Ref and Air Cond. Tech Unit 3

Question 1

A refrigeration system that maintains a space at a temperature between 35 degrees Fahrenheit and 40 degrees fahrenheit would be classified as what type of system?

Answer 1

medium temperature

Question 2

A refrigeration system that is intended to provide comfort cooling would be classified as what type of system?

Answer 2

high temp

Question 3

One ton of refrigeration is the equivalent of moving heat at

Answer 3

12,000 btu/hr

Question 4

The state of refrigerant at the inlet of the evaporator is approx

Answer 4

75% liquid 25% vapour

Question 5

The state of the refrigerant at the outlet of the evaporator should be

Answer 5

superheated vapour

Question 6

The state of refrigerant at the outlet of the condenser should be?

Answer 6

100% sub-cooled liquid

Question 7

When an air-conditioning system operates in a vacuum, which of the following is true?

a) air will leak out of the system
b) refrigerant will leak out of the system
c) air will be pulled into the system
d) refrigerant will be pulled into the system

Answer 7

air will leak out of the system

Question 8

The expansion device is responsible for?

Answer 8

metering refrigerant flow into the evaporator

Question 9

A properly operating compressor should have ___%________at its inlet and ___%________at its outlet

Answer 9

100% vapour 100% vapour

Question 10

Of the following compressors, which is a residential compressor that is forgiving when it comes to having liquid entering it?

a) reciprocating compressor
b) scroll compressor
c) the rotary compressor
d) screw compressor

Answer 10

b) scroll compressor

Question 11

Rotary compressors are typically used for applications such as

Answer 11

window air conditioners, household refrigerators, and some residential air conditioning systems

Question 12

Rotary compressors are usually ______ than reciprocating compressors of the same capacity

Answer 12

smaller

Question 13

The scroll compressor is the most commonly used compressor in

Answer 13

newly manufactured residential and light commercial air conditioning equipment

Question 14

The colour coding for an R-22 refrigerant cylinder is?

Answer 14

green

Question 15

The colour coding for an R-404A refrigerant cylinder is

Answer 15

Rose

Question 16

Of the following refrigerants, which has the lowest global warming potential (GWP)?

Answer 16

R-1234yf

Question 17

The three processes commonly used to describe refrigerant handling care?

Answer 17

recovering, recycling, and reclaiming

Question 18

The term that is used to quantify the amount of heat absorbed in the evaporator is?

Answer 18

net refrigeration effect

Question 19

The three regions on a pressure/enthalpy chart are:

a) high pressure, low pressure, critical pressure
b) superheated vapour, superheated liquid, depressurized liquid
c) superheated vapour, sub-cooled liquid, saturated
d) high-pressure liquid, low-pressure gas, low-pressure liquid

Answer 19

superheated vapour, sub cooled liquid, saturated

Question 20

The thumbprint shaped region on the pressure/enthalpy chart is called the:

a) saturation curve
b) saturation cycle
c) superheated curve
d) superheated region

Answer 20

saturation curve

Question 21

One of the challenges of plotting an R-407C system on a pressure/enthalpy chart is that this refrigerant:

a) is a single-compound refrigerant with one pressure for each temp
b) has a significant temperature glide
c) is a binary blend of R-32 and R-125, making it unstable
d) is easily mistaken for R-134a and R-410A

Answer 21

b) it has a significant temperature glide

c) is a binary blend of R-32 and R-125, making it unstable