POWER TRANSMISSION

Author: CARRILLO ANDRÉS ANTONIO.
Year: 2004.
University: MÁLAGA [www.uma.es].
Place of defense: E.T.S. INGENIEROS INDUSTRIALES.
Place of preparation: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS INDUSTRIALES.

Summary: The cooling and dryers in open cycle is a technology that, at present, is available on a comercial.La possibility of using solar energy for the regeneration of desiccant offers economic and environmental benefits, which justifies a study detallado.Esta thesis develops herramientoas computational for the study of solar cooling systems with desecantes.Estas tools cosisten in a number of models written for the simulation program TRNSYS, and a methodology for the coupling of the sub representing the building, the central processing unit desiccant air and the solar system to produce heat for regeneration, which must be resolved simultaneously in order to take into account the strong interactions between ellos.La desiccant wheel is considered a key element, which devotes special attention to their modeling, which uses a finite difference scheme that solves the equations numerically in partial derivatives that govern problema.Este model is validated by comparison with the results of a series of experiments being carried out with a wheel desiccant comercial.El high cost the computational model, which makes it feasible for simulations little seasonal avoided by previous generation of Tabular data on the behavior of the desiccant wheel, which (assuming the hypothesis regime cuasi-estacionario) time simulation, the resolution the desiccant wheel is limited to a proceeding interpolación.Otro important aspect, which pays special attention is the problem of controlling the scheme when using simulation step time of order horario.Finalmente, presents a case study to demonstrate the potential for extensive analysis tools developed.

Author: VIKTOROV DANOV STOYAN.
Year: 2005.
University: POLITÉCNICA DE CATALUÑA [www.upc.edu].
Place of defense: sala de conferències etseiat.
Place of preparation: ETSEIB, EDIFICI H PLANTA 8 Campus SUD.

Summary: It has been developed and built an infrastructure-oriented experimental validation of models of compact heat exchangers fins and tubes and cooling systems with overfeeding liquid. The aim has been to obtain reliable experimental data, with geometric and boundary conditions precisely defined, in order to compare results unequivocally with numerical simulations. This paper presents mathematical models, target validation, and a detailed description of the circuit air, coolant fluid, and coolant phase shift, which make up the infrastructure. These three channels are responsible for ensuring a stable and controlled for prototypes and tested for the cooling system with overfeeding liquid in a wide range of temperatures, flows and másicos powers. The design allows for the testing of prototypes of heat exchangers with different geometries and dimensions. They are presented in detail measuring instruments with their details, assembly, also describes the components and parameters of the unity of data acquisition. Special attention has been devoted to the calibration of measuring instruments as an essential part of the process of preparing the trials. It describes the process of estimating the uncertainties systematic sensors calibrated. It describes in detail the design and the methodology adopted for the analysis of uncertainty of the experimental results. The processing and analysis of the experimental data has been carried out automatically with a specially developed computer code, which is responsible for calculating the results from the measured variables, to carry out detailed analysis of uncertainties, and compare numerical results and experimental. We present experimental results obtained with the pilot developed infrastructure. We present detailed studies of compact heat exchangers in terms of cooling air, using liquid refrigerant and phase shift. It also presented results of the pilot study of liquid cooling with overfeeding. The results have been checked and verified through energy balances in all components, where the same physical quantity has been assessed in independent measurements. In order to allow the use of more general experimental results are also presented data crude variables measured during the tests. It has proposed a methodology for the validation model of compact heat exchangers based on systematic comparisons of numerical results and experimental. These comparisons have been analyzed in statistical terms with the objective to quantify the differences and make an overall assessment of the benefits of numerical model under the conditions tested. The proposed methodology for the validation of the model compact heat exchangers can be used as a basis for validation methodologies in general.

Author: Herrero Martín Ruth.
Year: 2005.
University: VALLADOLID [www.uva.es].
Place of defense: E.T.S.de Ingenieros Industriales.
Place of preparation: ETSII Universidad de Valladolid.

Summary: It has built a system RESIHP (Refrigerator Evaporative Semi-Indirecto and SIstema Heat PIpe) located in a configuration recuperating energy to evaluate the recovery of residual energy at low temperature in a test manufactured for this purpose, this characterization is made by design methodology for experiments. Likewise, it has assessed the environmental quality inside that provided this system in a climatic chamber with which gave the bank trials assessing indoor air quality as well as the characteristic parameters of thermal comfort. Finally we performed modeling of systems consisting of the main installation as are the refrigerator evaporativo semi-indirecto, battery of heat pipes and air-to-air heat pump, located inside the chamber to ensure climate the parameters of thermal comfort.

Author: garcia pinar alberto.
Year: 2005.
University: POLITÉCNICA DE CARTAGENA [www.upct.es].
Place of defense: UPCT.
Place of preparation: UPCT.

Summary: This Doctoral Thesis shows a detailed study of the behavior termo-hidráulico dock spiral tubes inserted into smooth circular cross-section. The methodology of work has been mostly experimental, where results from friction factor and the Nusselt number were correlated in terms of numbers of adimensionales it depends on the problem. Further studies were conducted flow visualization of linking itself with the characteristics of the experimental results in loss of pressure and heat transfer. First has studied the behavior of laminar regime in the docks and transition. The results have shown that Reynolds numbers below 200, the flow remains virtually unchanged. For Reynolds numbers greater than 200 the laminar flow is severely disrupted by the dock, which resulted in an increase in heat transfer very remarkable. The dock prevents the establishment of recirculaciones cross that the effects of lead float in horizontal pipes and heat transfer occurs always pure forced convection. The springs produce an advance of the transition to Reynolds numbers between 700 and 1000 in terms of its geometry. The characteristics of the flow in this region have been determined using the technique of flow visualization by bubbles of hydrogen as well as the measurement of velocity field through Velocimetría Particle Imaging (PIV) The study of the behavior of the docks in turbulent regime is done so thorough and for a family of six docks spiral. Emphasize correlations contributed to the Fanning friction factor and the Nusselt number for the family dock valid for Reynolds numbers between 1200 and 90000 and numbers Prandtl between 2.7 and 160. There has been a comparison between the docks and other enhancement techniques such as pipes mechanically deformed (corrugated and dimpled) and the spiral blades. Arguably for Reynolds numbers lower than 200 the best recommendation is to use smooth tubes. The range of Reynolds numbers between 200 and 700, blades and springs produce similar increases in the transfer of heat but the pressure drop in docks is lower. The range of Reynolds numbers between 700 and 2000 the most interesting undoubtedly will be the use of piers: they have the best performing termo-hidráulico with the added advantage of presenting a predictable operating in the region of transition. In fully turbulent flow (Re> 2000), the most interesting thing is mechanically deformed tubes used whenever the application permits. The docks will be the best alternative among the devices inserted. This Doctoral thesis presents results of both scientific and industrial interest. Emphasize data on the physical behavior of the flow in springs, which describes the different patterns of flow and its influence on the transition to turbulence. Correlations were also provided design allowing direct implementation in a software calculation and design of tubular heat exchangers.