Low Loss Header; Sizing The Solar Thermal System; Influence Of Alignment, Inclination And Shading - Viessmann VITODENS 242-F Technical Manual

Design information
(cont.)
Vitosol 300-T
Static height in
Absorber area in m 2
m
2
3
4

Low loss header

See technical guide Vitodens 200-W and 300-W.

6.6 Sizing the solar thermal system

Influence of alignment, inclination and shading

95
100
65
W 70
O
S
Shade reduces the energy yield
Position and size the collector array so that the influence of structures,
trees, etc. which create shadows, is minimised.
Installation options
VITODENS
System content in l Recom. expansion vessel
capacity in l
5 21.7
10 25.1
15 28.6
5 22.3
10 25.7
15 29.2
5 23.3
10 23.6
15 29.8
90
80
95
50
65
Recom. heat sink
(see page 73)
18 —
25
18
25
25 1.5 m uninsulated pipe
—
40 —
The yield varies subject to the method of installation of the collectors.
The highest yields result from south-facing pitched roofs. Compared
to this ideal, a roof with east-west orientation achieves only approx.
80 % of optimum yields.
Depending on application of the solar thermal system, we recommend
the following optimum angles of inclination:
■ Solar thermal system for DHW heating
30 to 45 °
This small angle of inclination takes the higher position of the sun in
summer into account.
■ Solar thermal system to back up central heating
45 to 60 °
Taking the lower position of the sun in spring, autumn and winter into
account.
The deliberately selected large angle of inclination in summer reduces
periods of stagnation.
For installation on walls or for horizontal installation on flat roofs, we
recommend sizing the collector area 20 to 30 % larger.
The Viessmann calculating program "ESOP" can be used to compare
different yields.
6
VIESMANN
75