Influence of the Thermophysical Fluid Properties of the New Ozone-Safe Refrigerants on Performance.
Influence of the Thermophysical Fluid Properties of the
New Ozone-Safe Refrigerants on Performance.
Didion, D. A.
International Journal of Applied Thermodynamics, Vol.
2, No. 1, 19-35, March 1999.
refrigerants; ozone; azeotropic mixtures; thermophysical
properties; two-phase flow; vapor compression cycle;
The selection a working fluid as a refrigerant for the
vapor compression cycle is discussed. For thermodynamic
performance to be optimized particular attention must be
paid to the fluid's critical point and molar heat
capacity. To achieve a reasonable balance between
volumetric capacity, which implies equipment size, and
coefficient of performance, which is efficiency, it is
necessary to select a fluid with a critical point such
that the application's condenser will operate in a
reduced temperature range of approximately 0.7 to 0.9.
It is also necessary to select fluids within a rather
limited range of molar heat capacity values. The
specifics as to how these properties effect the cycle's
performance are presented in detail. For a better
matching of the working fluid to a given application,
both azeotopic and zeotropic mixtures of fluids are
used. The characteristics and performance advantages and
disadvantages of these mixtures are discussed.