Comment by 3eb7988a1663

Supposedly water heaters are an amazingly good target for variable power. Water heating takes 18% of home energy use[0] and is already a well insulated storage device. Just heat it up as you are able with the day's sun.

If you are looking for a cooling solution, you could go the other way and make water chillers through a dedicated water tank. You would tie the HVAC to pipe air through a heat exchanger. Seems like all of that is well established engineering.

[0] DOE link on water heating https://www.energy.gov/energysaver/water-heating