TABLE OF CONTENTS Heat transfer is that branch of thermodynamics that is concerned with the transfer of energy from one point to another by virtue of temperature difference. There are three modes of heat transfer - conduction, convection and radiation. Conduction and radiation are true forms of heat transfer since these modes depend only upon temperature differential and the characteristics of the materials involved in the temperature exchange. Convection, however, not only depends upon the materials, temperature differentials but also is dependent upon mass transport.
Conduction is the molecule to molecule transfer of energy. The one directional equation of energy flow for a steady state condition is given by Fourier's Law of Conduction:
Q = [kA/L][T 1 - T 2]
Q = rate of heat flow in watts or J/s
k = thermal conductivity W/(m-K)
A = area perpendicular to heat flow
L = thickness in direction of heat flow
?T = (T 1 - T 2) difference in temperature within the material in the direction of heat flow, may be given in terms of C or K
Q:
What is the rate of heat flow through a wall constructed of brick and mortar which is 25 cm thick and is 3.0 m by 2.0 m in area. The temperature on one side is 165 C and 55 C on the other side. The average coefficient of thermal conductivity is equal to .750 W/m-K.
Answers
Q:
Q = [kA/L][T 1 - T 2]...
