1) Given the following tank of water with four heating elements in two groups, A and B, where the elements in each group are switched on and off together, what is the optimal way to heat the tank of water from cold (e.g. 10'C) to hot (e.g. 65'C)?
2) Once hot, what is the best way to keep the water in the tank hot?
The real life scenario is that I have an electric boiler which heats the water inside the tank and then when you want central heating it begins cycling around the system. For hot water it transfers the heat from the water in the boiler to the potable water on demand.
I run this thing for 10 hours a day, but I feel like that could be optimised (depending on usage, of course) but I'm trying to get my head around some basic stuff first.
Thanks in advance for any help!