hole in such a way before Oscar (he was a plumber by trade), I’m sure there had to be some inspiration for his idea. Cooling and heating a home can be done with very little energy simply by using a deep hole and the natural temperature of the earth. Oscar was also known for being the Plumbing Contractor who constructed “the bomber factory” located at Carswell Air Force Base (known now as JRB Ft Worth). He held the patent for an oil fueled citrus tree warmer and an aircraft wing made of paper.

Please make a Rocket Mass Heater Sand Battery on a four-wheel dolly that can, when moved, pass through a standard outside door. When it threatens to get very cold out overnight, we can fire up the rocket mass heater in the early evening and when it burns out, we can pull out the embers from the burn chamber, cap the rocket heater ports (wood feed, cleanout, chimney) to keep the heat in, then roll the entire apparatus on the dolly wheels into the home to radiate heat slowly until morning. (or uncap the rocket heater ports in the home releasing the energy more quickly. That would be super useful. With it permanently on a four-wheel dolly you could go with a larger sand battery.

Very informative video Robert. I am pouring sand in cinder block for the thermal mass right now as winter is on its way. Thank you for showing everyone these projects are something that can be done by anyone who wants to make themselves a little more self-sufficient. The J B high temperature epoxy is really asking for trouble. Arc welding is the only safe and proven way to weld any rocket stove. SAFETY IS JOB ONE, PERIOD !!!

Not to get too technical, but with A/C there is also reactance that comes into play and potential for the radiative resistance of the wire to turn some of the input energy into radio waves. In an antenna this is good but something like this you want the radiation resistance low and the loss resistance high. At 50 or 60 hz it doesn’t have a huge effect as it does at higher frequencies but it is something that can be optimised for in the design of the heating element.

Because you are a chemist mate ,I've always been fascinated by the chemicals they use on those weld sticks to make a controllable arc molten metal..pretty incredible considering the chaos at the weld moment. You could easily do a video on how they designed the welding stick

0:22 learnt this one many moons ago with my coffee tin forges .. best way to put out your charcoal fire without getting it wet and having to Wat for it to dry out to relight .. pour a bucket of sand thru it and boy howdy..... i cant believe i just wrote that.... any ways gets alot hotter that you would thing it would lol would recommend finer beach sand over the courses stuff tho .... flows better over the charcoal and out the bottom

Pretty impressed by the Peltier generator - even if it's milliwatts, it should still be able to drive the microcontroller and make some airflow to recover heat in a power outage. I was thinking gravel/air thermal battery as heat extraction from pipes in sand has a low surface area - probably not enough to provide hot water on demand. It would be good to see these options as other YT channels come unstuck at the point of heat extraction.

I remember quite vividly the last time I burned the soles of my feet walking on the hot sand of the beach... So theoretically, if you live in a house on a beach, you could collect the hot sand at the end of each day to power up your house during the night, dump the sand back on the beach in the morning and do that over and over again. Good news for people living in deserts 😋

This guy really needs a tv show!

One great advantage of using a sand battery to store the heat is that it makes a great insulator for some of the very high-efficiency, very safe, electrical batteries (like liquid sodium or sodium-sulphur) which have far greater (for some, like lead or magnesium-antimony, infinite) recharge cycles but need very high temperatures to work. Putting such batteries into a large volume of sand allows for the heat to be stored in the sand and electricity to be stored in the electrical portion in the middle of the sand, meaning no inefficient conversion is needed to turn stored heat into electricity for all the peripheral uses like communications, refrigeration, entertainment, computing, lighting and home automation. The best of these technologies outperform pumped water storage in both efficiency and immediacy of response to demand. As for resistance wire, if the right ones are chosen, the temperature coefficient of resistance will increase the resistance enough with temperature to avoid local overheating and concentrate the heat into the coolest parts of the sand.

I've binge watched dozens and dozens of your videos at a time and your subjects are right up my alley. I was wondering if broken glass would be a good storage medium because I know the route and schedule of the trash collection truck. So I usually can find something to do experiments with for nothing just time and and a drive around the neighborhood. So much glass ends up in the landfill, wether its a window or broken dishes or a broken water glass. Would it retain heat as good as sand . And would it be better if you keep flat pieces stacked whole sideways or vertical or smashed up into small pcs maybe using a cement mixer with some rocks with the glass. I wouldn't want to guess how many millions of tons of glass that doesn't get recycled and ends up buried in the ground

Hi Rob, could you use a copper central heating tank as a sand battery as you can fit a heater easily and it already has a coil of copper pipe fitted for water or hot air, maybe even paint the tank black and use solar. All the best Chris😊

Quite a few videos on how to extract heat from diesel heater (Vevor) exhausts, it makes a lot of sense as the heat being lost is not insignificant - best idea so far seems to be the EGR cooler from HDi diesel (EGR COOLER 1618R4) cars although a sand battery might be another option, cheers

Robert, I thought you might haved a copper coil connected to the pipe outlets, and used it for a water heat exchange, Looking I little cold, dress your baby in insulation 😊 And attach a cooking plate for a bbq 😋 Good job on the sand battery rocket stove 🎉🥳🔥💖 Now make a send battery connect to a solar vacuum tube heater 🎉🎉🎉

Consider wax as a heat battery. Mixing the two is being used now and apparently very effective . I seem to remember wax is 16 times more effective then concrete , 3 times more then water in heat retention. The key is keeping it out of the 400 degree range placement. I'm building a rocket mass batch system using the bell system and hoping to find the sweet spot (400 degree )area to place these cans of wax , sand mix at the bottom of the bell or in a chamber built within that is safe.

I had teachers... many of them... i thought they were very bad at their job... you are proving me right. They were condescendant and didn't look like they were happy with their lives. Except maybe for that music teacher.

A thing I've been pondering, is how to put a heat engine on a heater exhaust to extract all the heat that's lost up the chimney- both getting it to do work (charging things, or running a supplemental resistance heater), and putting the cold side in the house, so you get the heat where you wanted it Anyway. it just seemed like it might be a way to get more bang for your heating fuel buck.

Question, why you not use it to heat it for a water heater standard in houses because it will save people lots of money through the energy bill ?

You may want to take a look at Kuznetsov stove. Likely the most efficient stove. It can be build in any forms and in any size, as long as the basic thermodynamic principles are being preserved, when constructed.

One of my favorite videos you've done this year! So happy you got into welding and it's so much fun to watch welding projects that have real-life applications, especially in the winter season. Thanks!

It's worth noting that while sand is inexpensive in a simple sense, the monstrous sand mining industry is fraught with global implications. I don't say that to be a contrarian to the idea of sand batteries as I fully endorse the technology. I think it's worth highlighting that a non-trivial segments of sand mining externalizes costs to marginalized communities and reeks havoc on ecosystems as a way to keep it "cheap."

Thank you, Robert.... Water is a big issue in my country. We tried immigrant but didn't work. Now, we are back and searching for solutions. Your videos are helping me to reach into solutions....That's is all occupying my mind. Thank you again. 😊

I've watched the video about a gentleman that lives in Alaska. He has done a large bulk battery system. He believes he will only burn 1 cord wood all winter to offset the battery

So the fractal capacitor network captures atmospheric power and dumps it into a sand battery? This is sounding like the people's power grid. Good on you

Nice one Rob, thanks for sharing 👍

Like red sand is practically given away and it's a way to clean up that waste product.

I love your sand battery work.

Robert Murray I just adore your work and your videos mate. I have learned so much over the your watching you do your thing sir. Robert thank you so very much for sharing your vast knowledge with me. It’s appreciated by me anyway.

Fantastic Rob - The biomeiler is an alternative approach using mass, but with the help of microbes to make heat as opposed to fire/electricity. The benifit is that you don't sand. Many thanks again.

Apart from everything I just said if you go to a builders merchant and get some iron oxide cement pigment it and add it you will improve the thermal conductivity.

Well folks have paid due respect for your ingenious projects, so I will simply say "Thank You" for taking the time to share your knowledge with us. I have the parts required, but have been just dragging my feet. After watching this I am going to have to get off my duff, and pull the welder out. Usually this time of year in Northern Central British Columbia it's about -15-20 c at least, This year is much warmer, so working out side is not to bad. Thanks again for the knowledge, and encouragement. Merry Christmas.

should look into the projects done by paul wheaton and the permies folks on racket mass heaters, they build large heating stoves using j-tubes and long exhaust systems routed through clay, daub, or pebbles to burn wood super cleanly and create a lot of radiant heat and stored heat (via the mass).

Interesting stuff . Peltiers are really awesome and the uses are incredible. :O)

Has anyone done any work combining a sand battery with a parabolic solar reflector?

Pretty amazing, one could dig a hole in the garden, put some Insulation and sand with a copper spiral streamed water and thats it, even a new business probably, really great one it is.

Home hot water heaters eventually leak water and get replaced. Why not fill the old tank with sand and turn it into a battery? I’m going to watch for one to try this.

I friggin love it mate, you are awesome

Yet another 😃 grate informative movie 🍿 🎥

I’m with the gas company. My boss wanted me to contact you and assure you that we are going to need that tank back now…🙄🤨

Just discovered you guys today...and i really appreciate your quality ❤️🙏🌈👍

Hi Rob, you can buy black sand I was wondering if a solar powered sand battery could be made from this especially if a concentrator lens is used or maybe mirrors 👍

lol...."it's dirt, hence, i'ts dirt cheap." lol

To mix a Rocket stove with a sandbattery I think is real smart solution for with a wirl around the pipe a big surface can get heated up and slovly provide heat to the room! /Mikael PS. Do not be square just be rund and jolly 😂! DS.

❤ Thank you very much!

Nice easy idea

I heard England has some food crisis thing, trying to import out-of-season fruit post Brexit. I thought of Sand Battery for extending growing season of greenhouses

All very interesting. Thanks.

Sang's ability to insulate, due to terrible thermal flow rate, is also a great property - adding a water coil into the sand battery gives a useful source of flash steam (low grade) for exchange with the environment. Using an adequate sizing to maintain envelope temperatures to "manageable" increases usefulmess - don't worry, Austrian /Bavarian mass heaters were there already... Thanks to geopolitics and social hysteria, we are in the "forever crisis" - and markets will expand to infinity (or so it seems)... Australia has lots of iron ore - haematite - of various grades (geared to mine and export at scale), which can have a life as sand battery media - and can easily be converted to iron after it is no longer needed.

Oh boy.. as a long time Rocket Mass Heater builder, ive got a lot to cringe about here. First, very cool! I always appreciate your work . Now, the 1-2-4 proportion is an ideal that "always works" but the proportions can be fudged for reasons. The full explanation is long and full of qualifiers. ;) One of my main objections to how you put this together is that you're taking heat directly from the combustion process. This lowers the temperature inside the combustion unit, reducing its efficiency by a large margin. Best practice is to take heat from AFTER the combustion process, I.E. after the riser. Of course this will make a much taller device but there is a workaround. My second objection: inside a well running RS, temperatures can rise to 1000° C, which in combination with excess O2 will burn the carbon out of your steel rather quickly. What you'll get is a pile of shards that was once a steel combustion unit. Those little 4 inch cookers are fine if they're NOT insulated or (in this case) surrounded in sand. Best practices (again), use refractory material for the combustion unit, whenever possible.

THis is how the Sioux people used to cook; They got rocks red hot and then poured into cookers made out of Bison stomachs.

Nice. Very good stuff 👍🏽

Have you considered one or more fans on the exhaust pipe to scavenge the airflow for electricity? Many of your videos are singular ideas. Have you thought about combining several ideas into one machine? Like sand battery, wind, solar, battery bank, water heater, rocket stove, radiant heating, water heater… fresnel lens, steam, generator, sterling, oven for cooking. An open source multi-prong approach is largely achievable for diy. A smoke microcontroller could monitor the most efficient combo for weather conditions and seasonal loads. It could track usage as well to adapt for energy capture. This more complex vision could be approached in logical stages and slowly build upon itself. The efficiency of any single approach would find an overall median efficiency, and provide redundancy. I’m always baffled by the silver bullet approach- seeking the one ring to rule them all. While a broader approach may unlock a wider adoption- works anywhere , just add or subtract various elements for your region.

Rather than sand, flint is also a bane of farmers lives and can be picked up relatively easily, certainly on the small scale.

Awesome channel.. Love to know your thoughts on smudge pots.. real extreme.. tho 👍

I was running beads with arc welder and using a torch at 6 years old. It is easy once ya can just get started.

I'd use all wind solar and rain fuel to heat a sand battery, then have a sterling engine and maybe a flywheel battery for electricity can also have all your wonderful scavenging ideas

Just one person mentioned old hot water cylinders. I'm thinking (for the money-conscious DiYer): * Get an old cylinder off your local internet market place. People are still getting rid of old units, some even have copper inners! Sometimes available for free, just to get it off the owner's hands. * Get an old vehicle radiator from a wrecker, install into the middle of the cylinder before filling with sand * Alternatively, people are always throwing out cheap oil radiator/heaters, some are quite small * Cylinders already come with very good insulation AND many of the better ones have an insulated hole designed for a heating element to be inserted and replaced, with a view to preventing electrolytic degeneration of an element immersed in water. With one of these you could experiment indefinitely with different resistive elements, different wattages, different resistances to suit your solar or other electrical energy you are wanting to store. * The radiator (either vehicular or heater-type) already has fins designed for effective heat-exchange. If still 100% liquid-proof, it would provide a secondary option for pumping heat INTO the sand-battery (say hot oil heat-exchange from another source). At the very least, a small computer-fan could force air through the radiator (surrounded by hot sand) at whatever speed desired (perhaps even run from a Peltier device if you wish). Any small leaks in the radiator certainly wouldn't affect its use as an air-driven heat exchange.

A video about the magnetocaloric effect and its applications would be cool

Wonder if you could walk us through the effiiency map of this rig as it stands. its possibly a useful way of showing further engineering skills

I've never heard of that 1-2-4 ratio for rocket stove. I've built a bunch and I think the important aspect is the 4 or longer is better, and that the dia opening is the same as dia flue. I think if you built a rocket stove with a different ratio like 2-1-4 or something would see equal performance.

How about instead of decorative fake logs in a gas fireplace you stack a few sections of railroad track? They absorb some of the heat that would normally go up the chimney and continue to radiate for a while after the flame goes out. Or maybe a big anvil or whatever...

We love ya Rob!!! I wonder if you could do a real world heating exercise with zeolite?

We use tichelheather Burn till 1100.degrees celsius..and stay warm for12 or 24 hours ..

9:47 you can also use it to heat air .. all you have to do is pour the sand out from a decent height and as it falls each grain separates further from those around it and the air rushing between it saps its heat away and because of the huge surface area of all those grains it transfers that heat very very quickly if you have an old industrial chimney or maybe a shot tower around that would be ideal conveyor the sane up let it fall let it heat the air in the chimney let it rise up thru a turbine then out the top and wallah silicosis for all uh i mean power for all

I have already been working on this type of system. But, being on a fixed income, resources need to be of recycled materials that not only cut the cost of building the unit, but alsi means that you are better likelyhood to find replacement naterials to recycle as opposed to new items that you buy and say a prolonged grid down either due to natural causes or a man made economic collapse. So, as I've already been using "sand" mixing into cement to make concrete, I am now storing up a resource that I can get plenty of "sand" from. Folks might be wondering why I have my sand in quotation and that is because it is recycled from a source that sand was used to make that resource. Glass. Crushed glass is sand if crushed into small enough granules. And anyu broken glass I come upon, I collect up and store away for future use. Yes, a proper heat storage is large for the home and greenhouses and requires a lot of sand. Yet glass is thrown away on a daily basis and is easy to collect and store. Now and then crush it up and store it in a bin of some sort so it takes up less space. If you are mindful about it, then it is easy to gather what you need and more. Remember, to buy sand is going up as fuel/transportation costs are going up. It costs me nothing to bring home some broken glass someone is or has discarded. After all, if it is on my way to wherever I am going anyway, then the cost is in the going to and from where I need to go and thus for a minute of my time to pick it up, it is otherwise free.

Your Peltier device is a diode you can cause heat to flow bidirectionally if you reverse the polarity of the DC current. Just make sure the voltage and current are regulated.

just the opposite it takes 8 minutes to boil the water and 8minutes for it to be not warm enough so I live in another gd universe love ya❤️‍🔥 gottago

Regarding insulation cinder toffee overcooked now you have a really cheap foam carbon.

0:58 or if your old school a brick in the fireplace to heat it up and then ...after wrapping it in something you dont might getting sooty you can put it in your bed to warm it up

was wondering as I have a couple of storage heaters left over and still in place could I power them up from say a couple of 400W solar panels, DC and yes I know they probably won't get as hot if they were powered from the mains but they might be warm enough.

Anyone looking to do a bit of welding, I have large welders, but needed to get a few welds in a area with only 120 v , Amazon had a tiny welder, stick/arc it was hers in less than two days. It's 120/240v and was less than $60 with the few $$$ I had off, it worked really well for what it was. Very capable for what it is, the show box welders as long as they can be returned, I'd get one. If it lasts 5-6 projects. It's worth it. Buy one look at the reviews, if it atleast works , give it a try, be sure if can be returned!

Hey Rob, what do you think about using sand in a vacuum heat tube? Do you think it would it be better to use sand to surround the copper tube, or copper scrubbing pads, or nothing, or what?

Love it.

Can you use a heelat pump to heat with or maybe use the Stirling for both heating and cooling?

im into building rv's ,using a rocket stove and a water heating element in a sand battery could make a nice alternative to a more draining heating system .rocket stove could power it when batteries are down or when we parked somewnere. question is would the electricity from it would be enough to power a fan to distribute the heat?

Awesome as usual :)

Rob sounds great only 1 question if you run a copper coil in the sand battery that can get to 500 C and you run water in the coil will it not fllash into steam or what else can you use

It strikes me that even the major energy companies must be fully aware that their monopoly on energy is in inevitable danger of being lost in the near future because of the potential use of very cheap, self sufficient and highly reliable power systems, such as the inevitable use of sand batteries eventually comes to fruition, and that they will in the meantime, become unfortunately even more susceptible to using every excuse they can find to justify their profiteering tactics as much as possible before they deservedly lose their greedy monopolising grip on all our energy resources!

Thermal mass storage reminds me about insulation, and homemade STARLITE. I believe it should be as insulating against hot sand as against an open flame right?

Thanks, how long did your 12v sand battery to reach 200deg?

If you use rock and drill it you can put your exhaust gas through the stone and not have to worry about moisture like you do with sand and gravel or even concrete. Just saying, why make a container when a stone slab is already solid and very thermally stable because of the forces that made it.

Wouldn't clay subsoil be a good substitute for sand? It could be dried to be used in freestanding batteries or, if part of a building, dug up and replaced after waterproof tanking was put into the pit with some heat-proof insulation between it and the clay. The clay can dry out in situ.

Rob could you do a video on why you can or can't use 240 volt house hold cable (up to say 6mm squared or whatever they call it) and use It to wire up batteries for a DIY solar system. You'd be amazed how many people would watch that. Mind you all the sparkies will have a cow tripping over themselves to comment how you can't do It. Hey let's prove them wrong? I saw a video where a guy used copper pipe to connect batteries as well and he heat shrank the part in the middle between each point that attaches to each battery. It would make a great video.

I want to create a space heater for my shed that will be formed from a clip-lid 44 gallon drum filled with sand that will sit on a pallet to better distribute the weight (and keep the heat off my wood floor. I'll feed it with a solar panel and I like the idea of using a kettle element as the heater. I'll set the element in the bottom of the drum. I am just wondering how to go about the power feed. I'm thinking of setting a metal flange in the middle of the drum base to accept the element but could use some suggestions how I could make the electrical connection without shorting or melting the insulation. Is a Plaster of Paris plug a way to go or is there something better (cement perhaps)? I will of course have the unit temperature controlled. I have no need for hundreds of degrees but something say 40C-ish would be dandy on a cold winter day.

a bone and a question for yer: First which supermarkets are selling £5 for kettles as struggling to find one below £30, and Second, could it be possible and/or economic to take the heat that would normally be radiated out from a fridge/freezer compressor pump and turn it into useful stored energy using sand batteries for keeping the house warm?

instead of sand what about crushed up building rubble might be a good recycling idea

Please could you expound on the topic of using the chloride salt as a heat storage mechanism?

Yes got that kicking around well perhaps ingenus to say simplisit y places...

Yes Cave man economics is back I still have a chance to make something useful.

Two words Rob; welding spud. I only know them because we made a five gallon wax pot about 30 years ago

Demonstrate Ohm's law with the wires strung and a hot wire in your hand. Drag that down the length of the stretched out wire to shorten it, and in a gesture, a small portion of the wire may be seen to get hot.

Thinking of placing a 5kw dolar panel array on the roof supplying heating elements in a sand battery, any tips on how to size this thing would be appreciated

Recycled glass could be used. it is made of sand, after all!

A guy called *lee jones* here on KZfaq uses a sand battery in his home. He does the burn outside then brings it inside once it has got up to temperature.

So this may seem like an odd question but could I use the elements from a toaster in a sand battery without any extra coating? I was thinking of using this with omniballs to possibly warm my small green house over the coming winter.