Regulus KPG1H-ALC, Installation And Operation Manual

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(Tab. 2 is valid for elevation up to 20 m only, otherwise
the size shall be calculated.)
8.1 - Expansion vessel sizing
A solar expansion vessel shall be sized for a temperatu-
re difference between the min. winter temperature and
the max. summer temperature. The working range of
expansion vessels is from -10 °C to +130 °C. Further it
shall be able to contain fluid volume of all collectors in
case of stagnation (max. collector temperature at no flow
and high sunshine intensity). In solar thermal systems
with forced circulation such pressure expansion vessels
shall be only used that are fitted with a propylene-glycol
resistant membrane and whose min. working pressure is
6 bar. Installation shall be done in a position with the dia-
phragm flooded. In case the hear carrier starts boiling,
the diaphragm mustn’t get in touch with steam!
The recommended size of an expansion vessel see
Table 2 .
Tab. 2: Expansion vessel recommended size. Max. 30 m
of the inlet and outlet piping together.
8.2 - Calculation of a system working pressure
The pressure in the solar thermal system is calculated
using the relation
p = 1.3 + (0.1 h)
p…pressure in a solar thermal system [bar]
h…height from a pressure gauge to the middle of a col-
lector field [m]
Adjust the pressure by discharging solar liquid after the
pressure test is done.
8.3 - Calculation of expansion vessel preset
pressure
Before filling the system, adjust the initial overpressure
in the expansion vessel to a value by 0.5 bar below the
calculated system pressure.
p
exp
= p - 0.5 [bar]
In order to set the pressure, use a current car-tyre pres-
sure gauge of a suitable pressure range.
The expansion vessel has a current tyre valve under its
lid.
8.4 - Examples of calculating working pres-
sure and expansion vessel pressure
8.4.1 - An example of calculating system working
pressure
The height from a pressure gauge to the middle of a
collector:
h = 10 m
Pressure in the solar thermal system (the system is to be
pressurized to this value):
p =1.3 + (0.1 h) = 1.3 + (0.1 . 10) = 2.3 bar
8.4.2 - An example of calculating expansion vessel
pressure
Before filling the system, the preset pressure in the
expansion vessel shall be adjusted to the value of:
p
exp
= p - 0.5 = 2.3 - 0.5 = 1.8 bar
Number of
collectors
Expansion vessel
size
Max. piping
length
3 18 Max. 30 m of
the inlet
and outlet
piping
together
4 25
5 40
6 60
8 60
9 80
10 80
12 100
8. EXPANSION VESSEL SIZING AND WORKING PRESSURE CALCULATION
Fig. 27: Expansion vessel