PERFORMANCE EVALUATION OF LOW EXERGY SYSTEMS DEPICTING DECENTRALIZED DEDICATED OUTDOOR AIR SYSTEM COUPLED WITH RADIANT COOLING IN THE TROPICS

Ph.DDOCTOR OF PHILOSOPH

Model Predictive Control of HVAC Systems: Design and Implementation on a Real Case Study

The final aim of this work is to design, implement and test a controller on a real testbed kindly provided by KTH. The control paradigm presented in this thesis is a MPC that aims at saving energy as well as keeping the temperature and the CO2 concentration in a comfort range that guarantees the wellness of room occupants. To improve the knowledge of the plant, we also study the problem of modeling both the dynamics of of the system to be controlled and of the dedicated actuation syste

A review of advanced air distribution methods - theory, practice, limitations and solutions

Ventilation and air distribution methods are important for indoor thermal environments and air quality. Effective distribution of airflow for indoor built environments with the aim of simultaneously offsetting thermal and ventilation loads in an energy efficient manner has been the research focus in the past several decades. Based on airflow characteristics, ventilation methods can be categorized as fully mixed or non-uniform. Non-uniform methods can be further divided into piston, stratified and task zone ventilation. In this paper, the theory, performance, practical applications, limitations and solutions pertaining to ventilation and air distribution methods are critically reviewed. Since many ventilation methods are buoyancy driving that confines their use for heating mode, some methods suitable for heating are discussed. Furthermore, measuring and evaluating methods for ventilation and air distribution are also discussed to give a comprehensive framework of the review

Full Proceedings, 2018

Full conference proceedings for the 2018 International Building Physics Association Conference hosted at Syracuse University

Numerical and Experimental Investigations on Corrosion and Self-Protection Processes in Reinforced Concrete

The chloride induced corrosion of steel in concrete is one of the biggest durability issues affecting structures worldwide. Concrete structures that are installed in marine environment and those exposed frequently to de-icing salts in the winter season, such as bridges and parking structures, are particularly susceptible to corrosion induced damage. In worst cases, the structure is unable to fulfil its entire service life and needs extensive repairs or is decommissioned quite early. Such situations can have a strong impact on society which is dependent on infrastructures for mobility and transportation of essential materials. Moreover, the economic losses are predicted in billions in the coming future and can impact the global economy. In an attempt to increase the service life of concrete structures with respect to chloride durability, Layered Double Hydroxides (LDH) are introduced as chloride ion entrapping additive in concrete. LDH encapsulates chloride ions from the environment which can extend the service life of concrete structures. It can also be tailored to deliver corrosion inhibiting ions which can mitigate the chloride induced damage in concrete. A new concrete mix with LDH was developed in this work for building long lasting infrastructure exposed to chloride ingress in submerged marine zones. Predictive modelling approaches are used to study the corrosion processes and chloride durability of concrete. Multi-ion transport model is used to predict the efficiency of LDH in concrete concerning chloride ingress. Computational results are presented which compare chloride ingress in concrete with and without LDH. Formation factor has been used in this study to determine the microstructure related properties of concrete with and without LDH. Additionally, experimental investigations are presented which report on the stability and chloride binding capacity of LDH in synthetic alkaline solutions, concrete pore solutions, mortars and also in concrete. The compatibility of LDH with cement is also presented. The work highlights that LDH is able to improve the chloride durability of concrete. Furthermore, In-situ investigations are carried out to understand the stability of LDH inside concrete

Development of solid phase extraction flow-based tools for environmental monitoring

The development of new analytical tools can be considered a non-stop challenge due to the constant search for new improved features and also to the emerging environmental contaminants. Flow-based methodologies stand out in contributing for this analytical challenge, providing the automation and miniaturization of the analysis including sample pre-treatment. This thesis was developed based on two major objectives, one of them was to develop new miniaturized and automated analytical tools based on flow analysis for environmental monitoring. When designing new methodologies, another essential objective was to simplify sample preparation by coupling these techniques, based on solid phase extraction (SPE), within the developed flow-based system. The developed methodologies were optimized based on the same principles: minimize the use of reagent, make greener choices of the reagents, minimize the effluent production, lower the limits of detection and quantification, simplify and minimize sample/reagent handling. The use of the in-line SPE strategy showed to bring advantageous features to the analytical method (lowering limits of detection and quantification). The in-line SPE was achieved by using commercial resins (NTA and Chelex 100) and also a lab-made polymer inclusion membrane (Chapter 3). A biparametric sequential injection system for the determination of copper and zinc in water and soil leachates was developed (Chapter 3). The strategy was to use a non-specific coulour reagent (4-(2-Pyridylazo)resorcinol – PAR) and explore the use of two different sorbent materials to selectively separate the two different metal ions in the same manifold. A polymer inclusion membrane (PIM) and the commercial resin Chelex 100 were the chosen materials to selectively retain zinc and copper, respectively. It was the first time that a PIM was used with this purpose in a flow system. A spectrophotometric method for iron quantification using a newly designed chromogenic chelator was developed (Chapter 4). This low toxicity iron chelator was a specially designed 3-hydroxy-4-pyrydinone functionalized with ethers. Furthermore, this reagent demonstrated to display high affinity and specificity for iron ions. With the main objective of quantifying iron in a variety of water samples (fresh and marine water) a strategy including SPE was added to the manifold. By using an in-line SPE process, resorting to a NTA resin column coupled to the flow system, sample matrix clean-up and also the enrichment of the analyte was achieved. A method for the screening of biogenic amines in waters was developed (Chapter 5). The system was divided in two analytical parts. The first one was devoted to the pre-concentration of the analyte using a column packed with Chelex 100; the second was the derivatization of the biogenic amines using fluorescamine for the fluorescent detection of the analyte. This method intended to be a suitable and ease to operate system to obtain real-time information about biogenic amines content in water. A flow injection system for the spectrophotometric determination of the total zinc content in plant digests was developed (Chapter 6). By using a NTA resin column, zinc pre-concentration and the removal of possible interferences was accomplished. A specially designed multi-reflection flow cell coupled with a light emitting diode was the chosen detection system for the spectrophotometric determination of zinc using Zincon as colour reagent. The physical configuration of the flow cell contributed to improve the limit of detection and minimize refractive index gradients produced by the mixture of the reagents.O desenvolvimento de novas ferramentas analíticas pode ser considerado um desafio constante, devendo-se tal à busca incessante de características analíticas cada vez melhores e também ao surgimento de novos contaminantes ambientais. Os métodos em fluxo destacam-se ao contribuir para este desafio analítico, nomeadamente na automatização e miniaturização da análise, incluindo o tratamento da amostra. A tese foi desenvolvida com base em dois objetivos principais, um dos quais se centrou no desenvolvimento de novos métodos analíticos em fluxo para a monitorização ambiental. No planeamento de novos métodos teve-se em consideração outro grande objetivo, a simplificação do tratamento da amostra, associando para tal técnicas de extração em fase sólida ao sistema de fluxo desenvolvido. A otimização dos sistemas analíticos teve por base os mesmos conceitos: minimizar o consumo de reagentes; fazer uma escolha mais ecológica relativamente aos reagentes; minimizar a produção de efluentes, melhorar limites de deteção e quantificação; simplificar e minimizar o manuseamento de amostras/reagentes. Ao recorrer a processos de extração em fase sólida em linha, conseguiu-se uma melhoria das características analíticas associadas ao método (baixando o limite de deteção e quantificação). De uma forma geral, a extração em fase sólida em linha foi realizada recorrendo à utilização de resinas comerciais (NTA e Chelex 100), mas também foi utilizada uma membrana produzida em laboratório (Capítulo 3; membrana de inclusão de polímeros – PIM). Foi desenvolvido um sistema biparamétrico por injeção sequencial para a determinação de cobre e zinco em águas e lixiviados de solos (Capítulo 3). A estratégia usada para o desenvolvimento deste método envolveu o uso de um reagente de desenvolvimento de cor não específico - (4-(2-piridilazo)resorcinol – PAR) - e o explorar da utilização de diferentes materiais adsorventes para separar seletivamente os dois iões metálicos no mesmo sistema. Para tal recorreu-se a uma membrana de inclusão de polímeros (PIM) e a uma resina comercial (Chelex 100) com o intuito de reter e separar o zinco e o cobre, respetivamente. De salientar que foi a primeira vez que uma PIM foi utilizada com este objetivo num sistema de fluxo. No Capítulo 4 foi desenvolvido um método espectrofotométrico para a determinação de ferro em águas naturais utilizando um quelante cromogéneo desenvolvido recentemente. O quelante de ferro de toxicidade baixa pertence ao grupo das 3-hidroxi-4-piridinonas funcionalizado com éteres. Este reagente demonstrou ainda ter uma elevada afinidade e especificidade para o ferro. Com o objetivo de aplicar o método à determinação de ferro em diferentes tipos de águas naturais (doces e salinas), foi incluído no sistema de fluxo um passo adicional de extração em fase sólida. Para tal, utilizou-se uma coluna empacotada com resina de NTA, a qual permitiu realizar a limpeza da matriz da amostra e também a possibilidade de se concentrar o analito de interesse. viii Foi desenvolvido um método para o despiste de aminas biogénicas em águas (Capítulo 5). O sistema foi dividido em duas fases fundamentais. A primeira fase consistiu na pré-concentração do analito recorrendo a uma coluna empacotada com Chelex 100 acoplada ao sistema de fluxo; de seguida procedeu-se à derivatização das aminas com fluorescamina para a sua deteção fluorimétrica. O método desenvolvido tinha como principal objetivo ser de fácil execução, mas que desse uma resposta em tempo real sobre o conteúdo em aminas biogénicas em águas. Foi desenvolvido um sistema por injeção em fluxo para a determinação de zinco total em plantas (Capítulo 6). Com a implementação de uma coluna de NTA no sistema de fluxo conseguiu-se a pré-concentração de zinco e também a remoção de possíveis interferentes presentes na amostra. Como sistema de deteção foi utilizada uma célula de fluxo multi-reflexão acoplada a um LED, visando a determinação espectrofotométrica do zinco utilizando Zincon como reagente de desenvolvimento de cor. Devido à configuração física da célula de fluxo, esta contribuiu para a minimização da influência da refração produzida pela mistura dos reagentes e para o melhoramento do limite de deteção do método

Developing an integrated framework to quantify sustainability indicators in the context of urban systems

Urban systems can be considered living organisms driven by flows of matter and energy (biophysical approach). In addition, the fact of concentrating many people in a small space also implies socioeconomic aspects of coexistence. Currently 60% of the world's population is concentrated in cities. This makes cities great consumers of natural resources, generating a large amount of greenhouse gas emissions, as well as waste. Therefore, this thesis aims to apply and to develop methodologies to determine and quantify the degree of sustainability that Spanish cities have and thus identify their weaknesses. Therefore, this thesis is intended to serve as support for political leaders when making decisions and to create lines of action to improve and achieve the goal of a sustainable city