Viessmann VITOCELL 100-W - Page 21

2. Calculating the required heat-up output for the calculated cyl-
inder capacity:
700 · (60 – 10)
Z
A
²
A
= Φ
A
=
860 · 0.833
= = 49 kW
V · c · (T
a
– T
e
)
²
A
or Φ
A
= Heat-up output in kW
V = Cylinder capacity in l
c = Spec. thermal capacity
1 kWh
860 l · K
T
a
= Cylinder storage temperature in °C
T
e
= Cold water inlet temperature in °C
Size the boiler and circulation pump for cylinder heating according to
the required heat-up output.
To guarantee adequate heating of the building during winter too, add
this heat amount to the heat load. EnEV [Germany] permits this sup-
plement for the following reasons:
1. This is commercial utilisation.
2. There is no output restriction when using a low temperature boiler.
Sizing
(cont.)
DHW heating
VIESMANN
21
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