Application Guidelines
12
AB141686422149en-US0401
Operating conditions
The operating envelope for VRJ scroll
compressors is given in the figure below, where
the condensing and evaporating temperatures
represent the range for steady-state operation.
Under transient conditions, such as start-up
and defrost for heat pump applications, the
compressor may operate outside this envelope
for short periods.
The operating limits serve to define the
envelope within which reliable operations of the
compressor are guaranteed:
•
Maximum discharge gas temperature: +275°F
•
Suction superheat is dedictated by the
minimum sump superheat (see graph p16).
•
Maximum superheat of 40°F
•
Minimum and maximum evaporating
and condensing temperatures, as per the
operating envelopes.
All the below limits, temperatures and speeds,
are secured by the parameters in the drive and
application controller software’s.
The discharge temperature depends mainly on
the combination of evaporating temperature,
condensing temperature and suction gas
superheat and speed. Discharge gas temperature
should be controlled with an insulated sensor
attached to the discharge line, 6 in. from the
compressor shell. Maximum discharge gas
temperature must not exceed 275°F when the
compressor is running within the approved
operating envelope.
Refer to “Danfoss VRJ Installation and Operation
instructions” for connection details, and to
“Sensor Selection Guideline” manual for
selection details and technical brochures about
temperature sensors.
Application envelope
Maximum discharge gas
temperature
35
45
55
65
75
85
95
105
115
125
135
145
155
900 - 4500 RPM
2100 - 3750 RPM
2200 - 3300 RPM
2300 - 2850 RPM
2400 RPM Derated
1100 - 4500 RPM
1300 - 4500 RPM
1500 - 4200 RPM
1800 - 4200 RPM
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80
Saturated evaporating temp. (°F)
S
a
tura
te
d
c
onde
ns
ing
te
mp.
(
°F)
2
6
10
14
18
22
26
30
34
38
42
46
50
54
58
62
66
70
-40
-36
-32
-28
-24
-20
-16
-12
-8
-4
0
4
8
12
16
20
24
(°C)
(°
C)
Summary of Contents for VRJ
Page 2: ......
