Tesis doctoral de Arturo González Gil
Due to unsustainable growth of air conditioning market, a great interest in solar cooling technologies has emerged. The coincidence between availability of solar irradia-tion and peaks of cooling demand makes solar cooling a very attractive option to replace conventional refrigeration machines based on electricity. What is more, solar cooling sys-tems normally use natural refrigerants that are not harmful to the environment. However, an improvement of the current technology is needed for solar cooling systems to compete with electricity-powered air conditioning systems. in this work, a novel air-cooled single-double-effect libr/h2o absorption prototype is proposed as a solution to improve the viability of solar cooling systems. This prototype presents the following distinguishing features: firstly, it is directly air-cooled, which means that no cooling tower is needed; secondly, it is made up by compact heat exchangers, which allows for a reduced size of about 1 m3; thirdly, it incorporates an adiabatic ab-sorber operating with flat-fan solution sheets, which permits the working solution not to crystallize at high ambient temperatures; lastly, it can be powered by solar heat in its sin-gle-effect mode (4.5 kw), or by an alternative source such as fuel or waste heat in its dou-ble-effect stage (7 kw). In this way, 100% of the cooling demand may be supplied by a sin-gle absorption machine using solar energy as far as possible or, when it is not available, efficiently utilizing a fuel or even waste heat, for instance in a trigeneration system. this thesis includes a detailed description of that single-double-effect absorption prototype as well as the fundamentals for its numerical simulation. Likewise, experimental results from a testing campaign carried out in Madrid during 2010 are presented and dis-cussed. A solar facility with evacuated flat-plate collectors was used to test the single-effect operation mode of the prototype. In turn, the double-effect stage was fired by a thermal oil facility with electrical resistances. As relevant results of the whole experimental campaign it is worth mentioning that the single-effect stage was able to work with cop values around 0.6, whereas the double-effect mode permitted to achieve values of about 1.0. The chilled water temperatures mostly ranged between 14°c and 16°c in single-effect operation mode, while they were around 12°c for the double-effect stage. Besides, it is highly noteworthy that after some 125 hours of operation under a wide range of condi-tions (outdoor temperatures up to 39.5°c), no solution crystallization was noticed. on the other hand, this work includes an in-depth description of the absorber as-sembled in the single-double-effect prototype. Furthermore, a mathematical model is de-veloped for simulation of air-cooled flat-fan sheets adiabatic absorbers. As far as we know, there is not any numerical modeling for this kind of absorbers in the literature. Based on that model, which was as well experimentally validated in this study, the capacity of the prototype absorber is optimized as a function of the energy consumption of its ancillary equipment (solution pump and fan). finally, the positive results derived from this work may be regarded as an important contribution to the development of air-cooled libr/h2o absorption technology. Even though a few improvements in the prototype are still required, it seems that the proposed system represents a feasible alternative to overcome some of the major obstacles concern-ing solar air conditioning. on the other hand, this work includes an in-depth description of the absorber as-sembled in the single-double-effect prototype. Furthermore, a mathematical model is de-veloped for simulation of air-cooled flat-fan sheets adiabatic absorbers. As far as we know, there is not any numerical modeling for this kind of absorbers in the literature. Based on that model, which was as well experimentally validated in this study, the capacity of the prototype absorber is optimized as a function of the energy consumption of its ancillary equipment (solution pump and fan). finally, the positive results derived from this work may be regarded as an important contribution to the development of air-cooled libr/h2o absorption technology. Even though some improvements in the prototype are still required, it seems that the proposed system represents a feasible alternative to overcome some of the major obstacles concern-ing the solar air conditioning.
Datos académicos de la tesis doctoral «Novel single-double-effect libr/h2o absorption prototype with a highly efficient direct air-cooled adiabatic absorber«
- Título de la tesis: Novel single-double-effect libr/h2o absorption prototype with a highly efficient direct air-cooled adiabatic absorber
- Autor: Arturo González Gil
- Universidad: Carlos III de Madrid
- Fecha de lectura de la tesis: 23/11/2011
Dirección y tribunal
- Director de la tesis
- Marcelo Izquierdo Millan
- Tribunal
- Presidente del tribunal: Francisco javier Rey Martinez
- José daniel Marcos del cano (vocal)
- nestor Garcia hernando (vocal)
- robert Ghirlando (vocal)