Heat bank for under a kitchen worktop

[Doctor Drivel]

Depends on sizing. The size will be less than a conventional cylinder.

A heat bank is not a combi and many combis are more than adequate indeed. Cylinders do not have constant temperature flows due to stratification. Heat bank provide a more stable temperature delivery.

You size it up. You need to understand stratification, sending water into the cylinder hot and maintaining the stratification to ensure very hot water is always at the top. Then a heat bank, with the same stored energy as a conventional cylinder, will outdo it.

[Doctor Drivel]

Good point!

[John Stumbles]

Aah yes - that's the word I was looking for! ;-)

[meow2222]

Just think, you could make a direct contact boiler with 99% efficiency.

NT

[meow2222]

Out of interest, what would happen if one used a thin oil as the primary fluid, storing it at upto perhaps 150C? Tank size would be smaller, and the same volume of insulation would give thicker insulation, perhaps offsetting the greater heat loss.

Think I'd be inclined to avoid soldered joints though!

A bit more seriously, if there isnt enough space under the worktop, it would be poss to use a small secondary tank as well, hooking it up to work as the lower temp end of the setup. This would also be ripe for the later addition of solar heat if ever wanted.

NT

[meow2222]

And of course a drain heat exchanger reduces hot water requirement for showers.

[John Rumm]

You may have trouble getting the boiler to heat it to that temperature (without modifications to its sensors and software etc)

Also the specific heat capacity of oil lower than water...

[Andy Hall]

.. and other components made from plastic would likely melt

[meow2222]

And where mains water met the heat exchanger suddenly you'd be handling superheated pressurised steam.

Thinking about SHC, the storage tank need not store oil necessarily, it might have a fill of lumps of some higher shc material, with the oil run through it. Water sure is cheaper though, and has a very healthy shc.

NT