Frío industrial y aire acondicionado

Este texto pretende recoger los contenidos de la asignatura Frio Industrial,impartida durante diez años en la Escuela Técnica Superior de Ingenieros Industriales de la Universidad de Castilla-La Mancha, y que han sido actualizados permanentemente durante este tiempo. La asignatura se mantiene tras los recientes cambios de planes de estudio, perteneciendo ahora al Máster de Ingeniería Industrial. Tras seis años en los que este texto se ha editado desde la propia Escuela, pretendemos ahora dar el salto al Servicio de Publicaciones de la Universidad de Castilla-La Mancha, esperando que esto sirva para ampliar la difusión del texto a otras escuelas, no necesariamente de dentro de la universidad

Effect of fatty acid composition of methyl and ethyl esters on the lubricity at different humidities

Lubricity of individual fatty acid methyl or ethyl esters and biodiesel fuels has been measured using a high frequency reciprocating rig (HFRR). Tests have been carried out varying the ambient humidity to assess the effect of this parameter on the lubricity of the fuels. The European standard proposes a single humidity correction factor for all the fuels, regardless their composition. It has been proved in this study that this factor is not constant and it depends on the fuel composition. For this reason two different correlations have bee n proposed for the estimation of the humidity correction factor and normalized wear scar as a function of different fuel compositional characteristics. The influence of the water content on the lubricity and the relationship between humidity and water content of the fuel has been studied revealing that the effect of the air humidity is an indirect effect of the hygroscopy of the fuel

Analysis of labour market needs for engineers with enhanced knowledge in renewable energy in some European and Latin-American Countries

One of the main challenges related to the renewable energy labour market is that of human capital and as a consequence the educational profile of future employees is of paramount importance. Unfortunately, the skill level gained at University does not always fit with the practical needs of industry thus reducing the benefit-cost ratio of new employees and slowing down the transition to a green economy. Within this context, ‘The Crux’ project co-funded by EU under the framework of the Erasmus + programme aims at improving the renewable energy engineering curriculum at different university levels in several Universities of Latin America and Europe. In order to better appreciate the potential impact of the project, a survey on the labour market need for specialists with enhanced knowledge and skills in renewable and sustainable energy technologies has been conducted in the related EU and Latin America countries. More precisely, 60 organizations have been interviewed and almost 70% of them are interested in employing engineers with enhanced knowledge on renewable energy in the next three years. The analysis has shown significant discrepancies between EU and Latin American organizations. In fact, while future employees in EU countries will be mainly related to solar energy and management, the former together with wind and biomass will represent the main renewable energy working sector in Latin American countries. Moreover, MSc level will be the most demanded in EU while bachelor education seems to satisfy the future industry requirements in Latin America. Despite each country having its own needs, the research carried out under this EU project confirms the potential of renewable energy education on the global labour market in the near future

Prediction of the cetane number of biodiesel using artificial neural networks and multiple linear regression

Models for estimation of cetane number of biodiesel from their fatty acid methyl ester composition using multiple linear regression and artificial neural networks were obtained in this work. For the obtaining of models to predict the cetane number, an experimental data from literature reports that covers 48 and 15 biodiesels in the modeling-training step and validation step respectively were taken. Twenty-four neural networks using two topologies and different algorithms for the second training step were evaluated. The model obtained using multiple regression was compared with two other models from literature and it was able to predict cetane number with 89% of accuracy, observing one outlier. A model to predict cetane number using artificial neural network was obtained with better accuracy than 92% except one outlier. The best neural network to predict the cetane number was a backpropagation network (11:5:1) using the Levenberg-Marquardt algorithm for the second step of the networks training and showing R = 0.9544 for the validation data

Emission factors for PM2.5, CO, CO2, NOx, SO2 and particle size distributions from the combustion of wood species using a new controlled combustion chamber 3CE

The objective of this research was to determine emission factors (EF) for particulate matter (PM2.5), combustion gases and particle size distribution generated by the combustion of Eucalyptus globulus (EG), Nothofagus obliqua (NO), both hardwoods, and Pinus radiata (PR), softwood, using a controlled combustion chamber (3CE). Additionally, the contribution of the different emissions stages associated with the combustion of these wood samples was also determined. Combustion experiments were performed using shaving size dried wood (0% humidity). The emission samples were collected with a tedlar bag and sampling cartridges containing quartz fiber filters. High reproducibility was achieved between experiment repetitions (CV < 10%, n = 3). The EF for PM2.5 was 1.06 g kg(-1) for EG, 1.33 g kg(-1) for NO, and 0.84 g kg(-1) for PR. Using a laser aerosol spectrometer (0.25-34 mu m), the contribution of particle emissions (PM2.5) in each stage of emission process (SEP) was sampled in real time. Particle size of 0265 pm were predominant during all stages, and the percentages emitted were PR (33%), EG (29%), and NO (21%). The distributions of EF for PM2.5 in pre-ignition, flame and smoldering stage varied from predominance of the flame stage for PR (77%) to predominance of the smoldering stage for NO (60%). These results prove that flame phase is not the only stage contributing to emissions and on the contrary, pre-ignition and in especial post-combustion smoldering have also very significant contributions. This demonstrates that particle concentrations measured only in stationary state during flame stage may cause underestimation of emissions. (C) 2017 Elsevier B.V. All rights reserved

Application of quartz tuning forks and extensional microresonators for viscosity and density measurements in oil/fuel mixtures

Real time monitoring of the physical properties of liquids is of great concern in the automotive industry. For example, tracking the viscosity of lubricating oils is of great importance because they are exposed to dilution with diesel fuel as result of late-injection processes, which are essential for regenerating diesel particulate filters. Here we describe two in-plane movement based resonators and their capability to assess oil dilution with diesel and biodiesel fuels. One of the resonators is a state-of-the-art micron-sized AlN-based rectangular plate, actuated in the first extensional mode in the MHz range. The second resonator is a commercially available millimeter-sized quartz tuning fork, working at 32.7 kHz. Electrical impedance measurements were performed to characterize the performance of both resonators in various liquid media over a wide range of viscosities. These measurements were compared with the results obtained with low-cost electronic circuits also developed in this work. In order to track density and viscosity of different fluids we have measured two parameters by various techniques: the resonance frequency and the quality factor