Chapter 1
Basics of Heat Transfer
1134E
A 1short ton (2000 lbm) of water at 70°F is to be cooled in a tank by pouring 160 lbm of ice at
25°F into it. The final equilibrium temperature in the tank is to be determined. The melting temperature and
the heat of fusion of ice at atmospheric pressure are 32°F and 143.5 Btu/lbm, respectively
Assumptions
1
Thermal properties of the ice and water are constant.
2
Heat transfer to the water is
negligible.
Properties
The density of water is
62.4 lbm/ft
3
,
and the specific heat of water at room temperature is
C
=
1.0 Btu/lbm·°F
(Table A9). The heat of fusion of ice at atmospheric pressure is 143.5 Btu/lbm and the
specific heat of ice is 0.5 Btu/lbm.°F.
Analysis
We take the ice and the water as our system, and disregard any heat transfer between the system
and the surroundings.
Then the energy balance for this process can be written as
( ) ( )
0
0
water
ice
energies
etc.
potential,
kinetic,
internal,
in
Change
system
mass
and
work,
heat,
by
nsfer
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 Fall '10
 Dr.DanielArenas
 Thermodynamics, Energy, Mass, Heat, Heat Transfer, Qave

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