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Homework * ASC 111 * Group 3

Multiple Choice
Identify the choice that best completes the statement or answers the 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.
 

 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
 

 3. 

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
 

 4. 

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
 

 5. 

The temperature inside the refrigerator fresh food section should be about ____.
a.
25 degrees F
b.
30 degrees F
c.
35 degrees F
d.
40 degrees F
 

 6. 

A ton of refrigeration is equal to ____.
a.
1 ton of ice
b.
288,000 Btu/24-hr.
c.
144 Btu/hr.
d.
12,000 Btu/min.
 

 7. 

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
 

 8. 

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
 

 9. 

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
 

 10. 

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
 

 11. 

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
 

 12. 

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
 

 13. 

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
 

 14. 

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
 

 15. 

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
 

 16. 

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
 

True/False
Indicate whether the statement is true or false.
 

 1. 

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.
 

 2. 

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

 3. 

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.
 

 4. 

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.
 

 5. 

The evaporator can be thought of as a “heat sponge.”
 

 6. 

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

 7. 

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

 8. 

Only liquid refrigerant should enter the metering device.
 

 9. 

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

 10. 

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.
 

 11. 

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

Completion
Complete each statement.
 

 1. 

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

 

 2. 

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

 

 3. 

The _________________________________ is referred to as a kinetic displacement compressor.
 

 

 4. 

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

 

 5. 

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

 

 6. 

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

 

Short Answer
 

 1. 

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

 2. 

What is the purpose of the metering device?
 

Matching
 
 
Using the pressure temperature chart below, match the refrigerant with its correct pressure at 40°F.

 
REFRIGERANT
 
REFRIGERANT
 
REFRIGERANT
      
TEMP_____________________TEMP______________________TEMP________________________
°F
12
22
134a
502
°F
12
22
134a
502
°F
12
22
134a
502
               
–60
19.0
12.0
 
7.2
12
15.8
34.7
13.2
43.2
42
38.8
71.4
37.0
83.8
–55
17.3
9.2
 
3.8
13
16.4
35.7
13.8
44.3
43
39.8
73.0
38.0
85.4
–50
15.4
6.2
 
0.2
14
17.1
36.7
14.4
45.4
44
40.7
74.5
39.0
87.0
–45
13.3
2.7
 
1.9
15
17.7
37.7
15.1
46.5
45
41.7
76.0
40.1
88.7
–40
11.0
0.5
14.7
4.1
16
18.4
38.7
15.7
47.7
46
42.6
77.6
41.1
90.4
–35
8.4
2.6
12.4
6.5
17
19.0
39.8
16.4
48.8
47
43.6
79.2
42.2
92.1
–30
5.5
4.9
9.7
9.2
18
19.7
40.8
17.1
50.0
48
44.6
80.8
43.3
93.9
–25
2.3
7.4
6.8
12.1
19
20.4
41.9
17.7
51.2
49
45.7
82.4
44.4
95.6
–20
0.6
10.1
3.6
15.3
20
21.0
43.0
18.4
52.4
50
46.7
84.0
45.5
97.4
–18
1.3
11.3
2.2
16.7
21
21.7
44.1
19.2
53.7
55
52.0
92.6
51.3
106.6
–16
2.0
12.5
0.7
18.1
22
22.4
45.3
19.9
54.9
60
57.7
101.6
57.3
116.4
–14
2.8
13.8
0.3
19.5
23
23.2
46.4
20.6
56.2
65
63.8
111.2
64.1
126.7
–12
3.6
15.1
1.2
21.0
24
23.9
47.6
21.4
57.5
70
70.2
121.4
71.2
137.6
–10
4.5
16.5
2.0
22.6
25
24.6
48.8
22.0
58.8
75
77.0
132.2
78.7
149.1
–8
5.4
17.9
2.8
24.2
26
25.4
49.9
22.9
60.1
80
84.2
143.6
86.8
161.2
–6
6.3
19.3
3.7
25.8
27
26.1
51.2
23.7
61.5
85
91.8
155.7
95.3
174.0
–4
7.2
20.8
4.6
27.5
28
26.9
52.4
24.5
62.8
90
99.8
168.4
104.4
187.4
–2
8.2
22.4
5.5
29.3
29
27.7
53.6
25.3
64.2
95
108.2
181.8
114.0
201.4
0
9.2
24.0
6.5
31.1
30
28.4
54.9
26.1
65.6
100
117.2
195.9
124.2
216.2
1
9.7
24.8
7.0
32.0
31
29.2
56.2
26.9
67.0
105
126.6
210.8
135.0
231.7
2
10.2
25.6
7.5
32.9
32
30.1
57.5
27.8
68.4
110
136.4
226.4
146.4
247.9
3
10.7
26.4
8.0
33.9
33
30.9
58.8
28.7
69.9
115
146.8
242.7
158.5
264.9
4
11.2
27.3
8.6
34.9
34
31.7
60.1
29.5
71.3
120
157.6
259.9
171.2
282.7
5
11.8
28.2
9.1
35.8
35
32.6
61.5
30.4
72.8
125
169.1
277.9
184.6
301.4
6
12.3
29.1
9.7
36.8
36
33.4
62.8
31.3
74.3
130
181.0
296.8
198.7
320.8
7
12.9
30.0
10.2
37.9
37
34.3
64.2
32.2
75.8
135
193.5
316.6
213.5
341.2
8
13.5
30.9
10.8
38.9
38
35.2
65.6
33.2
77.4
140
206.6
337.2
229.1
362.6
9
14.0
31.8
11.4
39.9
39
36.1
67.1
34.1
79.0
145
220.3
358.9
245.5
385.0
10
14.6
32.8
11.9
41.0
40
37.0
68.5
35.1
80.5
150
234.6
381.5
262.7
408.4
11
15.2
33.7
12.5
42.1
41
37.9
70.0
36.0
82.1
155
249.5
405.1
280.7
432.9

a.
R-12
c.
R-502
b.
R-134a
d.
R-22
 

 1. 

80.5 psig
 

 2. 

37 psig
 

 3. 

68.5 psig
 

 4. 

35.1 psig
 
 
Match the refrigerant cylinder with the correct color code.
a.
R-11
f.
R-114
b.
R-12
g.
R-500
c.
R-22
h.
R-502
d.
R-113
i.
R-717
e.
R-134a
 

 5. 

orchid
 

 6. 

light blue
 

 7. 

green
 

 8. 

silver
 

 9. 

purple
 

 10. 

yellow orange
 

 11. 

white
 

 12. 

dark blue
 

 13. 

orange
 
 
In the illustration below, identify the indicated components.

grp003-1.jpg
a.
Compressor
c.
Metering Device
b.
Evaporator
d.
Condenser
 

 14. 

abort heat from the system
 

 15. 

is the heart of the refrigeration system
 

 16. 

rejects both sensible and latent heat from the refrigeration system
 

 17. 

a valve or small fixed-size tubing or orifice that meters liquid refrigerant into the evaporator
 



 
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