Glossary
to accompany
Thermodynamics: An Engineering Approach, 5th edition
by Yunus A. Çengel and Michael A. Boles17equilibrium composition of a reacting mixture is equal to the number of chemical species
minus the number of elements present in equilibrium.
Equivalence ratio is the ratio of the actual fuel–air ratio to the stoichiometric fuel–air
ratio.
Ericsson cycle is made up of four totally reversible processes:
1-2 T = constant expansion (heat addition from the external source),
2-3 P = constant regeneration (internal heat transfer from the working fluid to the
regenerator),
3-4 T = constant compression (heat rejection to the external sink),
4-1 P = constant regeneration (internal heat transfer from the regenerator back to the
working fluid).Evaporation is the phase change from liquid to vapor and occurs at the liquid–vapor
interface when the vapor pressure is less than the saturation pressure of the liquid at a
given temperature.
Evaporative coolers, also known as swamp coolers, use evaporative cooling based on
the principle that as water evaporates, the latent heat of vaporization is absorbed from the
water body and the surrounding air. As a result, both the water and the air are cooled
during the process. Evaporative coolers are commonly used in dry climates and provide
effective cooling.
Evaporator is a heat exchanger in which the working fluid evaporates as it receives heat
from the surroundings.
Exact differentials are the differential changes for point functions (i.e., they depend on
the state only, and not on how a system reaches that state), and they are designated by the
symbol d. Properties are an example of point functions that have exact differentials.
Excess air is the amount of air in excess of the stoichiometric amount.
Exergy (availability or available energy) is property used to determine the useful work
potential of a given amount of energy at some specified state. It is important to realize
that exergy does not represent the amount of work that a work-producing device will
actually deliver upon installation. Rather, it represents the upper limit on the amount of
work a device can deliver without violating any thermodynamic laws.
Exergy balance can be stated as the exergy change of a system during a process is equal
to the difference between the net exergy transfer through the system boundary and the
exergy destroyed within the system boundaries as a result of irreversibilities (or entropy
generation).