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Vol. 2.6 © 2020 Hanbell Precise Machinery Co., Ltd. All rights reserved
Dual IGV relationship for different models
Both RT series and heat pump are equipped with double IGV mechanism. The actuators
are set up separately while the operations of IGV1 and IGV2 are coupled. The formula is as
follows:
Table 3.3.1 Equations describing the relationship between the two IGVs
3.3.2 Energy savings with variable frequency compressor
Centrifugal compressors are equipped with a motor which drives the high speed shaft
through speed-up gears. Refrigerant gas is compressed and accelerated by the centrifugal
effect of the impellers which rotating at high speed. In the diffuser, most of the kinetic
energy gained is converted into pressure energy.
Obviously, the energy gained from the impeller is ultimately applied by the motor.
Compressor Input power is as follows:
P=H
．
m/
η
P = compressor input power
H = energy head
m = mass flow rate of refrigerant
η
= motor efficiency
According to the Laws of Similarity in fluid mechanics:
∝
∝
∝
IGV1
100
90
80
70
60
50
40
30
20
10
IGV2
100
100
100
100
95.2
87.8
77.6
64.5
48.5
29.6
IGV1
100
90
80
70
60
50
40
30
20
10
IGV2
100
98.9
96.3
92.7
88.4
83.1
76.3
66.8
53.2
33.5
IGV1
100
90
80
70
60
50
40
30
20
10
IGV2
100
100
97.7
93.4
86.9
78.5
67.9
55.4
40.8
24.2
1.969E+00
-1.020E-02
0.000E+00
0.000E+00
Model
y = 5.5+1.969x -1.020E-02x
2
,其中 x=IGV1,y=IGV2
constant
a
b
c
d
e
RT-221
5.500E+00
e
5.464E+00
3.317E+00
-5.588E-02
5.023E-04
-1.808E-06
Model
1.When 100≧IGV1＞90，IGV2=100
2.When 90≧IGV1＞0,y=a+bx+cx
2
+dx
3
+ex
4
,其中 x=IGV1,y=IGV2
RT-160T
RT-180T
RT-200T
RT-161
y =5.464E+00+3.317E+00x-5.588E-02x
2
+5.023E-04x
3
-1.808E-06x
4
constant
a
b
c
d
e
7.849E+00
2.320E+00
-1.440E-02
0.000E+00
0.000E+00
Model
1.When 100≧IGV1≧70，IGV2=100
2.When 70＞IGV1＞0， y=a+bx+cx
2
+dx
3
+ex
4
,其中 x=IGV1,y=IGV2
RT-120T
RT-130T
RT-140T
RT-111
y = 7.849+ 2.320x-1.440E-02x
2
constant
a
b
c
d
