Operating Principles; General; Refrigerant; Compressor - Trane RTXC-XE Series Installation, Operation And Maintenance Manual

Operating Principles

General

Refrigerant

Compressor

40
The refrigeration cycle of RTXC-XE/XE-HSE is conceptually similar to that of other Trane air-
cooled screw heat pumps, including single refrigerant circuit unit, dual refrigerant circuit unit,
and assembly unit with master-slave control system. RTXC110XE/XE-HSE apply single refrigerant
circuit with one compressor with economizer and one water loop. RTXC180/220XE/XE-HSE units
use dual refrigerant circuits with two compressors with economizer and one water loop, while
RTXC160/200XE/XE-HSE are without economizer. RTXC310/330/360/400/440XE,
310/330/360/400/440/500/560XE-HSE units are duplex units assembled by customer on site.
17 shows the schematic of a single refrigerant circuit with economizer and partial heat recovery
option.
Figure 17. RTXC-XE/XE-HSE Single Refrigerant Circuit (Economizer Only for
RTXC110/180/220XE/XE-HSE)
Equipment Damage!
Use only refrigerants specified on the unit nameplate and Trane OIL00388.
Failure to do so may cause compressor damage and improper unit operation.
The compressor is of cast iron, semi-hermetic construction, twin screw type. Each compressor
has two rotors - "male" and "female" - which provide compression. The male rotor is attached to,
and driven by, the motor, and the female rotor is, in turn, driven by the male rotor. Separately
housed bearing sets are provided at each end of both rotors. A two-pole, hermetic, induction
motor (3000 rpm at 50 Hz, 3600 rpm at 60 Hz) drives the compressor rotors. The motor is cooled
by suction refrigerant gas, entering the end of the motor housing through the suction line.
The female side port provides a capacity step from 30% to approximately 60% displacement. The
slide piston uncovers a series of radial ports in the top of the male rotor bore area of the housing,
providing continuously variable unloading from 60% to approximately 100% of compressor
suction flange volume flow rate.
NOTICE
Figure
RTXC-SVX003D-EN