Deck 21: Evaporators and the Refrigeration System

Question 1

The capacity (tonnage) of the heat exchanger can vary with its height and depth.

Answer 1

False

Question 2

The ____ of the liquid refrigerant determines the coil operating temperature.

A) freezing point
B) melting point
C) transition temperature
D) boiling temperature

Answer 2

D

Question 3

A direct expansion-type evaporator is also called a ____.

A) flooded evaporator
B) dry-type evaporator
C) multi-circuit evaporator
D) stamped evaporator

Answer 3

B

Question 4

A typical evaporator operating temperature in an air-conditioning system is ____.

A) 40°F
B) 55°F
C) 75°F
D) 200°F

Question 5

____ is the best method of checking to see when a refrigerant coil has a proper level of refrigerant.

A) Boiling temperature
B) Superheat
C) Dryheat
D) Vapor temperature

Question 6

A refrigeration system designed for the storage of flowers or candy is considered a ____ type.

A) high temperature
B) medium temperature
C) low temperature
D) sharp freezing

Question 7

The process of removing heat from a place where it is not wanted and transferring that heat to a place where it makes little or no difference is known as ____.

A) cooling
B) refrigeration
C) defrosting
D) temperature balancing

Question 8

The film factor is a relationship between the medium giving up heat and the heat-exchange surface.

Question 9

The refrigeration evaporator is a component that absorbs heat from the conditioned space into the refrigeration system.

Question 10

The ____ in a refrigeration system is responsible for absorbing heat into the system from whatever medium is to be cooled.

A) evaporator
B) thermostat
C) compressor
D) condenser

Question 11

The household refrigerator fresh-food compartment typically ranges from ____.

A) 25 to 35°F
B) 28 to 40°F
C) 30 to 42°F
D) 32 to 45°F

Question 12

A typical superheat for an evaporator operating under normal conditions would be ____.

A) 4 to 6°F
B) 6 to 8°F
C) 8 to 12°F
D) 14 to 16°F

Question 13

If an evaporator has a pressure drop of 10 psig and the low side pressure is 15 psig, what is the pressure at the inlet of the evaporator?

A) 5 psig
B) 10 psig
C) 15 psig
D) 25 psig

Question 14

High-temperature refrigeration applications will normally provide box temperatures of ____.

A) 20 to 40°F
B) 32 to 50°F
C) 47 to 60°F
D) 50 to 67°F

Question 15

The boiling temperature and its relationship to the system exist in the ____.

A) coil
B) thermostat
C) condenser
D) evaporator

Question 16

A stamped plate evaporator usually does not use a fan to move air across it.

Question 17

Evaporators that are operated full of liquid and are equipped with a device to keep the liquid refrigerant from passing to the compressor are known as ____.

A) locked evaporators
B) seized evaporators
C) flooded evaporators
D) stoned evaporators

Question 18

If the application requires a coil design to operate below freezing, there must be provision for ____.

A) flooding the evaporator
B) adding refrigerant
C) defrost
D) suction pressure control

Question 19

The household refrigerator fresh-food compartment is a good example of ____ refrigeration.

A) low-temperature
B) medium-temperature
C) high-temperature
D) average-temperature

Question 20

Low-temperature food storage applications generally start at ____.

A) -20°F
B) 0°F
C) 32°F
D) 40°F

Question 21

____________________ evaporators are used when the coil would become too long for a single circuit,percent vapor.

Question 22

What is a bearing washout?

Question 23

____________________-temperature refrigeration produces temperatures below the freezing point of water.

Question 24

Every central split cooling system manufactured in the USA today must have a Seasonal Energy Efficiency Ratio (SEER) of at least 10.

Question 25

What do the temperature ranges for commercial refrigeration refer to?

Question 26

A defrost system that pipes the compressor discharge vapor directly to the evaporator is called a(n) ____________________ type.

Question 27

When the refrigerant vapor is saturated with heat it is known as a(n) ____________________.

Question 28

To check the performance of a dry-type evaporator, the service technician would first make sure that the refrigerant coil is operating with enough liquid inside.

Question 29

Describe a flooded coil.

Question 30

Define superheat.

Question 31

SEER is calculated based on the total amount of cooling the system will provide over the entire season, divided by the total number of ____________________ it will consume.

Question 32

Why are the fins of a low temperature evaporator spaced wider apart than those on a high temperature evaporator?

Question 33

As a rule of thumb, the temperature of the evaporator should be about ____________________°F colder than the box temperature.

Question 34

What is a starved coil?

Question 35

___________________ the air means to remove the moisture, and this is frequently desirable in refrigeration systems.

Question 36

What are some typical problems on the liquid side of a liquid cooling evaporator?

Question 37

Define saturated vapor.