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Question 1

The function of an evaporator is to ___ heat (from/to) the ___

Answer 1

remove; material being cooled

Question 2

the capacity of an evaporator is affected by the

Answer 2

cleanliness of the evaporator

Question 3

basic evaporator configurations depend on whether they have one or more tubes and whether or not they have

Answer 3

extended surface areas

Question 4

multiple circuit evaporators have headers or distributors that direct refrigerant to each coil from ____ expansion valves

Answer 4

one

Question 5

A comfort cooler __ humidity of moist air by cooling the air temperature ___ the dew point

Answer 5

reduces; below

Question 6

unlike a dry expansion evaporator refrigerant in a flooded evaporator enters as ___ liquid and exits as ___ vapor

Answer 6

all; part

Question 7

in a secondary refrigeration system the refrigeration removes heat from the material to be cooled. This refrigerant then transfers heat to the ___ refrigerant. In the process the ____ refrigerant boils.

Answer 7

secondary; primary

Question 8

a eutectic solution is a brine in which the concentration of salt is precisely set to achieve the lowest possible

Answer 8

freezing point

Question 9

which evaporator arrangement offers the greatest flexibility

Answer 9

two evaporators in parallel each with its own expansion valve

Question 10

a cascade refrigeration system has more than one

Answer 10

compressor, evaporator, condenser, and refrigerant

Question 11

the basic laws of thermodynamics that apply to refrigeration state that

Answer 11

heat flows from a warmer substance to a cooler substance

Question 12

the net refrigeration effect can be increased by ___ the refrigeration

Answer 12

subcooling

Question 13

using a heat exchanger to lower the temperature in the liquid line and raise the temperature in the suction line has the advantages of reducing

Answer 13

the amount of liquid refrigerant entering the compressor

Question 14

the amount of oil entering an evaporator can be reduced by using an

Answer 14

oil separator

Question 15

if the fluid being cooled by an evaporator circulates through the coil rather that moving slowly or not at all the performance of the evaporator improves because of the

Answer 15

increased temperature difference across the wall of the evaporator

Question 16

an evaporator can be defrosted by

Answer 16

reversing the flow of refrigerant

Question 17

to remove rust scale and sludge from a shell and tube evaporator you should use an ___ as necessary

Answer 17

brush

Question 18

a water coil can be winterized by draining out the water and

Answer 18

leaving the coil dry for the winter

Question 19

frost buildup on an evaporator coil is increased by ___ airflow and ___ air

Answer 19

low; humid

Question 20

bent fins reduce the cooling capacity of an evaporator because they

Answer 20

reduce the area exposed to the air

Question 21

the purpose of the metering device in a refrigeration system is to

Answer 21

control the flow of refrigeration into the evaporator

Question 22

The operation of an AXV is controlled by the

Answer 22

pressure in the evaporator

Question 23

in controlling the flow of refrigerant into a flood evaporator the float of a high side float valve is located (at/on) the

Answer 23

high pressure side of the valve port

Question 24

if floodback occurs in a system using an AXV a likely cause is

Answer 24

ice on the spring chamber above the diaphragm

Question 25

a common problem with TXVs is ice in the valve port, the proper way to correct this problem is to

Answer 25

replace the filter-drier