8 Function of the check valves [Expert]
2020/10
997655810x-mub-en – V08
27
8
Function of the check valves [Expert]
The check valves in this station prevent unwanted gravity circulation within their range of use.
The functioning of the check valves depends:
•
on the system height
•
on the temperature difference between storage tank and collector
•
on the solar fluid used
The diagram below indicates if the check valves integrated in the station are sufficient for your
installation. If the check valves are not sufficient, additional components must be installed to
prevent gravity circulation. You can install, for example, syphons ("heat traps"), 2-way valves
(zone valves) or additional check valves.
Example:
•
The station is equipped with two check valves per storage tank circuit
(2 x 200 mm wc = 400 mm wc).
•
You use a mixture of water and 40% strength propylene glyclol as solar fluid.
•
The installation height between collector and storage tank is 10 m.
Ins
tal
lat
ion hei
ght
in
m
Temperature difference between storage tank/collector in K
Result:
The check valves prevent gravity circulation up to a temperature difference of about 62 K.
If the temperature difference between the collector and the tank is larger, the difference in density
of the solar fluid will be so large that the check valves are pushed open.
Circulation
Solar fluid
