COOLING PROCESSES PROCESSES

Author: SIERES ATIENZA JAIME.
Year: 2005.
University: VIGO [www.uvigo.es].
Place of defense: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS INDUSTRIALES.
Place of preparation: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS INDUSTRIALES.

Summary: The aim of this thesis has been the theoretical and experimental study of the processes of heat transfer and mass transfer in distillation columns wrapped for refrigeration by absorption with amoníaco-agua. The theoretical study has been carried out through numerical simulation, and the pilot through the design, construction and evaluation of a bank of tests. Discusses the importance of theory and the effects of the purification process in ammonia vapors occurring in the generator in a system that dampens amoníaco-agua, contemplándose the possibility of using an evaporator type dry or flooded. We present a model for analyzing differential calculus processes simultaneous transfer of color and masses that occur in the various components of a system that dampens NH3-H2O. The model has particularized and implemented computer to simulate two components typically used for the purification process of the mixture amoníaco-agua: a stretch of packed column and a rectifier. For the column is considered a kind of random packing and the recitificador, a type serpeentín helical geometry. It has been developed, in addition, a simplified model for a stretch of packed column, which could be used to estimate volumetric coefficients of mass transfer from experimental measurements. The experimental work has been carried out through the design and construction of a bank of tests. The bench trial is designed to analyze a section of column packed function as section correction or exhaustion and working conditions similar to those found in a cooling system by absorbing amoníaco-agua for refrigeration production of approximately 10 kW. It describes the bank built test, indicating the various components used and their disposition. It also describes the data acquisition system which has been equipped with indication of the types of sensors used, as well as their main features and its location at the facility. We present experimental results obtained and analysis. It has analyzed the structured packing and packaging Sulzer BX random chairs Berl ceramics 1 / 2 "rings Rasching glass 15 mm and chairs Novalox ceramics 1 / 2". Based on the measurements were obtained and analyzed various parameters that are commonly used to characterize the process of mass transfer in packed columns. We discuss the suitability of each of these parameters and the results of some of them are compared with those available in the scientific literature. By applying models developed calculation and the experimental data measured, it has been possible to determine the mass transfer coefficients for the packages tested, which are an essential parameter for sizing and currently are not available for these systems. There have been correlaicones coefficient of volumetric mass transfer for packaging analyzed. These correlations are useful and important in the design of a column packed in cooling systems for absroción with NH3-H2O.

Author: GONZÁLEZ MARTÍN MANUEL IVÁN.
Year: 2006.
University: BURGOS [www.ubu.es].
Place of defense: ESCUELA POLITÉCNICA SUPERIOR.
Place of preparation: ESCUELA POLITÉCNICA SUPERIOR.

Summary: In this work has been designed, built and tested a prototype experimental solar refrigerator by adsorption. Its most innovative features are: Use the pair of working activated carbon / methanol. The variety of activated charcoal is the CNR115, manufactured by NORIT. According to our measurements, this variety gives equal to other factors, cycle efficiencies higher than those of other varieties described in the literature. It incorporates a catchment system for solar concentration, based on the compound parabolic concentrator (CPC). Our design CPC is unprecedented and allows an abstraction combining solar diurnal efficient with adequate refreshment night generator machine. Water-cooled condenser from a tank attached to the prototype. The circulation of water is guaranteed by means of a continuous flow pump, powered by a small photovoltaic module. Registration System pilot of the continuous concentration of methanol in the bed of coal, which can crawl in a very detailed thermal exchanges in all elements of the machine and in all stages of cooling. The machine was tested experimentally during the summer of 2005. The average efficiency (COP) during the campaign of measures was 0.09, a value comparable to that displayed by other similar prototype described in the literature. It also has developed a computational model to simulate the operation of the prototype, which has studied what design parameters should be amended in order to optimize the performance of future versions of the former. Among them are the need to increase the uptake of solar maximum efficiency of the generator, to implement a design more compact set of evaporator / compound cold and increase the contact area between the methanol content in the evaporator and gender to be cool.