Solar Coverage - Viessmann VITODENS 222-F Technical Manual

Design information

Solar coverage

70
60
50
40
30
20
10
300 350 400
Energy (yield) in kWh/(m²/p.a.)
A Conventional sizing for DHW systems in detached houses
DHW demand of apartments
The following details are required for an estimation of the required
solar collector area.
Determining the required solar collector area
Note
Select the solar collector area only within sizing limit
oversized solar collector areas can lead to stagnation.
60%
50%
40%
100 150
DHW demand l/d
A South 30°
B South-west 30° and south-east 30°
C West 30° and east 30°
D South-west 90° and south 90°
1. Determining the DHW demand (see page 65).
Assuming: 40 l/day per person ≙ 160 l/day.
2. Draw a vertical line to the required solar coverage (assumption:
50 %).
3. Draw a horizontal line to the existing roof orientation/inclination
(assumption: south 30°).
VITODENS
(cont.)
450 500 550 600
H , since
200 0 0.5
The solar coverage indicates what percentage of the annually
required energy for DHW and central heating can be covered by the
solar thermal system.
Designing a solar thermal system always entails finding a good com-
promise between yield and solar coverage. The higher the selected
solar coverage, the more conventional energy is saved.
However, this is linked to an excess of heat in summer. This means
a lower average solar collector efficiency and consequently lower
yields (energy in kWh) per m
DHW demand:
■ Standard demand: 30 - 40 l/day per person
■ Higher demand: 40 - 60 l/day per person
Example for the following sizing aids: Detached house with 4 occu-
pants, solar collector type Vitosol 300-T.
H
1 1.5 2 2.5 3 3.5
Collector area m²
E South-east 90°
F West 90°
G East 90°
4. Extend the intersection downwards and read off the required solar
collector area.
The example results in 2.5 m
5. Selection of the solar collector area that is physically possible:
In the example 3.0 m 2 .
2
absorber area.
A B
C
D
E
F
G
4 4.5 5 5.5 6
2
.
VIESMANN
5
65