Viessmann Vitocell 100-H Technical Manual page 15

Sizing
(cont.)
v = Number of similar draw-off points per similar residential
unit
w = Draw-off demand in Wh
v
(n · p · v · w ) must be calculated for each relevant draw-off point per
v
similar apartment.
With the aid of the calculated demand factor N, the tables on
pages 9 and 10 enable the selection of the required DHW cylinder at
the appropriate heating water flow temperature. For this, select a DHW
cylinder whose N factor is at least equal to N.
L
The demand factor N is identical to the number of standard residential
units in the building project.
Table 5
No. of residential Room factor
units r
n
4 1.5
10 3
2 4
4 4
5 5
Form for calculating the heat demand for DHW heating in residential buildings
Calculating the demand of residential units with centralised supply
systems
Calculating the demand factor N for determining the required DHW cylinder size
Project
Occupancy factor p based on statistical values as per table 5, page 15
1 2 3
Sequential Room fac- No. of resi-
number of tor dential
residential units
unit r n
groups
1 1.5
2 3.0
3 4.0
4 4.0
5 5.0
DHW heating
Occupancy fac- Amenities in the residential unit
tor Number, description
p
2.0 1 shower cubicle with standard shower
head
1 washbasin in the bathroom
1 sink in the kitchen
2.7 1 bath 140 l
1 washbasin in the bathroom
1 sink in the kitchen
3.5 1 shower cubicle with mixer tap and
deluxe shower head
1 shower cubicle with standard shower
head (in a physically separate loca-
tion)
1 washbasin in the bathroom
1 sink in the kitchen
3.5 1 bath 160 l
1 shower cubicle with deluxe shower
head in a separate room
1 washbasin in the bathroom
1 bidet
1 sink in the kitchen
4.3 1 bath 160 l
1 washbasin in the bathroom
1 bidet
1 bath 140 l, in the guest room
1 washbasin in the guest room
1 sink in the kitchen
4 5 6
Occupancy No. of draw-off points to consider (per
factor residential unit)
p n · p No. of
draw-off
points
v
4 2.0 8.0
10 2.7 27.0
2 3.5 7.0
4 3.5 4.0
5 4.3 21.5
It does not necessarily correspond to the actual number of residential
units.
Example:
For a residential building project, design the DHW system on the basis
of demand factor N.
The numbers of similar residential units, the room factor and the equip-
ment level listed in table 5 have been taken from the building plans.
The occupancy factor p was determined using the room factor r and
table 1 on page 13.
The number of draw-off points to be used in the design was calculated
using table 2 on page 13 and table 3 on page 14.
Project no:
Sheet no:
7 8
Initials Draw-off
demand
w
v
in Wh
1 NB1 5820
1 NB1 5820
1 BRL 7320
1 BRN 3660
1 NB2 6510
1 BRL 7320
1 NB2 6510
(0.5) NB1 5820
Apply for the demand calculation
No. of draw-off points, description
according to table 2 on page 13
1 shower cubicle (BRN)
according to table 2 on page 13
1 bath (NB1)
according to table 3 on page 14
1 shower cubicle (BRL)
according to table 3 on page 14
1 bath (NB2)
1 shower cubicle (BRL)
according to table 3 on page 14
1 bath (NB2)
1 bath (NB1) with 50 % of the draw-off
demand w
v
1 washbasin (WT)
1 bidet (BD)
9 10 11
Comments
v · w n · p · v · w
v v
in Wh in Wh
5820 46560 NB1 for
BRN
5820 157140
7320 51240
3660 25620
6510 91140
7320 102480
6510 139965
5820 62565 50 % w
to table 3 on
page 14
VIESMANN
4
acc.
v
15