Problems 339
- 2.3. 4. 5.6. 7.
Problem 11.11
11 .1. Investigate the value of temperature for the following
items. Write a brief report discussing how these values
are used in their respective areas.
a. What is a normal body temperature?
b. What is the temperature range that clinically is
referred to as fever?
c. What is a normal surface temperature of your body?
Is this value constant?
d. What is a comfortable room temperature range?
What is its significance in terms of human thermal
comfort? What is the role of humidity?
e. What is the operating temperature range of the
freezer in a household refrigerator?
11.2. Using Excel, or a spreadsheet of your choice, create a
degrees Fahrenheit to degrees Celsius conversion table
for the following temperature range: from 50 F to
130 F in increments of 5F.
11.3. Alcohol thermometers can measure temperatures in the
range of 100 F to 200F. Determine the temperature
at which an alcohol thermometer with a Fahrenheit
scale will read the same number as a thermometer with
a Celsius scale.
11.4. What is the equivalent value of T50°C in degrees
Fahrenheit, Rankine, and Kelvin?
11.5. What is the equivalent value of T100°F in degrees
Rankine, Celsius, and Kelvin?
11.6. The inside temperature of an oven is maintained at
450 °F while the kitchen air temperature is 78 °F. What
is the oven / kitchen air temperature difference in
(a) degree Fahrenheit, (b) degree Rankine, (c) degree
Celsius, and (d) Kelvin?
11.7. Obtain information aboutK- ,E- , andR-type ther-
mocouple wires. Write a brief report discussing their
accuracy, temperature range of application, and in what
application they are commonly employed.
11.8. A manufacturer of loose-fill cellulose insulating material
provides a table showing the relationship between the
thickness of the material and itsR-value. The manu-
facturer’s data is shown in the accompanying table.
Calculate the thermal conductivity of the insulating
material. Also, determine how thick the insulation
should be to provideR-values ofa.R-30
b.R-20
11.9. Calculate theR-value for the following materials:
a. 4-in.-thick brick
b. 10-cm-thick brick
c. 12-in.-thick concrete slab
d. 20-cm-thick concrete slab
e. 1-cm-thick human fat layer
11.10. Calculate the thermal resistance due to convection for
the following situations:
a. warm water withh200 W/m
2
K
b. warm air withh10 W/m
2
K
c. warm moving air (windy situation)h30 W/m
2
K
11.11. A typical exterior masonry wall of a house, shown
in the accompanying figure, consists of the items in the
accompanying table. Assume an inside room tempera-
ture of 68F and an outside air temperature of 10F,
with an exposed area of 150 ft
2. Calculate the heat loss
through the wall.
Problems
R-value (units?) Thickness (in.)
R-40 11
R-32 9
R-24 6.5
R-19 5.25
R-13 3.5Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).圀圀圀⸀夀䄀娀䐀䄀一倀刀䔀匀匀⸀䌀伀䴀圀圀圀⸀夀䄀娀䐀䄀一倀刀䔀匀匀⸀䌀伀䴀