TERMODYNAMICS

Author: DELGADO TORRES AGUSTÍN MANUEL.
Year: 2006.
University: LA LAGUNA [More theses of this university] [www.ull.es].
Place of defense: FACULTAD DE FÍSICA.
Place of preparation: FACULTAD DE FÍSICA.

Summary: In this thesis is the study of the use of thermal energy from solar energy to power the process of desalination by reverse osmosis. Faced with the combination of this process with wind systems and solar photovoltaic systems, the literature review conducted in relation to the combination with solar thermal systems reveals a significant shortage of proposals for design and implementations. To make the link it has been assumed that part of the thermal energy supplied by the solar heat is converted into mechanical energy by means of a cycle of power based on the Rankine cycle. This mechanical energy is used to cover the main energy of a unit of reverse osmosis seawater. On the other hand provides for the possibility of subsequent use of the thermal energy released by the Rankine cycle in other applications such as desalination preheat itself seawater fed into the reverse osmosis unit or a distillation unit, being analyzed in detail the first option. There has been an analysis of solar desalination system assuming that the solar heat can be formed by low temperature sensors (drawings, concentration or parabolic segments CPC and vacuum tubes) or sensors concentration in a shaft with monitoring (sensor-parabolic cylinder). In each of the two options has been done analyzing the solar cycle with different substances such as working fluid and Rankine cycle with two configurations of the solar cycle as a whole: configuration for direct steam generation and configuration with heat transfer fluid . Our results indicate that the low temperature technologies analyzed be possible to achieve yields of solar cycle of up to 10%. Against this setting, with models of transducers parabolic cylinder-analyzed it is possible to achieve yields of solar cycle over a 22%. In the case of these sensors is analyzed in detail the behavior of the performance of solar cycle using toluene and siloxanos as working fluids organic Rankine cycle with overheating and regeneration. As for the reverse osmosis system of seawater, it is considered that it makes use of devices exchangers pressure to recover the energy of rejection at high pressure and membranes winding spiral last generation. The results of the coupling of the reverse osmosis unit with a solar thermal sensors consist of parabolic cylinder-indicate that it is possible to obtain, of course a value of solar irradiance on the opening of direct probe of 850 W per square meter, up to 109 l / h and between 88 l / h and 94 l / h of desalinated water per square meter of surface opening of the solar thermal whether the organic Rankine cycle regenerative used toluene or siloxanos as working fluids, respectively, and the temperature of condensation cycle sets in 35Â ° C. With a configuration of organic Rankine cycle double cascade is possible to obtain to 75 l / h and 55 l / h of desalinated water per square meter of surface opening of the sensor if used toluene and hexametildisiloxano as working fluids upper respectively. In that case, the electrical power produced by the lower cycle with isopentano as fluid job will be sufficient to meet the energy in the form of electricity system different from the high-pressure pump of the reverse osmosis unit.