Sand battery heater

Storage heaters aren't new. Been around in the UK since the 70s (with the introduction of economy 7 tariffs).
Just concrete / sand with heating element and insulation. I'm now intreged as to how hot they get!
 
You're a nice guy. I'll pay you a visit someday with an off-grid solution.
 
richjdavies said:
Storage heaters aren't new. Been around in the UK since the 70s (with the introduction of economy 7 tariffs).
Just concrete / sand with heating element and insulation. I'm now intreged as to how hot they get!
Click to expand...

Storage chillers are also common, and more relevant to our climate. Used on big buildings, and also on deep mines. See:
bbegroup.com

Mine Thermal Storage - BBE Group

BBE have designed, developed and constructed the following three different types of thermal storage for use on mine cooling systems. These include thermal
bbegroup.com bbegroup.com
 
I quickly checked the thermal capacity of materials and at #1 we have diamond which is about 5x more thermally conductive than the #2 item which is silver.

So simply get a 20x20cm diamond cube and heat it up, it should be able to store and provide a lot of heat overnight?
 
Speedster said:
But putting a m3 water tank in your bedroom isn't really feasible. Sticking a bucket full of sand on top of a closet is a lot more doable.
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If you have solar panels I'd imagine you have an attic or a space around the house.

And a cube of water will store 70kwh before reaching 80 degrees while a bucket of sand will only store 3kwh before reaching 450 degrees.

I personally wouldn't put a 450 degree bucket of sand on my cupboard either, when I can get the same storage capacity using two buckets of 80 degree water.

At the end of the day you're just dividing the space needed for water storage by half when going with sand. And you're doing that by adding a mountain of headaches and dangerous hazards.

Not worth it.
 
animal531 said:
I quickly checked the thermal capacity of materials and at #1 we have diamond which is about 5x more thermally conductive than the #2 item which is silver.

So simply get a 20x20cm diamond cube and heat it up, it should be able to store and provide a lot of heat overnight?
Click to expand...

Very funny, but thermal conductivity is not the same as heat capacity. This thread could derail like a typical MyBB one...
 
Gordon_R said:
Very funny, but thermal conductivity is not the same as heat capacity. This thread could derail like a typical MyBB one...
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Sand heat capacity is still lower than water by a lot. A simple example is the beach, at night how quick is that sand cold compared to the water?
 
Lupus said:
Sand heat capacity is still lower than water by a lot. A simple example is the beach, at night how quick is that sand cold compared to the water?
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Yeah but you can heat sand up to crazy temperatures while water should only be heated to around 80 degrees. So the useful storage capacity of sand ends up higher (if you're willing to risk third or fourth degree burns).
 
Lupus said:
Sand heat capacity is still lower than water by a lot. A simple example is the beach, at night how quick is that sand cold compared to the water?
Click to expand...

There are two sides to that scenario, and you can't really compare them. Water mixes freely, while sand is (mostly) rigid, and requires forced ventilation to reach deeper layers.

As I said early in this thread, thermodynamics is not simple, and a DIY project is unlikely to be of any value.
 
Maybe with steel shot or lead grit, it'll be much more effective at absorbing the heat

Steel shot like the type we use in our shotblast booth is tiny 0.2mm bits and is quite cheap per kg
 
Imo it is a waste of effort to do a sand setup

ie the season you would have the most excess is when you won't care for the heat you have saved up
Or may opt not to dump into it

Extra geyser dump makes sense just time shifted night time usage to day

But sure it you have exhausted all normal usage

And still have excess then by all means

But even then

Warming up the house while sun is shining with aircon/heater makes better sense your concrete floor/walls is just the "sand"

Adding extra steps for what?
 
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leon.davibe said:
Imo it is a waste of effort to do a sand setup

ie the season you would have the most excess is when you won't care for the heat you have saved up
Or may opt not to dump into it

Extra geyser dump makes sense just time shifted night time usage to day
Click to expand...
During the winter, I still have 5 hours of unused solar energy.

I don't have a geyser...
 
BBSA said:
During the winter, I still have 5 hours of unused solar energy.

I don't have a geyser...
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Yea f you ave that much excess it makes sense to want to use it

Depends on cost of materials imo

ie if the cost of setup comes close to the cost of a geyser tank i would rather do that

ie all season excess dump vs one

If cheap sure then you can do heat dump first

One size does not fit all
In the end your setup has to meet your needs

ie if the only need you have left to meet then sure that is where your focus will be
 
BBSA said:
I use quite a bit of gas to heat my house in the winter. It would be great if I could find ways to reduce that consumption using the spare solar energy.
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So you almost want that geyser plus some water radiators...

Very normal in Europe... Bit rarer here. What about underfloor heating anyone do that 'wet' here?
 
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