Sand battery heater

So I will need to use electricity then the sun is down?

This 12V one only uses 7.5W

 
So I will need to use electricity then the sun is down?
Get circulation wilo type pump that only uses like 20w a low speed the one i have is 3 speed unfortunately my killawatt type plug packed up so can't measure what it uses on speed 2/3
 
This 12V one only uses 7.5W

That is not bad.
 
If you have sand battery inside you can just let it lise heat to area around it without circulation pumps
 
Again, how long will the 150l of geyser water heated during the day stay hot while circulating in the radiator at night?
 
Again, how long will the 150l of geyser water heated during the day stay hot while circulating in the radiator at night?
25 Years ago, I had the 500w panel heaters in the bedrooms running 24/7/20. They take the chill out of the room and contents. You still had to wear a jersey etc. The oil multifin heater heats up a room quite quickly but uses a lot of power.

Thumb suck - If you keep the doors closed and let it warm up during the day - 150l with insulation on pipes etc should gain you a couple of hours. If you are starting off cold - I would guess less than an hour. Size of room, type of curtains and bedding will give different results.
 
25 Years ago, I had the 500w panel heaters in the bedrooms running 24/7/20. They take the chill out of the room and contents. You still had to wear a jersey etc. The oil multifin heater heats up a room quite quickly but uses a lot of power.

Thumb suck - If you keep the doors closed and let it warm up during the day - 150l with insulation on pipes etc should gain you a couple of hours. If you are starting off cold - I would guess less than an hour. Size of room, type of curtains and bedding will give different results.
That doesn't sound to promising.
 
That doesn't sound to promising.
Doesn't matter whether you're heating sand, water or strawberry milkshake.

You get out what you put in.

Roughly.

So if you have 10kwh of excess power going into your water during the day, then at night you will get the equivalent heating output of running a 1000W electric heater for 10 hours.

If you have 5kwh of excess power then you get the equivalent of running a 1000W electric heater for 5 hours, or a 500W heater for 10 hours.
 
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Doesn't matter if you're heating sand, water or strawberry milkshake.

You get out what you put in.

Roughly.

So if you have 10kwh of excess power going into your water during the day, then at night you will get the equivalent heating output of running a 1000W electric heater for 10 hours.

If you have 5kwh of excess power then you get the equivalent of running a 1000W electric heater for 5 hours, or a 500W heater for 10 hours.
The actual energy you get out depends on the efficiency of the storage and retrieval process. Some energy is typically lost due to heat loss, especially when using thermal storage systems.
 
I think the real problem here is that we don't have a great solution for heat<->power conversion, too much power is lost with heat. That's why on larger scale they use other means such as mechanical<->power. For example use power to pump water up a mountain, or to raise a giant weight.
 
The actual energy you get out depends on the efficiency of the storage and retrieval process. Some energy is typically lost due to heat loss
As long as your storage tank and the pipes going to your radiator are in your house, that heat is not lost as it goes into your house.

, inefficiencies in conversion (like converting electricity to heat),
Heating elements have a 1 to 1 conversion ratio. They are 100% efficient.

or other factors, especially when using thermal storage systems.
The only thing I can think of is the ~10W you need to run the circulation pump.
 
I think the real problem here is that we don't have a great solution for heat<->power conversion, too much power is lost with heat. That's why on larger scale they use other means such as mechanical<->power. For example use power to pump water up a mountain, or to raise a giant weight.

He wants to warm up his house in winter. So he doesn't need to convert heat back into electricity.
 
He wants to warm up his house in winter. So he doesn't need to convert heat back into electricity.

My point was mainly that storing the power as heat is wasteful.

If I had to do it I'd rather look at some pipes on the roof that pumps down to underneath the floor or into a room at night.
 
A sand battery can go inside my bedroom, so any energy loss will go inside the room.

Like I said earlier, 1 bucket of sand going from 20-450 degrees has around the same energy storage capacity as 2 buckets of water going from 20-80 degrees, and the water only weighs slightly more (storage capacity of 1.6kg sand = storage capacity of 2kg water).

So to match a 150L geyser holding 150kg of water you would still need 75L of sand which weighs 120kg.

Don't see that going on top of any cupboard...
 
My point was mainly that storing the power as heat is wasteful.
He has excess solar power that he isn't using.

If I had to do it I'd rather look at some pipes on the roof that pumps down to underneath the floor or into a room at night.

Pipes on the roof cool down as soon as the sun stops shining on them. Also, in winter they wont even heat up.

That's why solar water heaters use vacuum tubes.
 
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