This Thesis wants to follow the research line of refrigeration systems experimental characterization and modeling, using hydrocarbons (HCs) as refrigerants, started in 1994 by IMST group in the Institute for Energy Engineering of the Polytechnic University of Valencia. This line responds to the necessity of finding alternative solutions of the use of CFCs and HCFCs, since their ODP (Ozone Depletion Potential), and HCFCs, due to their GWP (Global Warming Potential).

Main objective of this Thesis was to analyze, using experimental measurements and with the help of a mathematic model validated with these measurements, the relation between working conditions and different energetic losses that exist inside the compressor when it works with R407C (HFC) and his potential replacement, Propane (HC) as a natural refrigerant environmentally friendly.

The mathematic model used, purely theoretic, allows obtaining internal variables of a reciprocating compressor given operating conditions. In order to this, model faces the two main physical problems that are present, the fluid flow dynamic (hydraulic problem) and the internal heat exchange (thermal problem), calculating each of them separately and solving the global problem repetitively. His use has permitted to explain experimental behaviors observed in different operating conditions, explaining in each of them the effect of internal energetic losses.

Compressor experimental characterization was done in a calorimetric test bench capable of automatically control of suction and discharge pressures, superheat and subcooling of the cycle. In this facility 124 experimental points have been obtained for both refrigerants, so covering the application range of medium and high evaporating temperature compressors. Furthermore, in order to be able to analyze the influence of compressor entry temperature, tests were made with two different superheats, allowing enlarging current information about optimal superheat in compressors that work with Propane. 

Experiments confirm that the use of Propane in hermetic piston compressors designed to work with R407C increases the efficiency, in this case for all operating conditions. This rise improves when evaporation and condensation temperature are higher, reaching 13% for the maximal evaporation and condensation temperatures tested.

Conclusions of this work want to encourage new high efficiency compressors development, which use Propane as a refrigerant fluid, and also the possibility of reuse existing models, prepared to work with other refrigerants and whose design can be adapted for his use with Propane.