True/False
Indicate whether the sentence or statement is true
or false.
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1.
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When
doing a job survey for a load calculation for a cooler or freezer you should know the design ambient
temperature, storage and humidity requirements, dimensions, insulation, type of construction,
exposure, infiltration, product specifics, miscellaneous loads and operations. True or
False?
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2.
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Whenever a product load having a higher temperature that the storage placement area,
the product will give its heat up until it reaches the storage temperature. Heat travels from HOT to
COLD!. Is this comment True or False?
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3.
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Typically when doing load calculations on a cooler or freezer a safety factor of 40%
is applied to the total refrigeration load calculated? True or False
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4.
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Product loads have specific heat, the amount of heat that must be removed from one
pound of a product to reduce the temperature of this one pound by 1 deg F. It has two values, one
above freezing and after the product has reached its freezing point. True or
False?
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5.
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An
air change load would not consider the amount of heat entering with the airstream into a freezer or
cooler assembly. True or False
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Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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6.
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To
maintain the desirable relative humidity in a general purpose cooler the general purpose cooler
involving meats, vegetables, and dairy products, it is common procedure to balance the low side to
the condensing unit @ a _____ temperature difference? This means the temperature difference between
the cooler air temperature and the refrigerant temperature in the evaporator should
be? a. | 10F to
12F | c. | 12F-
16F | b. | 17F to
22F | d. | 7F-9F | | | | |
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7.
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Transmission load is the amount of heat flow through wall, floors, and ceilings. The
heat gain is directly proportional to the temperature difference (TD) between the two sides of a
wall. The type and thickness of insulation used in wall construction, the outside area of the wall,
and the TD between the two sides of the wall are three factors that determine? a. | Wall
Load | c. | Cooler
Temperature | b. | Insulations Requirements | d. | Outside Temperature | | | | |
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8.
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“K” factor is the insulating value of any material rated by its thermal
conductivity. “U” factor is the overall coefficient of heat transfer, BTU per hour/per
square foot/per deg F. “X” is equal to the material thickness in inches. The following has
been established;
K = UX = X/R
U = K/X
=1/R
R = 1/U = X/K
Note: K= [ thermal conductivity, BTU per (hour)
(square foot) (F per inch of thickness)]
If the material
is cork or mineral wool rated at K =.30 and the thickness of the material is 10” what is the R
value of the material?
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9.
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“K” factor is the insulating value of any material rated by its thermal
conductivity. “U” factor is the overall coefficient of heat transfer, BTU per hour/per
square foot/per deg F. “X” is equal to the material thickness in inches. The following has
been established;
K = UX = X/R
U = K/X
=1/R
R = 1/U = X/K
Note: K= [ thermal conductivity, BTU per (hour)
(square foot) (F per inch of thickness)]
If the material
is cork or mineral wool rated at K =.30 and the thickness of the material is 10” what is the U
value of the material?
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10.
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Respiration for fresh fruits and vegetable is caused because they are alive. Even in
refrigeration storage they generate heat which is called the heat of
_________?
The temperature of the product depends on the respiration
rate. a. | Constipation | c. | Decomposition | b. | Respiration | d. | Perspiration | | | | |
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11.
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The
amount of heat that must be removed from one pound of a product to freeze this pound of product is
called? a. | Freezing
Point | c. | Latent heat of
confusion | b. | Ambient Point | d. | Latent heat of fusion | | | | |
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12.
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The
dimensions of a cooler are width 8’, length 28’ with height of 8’. What is the volume
of the cooler? a. | 1792 Cubic
Inches | c. | 1792 Cubic
Yards | b. | 1792 Cubic Micrometers | d. | 1792 Cubic Feet | | | | |
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13.
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The
product load of 2,000 pounds has a specific heat of 0.92 and a temperature drop of 50F. What is the
product load in BTU’s? a. | 91,500 | c. | 94,000 | b. | 92,000 | d. | 95,500 | | | | |
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14.
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Typically you would find 1 watt per square foot in a cooler. If the cooler had a
width of 8’ and a length of 28’what would be the watts be?
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15.
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If a
cooler has a ceiling L of 28’ and Width of 8’ and a heat load of 72 BTU per 24 hours per
one square foot of surface, what would be the total heat gain through the ceiling? a. | 16.128 | c. | 160,128 | b. | 16,128 | d. | 161,288 | | | | |
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