4 Dimensioning and planning
2014/11
99640766x-mub-en – V03
11
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
1.3 litres
60 °C
45 °C
0.8 litre
50 °C
1.0 litre
55 °C
1.4 litres
70 °C
45 °C
0.7 litre
50 °C
0.8 litre
55 °C
0,9 litre
80 °C
45 °C
0.5 litre
50 °C
0.6 litre
55 °C
0.7 litre
Calculation example for the dimensioning of the buffer tank:
Temperature buffer tank: 60 °C
Required withdrawal flow rate at the tap: 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 reheating?
20 l/min x 20 min = 400 l
400 l x 0.8 = 320 l
The heated part of the buffer tank must have a volume of 320 litres.
