Sand Battery Solar Water Heating Collector DIY version 2, How it's made.

For anyone who doesn't know this cheap DIY heating circulation system is intended to heat my greenhouse raised and insulated beds next winter.
This solar water heater will work in conjunction with my compost piles, which have also been converted via internal heating pipes into a heating source to supplement the heating which this solar water heater will also provide.
Daytime heating is provided by the solar sand battery and sun facing heating pipes in conjunction with the compost heating source, while night time heating will be provided by the compost heating system.
The goal is to grow tropical vegetables during winter, such as Ipomoea aquatica 'kang kong'.
This version has one continuous loop of aluminium pipe, swaged and solder joined together, with flux cored solder.
I detail how to solder join aluminium pipes using a few different solders such as aluminium brazing solder 4043, low temperature 400 degrees aluminium solder, and also standard plumbing solder.
I detail how to anneal aluminium pipes, using a vivid, and how to bend aluminium pipes by annealing and then filling with sand.
I show how I've swaged the aluminium pipes DIY style.
I pressure test the system DIY style.
this system is a big improvement on the first build, having no plastic, and one continuous loop.
I will test the system out after I build the new dual pile compost heating system.

[@gillquinn6767]

I started out as a metalwork teacher. Easy indicator for annealing aluminium is to rub a block of soap on it then heat until the soap turns black then allow to cool.

[@draculakickyourass]

Ohh,boy....As a guy who worked a LOT bending tubes for plumbing installations and air conditioners,my advices are to use copper pipe for AC and to bend it using a spring bender(cheap,it costs a beer or so).It would result in a single tube bended over the entire pannel. you can attach it to the pannel the same you did with those brackets and cover it with refractary cement plaste. It is black,exactly as you need to be and it have a high thermic transfer.Sorry for my bad english,greetings from Romania😉 Edit: For the heat battery you can use a tank isolated and filled with washed sand the in and out pipes need to have filters to avoid the sand to go thru the installation (same style as a sand filter of the pool). To wash the sand you can use that cement mixer you have there,load with sand,cover it with mosquito net and put a water hose over it.

[@DCAL084]

Maybe ill make a copper version in future to compare. Aluminium is much cheaper though.

[@chriswood1581]

Great job mate, it'll be very interesting to see how it performs. Is good to see someone bringing some proper data logging to these kind of projects.

[@DCAL084]

Cheers, Its good to hear that other people are interested in the data.

[@travismoore7849]

Solar water heater may work better with copper pipes and black sand in a foam insulated enclosure. Where the pips are on the bottom or center of the sand. The black sand acts as the solar collector. And the box slows the release of heat.

[@NdxtremePro]

It occurs to me, your biggest issue here is your design. The sand has a large surface area to lose the heat everywhere it is touching the metal. A more ideal situation would be to minimize the contact area the sand touches the metal, and maximize the amount of sand you have. A better design might be to build a box the solar water heater portion of this would be mounted to, insulate it and fill with sand. The use of a cube has the advantage the larger the size, the larger the mass of sand you can store while the ratio of sand that loses heat vs the total amount of sand is maximized for heat storage over the long haul. This gives you more and longer storage. I like this idea, I just don't think it will be very efficient.

[@evelynoclaret4689]

I was a little concerned about the mixed reviews, but I used it last year and hooked it up again this year and it was great kzbin.infoUgkx-izdrK3eF-HMvjzeBOxToD6Fx-4ulJUh . I couldn't get my 10' Intex pool above 76 degrees the year prior and last year I got it to 90 and had to put ice in it. This worked so well! I have just 1 mat hooked up to a 1,000 GPH Intex pump and it makes a significant reduction in the flow rate coming back into the pool, but that is to be expected with how far the water has to travel through the mat.

[@VRMediaI]

You could have Galvanic corrosion between the Aluminum and the corrugated steel.

[@alexnazarene3071]

Awesome. Would love to know what type of temps you are recording when it’s in the sun. Looking forward to the next videos

[@DCAL084]

Will keep it posted

[@kcbaskerville7084]

Yes

[@a.a.hofficial8021]

Hi sir, what do you can give me about mineral data for this project?

[@athinamargatina7271]

Is it maybe better to use a copper pipe for better heat conductivity?

[@DCAL084]

Yes, but copper pipes too expensive for my budget. Aluminium is still ok, but not as good as copper

[@athinamargatina7271]

And except of sand to use a % of vermiculite? Mix with sand?

[@DCAL084]

Sand is as far as i know a better conductor, (though both are not great conductors), plus the sand is very fine

[@slamdvw]

What app or temperature logging are you using?

[@DCAL084]

Jaalee temperature probes

[@FB0102]

Water would work better as a thermal battery than sand here. Water can hold about 5 times more thermal energy than sand, per weight. Sand is better than water in cases you need to heat it up at very high temperatures; where water would not work because it would boil; so sand is a better alternative there. But the sun won't heat it hot enough to boil, so water would be a better option.

[@unionse7en]

yep if he is ok dealing with water in a heating system he should definitely use it as the thermal battery, it can't be beat at those lower temps. Sand is pretty poor as a thermal bank at low temps (200f)...unless one is storing heat at electrical heating element temps and beyond 1000def F or so . But concrete or clay could be better than sand , depending on what is cheaply available. He should be learning about specific heats, volumetric spec heats, thermal conductivity.

[@donmcleod8307]

Why use sand? Wouldn't water be a medium to transfer heat? Nice work

[@DCAL084]

Water expands and evaporates, sand holds more heat and was easier to manage however water would transfer heat faster.

[@JB-vh7jy]

What size is the aluminum pipe?

[@DCAL084]

Its about 12 mm

[@JB-vh7jy]

@@DCAL084 thanks

[@forposterity4031]

Use flat paint instead of gloss. Any gloss will reflect heat.

[@DCAL084]

I was aware of that, i only had gloss at the time, i will go over it with flat black next month when i set it up.

[@velianlodestone1249]

This is actually a common misconception. - Gloss reflects heat as much as a matt paint; the reason it appears matt is because "Matting lowers the gloss/sheen by scattering the light in many directions leading to surface appearance less glossy." - but one thing you'll notice from that sentence - it scatters the light into all directions instead of a single direction.

[@DCAL084]

@@velianlodestone1249 ok, so in that case I wont need to use a matte paint. Im currently setting the system up outside at present, i will upload a new video in a few weeks detailing the new system.

[@gkatie248]

They have special black paint that heats up more and a different paint trap more of the sun rays. You can use both in this order to maximize results

[@mosesmanaka8109]

Who is this Neill you are talking about?

[@fionagardner4257]

Well as a pro welder, we use a wax marker and they come in all different temperature ranges, and also grinding aluminium on a grinding wheel as you have been doing is asking for a trip to A&E, your lucky that you have not had the wheel explode. a little knowledge is dangerous...........

[@DCAL084]

I had no idea!, useful information, luckily I didnt need to do too much aluminium grinding on the wheel so probably ok. Will definitely remember this in future...

[@arthurbalado6022]

DO not use sand. Sand has a thermal conductivity of less than 0.3 W/m.k, while steel wool has 45W/m.k that is is 135 times better at conducting heat. Better still use Aluminium Wool as a filler which should have a thermal capacity of 245W/m.k that is about 750 times better than sand. And if you need to use a high thermal conductivity glue try using Artic Silver adhesive which has a thermal conductivity of 7.5W/m.k. Sand is use for insulation in Casting to prevent heat transfer. Check videos to understand its usage. Sand is NOT a good substrate for thermal mass either. It is NOT recommended for Rocket Heaters as another example when NOT to use Sand. Good Luck with the project.

[@DCAL084]

Yes but air has even worse thermal conductivity than sand (0.03 W/(m K), thats 10 times worse than sand. Without the sand it would be air around the pipes. So in this way sand is better than no sand. Sand also holds more heat than air. The sand is giving me an extra hour of heating after clouds, this being 1.5 degrees C temp gain with no sun. I have the data in a video i will be uploading in a few weeks. As for steel wool and aluminium, great idea but expensive and heavy. I am currently planning on trying oil instead of sand for the next version later on. Edit: sand here has high quartz content

[@thehazelnutspread]

You may not be aware that they are using sand batteries to heat an entire town in Finland. This idea is starting to become very popular.

[@MrToni99]

Sand battery is a nonsens..when the sun goes down, the useful charged energy remain only a few hours...and this is not much..

[@DCAL084]

The sand works as a battery only during daytime, when the sun intensity drops, such as when it clouds over for a short period. Like a capacitor.

[@41546able]

To muck BS

[@mohammedmurad3787]

you main too much B.S. I DRINK TO THAT .

[@marco-me1uh]

this is not sand battery...

[@DCAL084]

Its a hybrid sand solar heat battery

[@Zootalaws]

@@DCAL084 denotes energy storage. A sand battery usually stores heat for many hours - yours doesn't seem to be storing anything for any appreciable length of time as any heat contained in the sand will be given back to the water and steel almost immediately. You've made a relatively inefficient solar collector, but have mixed up a bunch of tech in the process. If you look at a closed-circuit Solahart hot water heater, it's a basic plate collector filled with mineral oil and utilising a simple heat-exchanger coil in a tank of water. No pressure, no need for multiple materials, no need for pipes or bends. Insulation is effected by the air surrounding the plate collector inside a weatherproof glass-fronted casing. I've measured the mineral oil at over 250C in Western Australia and the heat exchanger caused the water inside the tank to boil I get what you're trying to do, but think you've over-engineered what should be a very simple thermosiphon collector. If you want to see how efficient a mineral-oil collector can be, go and buy the biggest truck or bus radiator from a wreckers and fill it with oil - any kind of oil - the cheaper the better. Join the outlet to the inlet for a proper siphon effect. Spray the radiator matt black and stand it in the sun. Even in Canterbury it will be too hot to handle in under half an hour.