Right!?- I saw a video with a guy doing a pool heater with passive solar; his whole setup was well thought out (he was probably an engineer), but when it came time to measure the temp of the water coming out of the heater he excitedly showed of his candy thermometer that measured up to 450F.
Don’t ever stop teaching RU-vid. Bought you a coffee because you are detailed, don’t waste time, and know how to state your theory or intent right up front.
When was the last time you saw 250°F water? One BIG benefit of sand is that you can easily go FAR above water's boiling point without a pressure vessel, giving you a way to offset the difference in heat capacity. Imagine 1000°F sand!
The only issue with this is ..sand for building is globally a resource under pressure. So best do some careful research.... as I told my gardening ex all soil is not mud..😂 Find out what's available and watch out for the unexpected.
You miss one point. But it’s otherwise a perfect demonstration of the principles of sand batteries. The purpose of making a battery is to store energy for you to use later when you want to use it. So putting in an insulated container is how you retain the heat for later and pipes would allow you to extract the energy when that time comes. Nice vid.
depends on where you put the sand container. If it's INSIDE the house, then DON't insulate it. If you put it OUTSIDE the house, then DO insualte it. You can't cheat thermodynamics
I was thinking about this as well. Presumably while the sun is out there is enough heat for the greenhouse and storing the heat for the night or for cold cloudy days will be more important. Maybe the mass needs to be big enough that it never hits a peak and levels out. That way the maximum amount of energy is stored and can be released more slowly as opposed to getting a max temperature for the watts available. I like the simplicity of the setup and it's a good video!
@@ursodermatt8809 Water brings with it a lot of complications. It boils at 100C so you don’t want to go beyond that unless you are ready to deal with steam and pressure. Corrosion. Leaks. Sand on the other hand can keep absorbing heat all the way up to ~1700C. The name of the game in batteries is getting maximum storage capacity out of a given volume/mass. A very elegant solution if truth be told.
I am probably going to try a similar experiment for this coming year (2024). Of all the questions and suggestions I’ve seen here, no one seems to realize that water can’t be heated above 250 degrees F or it just boils away. But sand can be heated to 1500 degrees F! I’m thinking I can build an insulated box outside the back wall of my 12x12 greenhouse to contain the sand battery, let it charge all summer long, and direct-connect the battery to the greenhouse with an insulated 3 or 4 inch PVC pipe. There would be a small fan that would turn on when the greenhouse inside temperature drops below 50 degrees and off at 70 degrees to recirculate the air from the greenhouse around the sand battery to reheat the inside of the greenhouse. The battery would certainly lose heat during the winter but it would still recharge during the day whenever the sun is shining to create the electricity for the heater element. Plus it would amass all that heat throughout the summer months and begin the winter with a surplus amount of heat energy stored in the sand. By the end of the winter I’m sure there wouldn’t be much surplus left - if any at all, but as the spring moves into summer it would start recharging all over again. I just want to keep my winter crops from freezing. I’ll have to see how this goes. I may need to have more than 1 or 2 batteries to make this last, but once I’ve got the numbers down it’ll be free heat all winter for my greenhouse. See “Polar Night Energy” for an example of how they are heating homes with a sand battery. Of course it’s just a matter of scale. My challenge is to find the right scale for my 12x12 greenhouse.
I think you are much better off using a small pump to circulate water through black tube on the roof and heat up 55 gallons of water or more. Check out my recent videos on this.
For optimal energy transfer from solar panel to resistor (heater) there should be done some trials with various values of resistors. Here was used, arbitralily, resistor = 15 Ohm. Since the solar panels have high internal resistance, and there is a voltage drop when they are loaded, first there should be measured voltage of 2 panels in series without load, and later adjusted the resistor to such value as to get the voltage under load close to 1/2 voltage of open circuit.
Good DIY demonstration of a sand heat battery. As you said water has a higher specific heat capacity than sand approx. 4200 J/kg/K to 830J/kg/K about 5 times. So 25 kgs of sand heated up by 500 Deg C would store 830*25*500 = 10.3 MJ not a lot, but the great advantage is it can be easily scaled up. Great video.
Hi thank you for that. It is good that you show us how to do it, however. I have been using immersion heaters as dump loads. To control our wind turbine. Over the years we added 5kw+ of Solar pv. The base voltage is 120vdc and the Dump load voltage is 138/9vdc into two tanks total capacity is 500ltrs +, each immersion is 2 kW. They are stepped to brake the WT seconds apart. It works very well with no problems since its installation in 2008. I would not dare tell you what to do but an accumulator of capacitors or batteries would give you a much better power range. You were working in the full Power of the Texas sunshine and if your sunshine range dips to 66% you will get no heat. With capacitors or batteries or both between the panels and the sand battery it will produce much more over a longer period. 55 years ago, they installed storage heaters in our dwelling houses. Some were 3jw.. They used economy 7 to heat the elements but the material used to store the heat were canisters of 4mm limestone chipping., dust free. 3 canisters approx 200mm in width sq and 500mm in depth. Made up a 3kw unit. Later on they used a fire brick of sorts. This is a much discussed item in renewable energy forums. Keep up the good work. Cheers.
If you need hot water, coil some copper tubing just below the surface of the sand. Then pipe it to wherever. It could be stream, so design appropriately.
This sand bank is kinda cool in a minimalistic way. Personally I would throw another $1250 at the system and get one of those DIY 12,000 BTU mini-splits with solar inputs and precharged lines that allow installation with a holesaw. No need for a vacuum pump. Unless it is very cold it will put 2-3 times as much heat into a space as resistance heating would and it's a solar powered air conditioner come summer with a seer of 22. It maybe the quickest ROI of any solar system. It can be hooked to the grid as well so even if the sun isn't quite enough it will draw the extra needed from the grid (or battery inverter) and for use at night. 2 grand and it starts making heat and AC at high efficiency and free when the sun shines.
@@texasprepperprojects In texas that $1000 or 2 if you needed everything would quickly pay for itself. Not as quick as a water heater element and a bucket of sand does but I'd bet a small fraction of a full system would take. I would think 2-3 years is not an overly optimistic guess. I don't know your rates but I remember your weather. The best feature in my case would be not lugging my window unit in and out every 6 months.
Totally agree. 240 watts is basically the same as 3 candles so for a little more money you could make something actually useful or for the cost of sand, solar panels and a pot you could have the heating ability of 3 candles.
@@scottjoyce85 - What you may not be visualizing is how easily this concept scales, compared to candles. If you want 2400 watts of heating capacity, you increase the number of panels, use them to heat more sand, and don't have 30 candles constantly burning down to nothing.
@jasonbroom7147 well obviously. But that's not what this video is. And it's still kinda silly to buy a solar array capable of 2400 watts and just heating sand. Never have an efficiency over 95%. If you have 2500 watts of solar then maybe a heat pump makes more sense and then we're talking like 300-500% efficient.... you also need to visualize that if you scale up the solar then you probably have to scale up the sand battery size..... won't be very portable for very long.
PV dump sand battery is also my current obsession. Debating whether to DC dump from the full array (175 VDC 34 A), take it from the 48V battery bank, or run it through my single-phase 120 VAC service. I've been considering pros and cons of each and keep coming back to 120 VAC as the most practical, in spite of the wear and tear on the inverter, etc. Would love to see more examples from the community here.
Britain had these 65 years ago, they were called block storage heaters, they charged at night using off peak electricity, they had a room thermostat that turned on an internal fan which would blow the heat out as required, they were discontinued because too many people bought them & off peak time ceased to exist.
Excellent! I would just put some fence around as a shield so not hit the hot pan by accident. I think if you can build a simple insulated box to put it in and out, it can hit peak temperature much faster. A smaller version with an insulation box would be great as a camp tent heater, where need less power from a smaller more portable panel, and will only use the heat at night. It's so simple any camper can do it!
The insulation on the cable is Butyl Rubber low energy heaters are called irradiant heaters as the heat is more lower temperature than say a 3kw fan heater
Love it brotha thank you for the update but believe it or not i do heat my house with sand in mass so we get very cold i see your points and i agree i have alot more solar then you have available along with the cost is alot higher then you spent but with higher capacity of weight comes more capacity to hold the pipes at 230degrees i really woukd love to send you out our sand battery to test and pick apart i could even come down with my campers sand battery and show you also im retired and my business partner does awesome so i could take the time away i have many friends in texas
Its a basic question he really was pretty deep with his answer i mean honestly hes still bias about sand batterys but its understandable in small scale there not really working because no one runs exhaust pipe threw it and noone is heating it with enough solar to heat it up to over 400c so no one actually has good data to show but they do work i heat my house with it and this guy is correct about alot of things minus running enough solar and sand content weight wise
You will not get your computed 8Amps in the example since those panels max out at 5-6A. Better to use direct formula to size the element resistance needed R=W/ (I x I) where W is power of pannels and I is panel nominal current 5A usually. 500W/25AA = 20 Ohm optimal. I would put 25 ohms to have it working even at 80 % of irradiance rather that designed for the peak power.
looks like you can add more sand to the pot... i would keep the wires at the bottom and run up inside walls .. can put inside metal garbage can with even more sand .👍👍 or use as a middle of day batteries full dump load . a insulated box over it that can be removed would save heat for later.
Great presentation. Basic Principles thought out logically that make good sense. I think this idea (concept) basically "as is" has so much potential for future development. The biggest obstacle being the effectiveness of today's Solar panel technology. As that technology improves (and it is) I can imagine scaled up versions of this basic design will be in a future niche of its own. Eg. Consider a building, with a sand filled, central back bone wall. Perhaps that same wall incorporating a "closed water" system with under ground heat sink. // Switch on/off between seasons.
I live in the south of Sweden. Our climate is similar to the northern states of the US (hence all the Swedish immigration to Minnesota and Illinois in the 19th Century) In winter time from december to March it can be temperatures down to -20. Mostly though it is grey and damp outside with temp +5 to -5 that time of the year. I have a cabin out in the woods and investigate and alternative and passive way to heat it. The climate is what makes me somewhat sceptical to this solution for myself. Besides that it is brilliant.
What a concise and applicable explanation of this concept. Anybody know where one might find more on this concept? I've been postulating on it for several years now.
What else would you like to know? Unfortunately I think this idea boils down to mass. You need a LOT of sand, like tons, to make a major impact on anything more than a hundred square ft.
I think I will try this in my chicken coops around the nest boxes, so the eggs are less likely to freeze. An insulated vent and tiny fan to the nest box bottoms. Great work, thanks. I'm still figuring out the whole electrical thing, it's always been hard for me to understand for some reason. I have some spare 380-watt panels I can use. I hope that is not too much for the element.
What is the voltage of the panel? That's the key thing to making this work well. You're probably better off using an electric dog bed or blanket for that purpose
@@texasprepperprojects It is the Hyundai 380-watt panel, Model Number HiA-S380HI STC Rating 380.0 Watts PTC Rating TBA Open Circuit Voltage (Voc) 47.80 Volts Short Circuit Current (Isc) 10.01 Amps
Nice, not just what you're doing, but how to work out what's best for your needs. I'm still trying to work through heat collection from solar ponds. You can get the surface area up at low marginal cost, but need mirrors in winter to bounce any low sun back on. Solar PV is much easier than all that wet stuff, plus there's no lost inertia with the heat batteries. Why ponds? e.g. pond liner, polycarbonate twin-wall cover, and mylar reflector. By the time you have increased the surface area with traditional "wet thermal" using copper pipes/ vacuum tubes etc, you might just as well use solar PV.
Great video, and good explanation of electrical theory. Small criticism. I want to maintain a min 15° c - max 30° c for my greenhouse tomatoes. ( PS, don't try growing tomatoes outside in Ireland), so I only need about 10 C of lift over the averages T in March- April. Thanks.
Bit concerned with the cardboard cover, there comes a point when the energy in matches the energy going out, hopefully before the temperature destoys the kit. Can't rely on active thermostats to stop your house burning down, needs inherent safety, which you're getting by not too much power for the pot.
I suspect you already covered this in another comment so sorry if thats the case but... I hear your argument around no need for conductive materials associated with the heating element... heat is heat... But I wonder if you'd get better distribution into the sand with a simple metal connection between the heating element and sand... More importantly, I wonder how quickly the heating element will burn out if it is not having the heat drawn away from itself as readily as it would in a liquid situation. The sand spreads the heat out I'm sure but SO SO much slower than a fluid that can circulate. Have you seen it overheat or blow out with this setup? Maybe it's truly a non-issue, but it would be a concern for me I think...
Water efficiently draws the heat out of the heating element and sand doesn't. Additionally water won't go above 212F while the sand does, as you measured. The higher operating temp burned out the heating element. You could find a high temp heating element but they would probably be expensive.
good explanation of the capability of sand batteries. I think its important to note that while water technically can hold more energy than sand thats only true in practical use while in liquid form. You can dump energy into sand a long time before your sand starts to boil away! I also think that you should explain that 240 watts of power is really only the same heating ability of 3 candles so don't expect amazing results.
That’s neat I didn’t know that could be done now why hasn’t anyone improved on it I’m tech savvy and I’m old so my point is some could make lots of money off a good idea it work so well here to much rain and over cast but love your presentation.
Would this work for a pool heater? Im picturing using solar panels as picnic tables with the sand battery hold it in place with these tables around the pool heater
there is a much better way to heat water thank this that is a LOT cheaper. Check this out instead. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ubIkEjnByrA.html
Will this keep warm overnight? I’m setting up a small green house now. I’m so glad there’s a safer way to heat it during freeze warnings. I was apprehensive about other forms of heating. Thanks so much❤
@@texasprepperprojects Not sure what you mean, one of these storage heater as big as a standard radiator can store enough energy to confortably heat a room for a full day. They use about 2.5KW .
How can you calculate how much sand to use? I am thinking about doing something like having say 200 pounds of sand maybe in a basement, the two panels heat that up and you let the heat leach out all night, maybe it heats the first floor floors of a small house and that has somewhat of a radiant effect. As you say this isn't going to heat your whole house with two little panels but with longer wire runs and the sunshine being free it might still be nice if it just took some of the edge off by acting as radiants floor heat on the first floor. Since this is just a bit of low budget boost and it's really "set it and forget it" that might be an interesting application. This would be good too if your basement had no insulation in the ceiling.
Green house is mostly made of glass so it will capture all 1000W of sun irradiance per meter squared instead of just few% of it limited by area of solar pannels and their 20% of efficiency. But capturing little extra in the bucket never hurts for a slow release over night.
Thanks, great information! Can you elaborate on how to choose the right heater, what parameters to look for? Looking at some heaters online they say don't use them without water... would any heater work with ac/dc or it has to be specific one, thanks in advance
That's hard to say. It is true that you need to have the heater in something when you turn it in. You really need to follow my math. Figure out how you are going to power it and work your way backwards. A 12v DC heater works, but they are designed to work on 12v.... so if you have a 37v panel from craigslist, you're not getting the best power out of it.
Well done, in particular I liked the lightning question round. Why necessarily couldn't you upscale this? 1 kilowatt to kilowatt worth of solar panels feeding into multiple elements of sand or some other median in a 55 gallon or larger container. Thinking wood stove replacement
You could. This is what they do in Europe. But I still don't think you can get it big enough to be practical enough for a house. I mean, I think for a 1,000sqft cabin you would need several tons of sand and thousands of watts of solar. In Europe they use geothermal heat for the sand. I just don't think that it scales up well without another heat source
You should try oil. This would heat your house scaled out. You can use oil and start circulation at night through radiators. Burry it underground insulated and done.
Water is much better than sand at storing energy. Water can store about 1 BTU / lb*degF vs sand at 0.2 BTU/lb*degF. What this means is, if you heat the sand from 75 - 600degF, and the water from 75 - 205degF, and you had 50lb of each, the sand battery would store 4180 BTU, and the water 7250 BTU. Sure, you can heat the sand higher, but at a certain point stuff gets dangerously hot, and you have to deal with more expensive materials to store it safely.
@@texasprepperprojects That's true. But they also make 200-2000W immersion heaters that are designed to be dunked into water for $20 on amazon. Yes, most are 120V, but you can put two in parallel. That in a 50 gallon drum will give you a lot of thermal storage, and it's easy to drain / use the water.
@@texasprepperprojects I'm not suggesting doing MPPT -> 120V. Do a similar thing to what you're doing, just run more in parallel. There's a 120V/2000W immersion heater on amazon that includes a temperature probe(!) for $21. Two of those in parallel would get you 1000W at 60V. (If you wanted 2000W you'd need 4). I'm also seeing 48V immersion heaters. 50 gal (400 lb) 'free' water vs $5 * 50lb *8 = $40. A steel 50gal drum would probably work for either. The nice thing about water is you can pump it through radiators if you want to speed up the heat dissipation. Another pro or con is that it's more thermally conductive; that's a pro if you want to get the energy out quickly, a con if you want to store it for a long time. And again, if you have to move it, it's much easier to drain 50gal of water through a hose pipe than it is to move 400lb of sand. I think both have their uses, for sure. The nice thing about sand is sometimes high temperature might be useful -- if you want to run a peltier / stirling generator for example.
Was just looking at ice cube makers, another way to store the solar energy. More of a challenge for a direct hook up. I don't know any more, except Texas shouldn't be needing space heating all year.
Ciao non so se hai già provato, ma se oltre le barre in alluminio aggiungi delle spugne di metallo otterrai una maggiore superficie di scambio aumentando la resa termica. Anche se devo considerare che avrai anche un minore flusso d’ aria. Poi ho notato che non hai considerato di isolare la parte esterna. Un giro di lana di roccia nelle ore serali ti dovrebbe garantire una resa maggiore. Tu giustamente fai notare che questo sistema non può certo scaldare casa, e vero ma tieni in considerazione anche di usare insieme ad un riscaldatore tradizionale pi puoi sensibilmente abbattere i consumi. Ciao e grazie per il tutto tempo che ci hai dedicato.
Compared to storage in water, DC isn't the best with any water around because of corrosion. A couple of years ago looked at plugging 400W of PV solar straight into my 3kW, 240V immersion heater. Couldn't see anything on the market to do a good conversion. Everything seemed to point to batteries with inverters. An experienced electrical/ electronics engineer could make something which doesn't use big capacitors and lasts. Basically after a DC to AC inverter with automatic voltage control for maximum power. The inverter for my 12V battery tries to keep the voltage steady, but if you draw too much current it trips out.
You don't need to do inverters for heating elements. A heater doesn't care if it I'd AC or DC. If you had 120v total of solar (4, 35v panels) you'd be set
How many Cubic Decimeter or Liter was the sand? In theory you can store 0,3Wh in 1dm3/K, hence if I have 1000l, with 120degC and want to take out energy until I have 30degC, I got 27kWh minus some losses. However, Heating up require a lot of more energy, which mostly depend on the insulation. Note: I need around 36kWh of energy (Underfloor Heating System, 34sqm), to heat my house in the Winter at -20degC outside temperature. I am Off-the-Grid in Estonia and I am ongoing testing a bigger thing with around 10m3, a Fronius Primo 4.6-1, a Fronius Ohmpilot with a 3kW Heating element. The rest of the Energy is used by my Victron MultiPlus-II 24/5000 for the rest of my property. Have fun P.S.: My next project for next year is around 600m3 under my Winter-Greenhouse, where the sand will be heated up to 60degC using a Fronius Symo 10kW, Fronius OhmPilot 9kW and an In-Flow Heater.
good idea . but would Magnifying glass pointing on the pot not produce more heat and if that pot surrounded with volcanic rocks make a better heat generating divice? we know magnifying glasses can set fire to wood ??? but applied to a pot filled with sand could be a safer bet of generating more heat from that pot?
whats the max temp of the element? does it burn out/break at some point? i bought a 550watt 120v charcoal lighter, along with many other resistave heating elements to start testing with. a couple of years ago i filled a 40 gallon trash can with sand, ran a copper coil pipe in the sand. planned on pumping water through this pipe down into the sane and the back up to a small heat exchange with a fan on the back side to help heat the house. its all still sitting here, but i have not done it yet and this was going to help me observe how this was going to work then scale up from there. batteries are expensive, but solar panels and sand is cheap, same with copper tubing and other misc things. water has a much high energy density, but it can only go to about 200f before it starts to steam then boil at 212f, but sand temps can climb much higher. i still need to figure out the amount of sand and the temp of the sane needed to heat the house for say 3 days in the coldest of cold winter days, it may end up being way more than what i am hoping for then in the summer maybe continue to cool zones with heat pumps.
it does. this is an ongoing issue i'm having with the sand battery actually. It ends up melting and coming apart. The heat exchanger thing is actually a waste of time. heat is heat is heat is heat. Copper tubes and fans don't make the heat any hotter. Just put the can of sand INSIDE the house and heat it up. Running it through air may make it heat FASTER but doesn't make it heat any BETTER / MORE. To heat an entire house? you will need literally TONS of sand sitting on top of a volcano. At best, you may be able to warm a ROOM.
i dont think you understand why i want to use a heat exchange. i am not wasting time on this. i plan on using the sand to store the thermal energy from solar during the day, then use water, pipes and heat exchange to pull the heat out as a source of heat for my basement. i understand how this stuff works more than you assume
I'm looking for a greenhouse solution. Just to keep things from freezing. I wonder if adding some solid stones, like a dense, smooth river rock mixed into the sand would help with the duration of the heat output. I'm in southern Arizona and right now the morning lows are hitting freezing and just below. The temp really drops quickly just before sun is up so stretching the time the heat is dissipated might be helpful. Thinking of building two units. One with the dense stones, the other without and experiment.
Could you run a copper pipe in and out of the sand that has water running through it and heat water this way along with generating power at the same time?
How is hot water generating power? Why would you do that when solar panels already creat e electricity? If you want to make hot water, use a solar hot water heater. If you want to make electricity, use solar panels. If you want to make a hot thermal mass, then you use the sand battery technique.
@@texasprepperprojects Is that the device you have wired between the panels and the heating element? Do you have a link? And thank you for the response This device looks like a project I could build to keep my plants from getting to cold. I live in Texas also and have harvested tomatos and haberneros the week of Christmas. This looks like something I could experiment with. I already have several solar panels.
Think beyond a greenhouse! This has many commercial, industrial, grid-scale, and even home applications. Anywhere heat is used for any purpose or with more effort and expense anywhere electrical power is needed.
I am kind of nervous when you don't process the equation to the variable you are looking vor! You were looking for current in Ampere. Why not writing: current = voltage / resistance?
heating element for 12 volt RV water heater Dernord makes 150W and 130W I have used my 14" SPARK pot belly stove. Also used a decorative 17" milk can. Both have places of honor in my bathrooms. My BUCK WARNER pot belly sits in the corner of the living room and has two electric range heating elements one above the other. I have heat fans on top to circulate air. All of them run on power supplied by solar power. The lady at the city office wanted to know if I had heat in my house. Yep, but the electricity portion of my bill is only $35 through out last winter. 😅
have you seen the 1/4'' x 1'' 40w 12v heaters for 3d printer 'hot ends'? i bought 10 and strapped them to my 10gl water bucket as a solar dump. they can get to 500f!
@@texasprepperprojects yeah but the other thing is they don't cost much, it's a nice way to heat things from 12v without conversion losses. I do also have a 240v element and a diesel water heater on a loop with the engine so i can even reclaim engine heat losses. (My build is in a camper) but I'm looking at ways to heat the living space as... well... winter...
Is there a better way of connecting the heating element with the sand? Maybe weld stainless steel fins to it? Just wondering as the device is normally supposed to be surrounded by water, if its surrounded by air and sand, perhaps its going to overheat? I was thinking additional fins would provide more surface area
yes, but a water tank heating element is designed to be in water, not sand, and the water never gets above 212F. The sand around the heating element will get much hotter, as the sand is no where near as effective as transferring the heat out and the element will now get even hotter, past what it was designed for.
It would be cool to do a DIY heated green house that charges batteries in the daytime and uses the batteries at night to heat, and maybe when there's a lack of power then draw from the grid.
Water can hold more energy at 195F and you can move it around wherever you need to with a small pump, tubing and a heat exchanger. You poured water into the sand for better heat transfer and capacity right?
Right, you can use an IBC with 1000l and heat it up to 60degC. With a temperature difference of 40degC, you have roughly 40kWh of heat energy. If you use a SandStorrage with the same energy. you can heat it up to 100degC and need with a temperature difference of 80degC 1,7m3 of sand I choose 100degC, because then you can put into the sand a stainless steal pipe and run water trough and use the heat as you wish
How long does it take to get to room temp? Was thinking it could be used to heat a tent or camper van at night. I don’t like the idea of the small diesel heaters that people use. Great job!
Well Clark course I picked the cloudiest day so far this month to try and build this thing so I have it all hooked up but we’re not producing anything so I’m not gonna know if it’s working until we get some sun. Can you wire directly from the solar panel right to that heating element?
@@texasprepperprojects I don't know much about the process, but find it really interesting. I guess it seems like an opportunity to pipe any hot water back down to the sand to store extra energy, but I really have no clue lol
Supporting heat for water tank? Like inline between woodburner and water tank? Thinking of a sand battery with insulation that goes along a suitable pipe
THought about doing this for my room which has no heater and has large windows so its always a few degrees cooler then then the rest. The idea was to use excess solar to do it but had no idea how long the heat would last and how much sand id need. From my experience sleeping on the beach, sands gets pretty cold quick at night so I didnt bother. Even the hot oil from my radiant heater gets cold in half an hour or so after its turned off. Youd need to cook a giant rock i think for hours to have it provide heat all night, and thats what they did with rocks in fires and put them under their beds back in the days, not surprising some warm sand wont do much. But its better then nothing, especially with excess solar might as well get some heat out of it, espesially to say transfer heat from a part that isnt getting and solar radiant energy, like the side of the houe not facing the sun.
if the problem is that your windows are single pane, then you're better off insulating them with pink foam and using an electric blanket. This is what we did in our old house during the Texas bizzard
texasprepperprojects explained the most crucial thing about your situation. Insulation (preventing heat to escape the room) is the most important thing. However , it can be costly and complicated to do (and you still can use his advice , or put some thick , multi layer fabric curtains for the purpose ). The next thing (and I'm talking in cost effective terms) is to use some kind of termal mass , like sand , or water , or heat bricks. Your oil radiant heater has low heat mass and puts out relatively low temperature , so , if you (for an example) brick it around (leaving one side open , for normal function during the day) , the time of heat radiation will be much prolonged , after you switch it off. Benefits of the sand battery that is displayed in this video are it's low cost , relative mobility and no cost to operate (if we exclude the cost of solar panels). It can be done with any metal container , or even clay pot , though , it can be troublesome to poke holes trough it (big , or small , depending on a need for mobility and the purpose - is it meant for heating room in the house , or permanent installation in the greenhouse , or chicken coop , or shed/workshop/garage...). Sand batteries can accumulate very high temperatures (which makes them better than water) , which can be used for longer periods of time , until all the heat/energy is depleted. If you have solar panels , or wind turbine , you'll easy solve this problem. Otherwise , it is all down to energy cost. Bear in mind , that in this video , solar panels produced about 240 W , but , during (let say) 8 hours , the amount of energy , stored as a heat is nearly 2 KW (1920 W). You'll get the same results , if you plug in the heating element of the same power rating (2 KW) in the wall outlet for an hour. If it has been done indoors , it will (probably) reach even higher temperature (than in the video). The rest is very well explained in the video , except the fact , that one can get low resistance heating elements , which are made for car/RV/camping use and there are , also , ceramic heating elements , that , usually last forever.
I know this is from 3 months ago, but could you do a video where you discuss the possibility of scaling this type of solution, along with the logistical challenges that would create? At some point, you're probably further ahead to use the current from a larger PV array to power a decent heat pump. Still, I'm wondering if something like what was demonstrated in this video, built to a 5x or even 10x size, could be housed inside of a thermal mass, creating a solar-electric alternative to a rocket mass heater?
I actually think that a 'better' option than anything else is to use a small DC pump to circulate water through a solar heater (basically black tubing). The TOTAL amount of money you spend on equipment and solar vs the amount of BTUs you would get from heating 55 gallons of water or more, I don't think can be beaten. Check out my other videos. I gained 20F in 35 gallons of water with a tiny pump and a pool heater. That's a lot of BTU for the dollar.
@@texasprepperprojects Right, the Black HDPE tubes/pipes start disintegrating above 70degC, hence in a ThermalStorage (Sand or underground) you can not archive more then 50degC otherwise it become soft and deform. Very Bad if you have 300m3 of sand on top. and then a 17x7m winter greenhouse on top. If I heat up the 300m3, I can get only the range from 50degC to30degC out and feed it controlled to the Underfloor Heating System of my house. this is 1800kWh of heat energy which would give me 50 days basic heating if they where no other losses. However, I have to verify the 50degC with the manufacturer of the HDPE pipe, maybe I can get 10 degC more
2 questions. Can you use wind turbines instead of solar panels And instead of sand container. Can it be hooked directly to an electric water heater's element where we can pump water to a radiator system?
You have a metal pot with hot sand inside, it appears not to be thermally insulated so a great deal of the electricity from solar panels is heating the air. Now that you have this heat in the sand what do you plan on doing with it?
Question: How long does the heat last once voltage stops? If you had that set up to heat up a greenhouse, how long would it continue to pump heat into the area once the sun goes down?
Check out the other series of videos where I actually test this out. Short answer, once they stop GETTING heat, they immediately start to LOSE the heat. About 5 hours.
Xcellent video :) I read below some discussion about the wattage of the solar panels themselves, and you stressed the point about the Voltage. Still, can the relationship between the Wattage of the Panel be correlated with the heating response of the element. I assume it can, and I assume it is related to both voltage and the Current that reaches the heating element. Can anyone here help me understand this relationship better ? Thanks.
A person could have a setup where they heat up this thing outside a camper, and then when the sun goes down, put the thing in the middle of the camper as supplemental heat. The cost of diesel will be lower. The amount of money saved may not make it practical ,or maybe it's so good diesel will never have to be used, so complete independence from fossil fuel could be possible. In addition, I wonder if it's practical to use direct sunlight to heat the sand. Concentrated sunlight with mirrors. I wonder if there's more efficiency from solar panels with electricity to heating element...however, efficiency might not matter enough because mirrors are so cheap compared to solar panels, one could buy 20 mirrors for the price of 2 solar panels.
The better idea is to put the sand inside and heat it from there. Just run the wires inside. Regarding using direct sunlight the issue is you have to be constantly re aiming your mirrors and such. Check out my videos testing parabolic mirrors and solar hot water heaters.
