Sizing The Solar Expansion Vessel - Viessmann VITOCAL 300-G Technical Manual

Design information
Heating stops when the temperature differential between the collector
temperature sensor and the cylinder temperature sensor (solar) is less
than half the hysteresis (standard: 6 K) or when the temperature cap-
tured by the lower cylinder temperature sensor equals the selected set
temperature.
Solar swimming pool water heating
See "Vitosol" technical guide.

Sizing the solar expansion vessel

Solar expansion vessel
Construction and function
With shut-off valve and mounting set.
3
A Heat transfer medium
B Nitrogen filling
C Nitrogen buffer
D Safety hydraulic seal min. 3 l
E Safety water seal
F Delivered condition (3 bar pre-charge pressure)
G Solar thermal system filled, without heat effect
H At maximum pressure and the highest heat transfer medium tem-
perature
Specification
a
Expansion vessel
A
B
Details regarding the calculation of the required volume see "Vitosol"
technical guide.
VIESMANN
58
(cont.)
a
Part no. Capacity
7248 241
7248 242
7248 243
7248 244
7248 245
A solar expansion vessel is a sealed unvented vessel where the gas
space (nitrogen filling) is separated from the space containing liquid
(heat transfer medium) by a diaphragm and the pre-charge pressure
is subject to the system height.
Ø a b Connection
l mm mm
18 280 370
25 280 490
40 354 520
50 409 505
80 480 566
Weight
kg
R ¾" 7.5
R ¾" 9.1
R ¾" 9.9
R1 12.3
R1 18.4
VITOCAL 300-G