Chapter hvac engineering Fundamentals: Part 1 Introduction

17.7
Specific Heat
C
p
The
specific heat
of a substance is the amount of energy it takes to
raise a unit mass of the substance by one degree in temperature. For
HVAC work, the specific heat of water in the liquid state is 1 Btu /
(lb
䡠
⬚
F). Water in the solid state (ice) has a specific heat of 0.487 to
0.465 Btu / (lb
䡠
⬚
F), which is easy to remember as 0.5 Btu / (lb
䡠
⬚
F).
Water as a vapor has a specific heat of 0.489 Btu / (lb
䡠
⬚
F) which can
also be rounded to 0.5 Btu / (lb
䡠
⬚
F) as for ice. In a process where energy
is added to or taken from a flowing stream of water, the specific heat
term evolves to
Engineering Fundamentals: Part 2
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