4 Dimensioning and planning
2017/07
99640141x-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 set at the
controller
Required tank volume
per litre of hot water
50 °C
45 °C
1.6 litres
60 °C*
45 °C
0.9 litre
50 °C
1.2 litres
55 °C
1.7 litre
70 °C
50 °C
0.9 litre
55 °C
1.1 litre
60 °C
1.3 litre
80 °C
50 °C
0.7 litre
55 °C
0.9 litre
60 °C
1.0 litre
*Calculation example for the dimensioning of the buffer tank:
Temperature of the buffer tank: 60 °C
Maximum withdrawal quantity needed: 20 l/min
Domestic hot water temperature set at the controller: 45 °C
How large must the tank be to allow for a continuous withdrawal during 20 minutes without post-
heating?
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.
