Re: The Physics Behind the Spanish Blackout

On 14/06/2025 1:46 am, Liz Tuddenham wrote:

Bill Sloman <bill.sloman@ieee.org> wrote:
 

On 13/06/2025 11:02 pm, Liz Tuddenham wrote:

Don Y <blockedofcourse@foo.invalid> wrote:
>
>

We have 6.5 useful solar hours.  Likely something like 10-4.  Peak usage
(for the utility) extends to 7P.  I.e., refrigeration is in high demand
for the entire "peak rate period" (my numbers trying to demonstrate that
7PM isn't anywhere near the point where you could consider NOT using
refrigeration -- so 3-7 most definitely would also have a heavy cooling
demand)

>
Is there any way you could 'store cold' rather than electricity?  Use a
solar-powered heat pump during the hours of sunshine to cool a large
tank of water, then reverse the the pump , which could be powered by a
relatively small battery and inverter, to run water-cooled air
conditioning during darkness.  (A DC powered electric motor on the heat
pump might be even more efficient - just remember to replace the brushes
regularly.)
>
That way you could take your biggest load off-grid entirely.

>
Why bother? Storing the power in a "power wall" style battery does
exactly the same job, with fewer intermediate stages to waste power
along the way.

 The storage of energy (in this case below ambient) in a tank of water is
a lot less environmentally damaging than batteries of any kind and
water-cooled air conditioning is more efficient than air-cooled.

What's especially "environmentally damaging" about batteries?
And efficiency is all about the energy you have to put in to get the effect you want. How does using water as the heat transfer medium make the system any more "efficient"?
And there's the practical point that water-cooled radiators are going to be condensers, and you are going to have to deal with the water that is going to keep dripping off them. My air-conditioning system drips water out of the unit that cools the air that get circulated back into the flat. That's mounted on our balcony outside the flat (which also keeps the noise it makes out of ear-shot).
--
Bill Sloman, Sydney