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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Adiabatické chlazení vzduchu / Adiabatic cooling air

Horina, Petr January 2018 (has links)
This thesis deals with the adiabatic cooling air. Adiabatic cooling is a possible kind of cooling and air humidification with low energy requirements. Experimentally, evaporative cooler is tested with different types of material in order to find out the most efficient and practically useful filling for adiabatic cooling that could be used as part of the air-conditioning equipment in practice. The results are used in the practical part. The project compares the application of air-conditioning equipment with/without adiabatic cooling in the possible design of the air-conditioning equipment for the shopping center. The use of the air conditioning system with adiabatic cooling, as a more efficient variant, is then applied to the design itself.
82

Compact Air Separation System for Space launcher/ Système de séparation d'air compact pour lanceur spatial

Bizzarri, Didier L.G. 01 September 2008 (has links)
A compact air separator demonstrator based on centrifugally enhanced distillation has been studied. The full size device is meant to be used on board of a Two Stage To Orbit vehicle launcher. The air separation system must be able to extract oxygen in highly concentrated liquid form (LEA, Liquid Enriched Air) from atmospheric air. The LEA is stored before being used in a subsequent rocket propulsion phase by the second stage of the launcher. Two reference vehicles are defined, one with a subsonic first stage and one with a supersonic first stage. In both cases, oxygen collection is performed during a cruise phase (M 0.7 and M 2.5 respectively). The aim of the project is to demonstrate the feasibility of the air separation system, investigate the separation cycle design, and assess that the separator design selected is suitable for the reference vehicles. The project is described from original base ideas to design, construction, extended testing and analysis of experimental results. Preliminary computations for a realistic layout have been performed and the motivations for the choices made during the process are explained. Test rig design, separator design and technical discussion are provided for a subscale pilot unit. Mass transport parameters and flooding limits have been estimated and experimentally measured. Performance has been assessed and shown to be sufficient for the reference Two Stage To Orbit vehicles. The technology developed is found suitable without further optimization, although some volume and mass reduction would be desirable for the supersonic first stage concept. There are many ways of optimisation that can be further investigated. The aim of this program, however, is not to fully optimize the device, but to demonstrate that a device based on a simple, robust, low-risk design is already suitable for the launch vehicles. On top of that analysis, directions for improvements are suggested and their potentials estimated. A complete assessment of those improvements requires further maturation of the technological concept through further testing and practical implementations. Directions for future work, general conclusions and a vehicle development roadmap have also been provided.
83

Air pollution impacts as indicated by roadside air quality monitoring stations : y Kong Hin-Kee, Henry.

Kong, Hin-kee. January 1999 (has links)
Thesis (M. Sc.)--University of Hong Kong, 1999. / Includes bibliographical references.
84

Méthodes de mesure in situ des performances annuelles des pompes à chaleur air/air résidentielles / In situ measurement methods of residential air-to-air heat pump annual performances

Tran, Cong-Toan 30 November 2012 (has links)
Aujourd'hui, la pompe à chaleur (PAC) est largement utilisée pour les applications de chauffage du bâtiment en raison de ses bonnes performances énergétiques. Elle est même considérée comme une source d'énergie renouvelable et, selon la Directive Européenne 2009/28/CE, la part «renouvelable» de l'énergie produite doit être calculée à partir de la performance annuelle. Il est donc important d'être à même de mesurer cette dernière. Or, il n'existe pas, pour les PAC air/air, de méthode fiable et simple permettant de mesurer la performance chez le client pendant une saison.Dans ce contexte, la thèse propose deux méthodes in situ qui répondent à ce besoin. La première est basée sur des mesures non-intrusives des propriétés du fluide frigorigène. Elle utilise le bilan énergétique du compresseur pour déterminer le débit du fluide. La deuxième, fondée sur les mesures côté air, utilise un ensemble de capteurs à fil chaud afin de mesurer le débit et les températures d'air.La thèse développe également une méthode de mesure intrusive du fluide frigorigène, qui n'est pas adaptée aux conditions in situ mais sert de référence pour valider les deux méthodes in situ. Les résultats expérimentaux montrent que la méthode de référence est précise non seulement en conditions stabilisées mais également en fonctionnement dynamique (y compris lors des dégivrages).La validation des deux méthodes in situ a été réalisée par une campagne d'essais spécifique en laboratoire. Une suite intéressante de la thèse consistera à intégrer la méthode non intrusive côté frigorigène directement dans l'équipement de mesure et d'affichage de la PAC. / Today, heat pumps (HP) are widely used as heating systems in building thanks to their high energy efficiency. They are even considered as a source of renewable energy and, according to the EU Directive 2009/28/EC, the amount of renewable energy has to be calculated from the annual performance. Therefore, it is important to be able to measure the annual performance. However, concerning the air-to-air HP there is no reliable and simple method which allows measuring the performance in situ during at least a season.In this context, the thesis proposes two in situ methods that could fill this gap. The first one is based on non-intrusive measurements on refrigerant side. It uses a compressor energy balance to determine the flow rate. The second one, based on air measurements, uses a distribution of hot-wire sensors to determine the air flow rate and temperatures.The thesis also develops an intrusive refrigerant method, which is not necessarily adapted for in situ conditions but can be used as a reference to validate the in situ methods. The experimental results show that the reference method is accurate both in stationary conditions and in dynamic operations (including during defrosting period).The validation of the in situ methods was performed by a specific test campaign in laboratory. As a perspective, the thesis makes it possible to develop on-board measurement methods using non-intrusive refrigerant sensors, providing an opportunity for manufacturers to display the in situ performance in real time.
85

Aktuální otázky regulace mezinárodní letecké přepravy / Topical issues of the regulation of international air carriage

Odstrčilíková, Tereza January 2016 (has links)
Topical issues of the regulation of international air carriage The main purpose of this work is to provide its readers with an overview of the many facets of passenger rights in such dynamic area as international air carriage. Development in this area has given rise to issues and challenges, including the overlapping of legal and geographical scopes of different air passenger protection instruments. Over the last decades, several air passenger protection regimes have developed across the world, in particular on international, European Union and national level. But does the patchwork work? The history of multilateral regulation in the field of international air transport with regard to air passenger rights could be said to have begun in 1929 when the Warsaw Convention was originally signed. The importance of the convention lies in unification of the rules concerning the documents of carriage and the liability of air carriers. In 1955 the Warsaw Convention was amended by the Hague Protocol, which substantially redrafted, modernized and simplified rules relating to the documents of carriage as well as doubled the limit of carrier liability with respect to persons. The Warsaw Convention's application was subsequently extended to the carriers actually performing the transport by air when a passenger...
86

Modelování obrazů proudění / Airflow modeling

Vičan, Martin January 2014 (has links)
The master thesis explores modelling fluid dynamics images in simulation software Star-CCM+ Version 8.04.007. Three proposed variants are modelled. The first variant describes modelling swirl diffusers, the second and third variant describe modelling wall diffusers. The results of modelling are processed in the form of scalar and vector arrays, which depict the velocity of flowing air, temperature and the age of air.
87

Optimalizace vzduchotechniky zimního stadionu / Optimization of air conditioning of the ice stadium

Zach, Daniel Unknown Date (has links)
This diploma thesis is divided into three parts: theoretical, calculation and experimental measurement. The issue of humid air and air-conditioning in winter stadiums is elaborately analysed in the theoretical part. In the calculation part, the dessertation focuses on the optimization of current draft of hockey hall air conditioning system. The hall is now in operation during the season, which means from September to March. In the dissertation are discussed two variants of the draft. The first variant is draft upgrade to year-round operation with condensing dehumidification. The second option is solved as a combination of air handler unit system and absorption dehumidification. This variant is also designed for seasonal and year-round operation of the ice rink. At the end of the dissertation are all of them compared in terms of annual costs. The experimental measurement is carried out on dehumidification of air from areas with high water gains, in this case swimming pool hall model. This problematics is solved by changing the speed of ventilator and using Peltier generator.
88

Compact air separation system for space launcher / Compact air separation system demonstrator for space launchers using in-fight oxygen collection

Bizzarri, Didier 01 September 2008 (has links)
A compact air separator demonstrator based on centrifugally enhanced distillation has been studied. The full size device is meant to be used on board of a Two Stage To Orbit vehicle launcher. The air separation system must be able to extract oxygen in highly concentrated liquid form (LEA, Liquid Enriched Air) from atmospheric air. The LEA is stored before being used in a subsequent rocket propulsion phase by the second stage of the launcher. Two reference vehicles are defined, one with a subsonic first stage and one with a supersonic first stage. In both cases, oxygen collection is performed during a cruise phase (M 0.7 and M 2.5 respectively). The aim of the project is to demonstrate the feasibility of the air separation system, investigate the separation cycle design, and assess that the separator design selected is suitable for the reference vehicles.<p><p>The project is described from original base ideas to design, construction, extended testing and analysis of experimental results. Preliminary computations for a realistic layout have been performed and the motivations for the choices made during the process are explained. Test rig design, separator design and technical discussion are provided for a subscale pilot unit. Mass transport parameters and flooding limits have been estimated and experimentally measured. Performance has been assessed and shown to be sufficient for the reference Two Stage To Orbit vehicles. The technology developed is found suitable without further optimization, although some volume and mass reduction would be desirable for the supersonic first stage concept. There are many ways of optimisation that can be further investigated. The aim of this program, however, is not to fully optimize the device, but to demonstrate that a device based on a simple, robust, low-risk design is already suitable for the launch vehicles. On top of that analysis, directions for improvements are suggested and their potentials estimated. A complete assessment of those improvements requires further maturation of the technological concept through further testing and practical implementations.<p><p>Directions for future work, general conclusions and a vehicle development roadmap have also been provided.<p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

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