Software to design a cooling tower

Treballs Finals de Grau d'Enginyeria Química, Facultat de Química, Universitat de Barcelona, Curs: 2021-2022, Tutor: Carles Fité PiquerCooling tower is a unit operation widely used in the chemistry industry. It is used to cool water that has lost its utility as a refrigerant because it has been used in condensers and heat exchangers. After cooling, water can be reused or send back to the environment without thermal damage. Although cooling towers can generate large steam plumes, which causes many people to associate this steam with smoke and pollution, it is a clean operation that takes advantage of the principle of cooling by water evaporation. In this project, a tool is created to facilitate the design for this type of operation. That is why an executable application has been made, using the python programming language. The program calculates the height of a counterflow water cooling tower for a given set of parameters: water and air inlet conditions, water outlet conditions and individual transfer coefficients. The solution is obtained by solving the mass and heat balances and differential transfer equations through the gas and liquid film along the cooling tower. This tool is though for a user that can be specialized or not in cooling towers, in order that the user can get design parameters easily and quickl

Antroponimia hispanoárabe. (Reflejada por las fuentes latino-romances).

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Energy retrofits in social housing. Analysis of its thermal behaviour.

468 p.This PhD thesis deals with the evaluation of energy renovations in buildings, facing the different parts involved in that process, such as data acquisition and monitoring, data treatment (by means of building models) and analysis of obtained results. The interest of the thesis was awoken by the current energy situation where the construction sector is responsible of over 40 % of the total energy consumption in the European Union. Besides, building energy consumption has kept rising in the recent years due to several factors, such as a growth in population, an increasing demand for healthy comfortable indoor environment and for higher comfort standards. Hence, reducing the need for energy sources is a key factor in the development towards a sustainable energy future. For that reason, energy efficiency in buildings is a priority goal for the European Union, and this energy and environmental situation requires improving the energy performance of buildings. Taking into account the age of the building stock in the European Union, and specially in Spain, and the low thermal requirements existed in the past, it can be stated that in order to reduce the energy consumption, the main effort must be focused on the challenges of improving the existing stock. This energy situation is closely related to global CO2 carbon emissions. A massive decarbonisation of the world economy needs to be achieved while improving the life standards of the global population. However, other aspects must be taken into account when energy issue is treated in buildings. In those areas or population sectors where immediate economic priorities override environmental concerns and climate change alone is often not sufficient, improving energy performance in buildings is also a way driven to alleviate the so called fuel poverty. Implications and benefits of energy renovations thus have consequences not only in the reduction of CO2 emissions and energy savings but also in financial and social aspects, closely connected amongst them, such as the reduction of mentioned fuel poverty. Thus, methodologies for evaluating in an accurate way the effect of different energy renovations are needed more and more by the different agents involved on building retrofits. For policy makers it is useful, on the one hand, to check whether a given energy renovation fulfils the conditions required by law; on the other hand, to check whether a given incentive has been invested in a suitable way or not. As for architects and engineers, to identify the most adequate energy renovations for a specific building and climatic area. Thus, the development of this thesis faces the different steps given in every analysis on building energy performance. It is started with the analysis of the building stock in this region. Afterwards, two kind of data acquisition are presented: in an empty dwelling, for obtaining data mainly from the passive characteristics of the building; and in several occupied dwellings, more led to obtain data about occupants’ behaviour and profiles. Obtained data from both studies are used afterwards to define two different building models. Finally, possibilities of evaluation of results obtained from mentioned building models are described. For presenting the development of mentioned work, this PhD thesis is divided into 4 different parts. The first one, which is the introduction, encompasses Chapter 1 and Chapter 2, where the state of art of the different aspects treated in this thesis are presented, and objectives and methodology are described, respectively. The second part exhibits the experimental research carried out in this thesis. Firstly, a field study of 10 social dwellings is reported in Chapter 3. Ten dwellings are selected to be representative of the different types of buildings built during the 20th century. This study provides a huge amount of data about the current situation of the social building stock. Indoor temperature and relative humidity is logged in each dwelling during a year, obtaining information not only about indoor comfort, but also about operating conditions of each dwelling and occupants' behaviour. Energy consumption information is gathered, by means of energy bills. Additionally, questionnaires are filled in by the occupants, complementing the information obtained by other sources. This study provides an overview of the real energy performance of the social apartments, as well as an important reference for defining later a representative operating condition profiles on social building sector. Analogously, Chapter 4 is focused on the description of a detailed monitoring of a representative dwelling, selected according to the previously carried out classification. This monitoring covers two scenarios: The first one, carried out in winter 2012, and a second one, carried out in winter 2013, after a thermal improving by means of a windows replacement is executed. Around 60 temperature sensors are placed within the vacant dwelling, obtaining data for characterizing in detail the thermal performance of the constructive elements of the dwelling. Afterwards, the treatment of the data obtained from this experimental part is carried out mainly using two kinds of simulation models. The development of mentioned models is dealt with in the third part. It embraces Chapter 5 (the white box model, TRNSYS) and Chapter 6 (grey box model). Data obtaining in the second monitoring (the detailed monitoring of the selected dwelling) are used for defining the RC Model, and validating and calibrating both the RC Model and TRNSYS model. Meanwhile, information obtained from the monitoring of the ten social apartments is used to define occupation and operating profiles representative of social building apartments. Finally, the last part of this thesis has focused on the simulation design and evaluation of results obtained from the above mentioned simulations. It is explained in two different chapters. Energy savings obtained as a result of improvements both on building envelope and heating systems, is presented and evaluated in Chapter 7, under economic, energy, environmental and comfort criteria. This study is carried out on a dwelling scale. The simulations show firstly the results of 64 possible combinations of energy savings measurements on the building envelope. After choosing one of the evaluated combinations, the impact of the different heating control strategies on the final energy consumption and indoor comfort are presented. Meanwhile, the exergy approach usefulness is evaluated in Chapter 8, where a brief literature review about this concept in buildings applications is presented, followed by two papers developed in the Faculty of Architecture of TU Delft. These papers explore the possibilities of this approach on the analysis of energy renovations on an entire building scale, using as base case the reference building of this PhD Thesis. Taking into account the work presented in this PhD Thesis, different aspects can be highlighted. The energy renovations in buildings present a great potential for reducing (in an important manner) the CO2 emissions of the construction sector, but also present significant social and economic benefits in the different scales. RC models and TRNSYS models can be a very useful and suitable tool in order to evaluate energy consumption in buildings. Finally, the importance of considering a holistic approach when energy consumption the of building stock is evaluated, has also been remarked in this thesis, and the role that aspects such as human behaviour, operating conditions (simulations in this thesis present differences of around 50% on energy consumption depending on the assumed operating conditions) and control strategies play in the global energy consumption is proved. In the close future, two different lines are identified to develop. The improvement and adjustment of the RC model must be developed, and later, the interaction of the RC model with the TRNSYS model, and both of them with the Energy System Plant (experimental plant for testing different building energy systems) must be explored. This way, a workflow starts on the field study of a given building which is used for defining the RC Model. Defined RC model calculates the energy demands, and that energy demands feeds the TRNSYS model, which is connected to the Energy Systems Plant. Thus, different energy systems are tested in laboratory under real conditions of energy demands. Moreover, the TRNSYS model calibrated in this PhD Thesis, as well as the first results obtained from it in the last part of this PhD Thesis must be the base to develop a building energy renovations handbook, useful for the different agents of the construction sector. This handbook, which can be developed with the support of the Laboratory for Quality Control in Buildings of the Basque Government (LCCE) will present economic, energy and environmental results of different energy renovation strategies, on different kind of existing buildings, in different climatic area, based on dynamic simulations and experimental data.Basque Government, through the Department of Education, Universities and Research's Personnel Research Training Program (BFI09-81

Antroponimia hispanoárabe. (Reflejada por las fuentes latino-romances) (parte final).

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Assessing drone trajectory error and improving flightpath predictability

The rapid growth of the drone industry aims to develop applications and implement them in a wide range of areas. This includes busy urban areas for services such as surveillance, deliveries and monitoring. In this context, it is essential to have an excellent design of the airspace. This thesis focuses on the analysis of a dataset from the Very Large Demonstration project of CORUSXUAM, which contributes to the U-Space mission of developing a safe, sustainable, efficient and fully digitalized airspace for integrated Urban Air Mobility which does not interfere with current ATM operations. The dataset includes flight plans, telemetry, and U-space predictions for 72 drone flights. The analysis involves comparing intended trajectories with actual flight paths to identify factors contributing to deviations from the flight plan and computing relevant performance parameters to assess the adherence of the drones to the flight plan. This is done with the use of dynamic time warping algorithms in order to establish a link between the telemetry points and the flight plan, which sets the basis for the next section of the project. Having processed the data, during this project we develop machine learning models to predict telemetry parameters based on the input flight plan. Several models are tested and evaluated to find the most suitable one for our objective. The project also involves visualizing and interpreting the data to gain insights of the drone performance and adherence to the flight plan. Position prediction opens up a new area of research and in this project the approach is to use an alternative method to define the spacing and size of the airways that compose the flight plans so as to dictate safety areas to prevent any possible conflict that could appear in future flights in a busy area if the spacing were to be below the thresholds. The results of this study demonstrate a successful progression from raw data to a comprehensive analysis, offering valuable insights for evaluating drone performance and predicting flight times. The development of various data visualization functions enabled efficient and effective interpretation of the data. While the obtained results with the available dataset are remarkable, the potential for further improvement lies mainly in acquiring a larger dataset with more features and samples, which would enhance the performance of the machine learning models and yield even more accurate predictions.Objectius de Desenvolupament Sostenible::9 - Indústria, Innovació i Infraestructur

Relaciones aire agua en sustratos de cultivo como base para el control del riego. Metodología de laboratorio y modelización

La sustitución del suelo agrícola por un sustrato de cultivo reduce considerablemente la capacidad tampón del medio en el que se desarrollan las raíces. Esto presenta la ventaja de facilitar el control del cultivo, y el inconveniente de hacerlo más vulnerable a la incidencia de factores no controlados. El conocimiento preciso de las propiedades físicas del sustrato, junto con el manejo del agua de riego, proporcionan las herramientas adecuadas para potenciar el control del cultivo mediante el control de las relaciones aire agua, y para minimizar las repercusiones negativas derivadas de la incidencia inevitable de factores no controlados. El estudio de las propiedades físicas de los sustratos se plantea como un modelo de cultivo, que a su vez consta de dos submodelos. El primero relaciona las variables medidas en laboratorio con las condiciones físicas creadas en el entorno radicular. El segundo relaciona estas condiciones físicas con la respuesta del cultivo. En este trabajo se aborda el primero de estos dos submodelos. El valor predictivo de un modelo es tanto mayor cuanto mayor sea la fiabilidad de las mediciones efectuadas, y cuanto más fiable sea el modelo de simulación empleado. La obtención de medidas fiables requiere el empleo de una metodología adecuada a las características del material sometido a análisis. Se han analizado cuatro metodologías de laboratorio: la descrita por De Boodt y colaboradores, el “Método de Referencia” de la International Society for Horticultural Science (ISHS), la metodología aplicada por el Agricultural Devepment and Advisory Service (ADAS) del Reino Unido, y la aplicada por el Laboratorio de Horticultura de la Universidad del Estado de Carolina del Norte. A partir de este análisis, se han planteado algunas modificaciones, y se han hecho nuevas propuestas. Las mediciones de laboratorio deben informar sobre su fiabilidad, es decir, sobre la exactitud y la precisión. Todas las metodologías empleadas hasta el momento informan adecuadamente sobre la precisión, pero ninguna lo hace sobre la exactitud. La picnometría de gases proporciona una determinación independiente del volumen ocupado por aire, y constituye una vía de solución a este problema. La saturación de las muestras por vacío, y la aplicación del principio de Arquímedes para evaluar el volumen ocupado por el material sólido, constituyen unas alternativas adecuadas al estudio de las variables relacionadas con la disponibilidad de aire y agua para el sistema radicular de la planta. El desarrollo metodológico se completa con un estudio del origen y la magnitud de los errores de medida en la metodología de laboratorio. Para la simulación del comportamiento hídrico del sustrato se plantea un modelo logarítmico normal, basado en la hipótesis de la distribución normal del logaritmo del diámetro de poro. La ley de capilaridad de Jurin relaciona la distribución del tamaño de poro con la distribución de aire y agua. El modelo se completa con dos parámetros de modulación. Se obtiene -de esta forma- un modelo totalmente conceptual, definido por cuatro parámetros: media, desviación estándar, desplazamiento y escalado, correspondiendo cada uno de ellos a una variable física concreta. El comportamiento de este modelo se compara con otros modelos -tanto experimentales (polinomios de tercer grado) como semi-experimentales (Van Genuchten)- empleados en la bibliografía para describir la curva de retención de agua. Tanto en el desarrollo de la metodología de laboratorio como en el estudio del modelo se ha empleado una gama de sustratos de características muy diferentes –naturales y sintéticos, orgánicos y minerales, granulares y fibrosos, con mayor o menor porcentaje de porosidad interna, etc-, que proporcionan información sobre la fiabilidad de la metodología y del modelo en condiciones muy diversas. Las variantes metodológicas introducidas –saturación por vacío y determinación de volúmenes por inmersión- proporcionan medidas más ajustadas de las variables, para informar sobre la disponibilidad de aire y agua en el medio poroso. La pérdida de sustrato durante la saturación representa, en algunos sustratos, una importante fuente de error. El factor que más influye en esta pérdida es la propia naturaleza del sustrato. La incidencia del tipo de cierre del contenedor portamuestras y del método de saturación es mínima. Se han ensayado distintas variantes de la rutina de laboratorio, que han permitido establecer una metodología con una incidencia escasa de errores de medida. Se ha planteado la picnometría de gases como método alternativo para obtener una medida independiente del volumen ocupado por aire en la muestra de sustrato tensionada. Se ha conseguido un control elevado del proceso de medida, pero, sin embargo, es necesario modificar la metodología, ya que la magnitud del error experimental se encuentra en el límite del intervalo admisible. El modelo logarítmico normal se ha comparado con el modelo de Van Genuchten, y con dos modelos polinómicos. El resultado es claramente ventajoso para el modelo propuesto. Su carácter conceptual le proporciona mayor capacidad de simulación que el modelo de Van Genuchten. El ajuste de los modelos polinómicos es claramente inferior a los otros dos. En el análisis de sensibilidad se ha estudiado la incidencia de los errores de estima de los parámetros del modelo en el valor calculado por el mismo. El valor de la media de la distribución normal incide en el valor de la tensión a la que se produce el error máximo, pero no en su magnitud. La magnitud del error es tanto mayor cuanto menor es el valor de la desviación estándar de esta distribución. La magnitud del error es función, además, de la magnitud de los errores de la media () y de la desviación estándar (). Finalmente, se ha estudiado la incidencia de los errores de medida. La falta de valores de referencia absolutos y relativos, limita la posibilidad de conocer la exactitud de las mediciones efectuadas. En esta situación, el estudio comparativo de los residuos, y de sus valores absolutos, proporciona una estimación de la incidencia relativa de errores sistemáticos (exactitud) y de errores aleatorios (precisión). La precisión muestra variaciones importantes de unos sustratos a otros. Respecto a las tensiones, la mayor variabilidad se presenta a valores bajos (de 0 a 30 cm de columna de agua), disminuyendo considerablemente para valores más elevados (50 a 100 cm de columna de agua). La variabilidad de las medidas tiene una componente debida a la heterogeneidad del sustrato y otra, a los propios errores de medida. Las metodologías aplicadas no discriminan estas dos componentes. La magnitud de la primera tiene una fuerte incidencia en el manejo del riego, por lo que es importante desarrollar rutinas metodológicas que permitan su evaluación