Calculating The Required Collector Surface Area; H Dhw Heating/Loading; H Swimming Pool Water Heating - Viessmann Vitosol
100 Technical Manual

3.1 Calculating the required collector surface area

3.1 Calculating the required collector surface area
DHW loading/heating
Collector area
Estimates based on meteorological
conditions such as annual global
radiation, cloud cover etc. are sufficiently
accurate for practical purposes. In order
to obtain a comprehensive summary of
the solar coverage for DHW loading, it is
recommended that this estimate should
form the basis of a calculation carried out
using the Viessmann computation
program (available on request from our
sales branch).
The coverage determined by this
program should be 50 to 60 % for
relatively small systems (detached
house), and at least 30 to 40 % for larger
2
systems from approx. 30 m
block).
Guide values for estimating the required
collector area can be drawn from the
table on page 40.
The collector area calculated on the basis
of this table has proved to be accurate in
practice.
Swimming pool water heating
The heat demand for swimming pools
depends on the nature of the swimming
pool (indoor or outdoor), its cover and its
location.
With outdoor pools, the heat requirement
is substantially influenced by fluctuations
in the air temperature, variable cloud
38
DHW cylinder capacity (solar calorifier)
The following values can be used as a
basis for calculating the cylinder storage
capacity (according to VDI 2067):
Residential properties
High requirements
Average requirements
Basic requirements
(apartment
Hotels, guest houses,
residential homes
Room with bath and
shower
Room with bath
Room with shower
Residential homes,
guest houses
*1
Empirical value: 30 to 50 litres/(d · person)
cover, the thermal insulation of the
swimming pool and the required pool
water temperature.
With indoor pools, the heat demand is
influenced by ventilation, humidity, air
temperature and the required pool water
temperature.
The total DHW cylinder capacity (solar
calorifier capacity + standby reservoir
capacity) should be sized on the basis of
1.5 to 2 times the daily requirements:
Hot water
V
requirement
cyl min
V
p
V
litres/(d · person)
cyl min
(DHW
temp. 45 ºC)
*1
V
p
60 100
30 60
15 30
P
t
w
t
k
170 260
t
cyl
135 196
74 135
37 74
If you want to maintain the pool water
temperature (i.e. not heat it up), it is
possible to use the guide values for
calculating the collector area in
conjunction with the heat exchanger area
(see table on page 40).
2 @ V @ P @ (t * t
)
p w
k
=
* t
t
cyl
k
= min. cylinder capacity in litres
empirical value:
75 to 100 litres/(d · person),
including standby volume
= hot water requirement in
litres/(d · person)
(acc. to the table on the left)
= number of persons
= hot water temperature at the
tap
= cold water temperature
= temperature of the hot water
inside the DHW cylinder
(50 to 60 ºC)
VITOSOL