After we saw the giant Finnish model, we built a sand battery for our bus-turned-tiny-house since propane heating gets expensive quickly, wood burning presents issues with ventilation, and we always have more solar power than we have use for. Currently I have the battery set up to be plugged in and turned on/off with a cheapo Christmas tree foot switch, and it's been wonderful and so much more efficient than I could've possibly imagined. A single, tiny space heater will drain our +300ah battery bank in a matter of hours, and all that heat disappears the second it's turned off. With the sand battery, though, we can leave it on all night, get the bus nice and toasty, and for upwards of 5 hours after it's been shut off we can *keep* the bus warm and cozy, and all without making so much as a dent on our battery bank. On top of that, should we get a week of rubbish weather where we're not getting a full recharge on the LiFe batteries, our baby alcohol burners under the battery heat it up just as well and, again, at a fraction of the price of propane. I had the same idea to use a series of peltier devices to reclaim some of the heat energy and put in into a heat dump for our hot water. Still need to sort out the logistics of that project, but we've been wonderfully pleased with our sand-in-steel heater. ^.^
Ethanol has an energy value of 29.7 MJ/KG compared to propane and butane at around 50MJ/KG. Gas if purchased in bottles over 6kg (the bigger the cheaper) for me, the price of Ethanol, even buying in bulk...gas works out much better. If you don't mind me asking, but where and for how much cost do you get your alcohol jamaraquai4224? I cannot get a Good deal on it anywhere. Even purchasing Small cannisters of butane, adding up the weight/calorific value, the small cannisters of butane work out better value for me; purchased in bulk of-course.
@@pa_maj.MARTINI-van-MAN I always have a supply of denatured alcohol on hand for woodworking. Locally it's roughly $15/gal, and after multiple tests, the alcohol burners burn through roughly 1/2c of alcohol in 2hrs. The sand battery heats up with the burners in 30mins. Make no mistake: I'm not saying that heating the sand battery with alcohol burners is more efficient than using butane, propane, or certainly gas, but ethanol burns clean where gas does not, and leading a mobile and minimal lifestyle, I don't have the luxury of hauling around multiple tanks of fuel. We use excess solar power to charge our sand battery: the burners work extremely well in a pinch, tho. (:
@@jamaraquai4224 I guess it was the "at a fraction of the price of propane" made me wonder. Yes, Ethanol burns clean and I do have a couple of gallons of the stuff for my alcohol stoves. Butane is a rather safe gas compared to propane (less pressure) and should burn clean like alcohol giving off carbon dioxide and H2O (good old water). Like any flame, complete combustion is what we're after jamaraquai. I guess if it's only now and then, using the alcohol stove to heat the sand battery, it's not too bad. Here in Northern Ireland, we'd never get enough solar for use in a sand battery for heating when a Good heater is really needed unfortunately. Anyway, all the best jamaraquai 👍
@@pa_maj.MARTINI-van-MAN Yeah, where you're at, wind turbines would be a much more stable source of energy for "charging" a sand battery. Sorry for any confusion we might have caused! (:
We did something similar in a college physics class. The class built it with salts rather than sand. We heated the salt until it melted then placed it in an insulated container. I believe it was epsom salts but can't remember for sure. It stayed hot for days. We slow cooked a ham using the residual heat the next day. We had a lot of fun in that class. Do your research on safety folks. Notice Rob is using kiln dried sand. If it is not properly dry moisture will come off of what you are heating, therefore do not enclose it in an airtight container to heat it. It might build up pressure otherwise and might rupture or on cooling collapse your vessel. Rob's playing with fire video applies to all things, not just fire. I really enjoy these kinds of videos. Thanks Rob!
With salts you get the additional energy storage in the phase transition of the molten/solid salt. but on the negative side, if that molten salt gets in contact with water, you get a pretty nasty surprise. Sand does not have such problem. Additionally, you could use the sand and water to create steam to run turbines too. I have played with the thought that could run a furnace exhaust through a sand battery for additional gains, if you use wood, gas or other combustion heaters.
@@inso80 I agree, though with proper precautions(ie...be smarter than what you are working with) it can done safely with salts. There are pros and cons to any energy storage system.
I've been watching your videos for some time now. I live off grid and the things you teach and demonstrate are amazingly useful to my lifestyle. I am going to try this out as a heater for winter in a 55gallon steel drum with copper coil to run water through. Ofcourse this will be a all around water heater as well not just for room heating. Thanks for the great videos and for teaching me so many things. I also may throw in a peltier or two to generate some electricity as well since the surface area will be substantial. Thanks for all the videos! 🐅
As a fellow off-gridder who has already built a sand battery, just bear in mind, that the larger your battery, the more time and energy it will take to "power" it. Obviously we have no idea what kind of excess energy you're working with, but a 55gal drum will take a pretty significant amount of time and energy to heat up sufficiently to warm a house and/or heat water. If you're constantly dumping energy into it, then you'll be fine (eventually), but if you can only feed the battery intermittently as is often the case with solar/wind power, then don't forget to plan way ahead for your shower. ;)
This video Sir is exactly why I've chosen to support you vs other youtubers. You seem to have a genuine desire to help your fellow man and are a great educator as well. As of late I've seen more videos concerning sand batteries being produced. Lots of folks are starting to experiment with different approaches to this fascinating topic. Might I ask Sir if you could possibly explore this subject further. There's not a lot of material out there yet and a collaborative effort might defer the time and cost of developing a turn key system. Thanks again Sir, Daniel Pattison
I've always liked the idea of using crushed glass that can't be recycled in a sand battery. It's not just free, some places will pay you to take their waste glass. You can guarantee that its chemically pure and inert, and you'll comfortably be able to heat it up to 1500K if you want without any volatility. It ticks all the boxes of clean energy storage, simple, cheap, reliable, and doesn't require raw material mining.
Very interesting. Had not given this a moments thought. Thank you. Sand is abundant and cheap to free. Glass beads like this used in industrial blasting cabinets are an option. Almost everything presents some potential hazard. We just prepare for those we know and pray for divine intervention for those we don't
Some of your videos are just completely ahead of the pack in terms of their long-term impact and I really think that this is one of them. Thank you so much for making this, Robert.
I'm inspired by your videos, so I bought myself a bag of fine sand today. I have (and use) a coal and wood stove, so tomorrow will fill up an iron kettle with sand and put it on the stove. Once the stove cools down, I will put that kettle under my chair 🙂 I hope to get some radiant heat from it.
A friend of mine is a potter, and has a tiny wood stove COVERED (and surrounded) by various clay pots and vases. It acts as his heat battery and radiator. (Don’t set a room temp clay pot on a hot stove, or dump water into a hot pot- heat shock can cause the pot to crack or explode). It works well.
Heres an experiment to try; I once made a battery out of (Sodium Sulfate) , i would heat up the ( Na2SO4 ) crystals till they melted into a liquid... then the liquid could be stored for many , many days; if you discharge an electrical arc (such as from a gas fire pit piezo) , the arc will begin a reaction where lots and lots of heat is given off as the liquid then returns to a solid crystal again; this process can be repeated ; over and over... a great battery. Thank you Robert for these videos to keep our minds sharp.
Hugely valuable lesson. Ohms law in plain english, with an understandable example & a practical application. Robert Murray-Smith, thank you. my brain -Thanks you so much. sweeping away the fog of a failed education 1 video at a time. I really like the diagrams you flash up. I pause the video and have learned so much from some of them & you don't over show anything. good on you.
In steam trains, they used sand boxes. One use was to sprinkle some sand on the track as required to increase grip. The other was to heat sand which would be distributed by the "sandman" to replace the sand in the cabin heaters for the passengers. The Seekers' song Morningtown Ride mentions, "sandman swings the lantern to show that all is well".
Hi. Love your direction. I have an old hot water heater that rusted out. Will not hold water but will hold 50 gallons of sand and comes complete with heating elements. I see a few ways to use it with your ideas. Keep the great ideas coming. Your an inspiration!!!
I know. But have already upgraded those with two stove eye elements. Working on getting the time to fill it with sand now. And going to experiment with the heater elements to see if i use low voltage from a 12 colt batrery, weather or not it will produce useful heat without burning out. Should heat up less if not given the 220 volts they were designed for. Thanks for the warning. I should of updated my reply when i started planning. Have a great Thanksgiving!!!
@@joelee2371 So, what's the difference? The heating coil here came out of a kettle. I would imagine the water in the kettle has heat transfered to it from the heating coil just like a water heater. As long as the medium (sand or water) is removing the heat buildup from the elements at a reasonable rate, everything should be ok correct? Otherwise Robert's experiment here will have an extremely short life span.
@@ffaubert1 the sand will not conduct heat away from the element as rapidly as water, and the element will overheat and burn up. The temp of the element can be reduced by reducing the voltage to the element but that defeats the purpose.
@@joelee2371 depending on use you wouldn't need to heat it as fast as one would want to heat water so you could run a lower voltage to it to preserve the elements. The sand will hold the heat longer as well. It all depends on what the application of the heated sand would be.
Your channel is fantastic! I built a 4-ft x 8-ft solar air heater that gets up to about 250F on a clear sunny day here in Texas. I also built a 4-ft insulated sand battery cube that has an "inner air coil" of 4-inch aluminum flex duct , and an "outer air coil" with about a ton of sand all around and in-between the air coils. Using a solar panel and a battery and a 12v marine bilge fan, I've been blowing hot air into the inner coil in tests and have been able to heat the inner core of the sand battery to over 100F using only solar heated air and solar-charged battery power. Can use the outer coil with another fan to take heat out of the sand battery into my shop! Next, I'll be adding a 12v resistive heating element to the system to see if I can get the internal temp to about 200F. Thanks for all the ideas!
Thanks for the feedback, I think the folks in Finland used a heat pump so it might need worth trying that as it would be cheaper to run than a heating element
Thank you. I'll think about that! My plan would be to use solar PV panels to charge a 12V battery bank to power the resistive heating element. Free power after initial purchase cost.
I just love your videos! I just had a thought about making a cheap sand battery. Just get a kitchen oven and fill it with sand, use the elements you get from it. Use the switches to control it. Put it on it's back. To let the heat out open the door. Its already insulated to 500 degrees if its an old self clean. Just a thought. Please keep up the great content!!!
Your channel has been a great source of inspiration for me and my family boy 6 year old son is very eager to attempt some of your projects I also couldn't help but think of connecting your ingenuity with the need in Ukraine going into this winter The rocket stove married with the hot water could could literally be a life saver.
Greetz! Love your videos Sir. Just a suggestion for your consideration and for anybody else thinking about experimenting with this idea... I would create a hole in the side of the container and mount the heater element through the hole from the outside in the same manner as it would be mounted through the wall of a water heater in order to keep the electrical connections out of the intense heat as they were obviously not intended nor designed to exist within a super-heated environment.
Wow, thankyou. That has helped me a lot. I just need to try out some stuff with temperatures of rotting garden waste. Was thinking about running water pipes through bales of hay but it seems apparent that a core of sand would be better. Which to my way of thinking would act both ways in as much that if the rotting material started to drop in temp the the sand would keep it warm thus allowing the material that is rotting to keep up the temp necessary for the rotting process. Sorry lots to think about here.
A rocket stove with a slightly larger chimney that fits over a smaller chimney with at least a 1 inch gap between both chimneys, Then fill the 1 inch gap with sand. You then have a rocket stove sand battery.
@@ThinkingandTinkering Quite a few people in the US Midwest create thermal mass collectors to capture the last bit of heat from the flue before it's expelled from the house. I've seen a 10' long by 28" square stone and sand mass bench with the flue from the rocket stove running through it. Ends are removable for cleaning if necessary, but if he burns properly seasoned hardwood or pellets there isn't a need. A few hours of burning kept the whole place warm all night, my dog ended up sleeping on it toward morning. Thanks Robert, love your videos and learn a great deal as always.
It may not be very effective, but combine that with a Stirling powered generator and you have a adaptive power source. While you are active, you can fire the stove and gain a lot of energy. At rest, you have the dribble out of the sand battery, to still run background stuff like a clock.
That practical use part near the end of the video puts the sand battery in to full perspective. Anyone who wants or is thinking about going off grid. There's your much cheaper way to store your energy and or excess energy. This would or should last a lifetime or possibly many life times and would be far far cheaper and easier to maintain than normal batteries. Thanks Rob ! 👍
Thank you, sir, very much for this simple and concise explanation. I may experiment with charging a sand battery with a compost pile/pit. The new haircut looks good, btw. Be well.
Similar to what I've done as a house heater.. I've got several PTC elements, filled up my woodstove with sand. ( can't use as a wood burner here 😣) these elements are 12v or 240 , 28 W each can reach 220°c simply stick elements into the same & I feed from my solar panels and also the option of using cheap rate 240v. I was going to make a sandbattery from a gas bottle but the stove is more handsome 😃 it works so well I'm now in the process of converting a electric top loading kiln that no longer used and can be wheeled about room to room. Next is using same elements to convert an old tea caddy for hot water! Love the Vids .... Check out the PTC elements only £6 each!!
This seems like the ideal way to use the sand battery idea. I would really like to make one myself. Can I ask a few more specific questions? About how big is your stove? How many PTC elements do you use and how are they connected - in series or parallel? How many solar panels are needed to make it a viable heater? Anything else that would be helpful to know? Where I live we have a lot of sunshine (and wind at times), but it can also be very cold. It would be so nice to have some extra heat in the house!
Something else to keep in mind is sand Isanti insulator. It's basically raw glass. To get proper conductivity without extreme temp. Clean washed sand like used in cement isn't the best. But beach sand is actually good has to do with being rolled by water and not cut or crushed. Dirty sand is good too. Just something I've found with my off grid thermal storage units (batteries) . Using as a dump load for my masonry stoves heat exchanger. End use is radiant floor heat. Turns a good evening fire into the night and next days room heat.
My mind is blown away. I love the way you teach. We support some farmers in Africa who rear Black Soldier Flies for their animal protein requirement. Some months in the year they get extreme weather too hot in the day and very cold at night. We've been looking for low-tech ideas that we can deploy to help these communities. The sand battery may just be the answer. Thank you for explaining the way you have done it in this video. If you have any other ideas on how we can use this device to warm as well as cool, please share. PLEASE 🙂
Brilliant, I was very interested in the commercial version of this that was covered on the BBC. I just need to fill my garage with sand now and get off this ridiculously expensive grid 🙂
Robert, would there be benefit from creating a fluid bed of the sand to increase efficiency of heat transfer from the element to the sand? Mark Rober fluidized a hot tub full of sand in one of his videos. One of the best elements to your videos is you keep things within reach of makers and tinkerers and don’t overcomplicate things. Fluidizing the sand does make it more complicated. By the way your content is absolutely top notch. Great instructions, explanations, delivery, enthusiasm and on camera charisma. 💫✨✨⭐️
I don't think so unless you stay under the boiling point of water. Mark did his fluid bed with air. Sand can go up to 700-1000C. 10x the temp of water.
@@tesla747 Thanks for considering this. What are your thoughts about why it would matter to stay below the booking point of water? I understand steam generation from moisture in the sand could be problematic if not vented though it would already have to be vented in order to allow the fluidizing air pressure to escape.
Thanks for these amazing videos, you explain concepts understandably and inspire people to get their hands on the stuff with DIY videos other channels mostly require expensive materials or expensive processes. :)
Definitely a great (and cheap!) way to smooth out intermittent energy and to reuse and store waste heat. A pan of water around your heat sink would have extended the run time, too. If we'd any sense, we would integrate these with wind and solar, and then rate the system output as a whole. Clay, glass, ash, and carbon make great storage too but sand is easy to handle. Mix in organic waste, and it would be a great flame bed for a syngas burner, too. Looking forward to what you and Luke do with these.
@@ThinkingandTinkering Agreed. Given what the power grid will pay, or won't pay, for electricity dumped onto the grid. If you were to take a domestic hot water tank and turn that into a sand battery, how long do you think that will stay hot for?
@@WriteInAaronBushnell I think this will depend on how much insulation it has and what max temperature you run it to for example. I think a lot of the value in a sand battery is that you can run it at very high temperatures which will of course stay hotter longer.
I've seen a video of someone putting a pot into something of similar size and making a solar powered oven. It was really well insulated as well. They collected heat all day and cooked at night
Very interesting. I want to build a 100w thermoelectric generator for my woodstove and I could put the generator in a larger pot of sand to extend its energy production after the fire has gone out!
this is very helpful. thank you! Im still at the mind experiment stage of making a sand battery to keep my horses’ water from freezing. Im thinking solar to charge a 12v battery. Battery to run heating element. heating element to charge sand battery. sand to release heat slowly below water buckets. This video illustrates the important step of “how the heck to you heat the sand”
including the battery is probably extra complication and expense you don't need. just run the solar to the heater let it heat up the sand all day and release the heat 24/7.
@@vidard9863 thanks - that sounds great! I will try that first. i have ordered a PTC element off amazon but i may have to ‘accidentally drop’ the kettle to get testing as per example above.
@@JAMcRae We have no horses, (yet:), but I was thinking of making one for our hot water. In our area people throw away (or give away) their old electric ovens when they buy new ones. I think the heating element of such an oven, and its electrical connections, might be better suited for a sand battery than a kettle's, since kettle water only reach 100°C and the sand may get 2-3 times hotter, or even more. I also plan to construct some sort of heat exchanger, maybe from metal pipes, that can control the transfer of heat to the water, ( I've heard that being scalded in the shower isn't as much fun as it sounds :D)... you've probably thought of that too, but I thought I'd mention it anyway, just in case. Good luck.
Totally a sand battery and very useful but I was hoping you would talk about the practicality of it 6 watts of heat would require a long preheat period when we likely would want to extract 1500 watts for any small room . The 6 watts could never keep up, but I love the idea. The dump load is a great idea even when people have battery storage with renewable energy when the battery is on float all power is diverted or just lost. There are people in Canada who heat their homes with 24 volts applied to long wires embedded in concrete slab. I wonder what the life expectancy of the element is when heated out of water the cooling agent. Thanks for the video your slant is always interesting.
Good point, I would like to see some experiments done to see how many kwhs it takes to heat a kg of sand using a heating element or heat pump. I think they use a heat pump in Finland
@@agritech802 20kg of sand in a SS stock pot, with 200w of solar panels with 2 cooking elements. An average 124W going in. Started at 9:00, a temperature censor on the side (not in the center), 10:40 warm to touch 115kwh, 12:10 - 105F - 304kwh, 12:50 - 120F - 381kwh, 15:46 - 168F - 734kwh, 16:43 - 175F - 849kwh, stop at 18:15 - 197F - 997kwh. Center of pot was 280F or 138 degree Celsius. I put a beach tower to keep the heat over night. 19:40 temperature is at 180F
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Wondering about a sand battery using a cast or stamped bundt pan for baking. 1) Fill the bundt pan with sand 2) place an oil lamp jar in the center of the pan, using the center of the pan as a chimney (Vortex?) 3) Heat the sand and allow it to radiate over night. Better than the clay pot heaters, easier to make? IDK thoughts Robert? Love the content, keep up the great work!
I'm a literal person and can see your idea...I like it, but I can't visualize what you mean about placing a lamp oil jar in the center of a Bundt pan and about it acting like a chimney?? Sorry really lol...no oil in the jar, pretty sure 😂 ..can it be any jar.. I'm confused, and if its in the center of the pan, how with it covering that center hole, could any draw happen, making something you describe as a chimney. I really want to know your concept...I have sand, jars, and a bundt pan I'd rather use this way...help lol
Hi Robert. I noticed you can get large storage heater elements or oven/grill elements on their own instead of using / dismantling a kettle. Not too expensive maybe less than kettle if you look at the lengths of them
Good point, we have enough e-waste as it is. Best thing to do would be to re-use existing stuff. I will try a water heating element from an old washing machine.
Its amazing how watching these videos can get my brain going. For example, with this sand battery, it made me think of the fans people buy to put on top of their wood burning stoves to circulate the warm air. I'm not sure how they work, but I know that they don't need anything but the heat in order to run. (internal Peltier device?) Again, always inspiring to watch your videos, Robert. Thank you. Cheers!
@@ThinkingandTinkering I couldn't help but think of Luke's off grid project, and his beautiful new rocket stove, being used to charge a sand battery along with one of these fans to circulate heat within his cabin.
Fascinating! I have to say that power supply looks like it came off the set of 'The Empire Strikes back'. I can only imagine the stories it could tell :)
That was a real treat Robert, a lot of effort gone into it, I would love to see it done in a bigger scale with the insulation and crunch some numbers on it to see how many kwhs does it take per kg to heat it and how long does it retain the heat at different masses. BTW, i think the work you are doing is incredible so I've joined up as a member to do my little bit to support what you're doing, keep up the great work👍👍
@@ThinkingandTinkering hello, there is also smaller scale company doing that type of battery - Caldera Warmstone - but they have only 2 wvideos on YT and no social media with no spec provided. CEO said he installed it in his house, but no more info about it.
Man, I love your flucking channel more than any other when it boils down to just getting stuff done. I've been watching for 6 months now but I've even set up an account through a buddy(I'm a wild guy without a base,however not feral yet) so most things you do are very relevant for my lifestyle and also it seems that I think or imagine something and you are already doing it. You also remind me of one of the few teachers that I had respect for when I was an uncontrollable teenager. So I hope u appreciate my gratitude. Unfortunately for you I'm flucking broke so no donations just now but if I ever get a few quid I would buy u a beer anyway. Greetings from a damn cold East Germany , With your advice it gets warmer. My motto is "do everything like you mean it and don't fluck about"......You are the epitome of my motto. Thank You Sir.
@@mdjawaideqbal2941 I interpret your use of "..." as this should be something trivial/obvious? I don't see how this could not be fascinating and still be trivial for someone else? I really dislike this sort of elitism, if I interpret you correctly.
@@Frejjan I never wanted to present it as "trivial".... I know there is lot of negativity in youtube so maybe you took it that way 🙂. Actually i was suddenly fascinated when i thought maybe your observation is related to second law if thermydynamics because i was lately studying it purely for fun. isnt it fascinating how science gives seemingly simple laws but when you dive into them the implications are huge! I also have one doubt i wished to ask... so can i ask you? second law of thermodynamics is stated for heat engines.. so is it applicable for electricity? after posting the above comment i had this doubt... i was just thinking in terms of useful energy.. but not interms of heat energy or electrical energy.. i have basic understanding of thermodynamics but i find it absolutely fascinating..
And i used "..." because i was myself fascinated when i realised maybe your comment is connected to the second law.. please dont take it as sarcasm or elitism... in fact i am one of the most unelite kinda guy you will come across...
The specific heat capacity of water is 4.18kJ/kg/C, whereas sand is is about 0.8kJ/kg/C so for each 1kg of water it can store about 5.2 times as much energy than sand. Another way of looking at it is 1kg of water at 100C with have the same energy content as 1kg sand at 520C (or 5.2kg of sand at 100C)! There's a good TH-cam video that compare water ice cubes with stainless steel ice cubes, 'Are Steel Ice Cubes Better Than Regular Ice?' . It's really surprising how much more energy dense water has of steel.
This is what I'm looking for. I'm in the middle of nowhere, I've been thinking along about this idea since I heard about it. I'm autistic so I need to know why and how. If you're the smartest person in the room you're a teacher or you're in the wrong room.
I hope you dive deeper into how to make a sand battery Robert. So many of us would love to be able to create our own sand battery. I bought some land and a fairly new 39 foot trailaer. I am going to build a large geenhouse over the entire trailer and want to be able to heat my greenhouse without hooking up to the grid. I live in zone 7 so winter is mild here thank goodness. I loved your rocket stove video and I bought a rocket stove a while back and it works fantastic but I believe building a large sand battery 🔋 for heating my greenhouse would be a wise thing to do. As always, we love your video demonstrations sir. You are an awesome teacher. Take care my friend. I look forward to seeing you in your next video. MRA
I have an old 160 litre hot water cylinder. How about cutting the top off of it. Fill it with sand. Use the immersion heater to heat the sand, use the internal coil to run water through it and use that as a heat source? Already has insulation round it. Seems like an easy solution. Off to b&q tomorrow for some kiln dried sand...
Amazing! Can you please tell us A) how long it took to heat the sand up to 200C using the 1/2 an amp element? and B) How long did the sand then take to cool back down?
New to the channel and firstime comment. This is the first time I've heard of a sand battery. Very fascinating! This is a simple question, with the kettle element drawing only a half of an amp, how long did it take for the sand to reach 200c? This kind of stuff really is fascinating.
oh ages mate and I did wrap the tin in ceramic fibre insulation to get it there and took the insulation away for the demo - I suppose I should have said that but I did say int he video you had to insulate it - but my bad - sorry
@@danielabrahams4061 The heat capacity of sand is around 830 watt.seconds per kilogram per degree centigrade. so a rise of 200 degrees for 2 kilograms at 6 watts should take 830*200*2/6 seconds, about 55 thousand seconds, about 15 hours. If well insulated could probably happen by next day.
Would it heat quicker if the sand was wet? Thinking the creation of steam/hot water rising up would heat the the higher grains, or am I off target here?
I don't know how he does it but he's always working on the experiments that I'm going to do next and then I end up not having to do them thank you very much sir because it's very difficult for me to do these experiments it's saving me a lot of trouble and possibly trauma
Luke could use a sand battery on his rocket stove while he's off gridding so that at night he doesn't have to wake up and stoke the fire so often. As the fire dies down the sand will release heat back into the air to keep him warm at night.
With the excellent explanation & demonstration, the cheap sourcing of parts, and after pausing to review the cool infograms (where have those electricity relationship triangles been all my life?), I'm not so afraid to practice with electricity. And I always wanted a sand heater, sand battery, sand anything!
My dad told me they use black sand in vacuum tubes as a solar charged sand battery... he said they reach past 300°F and maintain heat well through the night if they have enough mass.
Once I read a paper where molten wax mixed with graphite was used to store energy, it showed that the graphite inproved the thermal conductivity of the material, hence it could be heated faster and releease it's thermal energy quicker
Hey Robert, Try Paraffin wax as Carnot battery because every phase change including from solid to liquid gives you double the amount of storage heat capacity/Storage
it's a good idea mate and lots of materials will do a great job and you are right to point that out - but I did say that in the video - the benefit of sand is anyone can do it - but if you can afford better materials use better materials - thank you for taking the time to reinforce that point - cheers mate
Sand is not an optimal material for storing heat. More available are shale, rock and clay, which also are more dense and have higher specific heat. Example, clay specific heat 1.38kJ/kg'C, density 1.6kg/L (source: engineeringtoolbox). When building home, one could dig foundation slightly deeper, insulate sides and bottom, fill original dirt back, add circulation loop, insulate top, build floor. For 10x20m house and 1m deep, it would store 440MJ/'C=122kWh/'C. Concrete can go as high as 70'C, so for this 10x20m house range 20-70'C provides 6MWh of heat capacity, may be enough to heat this home through winter.
Thank you very much for all the education content that you put out! As soon as my budget will allow it, I will become a channel member and give some donation. Once again thank you very much and I wish you the very best!!
This has got me thinking on ways I might make a heat-storage unit for a large canvas camping tent...something involving a large metal bucket or small barrel of hot sand. More research is needed.
Specific heat of quartz 0.7 joules/gram/degree C. Specific heat of water 4.18 joules/gram/degree C. So, weight for weight, water can store 6 times as much heat. Therefore you would need to heat the sand from 20 to 500C to store as much energy as heating water from 20 to 100C. Density of quartz 2.65 g/cc - density of dry sand 1.6. A possible advantage of sand is that the air between the sand particles would lower the heat loss. I use a block of Serpentinite (density 2.6), heated in a microwave, then surrounded with insulation in place of a hot water bottle. Like sand it has the advantage that it doesn't evaporate. Then, the Bismuth in the Peltier Effect Device is going to melt at high temperatures. But a higher temperature would give a greater thermodynamic efficiency.
That's very interesting, I wonder if a sand with higher specific gravity like Galena would be better than quartz? Would be good to get some more feedback on that
@@agritech802 Galena Sand is sand containing Galena - which is Lead Sulphide with small amounts of other sulphides maybe Antimony Sulphide and Silver Sulphide. It is the most common Lead ore. I would not recommend Galena Sand for this application as depending on the temperature, it may decompose and emit toxic fumes. Additionally according to Wikipedia, Lead Sulphide has a molecular weight of 240 and a heat capacity or specific heat of 46 Joules per mole. This translates to a specific heat of 46/240 or approximately 0.2 joules per gram whereas quartz sand has the value of about 0.7 - in other words quartz sand can hold 3.5 times as much as Galena per gram, so although Galena is more dense, as a material it will hold less heat.
@@NdxtremePro Yes, with Sand you can hold twice as much heat - per gram as water heated to 100 C. You would need to insulate it well though to reduce heat loss at this temperature. Heat loss rises proportional to the surface area, whereas stored heat goes up by the volume. So heat storage in sand is favoured by having a large amount of sand.
@@hansscholte5472 it actually isn't "The global rate of sand use - which has tripled over the last two decades partially as a result of surging urbanization - far exceeds the natural rate at which sand is being replenished by the weathering of rocks by wind and water."
I absolutely love it. I've been thinking about building a sand battery for a while now. I feel totally inspired and ready to build this now. Would be great for charging small devices
If you work out a way to bottle your enthusiasm then you have given the whole world an equally great gift to the wonderful knowledge you post. Many thanks again. "Knowledge is a matter of science and no dishonesty or conceit whatsoever is permissible. What is required is definitely the reverse - honesty and modesty." Mao Zedong :)
I was going to build a peltier device based generator intended to attach it to the outlet of an internal combustion engine which heats to 800+ degree celcius normally, in order to reclaim some of that huge amount of energy wasted in the form of heat (up to 80%) and use that energy to produce some hydroxy gas and feed it back to the engine, make it a little more efficient. But when I studied peltier devices and found out about their inefficiency when used as electricity generators (as low as 11% for the usual commercially available) I dropped the idea. A modern steam turbine on the other hand is said to be highly efficient, 80%. But even a 10kw turbine (smallest i could find) and the accessories will be a significant part of the investment. Anyway, another excellent video sir, thank you.
I really like the idea of using a whole stack of peltier devices on a rocket stove sand battery. If you keep an eye on the burn time it would be easy enough to stop the sand getting too hot and frying your TEGs or rig a thermostat to a solenoid to shut down the air intake with a flap of steel or some such. That way you have a radiant room heater you can cook on and charge devices with. Be perfect Lukes offgrid ambitions.
Catching the sun's heat instead of the photons gives double the energy capture without the expensive solar panels and electronics. The sand battery is perfectly suited for this! Another version is a climate battery typically used in greenhouses. Same principle, different application and materials.
I eagerly watched this hoping to find a DIY technique for generating 1752 Amperes of current - then realised "1752" is the episode number lol. Thanks for the video, really enjoyed it :-)
This is great. I would like to make one that i could perhaps heat via a rocket stove, because wood is free, but portable enough to put in the living room fireplace. Reason being because the is no corresponding chimney above (removed in bedroom) and hence no flue. Loving your channel mate.
Great input. Well done. I've thought of having a house extremely well insulated (hay bale ? ) That makes use of passive energy for heat in the day. With an array of simple heat producing solar panels. The heat from the panels would go into a insulated room filled with columns of sand batteries. The heat from these would be used at night and possibly hot water. It's all in having a little fun.
![[MV] A leap of faith...ความเชื่อใจครั้งสุดท้าย (From "Petrichor the series")](http://i.ytimg.com/vi/U1piZH2CNXA/mqdefault.jpg)
After we saw the giant Finnish model, we built a sand battery for our bus-turned-tiny-house since propane heating gets expensive quickly, wood burning presents issues with ventilation, and we always have more solar power than we have use for. Currently I have the battery set up to be plugged in and turned on/off with a cheapo Christmas tree foot switch, and it's been wonderful and so much more efficient than I could've possibly imagined. A single, tiny space heater will drain our +300ah battery bank in a matter of hours, and all that heat disappears the second it's turned off. With the sand battery, though, we can leave it on all night, get the bus nice and toasty, and for upwards of 5 hours after it's been shut off we can *keep* the bus warm and cozy, and all without making so much as a dent on our battery bank. On top of that, should we get a week of rubbish weather where we're not getting a full recharge on the LiFe batteries, our baby alcohol burners under the battery heat it up just as well and, again, at a fraction of the price of propane. I had the same idea to use a series of peltier devices to reclaim some of the heat energy and put in into a heat dump for our hot water. Still need to sort out the logistics of that project, but we've been wonderfully pleased with our sand-in-steel heater. ^.^
nice share mate - always good to hear of a practical example - cheers
Ethanol has an energy value of 29.7 MJ/KG compared to propane and butane at around 50MJ/KG. Gas if purchased in bottles over 6kg (the bigger the cheaper) for me, the price of Ethanol, even buying in bulk...gas works out much better.
If you don't mind me asking, but where and for how much cost do you get your alcohol jamaraquai4224? I cannot get a Good deal on it anywhere.
Even purchasing Small cannisters of butane, adding up the weight/calorific value, the small cannisters of butane work out better value for me; purchased in bulk of-course.
@@pa_maj.MARTINI-van-MAN I always have a supply of denatured alcohol on hand for woodworking. Locally it's roughly $15/gal, and after multiple tests, the alcohol burners burn through roughly 1/2c of alcohol in 2hrs. The sand battery heats up with the burners in 30mins. Make no mistake: I'm not saying that heating the sand battery with alcohol burners is more efficient than using butane, propane, or certainly gas, but ethanol burns clean where gas does not, and leading a mobile and minimal lifestyle, I don't have the luxury of hauling around multiple tanks of fuel. We use excess solar power to charge our sand battery: the burners work extremely well in a pinch, tho. (:
@@jamaraquai4224 I guess it was the "at a fraction of the price of propane" made me wonder.
Yes, Ethanol burns clean and I do have a couple of gallons of the stuff for my alcohol stoves.
Butane is a rather safe gas compared to propane (less pressure) and should burn clean like alcohol giving off carbon dioxide and H2O (good old water).
Like any flame, complete combustion is what we're after jamaraquai.
I guess if it's only now and then, using the alcohol stove to heat the sand battery, it's not too bad.
Here in Northern Ireland, we'd never get enough solar for use in a sand battery for heating when a Good heater is really needed unfortunately.
Anyway, all the best jamaraquai 👍
@@pa_maj.MARTINI-van-MAN Yeah, where you're at, wind turbines would be a much more stable source of energy for "charging" a sand battery. Sorry for any confusion we might have caused! (:
We did something similar in a college physics class. The class built it with salts rather than sand. We heated the salt until it melted then placed it in an insulated container. I believe it was epsom salts but can't remember for sure. It stayed hot for days. We slow cooked a ham using the residual heat the next day. We had a lot of fun in that class. Do your research on safety folks. Notice Rob is using kiln dried sand. If it is not properly dry moisture will come off of what you are heating, therefore do not enclose it in an airtight container to heat it. It might build up pressure otherwise and might rupture or on cooling collapse your vessel. Rob's playing with fire video applies to all things, not just fire. I really enjoy these kinds of videos. Thanks Rob!
that's a good point mate - I actually meant to mention it but forgot - thanks for taking the time to point that out
With salts you get the additional energy storage in the phase transition of the molten/solid salt. but on the negative side, if that molten salt gets in contact with water, you get a pretty nasty surprise. Sand does not have such problem. Additionally, you could use the sand and water to create steam to run turbines too. I have played with the thought that could run a furnace exhaust through a sand battery for additional gains, if you use wood, gas or other combustion heaters.
@@inso80 I agree, though with proper precautions(ie...be smarter than what you are working with) it can done safely with salts. There are pros and cons to any energy storage system.
I've been watching your videos for some time now. I live off grid and the things you teach and demonstrate are amazingly useful to my lifestyle. I am going to try this out as a heater for winter in a 55gallon steel drum with copper coil to run water through. Ofcourse this will be a all around water heater as well not just for room heating. Thanks for the great videos and for teaching me so many things. I also may throw in a peltier or two to generate some electricity as well since the surface area will be substantial. Thanks for all the videos! 🐅
wow - thank you mate and thank you for posting that
It would be great if you could do a video of your project when you have done it.
Hey Robert, a little off topic but is your graphene battery you built in that scooter still working ? I’m wondering how it’s held up during this time.
As a fellow off-gridder who has already built a sand battery, just bear in mind, that the larger your battery, the more time and energy it will take to "power" it. Obviously we have no idea what kind of excess energy you're working with, but a 55gal drum will take a pretty significant amount of time and energy to heat up sufficiently to warm a house and/or heat water. If you're constantly dumping energy into it, then you'll be fine (eventually), but if you can only feed the battery intermittently as is often the case with solar/wind power, then don't forget to plan way ahead for your shower. ;)
@@davidmorinmusic i remember that scooter battery i wonder if its still holding the same charge and how many cycles has it done ?
This video Sir is exactly why I've chosen to support you vs other youtubers. You seem to have a genuine desire to help your fellow man and are a great educator as well.
As of late I've seen more videos concerning sand batteries being produced. Lots of folks are starting to experiment with different approaches to this fascinating topic.
Might I ask Sir if you could possibly explore this subject further. There's not a lot of material out there yet and a collaborative effort might defer the time and cost of developing a turn key system.
Thanks again Sir,
Daniel Pattison
I've always liked the idea of using crushed glass that can't be recycled in a sand battery. It's not just free, some places will pay you to take their waste glass. You can guarantee that its chemically pure and inert, and you'll comfortably be able to heat it up to 1500K if you want without any volatility. It ticks all the boxes of clean energy storage, simple, cheap, reliable, and doesn't require raw material mining.
that is a good idea mate - thank you for sharing
You will have to somehow grind up the glass. Tedious!
@@kitemanmusic not to mention bloody dangerous, the finer you get the more silicosis potential...
@@kitemanmusic And just how small would we have to grind them?
@@kitemanmusic ball Mill
Very interesting. Had not given this a moments thought. Thank you. Sand is abundant and cheap to free. Glass beads like this used in industrial blasting cabinets are an option. Almost everything presents some potential hazard. We just prepare for those we know and pray for divine intervention for those we don't
Some of your videos are just completely ahead of the pack in terms of their long-term impact and I really think that this is one of them. Thank you so much for making this, Robert.
I'm inspired by your videos, so I bought myself a bag of fine sand today. I have (and use) a coal and wood stove, so tomorrow will fill up an iron kettle with sand and put it on the stove. Once the stove cools down, I will put that kettle under my chair 🙂 I hope to get some radiant heat from it.
Interested in knowing how it worked for you!
How'd it work out?
A friend of mine is a potter, and has a tiny wood stove COVERED (and surrounded) by various clay pots and vases. It acts as his heat battery and radiator. (Don’t set a room temp clay pot on a hot stove, or dump water into a hot pot- heat shock can cause the pot to crack or explode). It works well.
Heres an experiment to try; I once made a battery out of (Sodium Sulfate) , i would heat up the ( Na2SO4 ) crystals till they melted into a liquid... then the liquid could be stored for many , many days; if you discharge an electrical arc (such as from a gas fire pit piezo) , the arc will begin a reaction where lots and lots of heat is given off as the liquid then returns to a solid crystal again; this process can be repeated ; over and over... a great battery. Thank you Robert for these videos to keep our minds sharp.
Hugely valuable lesson.
Ohms law in plain english, with an understandable example & a practical application.
Robert Murray-Smith, thank you.
my brain -Thanks you so much. sweeping away the fog of a failed education 1 video at a time.
I really like the diagrams you flash up.
I pause the video and have learned so much from some of them & you don't over show anything.
good on you.
Years I've been confused by this problem and in trying to get to the bottom point and I couldn't, now thanks to you it is apparent. many thanks...
In steam trains, they used sand boxes. One use was to sprinkle some sand on the track as required to increase grip. The other was to heat sand which would be distributed by the "sandman" to replace the sand in the cabin heaters for the passengers.
The Seekers' song Morningtown Ride mentions, "sandman swings the lantern to show that all is well".
Hi. Love your direction. I have an old hot water heater that rusted out. Will not hold water but will hold 50 gallons of sand and comes complete with heating elements. I see a few ways to use it with your ideas. Keep the great ideas coming. Your an inspiration!!!
The water acts as a coolant for the elements; otherwise they will overheat and burn out rapidly.
I know. But have already upgraded those with two stove eye elements. Working on getting the time to fill it with sand now. And going to experiment with the heater elements to see if i use low voltage from a 12 colt batrery, weather or not it will produce useful heat without burning out. Should heat up less if not given the 220 volts they were designed for. Thanks for the warning. I should of updated my reply when i started planning. Have a great Thanksgiving!!!
@@joelee2371 So, what's the difference? The heating coil here came out of a kettle. I would imagine the water in the kettle has heat transfered to it from the heating coil just like a water heater. As long as the medium (sand or water) is removing the heat buildup from the elements at a reasonable rate, everything should be ok correct? Otherwise Robert's experiment here will have an extremely short life span.
@@ffaubert1 the sand will not conduct heat away from the element as rapidly as water, and the element will overheat and burn up. The temp of the element can be reduced by reducing the voltage to the element but that defeats the purpose.
@@joelee2371 depending on use you wouldn't need to heat it as fast as one would want to heat water so you could run a lower voltage to it to preserve the elements. The sand will hold the heat longer as well. It all depends on what the application of the heated sand would be.
Your channel is fantastic! I built a 4-ft x 8-ft solar air heater that gets up to about 250F on a clear sunny day here in Texas. I also built a 4-ft insulated sand battery cube that has an "inner air coil" of 4-inch aluminum flex duct , and an "outer air coil" with about a ton of sand all around and in-between the air coils. Using a solar panel and a battery and a 12v marine bilge fan, I've been blowing hot air into the inner coil in tests and have been able to heat the inner core of the sand battery to over 100F using only solar heated air and solar-charged battery power. Can use the outer coil with another fan to take heat out of the sand battery into my shop! Next, I'll be adding a 12v resistive heating element to the system to see if I can get the internal temp to about 200F. Thanks for all the ideas!
Thanks for the feedback, I think the folks in Finland used a heat pump so it might need worth trying that as it would be cheaper to run than a heating element
Thank you. I'll think about that! My plan would be to use solar PV panels to charge a 12V battery bank to power the resistive heating element. Free power after initial purchase cost.
@@tjm1955 yes good idea but heat the sand directly or else you'll lose efficiency twice and shorten the length of your battery unnecessarily
nice work you have been up there mate - I read what you posted with fascination - thanks for sharing
I just love your videos! I just had a thought about making a cheap sand battery.
Just get a kitchen oven and fill it with sand, use the elements you get from it. Use the switches to control it. Put it on it's back. To let the heat out open the door. Its already insulated to 500 degrees if its an old self clean. Just a thought.
Please keep up the great content!!!
Your channel has been a great source of inspiration for me and my family boy 6 year old son is very eager to attempt some of your projects
I also couldn't help but think of connecting your ingenuity with the need in Ukraine going into this winter
The rocket stove married with the hot water could could literally be a life saver.
Greetz! Love your videos Sir. Just a suggestion for your consideration and for anybody else thinking about experimenting with this idea... I would create a hole in the side of the container and mount the heater element through the hole from the outside in the same manner as it would be mounted through the wall of a water heater in order to keep the electrical connections out of the intense heat as they were obviously not intended nor designed to exist within a super-heated environment.
Just simply friggin inspirational, there is so much we can do with this, like heating homes for the winter, I'm planning on something like this
I love how informative and personal your vids are, I feel like I'm hanging out with a friend building random stuff in the garage for fun. I love it
Thank you Robert , you are so helpful in explaining subjects .
I will always watch.
Very useful for heating the greenhouse seed trays from my wind generator. Thanks so much Merry Christmas to you .
Wow, thankyou. That has helped me a lot. I just need to try out some stuff with temperatures of rotting garden waste. Was thinking about running water pipes through bales of hay but it seems apparent that a core of sand would be better. Which to my way of thinking would act both ways in as much that if the rotting material started to drop in temp the the sand would keep it warm thus allowing the material that is rotting to keep up the temp necessary for the rotting process. Sorry lots to think about here.
that's clever mate - I like where you are going with this - cheers
Hey Rob, thanks for the video, possibly one my favourites so far 🥰 will be renewing my membership shortly.
A rocket stove with a slightly larger chimney that fits over a smaller chimney with at least a 1 inch gap between both chimneys, Then fill the 1 inch gap with sand. You then have a rocket stove sand battery.
I think that could work, but the type of sand is essential; what if it becomes a ‘rock’ in your chimney: you’ll never be able to move it anymore..
yep - though I have already done something similar mate
@@hansscholte5472 what kind of sand ?
@@ThinkingandTinkering Quite a few people in the US Midwest create thermal mass collectors to capture the last bit of heat from the flue before it's expelled from the house. I've seen a 10' long by 28" square stone and sand mass bench with the flue from the rocket stove running through it. Ends are removable for cleaning if necessary, but if he burns properly seasoned hardwood or pellets there isn't a need. A few hours of burning kept the whole place warm all night, my dog ended up sleeping on it toward morning.
Thanks Robert, love your videos and learn a great deal as always.
It may not be very effective, but combine that with a Stirling powered generator and you have a adaptive power source.
While you are active, you can fire the stove and gain a lot of energy. At rest, you have the dribble out of the sand battery, to still run background stuff like a clock.
Good introduction to sand batteries
That practical use part near the end of the video puts the sand battery in to full perspective. Anyone who wants or is thinking about going off grid. There's your much cheaper way to store your energy and or excess energy. This would or should last a lifetime or possibly many life times and would be far far cheaper and easier to maintain than normal batteries.
Thanks Rob ! 👍
exactly mate - we use so much energy in heating and hardly any in direct electric - thermal batteries make such sense to me
Also better for the environment.
Thank you, sir, very much for this simple and concise explanation. I may experiment with charging a sand battery with a compost pile/pit.
The new haircut looks good, btw.
Be well.
Similar to what I've done as a house heater..
I've got several PTC elements, filled up my woodstove with sand. ( can't use as a wood burner here 😣) these elements are 12v or 240 , 28 W each can reach 220°c simply stick elements into the same & I feed from my solar panels and also the option of using cheap rate 240v. I was going to make a sandbattery from a gas bottle but the stove is more handsome 😃 it works so well I'm now in the process of converting a electric top loading kiln that no longer used and can be wheeled about room to room. Next is using same elements to convert an old tea caddy for hot water!
Love the Vids .... Check out the PTC elements only £6 each!!
Edit.... Stick elements into the Sand.... not Same!!!!
This seems like the ideal way to use the sand battery idea. I would really like to make one myself. Can I ask a few more specific questions? About how big is your stove? How many PTC elements do you use and how are they connected - in series or parallel? How many solar panels are needed to make it a viable heater? Anything else that would be helpful to know? Where I live we have a lot of sunshine (and wind at times), but it can also be very cold. It would be so nice to have some extra heat in the house!
Something else to keep in mind is sand Isanti insulator. It's basically raw glass. To get proper conductivity without extreme temp. Clean washed sand like used in cement isn't the best. But beach sand is actually good has to do with being rolled by water and not cut or crushed. Dirty sand is good too. Just something I've found with my off grid thermal storage units (batteries) . Using as a dump load for my masonry stoves heat exchanger. End use is radiant floor heat. Turns a good evening fire into the night and next days room heat.
My mind is blown away. I love the way you teach. We support some farmers in Africa who rear Black Soldier Flies for their animal protein requirement. Some months in the year they get extreme weather too hot in the day and very cold at night. We've been looking for low-tech ideas that we can deploy to help these communities. The sand battery may just be the answer. Thank you for explaining the way you have done it in this video. If you have any other ideas on how we can use this device to warm as well as cool, please share. PLEASE 🙂
Possibly my favorite internet teacher.
100%
Fascinating, yes!! Particularly interested in using as a possible dump load for my hydro generator
yes I like the dump load idea - it has seemed like madness to me that it is usually just a resistor in air - what a waste
Brilliant, I was very interested in the commercial version of this that was covered on the BBC. I just need to fill my garage with sand now and get off this ridiculously expensive grid 🙂
ain't that the truth!
@@ThinkingandTinkering I do have a small follow up. Does the battery degrade over time or is this the future do you think?
@@seanhadley2672 The electronics might degrade but I doubt the sand will.
THANK YOU & HAPPY NEW YEAR YOU BEAUTIFUL LEGEND ❤
Robert, would there be benefit from creating a fluid bed of the sand to increase efficiency of heat transfer from the element to the sand? Mark Rober fluidized a hot tub full of sand in one of his videos. One of the best elements to your videos is you keep things within reach of makers and tinkerers and don’t overcomplicate things. Fluidizing the sand does make it more complicated.
By the way your content is absolutely top notch. Great instructions, explanations, delivery, enthusiasm and on camera charisma. 💫✨✨⭐️
I don't think so unless you stay under the boiling point of water. Mark did his fluid bed with air. Sand can go up to 700-1000C. 10x the temp of water.
@@tesla747 Thanks for considering this. What are your thoughts about why it would matter to stay below the booking point of water? I understand steam generation from moisture in the sand could be problematic if not vented though it would already have to be vented in order to allow the fluidizing air pressure to escape.
Thanks for these amazing videos, you explain concepts understandably and inspire people to get their hands on the stuff with DIY videos other channels mostly require expensive materials or expensive processes. :)
Definitely a great (and cheap!) way to smooth out intermittent energy and to reuse and store waste heat. A pan of water around your heat sink would have extended the run time, too. If we'd any sense, we would integrate these with wind and solar, and then rate the system output as a whole. Clay, glass, ash, and carbon make great storage too but sand is easy to handle. Mix in organic waste, and it would be a great flame bed for a syngas burner, too. Looking forward to what you and Luke do with these.
I agree - to my mind it is madness to use a dump load
@@ThinkingandTinkering Agreed. Given what the power grid will pay, or won't pay, for electricity dumped onto the grid. If you were to take a domestic hot water tank and turn that into a sand battery, how long do you think that will stay hot for?
@@WriteInAaronBushnell I think this will depend on how much insulation it has and what max temperature you run it to for example. I think a lot of the value in a sand battery is that you can run it at very high temperatures which will of course stay hotter longer.
Amazing thread
I have been searching for something like this for many months
I've seen a video of someone putting a pot into something of similar size and making a solar powered oven. It was really well insulated as well. They collected heat all day and cooked at night
that's clever
Damn, i need to just watch every single video you have. Each time i get a wild idea to try, you've tried it. Great stuff.
Very interesting. I want to build a 100w thermoelectric generator for my woodstove and I could put the generator in a larger pot of sand to extend its energy production after the fire has gone out!
Or put the sand on the stove
You are good at explaining things in an engaging tone
this is very helpful. thank you! Im still at the mind experiment stage of making a sand battery to keep my horses’ water from freezing. Im thinking solar to charge a 12v battery. Battery to run heating element. heating element to charge sand battery. sand to release heat slowly below water buckets. This video illustrates the important step of “how the heck to you heat the sand”
including the battery is probably extra complication and expense you don't need. just run the solar to the heater let it heat up the sand all day and release the heat 24/7.
cheers mate
@@vidard9863 thanks - that sounds great! I will try that first. i have ordered a PTC element off amazon but i may have to ‘accidentally drop’ the kettle to get testing as per example above.
@@JAMcRae We have no horses, (yet:), but I was thinking of making one for our hot water.
In our area people throw away (or give away) their old electric ovens when they buy new ones.
I think the heating element of such an oven, and its electrical connections, might be better suited for a sand battery than a kettle's, since kettle water only reach 100°C and the sand may get 2-3 times hotter, or even more.
I also plan to construct some sort of heat exchanger, maybe from metal pipes, that can control the transfer of heat to the water, ( I've heard that being scalded in the shower isn't as much fun as it sounds :D)... you've probably thought of that too, but I thought I'd mention it anyway, just in case.
Good luck.
Thanks so much for explaining Ohm's Law. I've watched several vids on sand batteries and nobody explains the math.
Totally a sand battery and very useful but I was hoping you would talk about the practicality of it 6 watts of heat would require a long preheat period when we likely would want to extract 1500 watts for any small room . The 6 watts could never keep up, but I love the idea. The dump load is a great idea even when people have battery storage with renewable energy when the battery is on float all power is diverted or just lost. There are people in Canada who heat their homes with 24 volts applied to long wires embedded in concrete slab. I wonder what the life expectancy of the element is when heated out of water the cooling agent. Thanks for the video your slant is always interesting.
Really ? I'm going to make a small one to check that out . Thanks 😊
Good point, I would like to see some experiments done to see how many kwhs it takes to heat a kg of sand using a heating element or heat pump. I think they use a heat pump in Finland
@@agritech802 20kg of sand in a SS stock pot, with 200w of solar panels with 2 cooking elements. An average 124W going in. Started at 9:00, a temperature censor on the side (not in the center), 10:40 warm to touch 115kwh, 12:10 - 105F - 304kwh, 12:50 - 120F - 381kwh, 15:46 - 168F - 734kwh, 16:43 - 175F - 849kwh, stop at 18:15 - 197F - 997kwh. Center of pot was 280F or 138 degree Celsius. I put a beach tower to keep the heat over night. 19:40 temperature is at 180F
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Wondering about a sand battery using a cast or stamped bundt pan for baking. 1) Fill the bundt pan with sand 2) place an oil lamp jar in the center of the pan, using the center of the pan as a chimney (Vortex?) 3) Heat the sand and allow it to radiate over night. Better than the clay pot heaters, easier to make? IDK thoughts Robert? Love the content, keep up the great work!
I'm a literal person and can see your idea...I like it, but I can't visualize what you mean about placing a lamp oil jar in the center of a Bundt pan and about it acting like a chimney?? Sorry really lol...no oil in the jar, pretty sure 😂 ..can it be any jar.. I'm confused, and if its in the center of the pan, how with it covering that center hole, could any draw happen, making something you describe as a chimney. I really want to know your concept...I have sand, jars, and a bundt pan I'd rather use this way...help lol
I have made the lamp (works great) and just use them to heat a piece of soapstone (pizza stone) and that works great for me! Good luck and stay warm!
Fun project. Thanks for sharing.
Hi Robert. I noticed you can get large storage heater elements or oven/grill elements on their own instead of using / dismantling a kettle. Not too expensive maybe less than kettle if you look at the lengths of them
Good point, we have enough e-waste as it is. Best thing to do would be to re-use existing stuff.
I will try a water heating element from an old washing machine.
You can just buy nichrome wire in bulk, if that's all you're after.
Its amazing how watching these videos can get my brain going. For example, with this sand battery, it made me think of the fans people buy to put on top of their wood burning stoves to circulate the warm air. I'm not sure how they work, but I know that they don't need anything but the heat in order to run. (internal Peltier device?)
Again, always inspiring to watch your videos, Robert. Thank you.
Cheers!
awesome mate - well there are two types one is a Peltier and the other - usually sold in India is a small striking motor
Lol... I couldn't help myself. A few minutes of 'research' confirmed that it is a type of peltier device that makes those fans run.
@@ThinkingandTinkering I couldn't help but think of Luke's off grid project, and his beautiful new rocket stove, being used to charge a sand battery along with one of these fans to circulate heat within his cabin.
@@ThinkingandTinkering Presumably you mean Stirling motor, not striking motor
Fascinating!
I have to say that power supply looks like it came off the set of 'The Empire Strikes back'. I can only imagine the stories it could tell :)
lolol - it is an old one but not the oldest I have lol
Thank you Robert, you are 1 clever man, im learning so much from you... Blessings to you x
That was a real treat Robert, a lot of effort gone into it, I would love to see it done in a bigger scale with the insulation and crunch some numbers on it to see how many kwhs does it take per kg to heat it and how long does it retain the heat at different masses. BTW, i think the work you are doing is incredible so I've joined up as a member to do my little bit to support what you're doing, keep up the great work👍👍
it's a good point mate - but it has already been done at a bigger scale just check out what the Finns have done
O Dem, that would be great, id love to see your results, do keep us in the loop for your update
@@ThinkingandTinkering hello, there is also smaller scale company doing that type of battery - Caldera Warmstone - but they have only 2 wvideos on YT and no social media with no spec provided. CEO said he installed it in his house, but no more info about it.
Man, I love your flucking channel more than any other when it boils down to just getting stuff done.
I've been watching for 6 months now but I've even set up an account through a buddy(I'm a wild guy without a base,however not feral yet) so most things you do are very relevant for my lifestyle and also it seems that I think or imagine something and you are already doing it.
You also remind me of one of the few teachers that I had respect for when I was an uncontrollable teenager. So I hope u appreciate my gratitude. Unfortunately for you I'm flucking broke so no donations just now but if I ever get a few quid I would buy u a beer anyway. Greetings from a damn cold East Germany ,
With your advice it gets warmer. My motto is "do everything like you mean it and don't fluck about"......You are the epitome of my motto. Thank You Sir.
I find it fascinating that it is so easy and efficient to go from electricity to heat, but much more difficult to go from heat to electricity.
Second Law of Thermodynamics...
@@mdjawaideqbal2941 I interpret your use of "..." as this should be something trivial/obvious? I don't see how this could not be fascinating and still be trivial for someone else? I really dislike this sort of elitism, if I interpret you correctly.
@@Frejjan I never wanted to present it as "trivial".... I know there is lot of negativity in youtube so maybe you took it that way 🙂. Actually i was suddenly fascinated when i thought maybe your observation is related to second law if thermydynamics because i was lately studying it purely for fun. isnt it fascinating how science gives seemingly simple laws but when you dive into them the implications are huge! I also have one doubt i wished to ask... so can i ask you? second law of thermodynamics is stated for heat engines.. so is it applicable for electricity? after posting the above comment i had this doubt... i was just thinking in terms of useful energy.. but not interms of heat energy or electrical energy.. i have basic understanding of thermodynamics but i find it absolutely fascinating..
And i used "..." because i was myself fascinated when i realised maybe your comment is connected to the second law.. please dont take it as sarcasm or elitism... in fact i am one of the most unelite kinda guy you will come across...
WOW absolutely fabulous now to up this into a steam generator thank you Murray....
Thank you very much for taking the time to make a video. I learned a lot from you today
The specific heat capacity of water is 4.18kJ/kg/C, whereas sand is is about 0.8kJ/kg/C so for each 1kg of water it can store about 5.2 times as much energy than sand. Another way of looking at it is 1kg of water at 100C with have the same energy content as 1kg sand at 520C (or 5.2kg of sand at 100C)!
There's a good TH-cam video that compare water ice cubes with stainless steel ice cubes, 'Are Steel Ice Cubes Better Than Regular Ice?' . It's really surprising how much more energy dense water has of steel.
yeah that's true but as I said in the video water has a sever limitation
This is what I'm looking for. I'm in the middle of nowhere, I've been thinking along about this idea since I heard about it. I'm autistic so I need to know why and how.
If you're the smartest person in the room you're a teacher or you're in the wrong room.
Great video would be interested to see wind turbine that you made work with that sand battery
I hope you dive deeper into how to make a sand battery Robert. So many of us would love to be able to create our own sand battery. I bought some land and a fairly new 39 foot trailaer. I am going to build a large geenhouse over the entire trailer and want to be able to heat my greenhouse without hooking up to the grid. I live in zone 7 so winter is mild here thank goodness. I loved your rocket stove video and I bought a rocket stove a while back and it works fantastic but I believe building a large sand battery 🔋 for heating my greenhouse would be a wise thing to do. As always, we love your video demonstrations sir. You are an awesome teacher. Take care my friend. I look forward to seeing you in your next video. MRA
I'm embarrassed to say that I thought a sand battery worked like a huge hourglass. Thanks for setting me straight on that one.
That could be one kind of gravity battery. Just flip it over when in need of power.
Thanks for the commenter that first mentioned the idea
I have an old 160 litre hot water cylinder. How about cutting the top off of it. Fill it with sand. Use the immersion heater to heat the sand, use the internal coil to run water through it and use that as a heat source? Already has insulation round it. Seems like an easy solution. Off to b&q tomorrow for some kiln dried sand...
nice
I'll suggest you make sure to not exceed the temperature safety limits for any materials in the hot water cylinder.
Hi Rob, It's a really good video. Thank you.
Amazing! Can you please tell us A) how long it took to heat the sand up to 200C using the 1/2 an amp element? and B) How long did the sand then take to cool back down?
Wait he did not tell us this info in the video,?
@@bombassbeefjerky9708 no he did not
I stacked broken concrete in a wire cage around my wood heater in my garage, amazing how much heat the concrete retained.
New to the channel and firstime comment. This is the first time I've heard of a sand battery. Very fascinating! This is a simple question, with the kettle element drawing only a half of an amp, how long did it take for the sand to reach 200c? This kind of stuff really is fascinating.
absolutely no way did that uninsulated cake tin hit 200C with only 6 watts. you're right to question it.
oh ages mate and I did wrap the tin in ceramic fibre insulation to get it there and took the insulation away for the demo - I suppose I should have said that but I did say int he video you had to insulate it - but my bad - sorry
@@ThinkingandTinkering Thanks this is really important info, would you mind sharing how long 'ages' is ball park, is it 6hrs or 24hrs for example?
@@danielabrahams4061 The heat capacity of sand is around 830 watt.seconds per kilogram per degree centigrade. so a rise of 200 degrees for 2 kilograms at 6 watts should take 830*200*2/6 seconds, about 55 thousand seconds, about 15 hours. If well insulated could probably happen by next day.
Would it heat quicker if the sand was wet? Thinking the creation of steam/hot water rising up would heat the the higher grains, or am I off target here?
I don't know how he does it but he's always working on the experiments that I'm going to do next and then I end up not having to do them thank you very much sir because it's very difficult for me to do these experiments it's saving me a lot of trouble and possibly trauma
lol - glad to help mate lol
Luke could use a sand battery on his rocket stove while he's off gridding so that at night he doesn't have to wake up and stoke the fire so often. As the fire dies down the sand will release heat back into the air to keep him warm at night.
for sure mate
With the excellent explanation & demonstration, the cheap sourcing of parts, and after pausing to review the cool infograms (where have those electricity relationship triangles been all my life?), I'm not so afraid to practice with electricity. And I always wanted a sand heater, sand battery, sand anything!
awesome mate
My dad told me they use black sand in vacuum tubes as a solar charged sand battery... he said they reach past 300°F and maintain heat well through the night if they have enough mass.
that is an awesome idea
Use stainless steal and frensel lenses to melt salt
Who does? Have any pictures?
Can you buy black sand is it more efficient what is the best material? To. Storeheat
Once I read a paper where molten wax mixed with graphite was used to store energy, it showed that the graphite inproved the thermal conductivity of the material, hence it could be heated faster and releease it's thermal energy quicker
Hey Robert, Try Paraffin wax as Carnot battery because every phase change including from solid to liquid gives you double the amount of storage heat capacity/Storage
Nah checkout codyslab video about parrafin vs beeswax - use beeswax, buy local :P 🐝
it's a good idea mate and lots of materials will do a great job and you are right to point that out - but I did say that in the video - the benefit of sand is anyone can do it - but if you can afford better materials use better materials - thank you for taking the time to reinforce that point - cheers mate
I wonder if yu could mix sand with wax?
There's zero chance of sand catching on fire and a leak would be less likely and less dangerous. Also no fumes.
@@Hamish_A but no phase change and therefore no additional storage though.
Sand is not an optimal material for storing heat. More available are shale, rock and clay, which also are more dense and have higher specific heat.
Example, clay specific heat 1.38kJ/kg'C, density 1.6kg/L (source: engineeringtoolbox). When building home, one could dig foundation slightly deeper, insulate sides and bottom, fill original dirt back, add circulation loop, insulate top, build floor. For 10x20m house and 1m deep, it would store 440MJ/'C=122kWh/'C. Concrete can go as high as 70'C, so for this 10x20m house range 20-70'C provides 6MWh of heat capacity, may be enough to heat this home through winter.
I really enjoy your videos, especially the bloopers. Question; Is it possible to DIY a Peltier at home, or is the device too complicated?
Thank you very much for all the education content that you put out! As soon as my budget will allow it, I will become a channel member and give some donation. Once again thank you very much and I wish you the very best!!
Could you use a load of sand underneath a floor? Heat the sand to low temperature and let it percolate up?
Same as floor heating. You can use a heater wire with sensor.
Wow. My head is spinning with these possibilities. Good job 👌
At those temps can you really use a copper water heat exchanger?
yes
This has got me thinking on ways I might make a heat-storage unit for a large canvas camping tent...something involving a large metal bucket or small barrel of hot sand. More research is needed.
Specific heat of quartz 0.7 joules/gram/degree C. Specific heat of water 4.18 joules/gram/degree C.
So, weight for weight, water can store 6 times as much heat. Therefore you would need to heat the sand from 20 to 500C to store as much energy as heating water from 20 to 100C.
Density of quartz 2.65 g/cc - density of dry sand 1.6.
A possible advantage of sand is that the air between the sand particles would lower the heat loss.
I use a block of Serpentinite (density 2.6), heated in a microwave, then surrounded with insulation in place of a hot water bottle. Like sand it has the advantage that it doesn't evaporate.
Then, the Bismuth in the Peltier Effect Device is going to melt at high temperatures.
But a higher temperature would give a greater thermodynamic efficiency.
With the sand being able to go as high as 1000 Celsius, does that mean the sand has the potential to hold 2 times as much heat?
That's very interesting, I wonder if a sand with higher specific gravity like Galena would be better than quartz? Would be good to get some more feedback on that
@@agritech802 Galena Sand is sand containing Galena - which is Lead Sulphide with small amounts of other sulphides maybe Antimony Sulphide and Silver Sulphide. It is the most common Lead ore.
I would not recommend Galena Sand for this application as depending on the temperature, it may decompose and emit toxic fumes.
Additionally according to Wikipedia, Lead Sulphide has a molecular weight of 240 and a heat capacity or specific heat of 46 Joules per mole. This translates to a specific heat of 46/240 or approximately 0.2 joules per gram whereas quartz sand has the value of about 0.7 - in other words quartz sand can hold 3.5 times as much as Galena per gram, so although Galena is more dense, as a material it will hold less heat.
@@richardamullens that's very interesting, thanks for the feedback, I may go back to the drawing board🙂
@@NdxtremePro Yes, with Sand you can hold twice as much heat - per gram as water heated to 100 C.
You would need to insulate it well though to reduce heat loss at this temperature.
Heat loss rises proportional to the surface area, whereas stored heat goes up by the volume. So heat storage in sand is favoured by having a large amount of sand.
Thank you for this interesting information and going over Ohms Law. 👍
here's a question: have you heard of compressed earth (dirt) bricks, and could they be used as an alternative to sand?
yes
Sand is much cheaper
@@hansscholte5472 the dirt's literally under my feet, I was just wondering.
@@hansscholte5472 it actually isn't "The global rate of sand use - which has tripled over the last two decades partially as a result of surging urbanization - far exceeds the natural rate at which sand is being replenished by the weathering of rocks by wind and water."
So thats why i couldnt trow out my old watter heater element...i knew that it will be usefull someday. Big thanks Rob!
never throw anything away mate lol
Could a sand battery {for heat} be combined with an accumulator {gravity/stored/potential}
yes
From someone with 0 knowledge of big brain stuff, sounds like your trying to make a time machine ey?!
From someone with 0 knowledge of big brain stuff, sounds like your trying to make a time machine ey?!
Brilliant Robert, I'd not heard about this before!
Fun videos as always! Thanks! Must add sand battery to list of projects now
I absolutely love it. I've been thinking about building a sand battery for a while now. I feel totally inspired and ready to build this now. Would be great for charging small devices
awesome mate - cheers
If you work out a way to bottle your enthusiasm then you have given the whole world an equally great gift to the wonderful knowledge you post. Many thanks again. "Knowledge is a matter of science and no dishonesty or conceit whatsoever is permissible. What is required is definitely the reverse - honesty and modesty." Mao Zedong :)
I was going to build a peltier device based generator intended to attach it to the outlet of an internal combustion engine which heats to 800+ degree celcius normally, in order to reclaim some of that huge amount of energy wasted in the form of heat (up to 80%) and use that energy to produce some hydroxy gas and feed it back to the engine, make it a little more efficient. But when I studied peltier devices and found out about their inefficiency when used as electricity generators (as low as 11% for the usual commercially available) I dropped the idea. A modern steam turbine on the other hand is said to be highly efficient, 80%. But even a 10kw turbine (smallest i could find) and the accessories will be a significant part of the investment. Anyway, another excellent video sir, thank you.
I am loving these sand battery videos. Keep them coming!
Cheers Robert I was thinking of charging a home leisure battery with my wood burning stove as the heat source. Just incase there is a power cut😉
I really like the idea of using a whole stack of peltier devices on a rocket stove sand battery. If you keep an eye on the burn time it would be easy enough to stop the sand getting too hot and frying your TEGs or rig a thermostat to a solenoid to shut down the air intake with a flap of steel or some such. That way you have a radiant room heater you can cook on and charge devices with. Be perfect Lukes offgrid ambitions.
for sure mate
Catching the sun's heat instead of the photons gives double the energy capture without the expensive solar panels and electronics. The sand battery is perfectly suited for this!
Another version is a climate battery typically used in greenhouses. Same principle, different application and materials.
for sure mate and cheers
Awesome video Robert. Thank you for a beautiful insight
I eagerly watched this hoping to find a DIY technique for generating 1752 Amperes of current - then realised "1752" is the episode number lol. Thanks for the video, really enjoyed it :-)
This is great. I would like to make one that i could perhaps heat via a rocket stove, because wood is free, but portable enough to put in the living room fireplace. Reason being because the is no corresponding chimney above (removed in bedroom) and hence no flue. Loving your channel mate.
that's a good idea mate
Great input. Well done. I've thought of having a house extremely well insulated (hay bale ? ) That makes use of passive energy for heat in the day. With an array of simple heat producing solar panels. The heat from the panels would go into a insulated room filled with columns of sand batteries. The heat from these would be used at night and possibly hot water. It's all in having a little fun.