Deck 3: Refrigeration and Refrigerants

Question 1

What happens when room temperature soda is poured into a glass of ice?

A) The ice gets colder.
B) The ice melts because it is giving up the "cold" to the soda.
C) The ice melts because it is absorbing heat from the soda.
D) The ice melts because the soda is colder than the ice.

Answer 1

C

Question 2

Ice melts in iceboxes because ____.

A) heat flows through the insulated walls
B) heat enters when the door is opened
C) heat enters when warm food is placed in the icebox
D) All of the above.

Answer 2

D

Question 3

The condenser ____.

A) rejects the heat from the refrigerant
B) controls the refrigerant flow throughout the system
C) adds superheat to the refrigerant
D) All of the above.

Answer 3

A

Question 4

Modern refrigerators have become state-of-the-art appliances and some models even include automatic beverage and ice dispensers, built in television screens and connections to the World Wide Web.

Question 5

Which of the following refrigerants has the lowest boiling temperatures at atmospheric pressure?

A) R-12.
B) R-22.
C) R-134a.
D) R-502.

Question 6

Refrigeration can be described as ____.

A) the process of making products cold
B) the process of introducing heat to a location where it is not wanted
C) the process of removing heat from a place where it is not wanted to a place where it makes little or no difference
D) None of the above.

Question 7

Reciprocating compressors have ____.

A) a piston and cylinder
B) two scrolls that mesh together
C) a rotor to compress the refrigerant
D) a large fan compressor component

Question 8

The evaporator in a refrigeration system ____.

A) reduces the boiling point of the refrigerant
B) condenses the refrigerant
C) absorbs heat from the product to be cooled
D) compresses the refrigerant vapor

Question 9

If a cylinder of R-22 is moved from a 100°F truck body into an 80°F shop, the quantity of liquid refrigerant in the cylinder will remain the same.

Question 10

High temperature refrigeration is that produced by ____.

A) heat from a furnace
B) an air-conditioning system
C) the vegetable cooling system of a refrigerator
D) the freezer section of a refrigerator

Question 11

When a refrigerant enters the compressor, it is a ____ and when it leaves the compressor, it is a ____.

A) low pressure low temperature superheated vapor, high pressure high temperature superheated vapor
B) low pressure low temperature superheated vapor, low pressure low temperature subcooled vapor
C) high pressure superheated vapor, low pressure superheated vapor
D) low pressure low temperature subcooled liquid, high pressure high temperature superheated vapor

Question 12

The boiling point of a refrigerant should be low enough at atmospheric pressure to keep the system pressure above 0 psig when operating at low temperatures.

Question 13

The temperature inside the refrigerator fresh food section should be about ____.

A) 25 ºF
B) 30 ºF
C) 35 ºF
D) 40 ºF

Question 14

The ____ are used to change the vapor to a liquid and the liquid form back into a vapor, the refrigeration cycle.

A) condenser and compressor
B) compressor and expansion device
C) expansion device and evaporator
D) condenser and evaporator

Question 15

The compressor in a refrigeration system ____.

A) raises the boiling point of the refrigerant
B) pumps the refrigerant throughout the system
C) Both a and b.
D) None of the above.

Question 16

Good ventilation is important when working around refrigeration equipment because modern refrigerants ____.

A) are toxic and can poison you
B) have an unpleasant odor
C) are heavier than air and may displace the oxygen around you
D) Both a and c.

Question 17

The ____ relationship correlates the vapor pressure and the boiling point of water and is the basis for controlling the cooling system's temperatures.

A) boiling/pressure
B) temperature/pressure
C) temperature/vapor
D) boiling/vapor

Question 18

A ton of refrigeration is equal to ____.

A) 1 ton of ice
B) 288,000 Btu/24 h
C) 144 Btu/h
D) 12,000 Btu/min

Question 19

The law requires technicians to recover refrigerant from all refrigeration systems so that they ____.

A) will not be released into the atmosphere
B) may be used again
C) may be reclaimed for future use
D) All of the above.

Question 20

The evaporator in a refrigeration system must be colder than the refrigerated space in order to absorb heat.

Question 21

The only location where the refrigerant vapor is superheated is in the evaporator.

Question 22

What is the purpose of the metering device?

Question 24

An expansion valve is the pressure reducing device that controls the flow of liquid refrigerant into the evaporator.

Question 25

The amount of heat a refrigerant contains with -40 degree F as the 0 heat content reference point is called ____________________.

Question 26

The evaporator can be thought of as a "heat sponge."

Question 27

The ____________________ is referred to as a kinetic displacement compressor.

Question 28

The ____________________ is another positive displacement compressor and is used for larger air conditioning and refrigeration applications.

Question 29

Only liquid refrigerant should enter the metering device.

Question 31

The halide leak detector should be used in well ventilated areas as the resulting blue or green flame indicates that phosgene gas is being produced.

Question 33

From a performance standpoint, a substitute for R-12 is ____________________.

Question 34

When the refrigerant leaves the metering device, it is not 100% liquid. Why?

Question 35

The refrigerant vapor picks up additional heat as it flows from the evaporator to the compressor. The heat is picked up from the ____________________.

Question 36

The discharge gas from the compressor is a high pressure, high temperature, superheated vapor.

Question 37

The four (4) major components of a vapor compression refrigeration system are the compressor, condenser, evaporator, and ____________________.

Question 38

Vapor is more dense than liquid and, as the liquid refrigerant boils, it has a tendency to sink.