Viessmann Vitocell 300-H Technical Manual page 26

Sizing
(cont.)
Calculating the required flow rate on the heating water side
= Flow rate on the heating water side in l/h
µ
HW
or Φ = Required continuous output in kW
²
req. req.
ΔT = Heating water temperature differential in K
HW
c = Spec. thermal capacity
1 kWh
860 l · K
860 ...
²
req.
= =
µ
HW
c · ΔT ΔT
HW
Φ 860 ... Φ
req.
= =
c · ΔT ΔT
HW
860 · 69
=
20
= 2967 l/h (total)
= 1484 l/h (per DHW
cylinder)
4
VIESMANN
26
²
req.
HW
req.
HW
DHW heating