Brochure

5757
3.6 Energy eciency index (EEI)
In 2003 a study of a major part of the circulation pumps on the market was
conducted. The purpose was to create a frame of reference for a representa-
tive power consumption for a specific pump. The result is the curve shown
in figure 3.16. Based on the study the magnitude of a representative power
consumption of an average pump at a given P
hyd,max
can be read from the
curve.
The energy index is defined as the relation between the representative
power (P
L,avg
) for the pump and the reference curve. The energy index can
be interpreted as an expression of how much energy a specific pump uses
compared to average pumps on the market in 2003.
(3.1)
(3.2)
(3.3)
(3.4)
(3.5)
(3.6)
(2,19)
⋅ =
n
n
QQ
A
B
AB
n
n
HH
A
B
AB
2








⋅
=
n
n
PP
A
B
AB
3








⋅ =
n
n
NPSHNPSH
A
B
AB
2








⋅
=
PPPPP
L,avg 25%50%75%100%
0.440.350.150.06 ⋅+⋅+ ⋅+ ⋅=
[ ]
−=
Ref
L,avg
P
P
EEI
If the pump index is no more than 0.40, it can be labelled energy class A. If the
pump has an index between 0.40 and 0.60, it is labelled energy class B. The
scale continues to class G, see figure 3.17.
Speed regulated pumps minimize the energy consumption by adjusting the
pump to the required performance. For calculation of the energy index, a ref-
erence control curve corresponding to a system characteristic for a heating
system is used, see figure 3.18. The pump performance is regulated through
the speed and it intersects the reference control curve instead of following
the maximum curve at full speed. The result is a lower power consumption
in the regulated flow points and thereby a better energy index.
Figure 3.16: Reference power as function
of P
hyd,max
.
Figure 3.17: Energy classes.
Figure 3.18: Reference control curve.
H
max
Q
100%
, H
100%
n
25%
n
50%
n
75%
H
H
100%
2
Q
0%
,
Q
25%
Q
50%
Q
75%
Q
100%
Q
100%
Q
75%
Q
50%
Q
25%
Q
n
100%
Q
0
1 10
Hydraulic power [W]
Reference power [W]
100 1000 10000
1000
2000
4000
3000
A EEI 0.40
Klasse
G 1.40 < EEI
F 1.20 < EEI 1.40
E 1.00 < EEI 1.20
D 0.80 < EEI 1.00
C 0.60 < EEI 0.80
B 0.40 < EEI 0.60