LT-S-L Technical manual
Figure 5-11. Motor liquid spray cooling joint
★
1
）
Note: Refer to 2.4 for the working condition
of motor liquid spray cooling joint
2
）
PT 100 motor temperature sensor is a standard accessory for controlling the
liquid injection solenoid valve.
5.4
Economizer System
Cooling capacity and efficiency will be increased by applying an economizer in
front of the expansion valve to get sub cool effect. Economizer has significant effect
especially in high pressure ratio working condition.
For a compound two stage compressor, the economizer is even more required.
Due to its two stage compression design, the economizer effect is magnified. The
increase of both cooling capacity and COP are more significant than those of single
stage compressor. The gas supplied by the economizer could reduce the discharge
temperature from low stage, which reduces the discharge temperature at high stage.
This increases the compressor performance, reliability and widens the application
limit.
Here are two typical application systems for the economizer:
5.4.1
Economizer System with Sub Cooler
With this form of operation, a heat exchanger (subcooler) is used to sub-cool
liquid refrigerant. The sub-cooling is achieved by injecting a part of the refrigerant
from the condenser through an expansion device in counter flow into the sub-cooler,
which then evaporates due to the absorption of heat. The superheated vapor is pulled
into the compressor at the economizer connection and mixed with the vapor, which is
already compressed in low stage.
The sub-cooled liquid is at condensing pressure with this form of operation, the
pipeline to the evaporator does not therefore require any special features, aside from
insulation. The system can be generally applied.
Typical LT economizer system with subcooler
