Civil Engineering Reference
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Fig. 12 Pipe friction resistance (example steel pipe [
8
])
ow, H
VL
and
H
VA
(dynamic) increase quadratically due to the widely varying losses in the
pipelines and
While H
geo
(static) remains constant, independent of the volume
fittings, as well as due to the increased friction, as seen in Fig.
12
.As
almost always, the hydraulic circuits for heat transport are closed, the geodetic
pressure difference H
geo
= 0. The pressure loss of the hydraulic circuit, H
A
in (Pa),
corresponds to the differential height, h in [m], according to the relation:
H
A
q
h
¼
ð
m
Þ
ð
44
Þ
g
where g is the gravity (9.81 m/s
2
).
(c) Pump selection and setting the actual values of the circuit operating parameters.
Similar to circuit curve, the pump curve is de
ned also as the relationship
between the delivery head (total pressure required for
fluid moving) and the volume
flow. But this time, the relationship is expressed not analytic, because it is deduced
experimentally and is the main feature of the centrifugal pumps used in hydraulic
circuits for heat transport.
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