1752 A DIY Sand Battery - The Theory, Practice And Use

foreign [Music] batteries they're the up and coming thing and they're super interesting and they're super interesting because they can store heat now the best way of thinking about a sand battery I think is to think about a hot water bottle with a hot water bottle you boil some water pretty quickly and pour it into the bottle these things are kettles they're about three kilowatts or so so you turn it on for five minutes get it boiling pour in your hot water bottle that hot water bottle will stay warm for absolutely ages the reason is we put a lot of energy into the water and that energy is going quickly but by its nature it comes out slowly so you get the same amount of energy out as we've put in it's just we've changed it we've changed it from quick to slow and of course that makes hot water bottles immensely useful if you've got backache or stomach aching really popular but water well it's great but it has its limitations one thing is you can't get it hotter than 100 degrees Centigrade because well it just boils away I mean you could put it in a pressure vessel but then you need a pressure vessel so water has severe limitations and there are better materials around turns out sand is pretty awesome for taking our energy in quickly and letting it out slowly and of course this stuff you can take six seven hundred degrees centigrade no problem at all so you can get an awful lot of energy in there now there are better materials that will do a much better job the limitation on them is they're a bit more rare and they're certainly more expensive this stuff of course is absolutely everywhere I mean it's dirt hence it's Dirt Cheap so it's really cheap really available does an excellent job and that makes it an all-round winner for a commercial installation of a sound battery and for syncing about sound batteries because sand batteries in the same way a hot water bottle take the energy in quickly let it back out again slowly we should get an awful lot of ambient heat from something like this where we can charge it up from maybe the men's or from maybe Renewables particularly wind that requires something like this so what do we need to do that well I pointed out earlier I've got a kettle this is a normal domestic Kettle that I've got from my local supermarket for five pounds it never ceases to astonish me how cheap these things are right in there you can see a heating element let's take that heating element out so in here there's some of this stuff this is resistance while it's the kind of one that you find in a toaster it's in your oven it's in a hob if you've got electric hob it's in a kiln it's in a vape cigarette and the property of this so when you put a current down it it'll get hot I've strung some there which is a bit difficult to see but it's right there and if I turn this up to 12 volts huh okay I'm applying a DC current to 12 volts it's about two and a half amps going through it that wire is getting hot I mean it's a bit hard to see it but if I have a bit of polystyrene then I can cut through that polystyrene with that wire there we go and that is how a polystyrene wire cutter is made so all of this stuff is made from basically the same thing and it doesn't matter if direct current or alternate current goes through it what you need to know is what is the resistance then what is the voltage and that'll give you the amount of amps that you need to draw because it follows Ohm's lawn it follows Ohm's law if it's DC or AC because it's a straightforward connection and it doesn't matter if you connect one end to the negative or the other end to the negative as long as there are two wires attached to it and you put a current down there that wire is going to get hot and that is called up in that now this has about two ohms this is about 26 ohms it's not just a coil of wire in there it's also packed with manganese magnesium oxide and the magnesium oxide is an insulating layer and then of course we have this metal pipes around and in this case it's stainless steel to protect it from the water but all that is is a coil of this stuff in a bit of pipe okay let's review that for a second because it is kind of important there is a relationship between volts and current and resistance and of course that's Ohm's law V equals IR where V is the volts I is the current in amps and R is the resistance or another way of looking at it is the voltage divided by the resistance equals the current drawn so when this was in a kettle it has a resistance of 26 ohms so let's make it simple and call it 24 ohms just for the calculations when it was in a kettle we plugged it into the men's at 240 volts for example so 240 divided by 24 is clearly 10. so it would draw 10 amps now if we take this and attach the same thing to a 12 volt battery so suddenly instead of having 240 volts we've got 12 volts and it's now 12 over 24 because the resistance is still 24 ohms and of course it's now going to draw half an amp so we can draw half an amp safely on this we know we can because we can draw um 10 amps safely on this so a half amp absolutely no problem at all now the issue is of course that um the power watts is volts times amps so when it was then plugged into the men's at 240 volts we're taking 10 amps it was to 2.5 kilowatt Kettle now we're going to plug it into 12 volts and it's half an amp it's dropped down to 6 Watts so this is a six watt heater if we put it onto a battery when we put it into a kettle and plug it into the men's it becomes a two and a half kilowatt Kettle the only thing that's changed is the voltage once we change the voltage and we keep the resistance fixed then as the voltage goes up the amps will go up as the voltage goes down the amps will go down and it's easy to calculate using ohms or what it's going to be so you just measure the resistance of this remember these things it's just because of why it doesn't matter if it's on the men's AC or if it's on the 12 volt battery we can use that as a six watt okay fascinating stuff but big whoop what can we do with it well we can use it to make a sound battery so here's my here's the element at the kettle if I clip a wire on there obviously if you're going to make this permanent you make a permanent clip and another wire on there and what I've got here is a cactin and the cake tin there's a little sand in it now pop that into my cake tin and add more sand over the top what we've got is a sand battery okay there's my sand battery and I put that onto a power supply alternatively a battery or something like that and turn that up to 12 volts there is it is indeed drawing half an amp actually 0.42 now what's going to happen there is that's just going to heat up it's going to heat up at a rate of about six watts and it's going to get hot it's going to get as hot as it can get and that's in hundreds of degrees with sound instead of with water which would only be 100 degrees so the longer you leave that head to heat the hotter that's actually going to get right the way up there as long as it's not giving the heat out okay so that's got nice and hot it's actually about 200 degrees Centigrade hence the gloves and of course you want to get the energy back out because that's a bit hot to be going putting on your belly button because it'll sting so the traditional ways of getting the energy out are basically to put a coil of copper in there and run some water through the water is obviously going to heat up and then you can use that hot water to do stuff that's one of the ways of getting energy out another way is to actually attach a um Sterling engine if you attach a stirring engine to it of course it's gonna keep running what I've got here these are what's called a Peltier device you find these in the little home fridges that you've got and if you apply a current to this it'll create a hot and cold side if you have a hot and a cold side it will drive a current right here is a big block of aluminum nice and cold here I've got my pelity device I'll pop that on there cold side down Hot Side Up and then we're going to pop that onto the device now device I've got attached earlier will have attached to this little motor here and as we lower that on that motor is going to start turning and there we go the motor turning like crazy and that will turn for some considerable time while there is a heat difference created here from the heat that we stored in that sand and we're now reconverting it back to electrical energy and that is why it's called the sand battery because that's gonna run for some considerable time now of course we're just doing a demonstration model so you can see the idea we can talk about the theory you see the parts that it's made up of but clearly we're just letting that in the ambient air we get much more out of this if we put a thick layer of insulation and obviously I'm wearing gloves that's pretty hot so you would want to put something on there to stop you having to touch it or go near it or burn yourself accidentally obviously and you'll notice it's not actually plugged in so there's no trickery going on it's just hot sand and a Peltier device you arrange that on my burger says Sterling engine or something like that you are going to have a sand battery that you can charge now obviously that charging you can do it from the mains right during offbeat periods you can do it from Renewables and then you can reclaim the energy it's more traditional to reclaim the energy by running the copper and using the heat energy that's in but that heat energy can buy directly translated into or back into electrical energy a problem with patio devices is they're not very efficient to in this Arrangement is not a very efficient way of doing it which is why they tend to do the hot water and as I say this is only a demonstration other things you'd want to do is certainly include insulation you'd probably want to include some kind of control of the heating and that's easy enough you can get these things which are called thermal cut-off switches this one's 200 degrees Centigrade you put that in series with the supply and just cut it off when it gets that temperature and less than a pound for something like that this thing is a microcontroller temperature controller it's about um three pounds and this runs up to 120 degrees same thing you stick that little sensor emptier sand while that in series it'll cut off the supply once it reaches its temperature now it's very traditional in wind turbines to have something called a dump load which is basically just a resistor instead of having a resistor if you put that resistor in sand and remember that heating element is nothing more than a resistor you put that in sand then you can capture the heat that you would normally dump when a wind turbine is going too fast so there's just so many uses for this you could either use it as an emergency store you can convert it into heat hot water it can convert it back to electricity you can use it to save energy from a wind turbine that you normally throw away fascinating thing how you might actually make one I hope you enjoyed the video thank you very much for watching and please do remember to like And subscribe

Channel: Robert Murray-Smith

Views: 276,456

Keywords: sand, battery, diy, how to, robert, fwg, tnt

Id: Icai6OOIh2M

Length: 12min 13sec (733 seconds)

Published: Sun Nov 20 2022