chillers

For each 1°F of added subcooling, the efficiency of a system will increase by approximately

1%

The rupture disc on a low-pressure chiller typically releases pressure at

10

A chiller barrel that has three passes will most likely operate with a design approach temperature of about

5

The portion of a chilled water system that cools the water that is used to cool the building is referred to as the

a. chiller barrel.

A variable frequency drive (VFD) is used to vary the

a. number of cycles per second of the power supplied to the system's motors.

Chilled water, when circulated throughout a building to provide comfort cooling, is referred to as a

a. secondary refrigerant.

With a wye-delta or star-delta configuration, the motor starts as a

a. wye configuration and then transitions to a delta configuration.

Instead of using a compressor, an absorption air-conditioning chiller uses which of the following as its driving force?

air

What is the voltage imbalance on a three-phase power supply if the voltage readings are as follows: L1-L2: 466 V, L1-L3: 470 V, and L2-L3: 459 V?

b. 1.29%

How does a centrifugal compressor create the pressure differential needed to move refrigerant through the system?

b. Fan-like action

What will occur if the strong solution in an absorption chiller becomes too strong?

c. The machine will stop cooling and the solution will crystallize.

All of the following methods can be used to control the capacity of a reciprocating compressor except

c. constant suction.

The two float-type metering devices are the

c. high-side float and the low-side float.

The flow through an orifice metering device

c. is constant as long as the pressure drop across the orifice remains the same.

The rate of heat exchange between two liquids

c. is greater than the rate of heat exchange between two gases as well as greater than the rate of heat exchange between a gas and a liquid.

Oil pumps used in conjunction with centrifugal compressors typically use

c. three-phase, fractional horsepower motors.

All low-pressure chillers use which type of compressor?

centrifugal

Which of the following best describes the bearings on a centrifugal compressor?

d. Babbitt construction with a steel sleeve

If a low-pressure chiller has a low-side leak, which of the following will most likely result?

d. High suction pressure and high discharge pressure

If air is present in an absorption chilled water appliance, which of the following will most likely occur?

d. Rust can form.

Which of the following statements is true regarding package-type chillers?

d. They require field-installed water lines.

Compressors that are cooled with refrigerant that leaves the evaporator are referred to as

d. suction-cooled compressors.

What component is incorporated into the marine water boxes to direct water through a shell-and-tube heat exchanger?

partitions

Lithium-bromide, Li-Br, is best characterized as a

salt

The solution that is pumped into the concentrator in an absorption chiller is referred to as the

weak solution