For those curious about what this actually looks like here are a couple of photos showing the Sunamp iPV in our kitchen cupboard. This is the smallest Sunamp size and provides similar hot water storage to a notional 70L cylinder. NB we have a 2nd unit which stores nominally the same as an 80-90L cylinder as well giving us a total of ~150L equivalent cylinder size. This is quite a modest amount of hot water storage but the re-heat time for the ASHP connected Sunamp is ~25mins so we generally have ample quantities of HW at all times (for 3 people). Oh and I also have access to the temperature data inside the Sunamp units thanks to help from @ben at Carbon Coop (see last image for details).
The scales are different on the 2 Sunamp temp guages because the ASHP unit operates to ~56C max and the iPV unit can go up to ~75C at times (very sunny days).
