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This is really fantastic! The cleanest DIY build I've seen so far! I've been watching a bunch of different videos on this concept and a lot of them have the solar panels wired directly into the heating elements, no inverter or controller necessary. Do you know how long the heat is retained? I'm considering building something like this for a greenhouse to keep it warm at night. One additional thought I had would be to run copper piping through the sand to heat water to be stored as an additional thermal mass. Not sure if that would steal efficiency or not. Finally, would you be willing to share your schematics? Or sell them? I'm not a fabricator but I'm thinking I could send the design to OSH Cut to have them fabricate it for me. Thanks again!

I just got given a similar face mill. Appreciate you posting the vid - the vid and the comments will be very helpful when I try it out. 👍👍

Seems like this could provide stable heat for a chicken coop.

😅heat rises,Try heating from the bottom.

Very nice work. Looking forward to seeing the evolutions.

There's a reason they all use oil. I think you need ten times as much sand to make this efficient.

good work sir, nice unit you have there.

How much sand do you think that element could heat? I have an old keg I have been thinking about making a sand battery out of. I think it would take about 80lbs of sand to fill.

heating element use dc power for it ?

so how big of an area can you heat up with that? also whats the top temperature it reaches? in terms of the heat it radiates

I get that everybody is chasing the "Next Big Thing" but I have a legitimate question! How would a liquid mass (water / Glycol Water) compare for thermal storage?? As I see it, it would be much easier to move the "Heat" around to a different room with a water based system. I have even toyed with the idea of a "Cooling" system in the warm months using the same "MASS" for thermal storage. I am also considering just using AC power to power the "MASS" after the batteries have been topped off, and the dump load would then just be the AC circuits being controlled based on Battery SOC. Since any system I build and actually scale up beyond an experimental size, would include batteries, and inverters already!

Loved your dog! 😍 Thank you for sharing. What you are doing not only saves money but think about no smoke, no cleaning chimneys, being able to cook on the surface, run copper tubing inside to heat water. The possibilities are endless. I will be waiting for your next videos.

Fantastic, great job! I was thinking on a larger scale if copper tubing could be coiled inside and run cold water in, hot water out..... I am looking for ways to heat hot water other than using solar with battery backup. I love this concept. I plan to use an old wood stove to heat my greenhouse but will use sand and heating elements with the solar panels, love all these great ideas and inventions, keep them coming. :) I am just editing to add, this could also work as a cook stove!

This is awesome! Thanks for sharing the info! Only a prototype but it looks super polished. I’m excited to see what you turn it into! Edit: Oh I see you have more updates since this one. I'll have to watch those too now :)

A far easier and cheaper way to store energy like this would be to get a water heater tank and bury it and run insulated piping. You would get way better thermal heat storage, with lower temps meaning less chance of things breaking due to high heat. You could bury 2 tanks one as a fill and one as a storage.

l'hiver dernier j'ai essayé un truc. positionner sur mon poele à bois une marmite en fonte de 20l remplie de sable. j'ai aussi introduit 3 modifications. j'ai ajouté sur mon poele 3 briques réfractaires. qui ont le même effet et intention que la marmite : augmenter l'inertie du poele Et j'ai aussi changé ma manière de faire du feu: l'intention étant de générer un gros volume de braises. donc allumer le feu avec une buche pour avoir un 1er lit de braise ensuite bourrer le poele de bois attendre que la flambée prennent laisser 20mn de flammes puis régler le ralenti un peu au- dessus de la valeur habituelle( quand le poele n'était pas trop chargé) afin qu'un peu plus d'O2 passe puisque le volume du poele est beaucoup occupé et que la circulation de l'air est un peu ralentie. résultat : avant j'obtenais une température en chauffe constante d'environ 20° (18° les jours de très grand froid) et une baisse nocturne de température. au petit matin la maison était à 16 ou 14 les jours très froids et il fallait attendre 1h pour que cela remonte suffisamment. j'utilisais entre 6 et 8 stères de bois. Avec la nouvelle méthode j'ai obtenu toujours 20° voir 22° et le passage de nuit à 18° et surtout j'ai utilisé 5 stères de bois et rechargé le poele 1/3 de fois en moins donc beaucoup d'économie de combustible et de travail.

something worth looking into is using 24v elements directly wired to a 22.5v open circuit solar panel. super simple.

That's a very nicely made project! Could you mount the thermistor to the inside wall of the tubing? That way half of it is transferring the heat directly to the air and the other half is transferring it to the sand. This might keep operating temps a little lower and improve the life expectancy. Great concept and implementation!

Anyone else wake up every night screaming in terror? Just wondering

Water holds significantly more heat than sand

my two cents, heat likes to go up, so i think, if the fins would be vertically attached to base instead of side pillars, it would get better heat transfer to fins and would not need side pillars.

If you live in the Forest you could just get some metal buckets with sand and put it in the bon fire with good insulation for 1 hour then bring it in your house and it'll last all night.

I used 24 gage Nichrome wire with two 29 volt solar panels and builders sand in large terracotta pots. Worked great with heat left one after being outside on 40 degree nights. They can be very simple.

Do you hook straight to solar panel?

I tried this on a small scale for a cat house. Entirely ineffective at least in my location. Something like trying to heat up the ocean by peeing in it.

That Aluminum _Looks NICE_

Xcellent , re: "400-degrees" & _Aging of the components_ If the heaters ARE capable of "baking" things. I suppose the Connections/Leads are (maybe?) the weakest part of the design? So I suppose for *_Longevity's Sake_* Those parts have to be pritty rugged? (but I supposed you've already thought of that) This is a really Nifty build. It's seems actually *Very BulletProof already* This thing COULD Last for _years_ with no moving parts. if only the elements can Last Longer. Xcellent Concept

The issues you are having with the smaller heating elements: 1: heat saturation of the sand vs component durability. These smaller heating elements don't like being run at their upper limits for too terribly long. 2: Heat transfer through the heat exchanger isn't happening fast enough. 3: Aluminum is a good material but it needs some help in this configuration. Copper foil sandwiched into the interior of the heat exchanger (possibly wrapped onto the sides) should increase the thermal transfer rate sufficiently. 4: Heat charging the sand. Heat transfer from the heat exchanger to the sand media can be enhanced with the addition of copper powder mixed thoroughly with the sand. I haven't directly experimented with any quantities nor generated any data point's personally. I would think that it would be a safe bet to start at .5% by volume and go from there. 5: Fine stainless steel mesh could be used to create a higher content copper % core for greater thermal transfer to a lower % bearing copper sand mix including sand with zero copper powder added. Hope I helped even a little bit Sir. Please do post a follow-up video. I'm curious to see how everything works out! ~Daniel

Wouldnt it be an idea to use concrete instead of sand? You could make any size and form you want easy and even put in some copper piping to Blow air trough to extract heat?

what about using a heating element from a hot water tank?

What's the advantage of using sand vs oil?

Britain had these 65 years ago, but they were way more sefisticated than these ugly monsters, they were extremely well insulated with a fan that circulated the hot air out when required via a wall thermostat, they heated at night when electricity was half price.

build box between house wall so one side is out in cold -30C and half is inside so the thermal heating thing works

I used my original wood stove a Jotul , filled up dried beach sand x 5 ptc elements and it works great!! I put mine directly into the sand and made a huge difference keeping my living room nice and warm 🤙

Russia didn’t cut off power to European countries.

is all that heat (500f) generated by that single solar panel that's inside, under a roof? I'm try to size panels for my need. I was thinking about +400w panels (x2) to drive a radiant heater or a sand storage. I'm wondering the size I need to keep a basement "warm" (like +60f is my hope so not to tax my gas furnace as much) in the middle of Ohio winter.

Is this true for cnc milling too? No coolamt on carbide?

I would like to see a drawing of how you built tha secondary burn chamber nice job love the stainless parts been wanting to build one but I want all the bells and whistles on it when I do also a retired machinist

I think the appeal of sand batteries is that you can heat them to extreme temperatures, I don't think your little thermistors can handle that amount of heat, so you could probably use regular dirt, for sand batteries hot air may be more applicable.

A DC water heater element works good too

I wish I had a machine shop to make cool stuff! I love the design, very Art Deco....Jules Verne level look! If you ever see the control room for the Panama Canal, it's very Art Deco, Jules Verne brass and glass look.

I seen designs that uses a heating element for electric hot water tanks. Some use the common household 120v heating element. Some use the 12v heating element from RV and campers

love the idea of a sand battery! But if I see your video, I can't help but thinking, where can I obtain my own aluminum mill, to make such georgeous products out of milled aluminum, for other projects and ideas?

Any updates on this?

I think it would be interesting to try and somehow merge this with a solar thermal system with one of those evacuated tubes. They're quite a bit more efficient since you're keeping the heat as heat rather than having the losses of using electricity as a middleman.

Nice build!

Would be great to have a big one of these near your wood furnace to help stabilize the heat from wood.

something poorly understood is IR emissivity. if you paint the heater with black stove paint, it will put out significantly more heat. the shiny surface of metals, especially copper and aluminum suck at releasing heat into the air from a hot body. thats how mylar blankets work. painting it dark black with stove paint will help it throw more heat. if you only paint one side, you will get a net throw effect in one direction. i wouldnt paint the heat fins, since the insulation of the paint will actually impead the heat transfer to the air though conduction. imo i would use copper heat pipes instead of aluminium for the fins but thats up to you. they are not so expensive and can conduct way more heat than solid metal of a much larger size. they make them for cooling laptops.

more thermal mass man

No wonder the dog looks bored and disinterested, he's a Detroit Lions fan. Lol