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4-1 сonstant pressure heat rejection in a condenser.

Refrigerant is the working fluid used in the refrigeration cycle.

Refrigerator is a cyclic device which causes the transfer of heat from a low-temperature
region to a high-temperature region. The objective of a refrigerator is to maintain the
refrigerated space at a low temperature by removing heat from it.

Refrigerator coefficient of performance is the efficiency of a refrigerator, denoted by
COPR, and expressed as desired output divided by required input or COPR = Q L/W net, in

Regeneration is the process of transferring energy with in a cycle from a working fluid
in a high temperature in part of the cycle to a lower temperature part of the cycle to
reduce the amount of external heat transfer required to drive the cycle.

Reversed Carnot cycle is a reversible cycle in which all four processes that comprise the
Carnot cycle are reversed during operation. Reversing the cycle will also reverse the
directions of any heat and work interactions. The result is a cycle that operates in the
counterclockwise direction. The reversed Carnot cycle is the Carnot refrigeration cycle.

Reversible process is defined as a process that can be reversed without leaving any trace
on the surroundings. Reversible processes are idealized processes, and they can be
approached but never reached in reality.

Second law of thermodynamics (increase of entropy principle) is expressed as the
entropy of an isolated system during a process always increases or, in the limiting case
of a reversible process, remains constant. In other words, the entropy of an isolated
system never decreases. It also asserts that energy has quality as well as quantity, and
actual processes occur in the direction of decreasing quality of energy.

Specific heat is defined as the energy required to raise the temperature of a unit mass of
a substance by one degree. In general, this energy will depend on how the process is
executed.

Specific heat at constant pressure Cp is the energy required to raise the temperature of
the unit mass of a substance by one degree as the pressure is maintained constant. Cp is
a measure of the variation of enthalpy of a substance with temperature. Cp can be
defined as the change in the enthalpy of a substance per unit change in temperature at
constant pressure.

Specific heat at constant volume Cv is the energy required to raise the temperature of
the unit mass of a substance by one degree as the volume is maintained constant. Cv is
related to the changes in internal energy. It would be more proper to define Cv as the
change in the internal energy of a substance per unit change in temperature at constant
volume.
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