Chilled water systems: Exam 2 Flashcards
Which of the following components are always installed in a chiller system?
- compressor suction line and chilled liquid lines
- evaporator coil and suction line
1.
Which of the following is NOT true about chillers using a water-cooled condenser in combination with a cooling tower?
- same water circuit is used for both the condenser and evaporator
- forced air fans are used in the cooling tower to aid evaporation
1.
The ARI standard recommends that chiller evaporators operate at a ___ chilled water temp
- 34F
- 44F
- 75F
- 44F
The ARI standard recommends that chiller evaporators operate at a ___ condenser inlet water temp
- 34F
- 44F
- 75F
- 85F
85F
Which of the following statements about low pressure chillers is false?
- they are the most identical to high-pressure chillers
- they are more heavily constructed than high-pressure chillers
2.
Which of the following statements about purge units is false?
- their function is to maintain a system free of air and moisture
- they run almost continuously to pump out noncondensables
2.
Scroll compressor chillers
- are positive displacement compressors
- are welded-hermetic units
- have capacities in the 10-25 ton range
- all of the above
- all of the above
Which of the following is NOT true about two stage compressor units?
- they have less piping due to the elimination of a second chiller and pumps
- refrigerant from the evaporator passes through the economizer before it enters the compressor
2.
Which of the following statements about the lubrication system of a centrifugal unit is false?
- it can deliver oil to the critical parts of the compressor and gearbox before the compressor motor begins spinning
- the oil is mixed with the refrigerant through the use of a sump pump
2.
The capacity of a centrifugal compressor is controlled by adjusting guide ______ at the centre of the impeller eye
vanes
Which of the following statements about evaporative condensers is true?
- it is a housing or shed into which air is drawn
- they are used when tap water cannot be used
- makeup water has added to replace water lost by evaporation
- all of the above
all of the above
T or F
As a chiller circulates water through a building, the water absorbs and removes heat from the conditioned areas
true
T or F
The compressor, condenser, metering device, and evaporator in a chiller are smarter than those in a standard air conditioner
false
T or F
The condenser used in chiller systems can be evaporative, air-cooled, or water-cooled
true
T or F
High pressure chillers are typically centrifugal chillers charged with R-123
false
T or F
Low pressure chillers are compression chillers that operate under low pressures
false
T or F
The type of compressor used in a chiller system depends on the number of tons of air conditioning needed
true