4 Dimensioning and planning
2015/12
996404631-mub-en - V02
9
4.1
Dimensioning of the tank
The following table helps you to calculate the approximately required volume of the buffer tank.
Temperature in
the buffer tank
Domestic hot water
temperature adjusted
at the controller
Required tank volume
for one litre of warm water
50 °C
45 °C
1.6 litres
60 °C*
45 °C
0.9 litres
50 °C
1.2 litres
55 °C
1.7 litres
70 °C
45 °C
0.7 litres
50 °C
0.9 litres
55 °C
1.1 litres
80 °C
45 °C
0.6 litres
50 °C
0.7 litres
55 °C
0.8 litres
Calculation example for the dimensioning of the buffer tank:
Temperature the buffer tank: 60 °C
Maximal withdrawal quantity needed: 20 l/min
Domestic hot water temperature adjusted at the controller: 45 °C
How large must the tank be to allow for a continuous withdrawal for 20 minutes without
reheating?
20 l/min x 20 min = 400 l
400 l x 0.9 = 360 l
The heated part of the buffer tank must have a volume of 360 litres.
