Summary


This thesis has arisen as a practical solution to the environmental problem related to the use of synthetic substances as working fluids in most of climatization equipments commercialized at present. Additionally, the thesis provides alternatives to the increasing demands for more efficient air-conditioning systems which contribute to the optimization of energy resources.

Therefore, one of the goals outlined in the development of this thesis has been the design and construction of different heat pump prototypes, particularly water to water type, based on components with different technologies, as well as evaluates their performance with the use of propane. Furthermore, this study attempts to encourage the development of new high-efficiency technologies, specifically using this hydrocarbon as working fluid.

The characterization of each prototype has been carried out making different charge studies in order to determine the minimum amount of propane in each one, looking for the maximum performance in terms of COP and capacity. These studies have lead to identify the most important operating parameters for each unit, which has allowed optimizing the performance of the components studied and the system as a whole.

Studies have shown that the main elements, such as the compressor or heat exchangers have a higher efficiency with the use of propane, compared to some synthetic refrigerants like the R407C. This is mainly due to the excellent thermodynamic and transport properties of propane, as well as the evolution of this refrigerant through the system components, which allow minimizing the irreversibilities associated with the different processes carried out inside these components.

From the point of view of the charge of propane, the tests have shown that the optimal charge is mainly depending on the design of the refrigerant circuit and the type of lubricant used. In the test, the optimal charges were obtained closed to 500 grams, which have led to high COPs under typical working conditions for heating and cooling, as well as specific cooling capacities rating from 25 and 33 per gram of propane.