This is new to me and it actually works, looks promising:

  It sounds interesting but I don't think I really understand it, it seems to heat the water pretty fast.
Carl2

I like it. Can't find a price for this unit (5kW) but thinking of signing up to find out. One of the major hurdles with renewable energy is storage and another is moving the energy around. This could be a solution to both.

Would have to fit a fait bit of kit into your house but PV on the roof, inverter, Sunamp storage and all associated boxes. Probably about £5000 inc. installation to save £500 per year. 10 years for payback. These are guestimate ballpark figures. Interesting.

You hit the nail on the head there Snowy, agreed this is an energy storage system. One of it's main advantages seems to be the ability to recharge the cells many many times, unlike using rechargeable batteries that have a relatively limited amount of recharge cycles, these heat batteries should last for 50 years or more. Impressive.

If everything in the video can be believed and we don't know about price yet but ... one to keep an eye on. Us humans will always need hot water.

I like the idea of a portable energy store (container size) so you have instant hot water that can be recharged with heat or electricity. If they can use the heat to output electricity as well then a total winner to replace existing CHP units.

Not practical for me but a great product esp. for small town size projects.

This is a really cool application of phase exchange tech that I once thought of as a slightly interesting fad. When Grandma was alive, we had heating pads that used the same phase exchange material. Just click the disk and it started a process that not only generated a fairly large amount of heat, but also looked cool in the process. I'm glad to see that there are more relevant uses for the material.

  Since Dave mentioned phase exchange and I'm used  to state exchange like water and ice I think I have a better grasp of the heat battery, I've seen the hand warmers available but never tried one.  So I guess it uses solar electricity for heat that it can store and can heat the water that passes through it, it goes through the water heater but is already hot.
  It would be nice if it worked in the reverse mode and could provide a cold for air conditioning.
Carl2

Modern air conditioning already makes use of phase (or state) exchange, where a compressed liquid (usually freon, of one type or another) is atomized through a tiny orifice while simultaneously being decompressed. Trouble is, this takes energy, since the "boiling point" of whatever material used must be low enough to chill the air effectively enough to be useful, and the lower the boiling point, the more pressure the refrigerant needs to be under to get it to condense into a liquid in order to continue the process. I'm sure that one day we'll find a more efficient way to do this, but this particular technology hasn't changed in almost a hundred years, when we used alcohol to do the same thing back in the early 1900's.

  They already have an electric diode that will remove heat from on surface and transfer it to another surface, they used to sell small coolers for use in cars to keep food and beverages cool.   That was about 40 years ago when I first ran across them,  but look how long it took led lighting to get used to light homes and cars, about 30 years.
Carl2