431

Question 1

refrigeration is the process of __ the air in a defined space

Answer 1

lowering temperature of

Question 2

the temperature of a material decreases if the material ___ and nothing else happens that would have the opposite effect

Answer 2

contacts a cooler material

Question 3

the two kinds of air conditioning are

Answer 3

comfort and process

Question 4

one of the physical states of matter is

Answer 4

gas

Question 5

you can cause matter to change its physical state by

Answer 5

adding or removing heat

Question 6

thermal energy that is directly related to the temperature of a material is called ___ heat

Answer 6

sensible

Question 7

a temperature of 45 degrees is about the same as ___ Celsius

Answer 7

7

Question 8

heat can be transferred from one place to another by the process of

Answer 8

conduction

Question 9

the latent heat of vaporization of a substance is the amount of heat the substance absorbs as it

Answer 9

evaporates

Question 10

a refrigeration system has been turned off for several days. it contains both liquid refrigerant and vapor. suddenly a line containing the refrigerant breaks. what happens inside the systems

Answer 10

the liquid refrigerant boils

Question 11

from the compressor refrigerant flows to the

Answer 11

condenser

Question 12

the graph below is the pressure temperature chart for a refrigerant. point ___ represents a condition of superheating

Answer 12

1

Question 13

compared to a dry bulb expansion evaporator a flooded evaporator of the same size

Answer 13

is more efficient

Question 14

the purpose of a cooling medium is to

Answer 14

remove heat from compressed refrigerant vapor

Question 15

an automatic expansion valve is a metering device that maintains a constant pressure in the

Answer 15

evaporator

Question 16

the properties of air that are important in psychometrics include

Answer 16

enthalpy

Question 17

in a sling psychrometer the wet bulb temperature is usually lower than the dry bulb. if the difference is very small you know that the air is quite

Answer 17

humid

Question 18

air that is saturated is air that is at the

Answer 18

dewpoint temperature

Question 19

relative humidity changes if the ___ changes but the specific humidity does not

Answer 19

dry bulb temperature

Question 20

to calculate the enthalpy of a sample of air you must include

Answer 20

latent heat of the water vapor

Question 21

in order to remove the moisture that enters a refrigeration system during repair you must evacuate the system by using a ___ to make all the moisture vaporize

Answer 21

vacuum pump

Question 22

one useful method of detecting leaks in a refrigeration system involves using an __ leak

Answer 22

electronic

Question 23

relative humidity can be measured directly with an

Answer 23

hygrometer

Question 24

which of the fallowing is a correct match between an electrical value and the instrument used to measure it

Answer 24

resistance; ohmmeter

Question 25

in the list below identify the line that correctly matches on of the classes of work area hazard to an example of that class of hazard

Answer 25

chemical; container of refrigerant