Re:Giant 'sand battery' holds a week's heat for a whole town
by pi-e-sigma on Thursday March 14, 2024 @04:58AM
(#39701700)
Typical residential air conditioning is using 4kW of power. So your 40MJ of energy would be used up in 40MJ/4kW=10000 seconds, or just 3 hours. And its only theoretical, because it assumes 100% efficiency in storage and conversion
Re:Giant 'sand battery' holds a week's heat for a whole town
by llm_trw on Thursday March 14, 2024 @07:19PM
(#39710158)
It's odd how often battery enthusiasts don't understand the difference between energy and power.
Re:Giant 'sand battery' holds a week's heat for a whole town
by nimos on Thursday March 14, 2024 @07:13AM
(#39702431)
Air conditioners have a COP of about 3 though. So really its more like 3.5kwh of storage. If you want to go lower temperature to store more then your COP drops.
Re:Giant 'sand battery' holds a week's heat for a whole town
by dragontamer on Thursday March 14, 2024 @08:09AM
(#39702826)
The temperature delta is the hard part for me to estimate here.
I know that IceBear left the water around 45F, so take that for what you will.
Either way, we aren't talking about entire swimming pools here. Just a small, single digit number of cubic meters of water.
Or in other words: 11kW-hrs of cooling, comparable to an entire Tesla Powerwall.
We aren't talking about entire swimming pools here. Just a few cubic meters of water. Shift the temperature delta as you see fit but... It's actually very space efficient.