306 Chapter 11 Temperature and Temperature-Related Parameters
know the answer to some of these questions: What is your body temperature? What is the
room air temperature? What is the temperature of the water that you used this morning to
take a shower? What is the temperature of the air inside your refrigerator that kept the
milk cold overnight? What is the temperature inside the freezer section of your refrigera-
tor? What is the temperature of the air coming out of your hair dryer? What is the surface
temperature of your stove’s heating element when set on high? What is the surface tem-
perature of a 100-W light bulb? What is the average operating temperature of the elec-
tronic chips inside your TV or your computer? What is the temperature of combustion
products coming out of your car’s engine? Once you start thinking about the role of tem-
perature in quantifying what goes on in our surroundings, you realize that you could ask
hundreds of similar questions.
Regardless of which engineering discipline you are planning to pursue, you need to
develop a good understanding of what is meant by temperature and how it is quantified.
Figure 11.1 illustrates some of the systems for which this understanding is important. Elec-
tronic and computer engineers, when designing computers, televisions, or any electronic
equipment, are concerned with keeping the temperature of various electronic components at
a reasonable operating level so that the electronic components will function properly. In fact,
they use heat sinks (fins) and fans to cool the electronic chips. Civil engineers need to have
a good understanding of temperature when they design pavement, bridges, and other struc-
tures. They must design the structures in such a way as to allow for expansion and contrac-
tion of materials, such as concrete and steel, that occur due to changes in the surrounding
temperatures. Mechanical engineers design heating, ventilating, and air-conditioning (HVAC)
equipment to create the comfortable environment in which we rest, work, and play. They
need to understand heat transfer processes and the properties of air, including its tempera-
ture and moisture content, when designing this equipment. Automotive engineers need to
have a good understanding of temperature and heat transfer rates when designing the cool-
ing system of an engine. Engineers working in a food processing plant need to monitor tem-
perature of the drying and cooling processes. Materials engineers need to have a good grasp
of temperature and heat transfer in order to create materials with desirable properties.■Figure 11.1
Examples of engineering systems
for which understanding of
temperature and heat transfer
is important.Copyright 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