Renovation - UFH + 2 showers

[Madrab]

There are other factors to take into consideration, the hot water will cool as cold is introduced therefore overall demand will rise to maintain temps. Is 8 mins 45secs long enough for a shower, depends on the user, I don't run a clock when I'm having one . Will there still be a need for HW after the showers, there's a lot to consider. You won't actually get 210L of 'hot' water, that's just the capacity of the cylinder.
It's always prudent to build headroom into HW capacity in a design when considering the max storage, may be an idea to consider a larger HW cylinder to give you flexibility, cold should be fine @ 50Gal. Water usage varies so it's difficult obtaining a true picture when calculating it down to the sec.

 

[Agile]

Since the stored capacity of this suggested design will hardly run both showers for 10 min each, that is hardly very adequate in my view.

But what has not been explained is just why taking two showers at the same time for nine minutes each is so essential?

Tony

 

[VXTfour]

Madrab, great information, thank you! I really appreciate the help you guys are providing.

Agile:. The numbers are just for working things out, I plucked 20l/min from thin air and just found a 210l tank because I was already on the site looking for boilers. This is a starting point to check feasibility. Why does it matter that I want to run two showers? We will all have different reasons for picking different setups. The point is: can I run them and HOW.

 

[Roger928]

But what has not been explained is just why taking two showers at the same time for nine minutes each is so essential?

Because it uses the system to its full potential that it was designed for.
Silly.