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26
Victorum EAHP Unit
Piping
Worked Example:
Using the above calculations and an example system volume of 200 litres;
•
A 8L expansion vessel pre-charged to 0.5 bar is sufficient.
•
A 10L expansion vessel pre-charged to 1.0 bar is sufficient.
NOTE: if any of the system data values change a different vessel would be required.
Positioning the vessel
It is recommended to position the vessel below the heat pump on the primary return pipe.
Pre-charge pressure of the vessel
Deciding the pre-charge pressure of the vessel is part of the vessel sizing procedure. If the vessel
is sized at 0.5 bar and the difference in height (H) is zero, then the vessel must be pre-charged to
0.5 bar. If the difference in height increases or decreases, then an additional charge pressure will
be required. Use the formula below to calculate the additional charge and add this to the pre-charge
pressure:
Calculations:
[1]
(
) =
1.94
100
[2]
(
) ,2 5% =
1.25
[3.1]
( ) =
0.63
~ [
=0 .5
]
[3.2]
( ) =
0.5
~ [
=1 .0
]
[1]
(
) =
200 1.94
100
=3 .88
[2]
(
) ,2 5% =3 .88 1.25= 4.85
[3.1]
( ) =
4.85
0.63
= 7.7
~ 8
[3.2]
( ) =
4.85
0.5
= 9.7
~ 10
(
)= (
(1 0+ 0.3)
)
