Symbols
A	heat transfer area, [m2]
cp	specific heat at constant pressure, [J/(kg K)]
$\dot{C}$	heat capacity rate, [W/K]
d	Novikov’s irreversibility degree, [-]
ECOP	ecological coefficient of performance, [-]
G	finite physical dimension, [J/K]
K	heat transfer conductance, [W/K]
I	entropic ratio, [-]
NTU	number of heat transfer units, [-]
Q	heat, [J]
$\dot{Q}$	heat transfer rate, [W]
S	entropy, [J/K]
T	temperature, [K]
U	overall heat transfer coefficient, [W/(m2 K)]
W	mechanical work, [J]
Greek Symbols
ε	effectiveness, [-]
η	efficiency, [-]
Subscripts
C	relative to the cycled fluid at the cold source
Co	relative to compression
CS	cold source or sink
Ex	relative to expansion
H	relative to the cycled fluid at the hot source
HS	hot source
HSi	hot source
I	irreversibility of the converter
IS	irreversibility of the system (source-converter-sink)
S	source or sink, relative to temperature difference of source and sink
T	total, relative to extreme temperature difference of the cycled fluid
0	ambient