46 TRG-TRC012-EN
1Male and female screw rotors
2Bearing lubrication and cooling, and rotor oil injection
3Outside of the tubes
4Electronic expansion valve and orifice plate
5) a) compression
b) condensation (desuperheat, condense, subcool)
c) expansion
d) evaporation
6Point 1, the suction inlet of the compressor
7Fully closed
8At part load, the opening created by the slide valve movement allows
refrigerant vapor to bypass from the rotor pockets back to the suction side
of the compressor. This reduces the volume of vapor available for the
compression process. It also reduces the amount of rotor length available
for compression.
9ASHRAE Guideline 3
10 Helps reduce maintenance costs, detects problems without compressor
disassembly, oil charges last longer, less environmental problems with
disposing of used oil, helps maintain the compressor’s efficiency and
reliability, and helps lower refrigerant emissions.
11 Cycling or varying the speed of the cooling tower fans, using a cooling
tower bypass pipe, modulating a throttling valve, using a chiller bypass
pipe, or employing a variable-speed drive on the condenser water pump.
12 The water flow rate through the chiller’s evaporator must stay between the
minimum and maximum evaporator bundle flow rates as specified by the
chiller manufacturer. The rate which the evaporator water flow rate changes
must be kept below a specified level.
Answers