問題一覧
1
The density of air at 35 °and 101 kPa is 1.05 kg/𝑚³. The humidity ratio is:
At t = 35°C = Psat = 5.6286 kPa
A. 0.036 kgvapor / kgair
2
If the sensible heat ratio is 0.80 and the cooling load is 100 kW, what is the amount of sensible heating?
A. 80 kW
3
Answer:
B. 2.03 kg
4
A coil has an inlet temperature of 60 °F and outlet of 90 °F. If the mean temperature of
the coil is 110 °F, find the bypass factor of the coil.
C. 0.40
5
If the latent and sensible heat loads are 20 kW and 80 kW respectively, what is the
sensible heat ratio?
A. 0.80
6
Answer:
B. 60.07
7
Answer:
A. 37.26 Pa
8
A rectangular duct has a dimension of 0.25 m by 1 m. Determine the equivalent
diameter of the duct.
A. 0.40 m
9
Wet material containing 215 % moisture (dry basis) is to be dried at the rate of 1.5 kg/s
in a continuous dryer to give a product containing 5 % moisture (wet basis). The drying medium consist of air heated to 373 K and containing water vapor equivalent to a partial pressure of 1.40 kPa. The air leaves the dryer at 310 K and 70 % saturated. Calculate how much air will be required to remove the moisture.
A. 50 kg/s
10
In an air conditioning system, if the re-circulated air is three times the outside air and the mass of the supply air is 20 kg/s, what is the mass of the outside air?
C. 5 kg/s
11
Answer:
A. 0.000491 𝑙𝑏/𝑓𝑡³
12
A certain sample of air has a temperature of 70 ̊F (partial pressure of 0.36 psia) and a
dew point temperature of 50 ̊F. The partial pressure of the water is vapor corresponding to a 50 ̊F dew point temperature is 0.178 psia. Determine the relative humidity RH.
A. 49.44 %
13
Air at normal atmospheric pressure has a temperature of 70 ̊F and a dew point
temperature of 50 ̊F. Determine the saturation ratio of the air. The humidity ratios
corresponding to dew point temperatures of 50 ̊F and 70 ̊F respectively are 0.00763
lb/lb and 0.01576 lb/lb respectively.
D. 48.41 %
14
Determine the sensible heat of 5 lb of air having a dry bulb temperature of 70 ̊F and a
humidity ratio of 0.0092 lb/lb, the latter corresponding to a dew point temperature of approximately 55 ̊F.
C. 84 BTU
15
If the total heat removed per pound of dry air is 10 BTU and the sensible heat removed
per pound of dry air is 6 BTU. Compute the sensible heat factor (SHR).
B. 0.60
16
Determine the approximate load on a cooling tower if the entering and leaving
temperatures are 96 ̊F and 88 ̊F, respectively and the flow rate of the water over the tower is 30 gpm.
B. 2000 Btu/min
17
The mass of an outside air at 50 ̊C in an air conditioning unit is 60 kg. Find the
temperature after mixing if the outside air mixed with 40 kg with recirculated air at 35 ̊C.
A. 44 ̊C
18
How do you call the water vapor content of air?
C. Humidity
19
Answer:
C. 83 %
20
A natural draft cooling tower has a 400-ton heat rejection load. The tower operates at
an efficiency of 52 % when the outdoor wet-bulb temperature is 75 ̊F and the entering water temperature is 90 ̊F. The temperature of the water leaving the tower is:
C. 82 °F
21
Air at 80 ̊F dry-bulb and 67 ̊F wet-bulb temperature enters a 42 ̊F cooling oil and leaves at 53 ̊F dry-bulb. Then the air is reheated to 66 ̊F. The cooling efficiency is:
D. 0.7
22
When air contains all of the water vapor it can hold, it is said to be ________.
B. Saturated
23
What is the instrument used to register relative humidity?
A. Hygrometer
24
Humidity is a measure of which of the following?
A. Water vapor content
25
In an air conditioning system, before the air is circulated to the required area, it is:
D. All of the above
26
The temperature at which water vapor in the atmosphere begins to condense is known
as the:
C. Dew point
27
Saturation temperature is the same as;
A. Dew point
28
When the bypass factor is B, the coil efficiency for sensible cooling of air is equal to:
C. 1 – B ✓
29
The psychrometric chart in air conditioning determines the _______________.
D. Moist air conditions
30
What is the value of air stratification in air conditioning design fit for human comfort?
C. Less than air temperature
31
Which of the following statement is correct?
The relative humidity of an air water vapor mixture ______________.
D. Is the ratio of the partial pressure of water vapor to the saturation pressure at the mixture temperature
32
In sensible cooling process, moisture content.
A. Does not change
33
What amount of air is required in a low bypass factor?
C. Lesser
34
What is the lowest temperature to which water could possibly be cooled in a cooling
tower?
B. The temperature of adiabatic compression
35
Combined process of cooling and humidifying is also known as:
C. Evaporative cooling process
36
In a cooling tower, the water is cooled mainly by _________.
C. Evaporation
37
Which of the following types of air dryers works by absorbing moisture on a solid
dessicant or drying material such as activated alumina, silicon gel or molecular sieve?
A. Regenerative dryer
38
The relationship of water vapor in the air at the dew point temperature to the amount
that would be in the air if the air were saturated at the dry bulb temperature is:
C. Relative humidity
39
A room 14 ft × 16 ft × 10 ft contains atmospheric air at 72 ̊F. The partial pressure of the water vapor in the air is 0.2140 psia. Barometer is standard. Compute the mass of dry air in the room.
A. 164.7 lb
40
A room 14 ft × 16 ft × 10 ft contains atmospheric air at 72 ̊F. The partial pressure of the water vapor in the air is 0.2140 psia. Barometer is standard. Compute the mass of the water vapor in the room.
B. 1.51 lb
41
A room 14 ft × 16 ft × 10 ft contains atmospheric air at 72 ̊F. The partial pressure of the water vapor in the air is 0.2140 psia. Barometer is standard. What is the dew point temperature, ̊F.
A. 55 ̊F
42
When the air is saturated the wet bulb depression is _____________.
A. Zero
43
A temperature measurement in an ordinary thermometer which has constant specific
humidity.
B. Dew point temperature
44
During sensible heating, the humidity remains constant but the relative humidity.
C. Decreases
45
The relative humidity becomes 100 % and where the water vapor starts to condense.
B. Dew point
46
What is the specific humidity of dry air?
D. 0
47
What is the temperature range of air in air conditioning application where the dry air
can be considered ideal gas?
D. 10 to 50 ̊C
48
In an air conditioning system, if the re-circulated air is three times the outside air and the mass of the supply air is 20 kg/s, what is the mass of the outside air?
C. 5 kg/s
49
A certain sample of air has a temperature of 70 ̊F (partial pressure of 0.36 psia) and a
dew point temperature of 50 ̊F. The partial pressure of the water is vapor corresponding to a 50 ̊F dew point temperature is 0.178 psia. Determine the relative humidity RH.
A. 49.44 %
50
Determine the sensible heat of 5 lb of air having a dry bulb temperature of 70 ̊F and a
humidity ratio of 0.0092 lb/lb, the latter corresponding to a dew point temperature of approximately 55 ̊F.
C. 84 BTU
51
The relative humidity becomes 100 % and where the water vapor starts to condense.
B. Dew point
52
Why should you avoid bending or twisting of fan blades in an air conditioning unit?
B. It will wear out the motor bearings and cause noise
53
A type of refrigerant that will not damage the ozone layer.
A. Hydro fluorocarbons (HCF's)
54
Which of the following is the type of refrigerant that damages the ozone layer?
D. All of these
55
The phenomenon that warm air rise and cold air settle is called:
A. Stratification
56
Air delivered to the room from the supply duct, moving at a velocity of 150 ft/min or
more is called:
A. Primary air
57
Carries needed to deliver air to the conditioned space. It is made of sheet of metals like aluminum, galvanized sheet steel and some structural materials that will not burn.
A. Duct
58
From what principle that air ducts operate?
A. Principle of Pressure Difference
59
It is used to deliver concentrated airstreams into a room. Many have one-way or two-
way adjustable air stream deflectors.
A. Register
60
It is used to control the air-throw distance, height, and spread, as well as the amount of
air.
A. Grille
61
It is used to deliver widespread, fan-shaped flows of air into the room.
B. Diffuser
62
Which of the following fans in air conditioning systems which can be classified as centrifugal flow?
C. Propeller fan
63
The most common controller in the heating and cooling systems.
A. Thermostat
64
A thermostat that functions as increase or decrease instead of starting and stopping
system is called:
A. Modulate
65
A number used to compare energy usage for different areas. It is calculated by dividing the energy consumption by the fottage of the conditioned area.
C. Energy Utilization Index
66
The ratio of the rated cooling capacity divided by the amount of electrical power used:
A. Energy Efficiency Ratio (EER)
67
Heat exchanger in which water flows by gravity over the outside of the tubes or plates.
A. Baudelot Cooler
68
The relative humidity becomes 100 % and where the water vapor starts to condense.
B. Dew point
69
Why should you avoid bending or twisting of fan blades in an air conditioning unit?
B. It will wear out the motor bearings and cause noise
70
A type of refrigerant that will not damage the ozone layer.
A. Hydro fluorocarbons (HCF's)
71
Which of the following is the type of refrigerant that damages the ozone layer?
D. All of these
72
Large-bulb alcohol thermometer used to measure air speed or atmospheric conditions by means of cooling.
A. Kata Thermometer
73
The phenomenon that warm air rise and cold air settle is called:
A. Stratification
74
Air delivered to the room from the supply duct, moving at a velocity of 150 ft/min or
more is called:
A. Primary air
75
Carries needed to deliver air to the conditioned space. It is made of sheet of metals like aluminum, galvanized sheet steel and some structural materials that will not burn.
A. Duct
76
From what principle that air ducts operate?
A. Principle of Pressure Difference
77
Which of the following is the common classification of ducts?
D. All of these
78
It is used to deliver concentrated airstreams into a room. Many have one-way or two-
way adjustable air stream deflectors.
A. Register
79
It is used to control the air-throw distance, height, and spread, as well as the amount of
air.
A. Grille
80
It is used to deliver widespread, fan-shaped flows of air into the room.
B. Diffuser
81
Which of the following fans in air conditioning systems which can be classified as centrifugal flow?
C. Propeller fan
82
The most common controller in the heating and cooling systems.
A. Thermostat
83
Copra enters a dryer containing 60 % water and 40 % of solids and leaves with 5 %
water and 95 % solids. Find the weight of water removed based on each pound of
original product.
A. 0.58 lb
84
The density of air at 35 °and 101 kPa is 1.05 kg/𝑚³. The humidity ratio is:
A. 0.036 kgvapor / kgair
85
In an auditorium maintained at a temperature not to exceed 24℃ and relative humidity not to exceed 60 %, a sensible heat load of 132 kW and 78 kg moisture per hour to be removed. Air is supplied to the auditorium at 18℃. How many kilograms of air must be supplied per hour?
A. 79,200 kg/hr
86
A room contains air at 27 ℃ dry-bulb and 19℃ wet-bulb. The total pressure is 1 atm.
The humidity ratio is most nearly equal to:
B. 0.0102 kg/kg
87
A room contains at 27℃ dry-bulb and 19℃ wet-bulb. The total pressure is 1 atm. The
enthalpy is most nearly _______.
C. 53.9 kJ/kg
88
A room contains air at 27℃ dry-bulb and 19℃ wet-bulb. The total pressure is 1 atm.
The specific heat is most nearly _______.
D. 1.012 kJ/kg-K
89
The temperature to which the air must be cooled at constant pressure to produce
saturation is called:
B. Dew point
90
A refrigerating plant for an air conditioning system is to have a capacity of 10 tons and
a coefficient of performance of 2.50 when operating with a refrigerating effect of 61.4
Btu/lb of refrigerant. Calculate the compressor internal horsepower, hp
D. 18.9
91
The mass of water vapor per unit volume of air ______________.
A. Absolute humidity
92
The heat transfer due to motion of matter cause by a change in density is called:
B. Convection
93
A newly designed isolation room that is to contain 40 people is to air-conditioned with
window air-conditioning units of 5 kW cooling capacity. A person at rest may dissipate heat at the rate of 360 kJ/hr. The room has 10 lightbulbs with each rating of 100 watts. If the rate of heat transfer to the room walls and windows is estimated to be 15,000 kJ/hr and the room air is to be maintained at a constant temperature of 21 ℃, calculate the number of window air-conditioning units required.
B. 2 units
94
The changing of solid directly to vapor, without passing through the liquid state is called:
C. Sublimation
95
Answer:
D. 375 kJ/kg
96
What amount of air is required in a low bypass factor?
C. Lesser
97
Determine the partial pressure of water vapor if the barometric pressure is 101.325 kPa and the humidity ratio is 0.05.
A. 7.54 kPa
98
Pump used to increase air pressure above normal, air is then used as a motive power.
D. Air injection
99
An old auditorium has a seating capacity of 1500 people and is to be maintained at 80
℉ (𝐷𝐵) and 65℉ (𝑊𝐵) when the outdoor air is at 91 ℉ (𝐷𝐵) and 75℉ (𝑊𝐵). Calculate
the quantity of the supply of air at 60℉ given that the solar heat is 110,000 Btu/hr, note:
Sensible heat per person is 225 Btu/hr
B. 93,229.17 lb/hr
100
Ten pounds of air at a dry bulb temperature of 50℉ with a specific humidity of 40 grains/lb dry air are mixed with 25 lb of air having a temperature of 85 ℉ and a specific humidity of 90 grains/lb dry air. Calculate the enthalpy of the mixture, Btu/lb dry air.
D. 29.9
Machine Design ( 1st Set )
Machine Design ( 1st Set )
Jacky Shane Luyas Buhia · 20問 · 2年前Machine Design ( 1st Set )
Machine Design ( 1st Set )
20問 • 2年前Transformers Board Exam ( EE ) Reviewer
Transformers Board Exam ( EE ) Reviewer
Jacky Shane Luyas Buhia · 43問 · 3年前Transformers Board Exam ( EE ) Reviewer
Transformers Board Exam ( EE ) Reviewer
43問 • 3年前Test 1~2
Test 1~2
Jacky Shane Luyas Buhia · 100問 · 3年前Test 1~2
Test 1~2
100問 • 3年前Test 2
Test 2
Jacky Shane Luyas Buhia · 99問 · 3年前Test 2
Test 2
99問 • 3年前[ PPE ] [ QUIZ 2 ]
[ PPE ] [ QUIZ 2 ]
Jacky Shane Luyas Buhia · 11問 · 2年前[ PPE ] [ QUIZ 2 ]
[ PPE ] [ QUIZ 2 ]
11問 • 2年前Transformers Board Exam ( EE ) Reviewer
Transformers Board Exam ( EE ) Reviewer
Jacky Shane Luyas Buhia · 79問 · 3年前Transformers Board Exam ( EE ) Reviewer
Transformers Board Exam ( EE ) Reviewer
79問 • 3年前[ PPE ] [ QUIZ 1 ]
[ PPE ] [ QUIZ 1 ]
Jacky Shane Luyas Buhia · 45問 · 2年前[ PPE ] [ QUIZ 1 ]
[ PPE ] [ QUIZ 1 ]
45問 • 2年前BES MRB ( Elements 101 ) - 1.docx
BES MRB ( Elements 101 ) - 1.docx
Jacky Shane Luyas Buhia · 100問 · 3年前BES MRB ( Elements 101 ) - 1.docx
BES MRB ( Elements 101 ) - 1.docx
100問 • 3年前Problem_Solving_01
Problem_Solving_01
Jacky Shane Luyas Buhia · 20問 · 1年前Problem_Solving_01
Problem_Solving_01
20問 • 1年前Compre_Quiz_4
Compre_Quiz_4
Jacky Shane Luyas Buhia · 19問 · 1年前Compre_Quiz_4
Compre_Quiz_4
19問 • 1年前References
References
Jacky Shane Luyas Buhia · 11問 · 1年前References
References
11問 • 1年前Elements_01
Elements_01
Jacky Shane Luyas Buhia · 100問 · 1年前Elements_01
Elements_01
100問 • 1年前Elements_01
Elements_01
Jacky Shane Luyas Buhia · 50問 · 1年前Elements_01
Elements_01
50問 • 1年前Problem_Solving_01
Problem_Solving_01
Jacky Shane Luyas Buhia · 15問 · 1年前Problem_Solving_01
Problem_Solving_01
15問 • 1年前Elements_02
Elements_02
Jacky Shane Luyas Buhia · 50問 · 1年前Elements_02
Elements_02
50問 • 1年前Conversions_01
Conversions_01
Jacky Shane Luyas Buhia · 15問 · 1年前Conversions_01
Conversions_01
15問 • 1年前Problem_Solving_02
Problem_Solving_02
Jacky Shane Luyas Buhia · 20問 · 1年前Problem_Solving_02
Problem_Solving_02
20問 • 1年前Problem_Solving_03
Problem_Solving_03
Jacky Shane Luyas Buhia · 11問 · 1年前Problem_Solving_03
Problem_Solving_03
11問 • 1年前問題一覧
1
The density of air at 35 °and 101 kPa is 1.05 kg/𝑚³. The humidity ratio is:
At t = 35°C = Psat = 5.6286 kPa
A. 0.036 kgvapor / kgair
2
If the sensible heat ratio is 0.80 and the cooling load is 100 kW, what is the amount of sensible heating?
A. 80 kW
3
Answer:
B. 2.03 kg
4
A coil has an inlet temperature of 60 °F and outlet of 90 °F. If the mean temperature of
the coil is 110 °F, find the bypass factor of the coil.
C. 0.40
5
If the latent and sensible heat loads are 20 kW and 80 kW respectively, what is the
sensible heat ratio?
A. 0.80
6
Answer:
B. 60.07
7
Answer:
A. 37.26 Pa
8
A rectangular duct has a dimension of 0.25 m by 1 m. Determine the equivalent
diameter of the duct.
A. 0.40 m
9
Wet material containing 215 % moisture (dry basis) is to be dried at the rate of 1.5 kg/s
in a continuous dryer to give a product containing 5 % moisture (wet basis). The drying medium consist of air heated to 373 K and containing water vapor equivalent to a partial pressure of 1.40 kPa. The air leaves the dryer at 310 K and 70 % saturated. Calculate how much air will be required to remove the moisture.
A. 50 kg/s
10
In an air conditioning system, if the re-circulated air is three times the outside air and the mass of the supply air is 20 kg/s, what is the mass of the outside air?
C. 5 kg/s
11
Answer:
A. 0.000491 𝑙𝑏/𝑓𝑡³
12
A certain sample of air has a temperature of 70 ̊F (partial pressure of 0.36 psia) and a
dew point temperature of 50 ̊F. The partial pressure of the water is vapor corresponding to a 50 ̊F dew point temperature is 0.178 psia. Determine the relative humidity RH.
A. 49.44 %
13
Air at normal atmospheric pressure has a temperature of 70 ̊F and a dew point
temperature of 50 ̊F. Determine the saturation ratio of the air. The humidity ratios
corresponding to dew point temperatures of 50 ̊F and 70 ̊F respectively are 0.00763
lb/lb and 0.01576 lb/lb respectively.
D. 48.41 %
14
Determine the sensible heat of 5 lb of air having a dry bulb temperature of 70 ̊F and a
humidity ratio of 0.0092 lb/lb, the latter corresponding to a dew point temperature of approximately 55 ̊F.
C. 84 BTU
15
If the total heat removed per pound of dry air is 10 BTU and the sensible heat removed
per pound of dry air is 6 BTU. Compute the sensible heat factor (SHR).
B. 0.60
16
Determine the approximate load on a cooling tower if the entering and leaving
temperatures are 96 ̊F and 88 ̊F, respectively and the flow rate of the water over the tower is 30 gpm.
B. 2000 Btu/min
17
The mass of an outside air at 50 ̊C in an air conditioning unit is 60 kg. Find the
temperature after mixing if the outside air mixed with 40 kg with recirculated air at 35 ̊C.
A. 44 ̊C
18
How do you call the water vapor content of air?
C. Humidity
19
Answer:
C. 83 %
20
A natural draft cooling tower has a 400-ton heat rejection load. The tower operates at
an efficiency of 52 % when the outdoor wet-bulb temperature is 75 ̊F and the entering water temperature is 90 ̊F. The temperature of the water leaving the tower is:
C. 82 °F
21
Air at 80 ̊F dry-bulb and 67 ̊F wet-bulb temperature enters a 42 ̊F cooling oil and leaves at 53 ̊F dry-bulb. Then the air is reheated to 66 ̊F. The cooling efficiency is:
D. 0.7
22
When air contains all of the water vapor it can hold, it is said to be ________.
B. Saturated
23
What is the instrument used to register relative humidity?
A. Hygrometer
24
Humidity is a measure of which of the following?
A. Water vapor content
25
In an air conditioning system, before the air is circulated to the required area, it is:
D. All of the above
26
The temperature at which water vapor in the atmosphere begins to condense is known
as the:
C. Dew point
27
Saturation temperature is the same as;
A. Dew point
28
When the bypass factor is B, the coil efficiency for sensible cooling of air is equal to:
C. 1 – B ✓
29
The psychrometric chart in air conditioning determines the _______________.
D. Moist air conditions
30
What is the value of air stratification in air conditioning design fit for human comfort?
C. Less than air temperature
31
Which of the following statement is correct?
The relative humidity of an air water vapor mixture ______________.
D. Is the ratio of the partial pressure of water vapor to the saturation pressure at the mixture temperature
32
In sensible cooling process, moisture content.
A. Does not change
33
What amount of air is required in a low bypass factor?
C. Lesser
34
What is the lowest temperature to which water could possibly be cooled in a cooling
tower?
B. The temperature of adiabatic compression
35
Combined process of cooling and humidifying is also known as:
C. Evaporative cooling process
36
In a cooling tower, the water is cooled mainly by _________.
C. Evaporation
37
Which of the following types of air dryers works by absorbing moisture on a solid
dessicant or drying material such as activated alumina, silicon gel or molecular sieve?
A. Regenerative dryer
38
The relationship of water vapor in the air at the dew point temperature to the amount
that would be in the air if the air were saturated at the dry bulb temperature is:
C. Relative humidity
39
A room 14 ft × 16 ft × 10 ft contains atmospheric air at 72 ̊F. The partial pressure of the water vapor in the air is 0.2140 psia. Barometer is standard. Compute the mass of dry air in the room.
A. 164.7 lb
40
A room 14 ft × 16 ft × 10 ft contains atmospheric air at 72 ̊F. The partial pressure of the water vapor in the air is 0.2140 psia. Barometer is standard. Compute the mass of the water vapor in the room.
B. 1.51 lb
41
A room 14 ft × 16 ft × 10 ft contains atmospheric air at 72 ̊F. The partial pressure of the water vapor in the air is 0.2140 psia. Barometer is standard. What is the dew point temperature, ̊F.
A. 55 ̊F
42
When the air is saturated the wet bulb depression is _____________.
A. Zero
43
A temperature measurement in an ordinary thermometer which has constant specific
humidity.
B. Dew point temperature
44
During sensible heating, the humidity remains constant but the relative humidity.
C. Decreases
45
The relative humidity becomes 100 % and where the water vapor starts to condense.
B. Dew point
46
What is the specific humidity of dry air?
D. 0
47
What is the temperature range of air in air conditioning application where the dry air
can be considered ideal gas?
D. 10 to 50 ̊C
48
In an air conditioning system, if the re-circulated air is three times the outside air and the mass of the supply air is 20 kg/s, what is the mass of the outside air?
C. 5 kg/s
49
A certain sample of air has a temperature of 70 ̊F (partial pressure of 0.36 psia) and a
dew point temperature of 50 ̊F. The partial pressure of the water is vapor corresponding to a 50 ̊F dew point temperature is 0.178 psia. Determine the relative humidity RH.
A. 49.44 %
50
Determine the sensible heat of 5 lb of air having a dry bulb temperature of 70 ̊F and a
humidity ratio of 0.0092 lb/lb, the latter corresponding to a dew point temperature of approximately 55 ̊F.
C. 84 BTU
51
The relative humidity becomes 100 % and where the water vapor starts to condense.
B. Dew point
52
Why should you avoid bending or twisting of fan blades in an air conditioning unit?
B. It will wear out the motor bearings and cause noise
53
A type of refrigerant that will not damage the ozone layer.
A. Hydro fluorocarbons (HCF's)
54
Which of the following is the type of refrigerant that damages the ozone layer?
D. All of these
55
The phenomenon that warm air rise and cold air settle is called:
A. Stratification
56
Air delivered to the room from the supply duct, moving at a velocity of 150 ft/min or
more is called:
A. Primary air
57
Carries needed to deliver air to the conditioned space. It is made of sheet of metals like aluminum, galvanized sheet steel and some structural materials that will not burn.
A. Duct
58
From what principle that air ducts operate?
A. Principle of Pressure Difference
59
It is used to deliver concentrated airstreams into a room. Many have one-way or two-
way adjustable air stream deflectors.
A. Register
60
It is used to control the air-throw distance, height, and spread, as well as the amount of
air.
A. Grille
61
It is used to deliver widespread, fan-shaped flows of air into the room.
B. Diffuser
62
Which of the following fans in air conditioning systems which can be classified as centrifugal flow?
C. Propeller fan
63
The most common controller in the heating and cooling systems.
A. Thermostat
64
A thermostat that functions as increase or decrease instead of starting and stopping
system is called:
A. Modulate
65
A number used to compare energy usage for different areas. It is calculated by dividing the energy consumption by the fottage of the conditioned area.
C. Energy Utilization Index
66
The ratio of the rated cooling capacity divided by the amount of electrical power used:
A. Energy Efficiency Ratio (EER)
67
Heat exchanger in which water flows by gravity over the outside of the tubes or plates.
A. Baudelot Cooler
68
The relative humidity becomes 100 % and where the water vapor starts to condense.
B. Dew point
69
Why should you avoid bending or twisting of fan blades in an air conditioning unit?
B. It will wear out the motor bearings and cause noise
70
A type of refrigerant that will not damage the ozone layer.
A. Hydro fluorocarbons (HCF's)
71
Which of the following is the type of refrigerant that damages the ozone layer?
D. All of these
72
Large-bulb alcohol thermometer used to measure air speed or atmospheric conditions by means of cooling.
A. Kata Thermometer
73
The phenomenon that warm air rise and cold air settle is called:
A. Stratification
74
Air delivered to the room from the supply duct, moving at a velocity of 150 ft/min or
more is called:
A. Primary air
75
Carries needed to deliver air to the conditioned space. It is made of sheet of metals like aluminum, galvanized sheet steel and some structural materials that will not burn.
A. Duct
76
From what principle that air ducts operate?
A. Principle of Pressure Difference
77
Which of the following is the common classification of ducts?
D. All of these
78
It is used to deliver concentrated airstreams into a room. Many have one-way or two-
way adjustable air stream deflectors.
A. Register
79
It is used to control the air-throw distance, height, and spread, as well as the amount of
air.
A. Grille
80
It is used to deliver widespread, fan-shaped flows of air into the room.
B. Diffuser
81
Which of the following fans in air conditioning systems which can be classified as centrifugal flow?
C. Propeller fan
82
The most common controller in the heating and cooling systems.
A. Thermostat
83
Copra enters a dryer containing 60 % water and 40 % of solids and leaves with 5 %
water and 95 % solids. Find the weight of water removed based on each pound of
original product.
A. 0.58 lb
84
The density of air at 35 °and 101 kPa is 1.05 kg/𝑚³. The humidity ratio is:
A. 0.036 kgvapor / kgair
85
In an auditorium maintained at a temperature not to exceed 24℃ and relative humidity not to exceed 60 %, a sensible heat load of 132 kW and 78 kg moisture per hour to be removed. Air is supplied to the auditorium at 18℃. How many kilograms of air must be supplied per hour?
A. 79,200 kg/hr
86
A room contains air at 27 ℃ dry-bulb and 19℃ wet-bulb. The total pressure is 1 atm.
The humidity ratio is most nearly equal to:
B. 0.0102 kg/kg
87
A room contains at 27℃ dry-bulb and 19℃ wet-bulb. The total pressure is 1 atm. The
enthalpy is most nearly _______.
C. 53.9 kJ/kg
88
A room contains air at 27℃ dry-bulb and 19℃ wet-bulb. The total pressure is 1 atm.
The specific heat is most nearly _______.
D. 1.012 kJ/kg-K
89
The temperature to which the air must be cooled at constant pressure to produce
saturation is called:
B. Dew point
90
A refrigerating plant for an air conditioning system is to have a capacity of 10 tons and
a coefficient of performance of 2.50 when operating with a refrigerating effect of 61.4
Btu/lb of refrigerant. Calculate the compressor internal horsepower, hp
D. 18.9
91
The mass of water vapor per unit volume of air ______________.
A. Absolute humidity
92
The heat transfer due to motion of matter cause by a change in density is called:
B. Convection
93
A newly designed isolation room that is to contain 40 people is to air-conditioned with
window air-conditioning units of 5 kW cooling capacity. A person at rest may dissipate heat at the rate of 360 kJ/hr. The room has 10 lightbulbs with each rating of 100 watts. If the rate of heat transfer to the room walls and windows is estimated to be 15,000 kJ/hr and the room air is to be maintained at a constant temperature of 21 ℃, calculate the number of window air-conditioning units required.
B. 2 units
94
The changing of solid directly to vapor, without passing through the liquid state is called:
C. Sublimation
95
Answer:
D. 375 kJ/kg
96
What amount of air is required in a low bypass factor?
C. Lesser
97
Determine the partial pressure of water vapor if the barometric pressure is 101.325 kPa and the humidity ratio is 0.05.
A. 7.54 kPa
98
Pump used to increase air pressure above normal, air is then used as a motive power.
D. Air injection
99
An old auditorium has a seating capacity of 1500 people and is to be maintained at 80
℉ (𝐷𝐵) and 65℉ (𝑊𝐵) when the outdoor air is at 91 ℉ (𝐷𝐵) and 75℉ (𝑊𝐵). Calculate
the quantity of the supply of air at 60℉ given that the solar heat is 110,000 Btu/hr, note:
Sensible heat per person is 225 Btu/hr
B. 93,229.17 lb/hr
100
Ten pounds of air at a dry bulb temperature of 50℉ with a specific humidity of 40 grains/lb dry air are mixed with 25 lb of air having a temperature of 85 ℉ and a specific humidity of 90 grains/lb dry air. Calculate the enthalpy of the mixture, Btu/lb dry air.
D. 29.9