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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.

Diffusion analysis of degradation of an industrial ventilation system

Zuk, Paul John. January 1980 (has links)
Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 64-65).

An evaluation of industrial ventilation troubleshooting methods /

Booth, Derrick W. January 1998 (has links)
Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [148]-150).

Use of hybrid ventilation techniques for improved energy efficiency of fan systems

Clark, Craig 08 April 2010 (has links)
The goal of this thesis was to improve the energy efficiency of building ventilation systems by exploring new methods of applying natural ventilation concepts. Strictly natural systems have limitations in which climates they can function or can provide optimal performance; these limitations lead to the use of mechanical or hybrid ventilation. This study looked at methods of combining the operation of the systems, such that the natural components improve the efficiency of the mechanical system.

Wake survey behind a rotating ventilator /

Rashid, Dewan Md. Harunur. January 2002 (has links)
Thesis (M. E.)--University of New South Wales, 2002. / Also available online.

A study of displacement ventilation systems for use in Hong Kong /

Lee, Chun-kwong. January 1998 (has links)
Thesis (M. Phil.)--University of Hong Kong, 1998. / Includes bibliographical references (leaves 50-54).

Proposed method of ventilating the Frood Mine

Mutz, Herman Jacob. January 1931 (has links) (PDF)
Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1931. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed May 21, 2010)

The application of tracer-gas techniques for measuring airflow in HVAC systems

Cheong, Kok-Wai January 1994 (has links)
No description available.

Airflow characteristics of modulated louvered windows with reference to the Rowshan of Jeddah, Saudi Arabia

Maghrabi, Amjed Abdulrahman January 2001 (has links)
The main aim of this research project is to assess the potential of the modulated louvered windows (ML W) to provide ventilation as a cooling source to achieve thermal comfort inside buildings. It presents an intensive analysis of the characteristics of airflow as function of the various MLW parameters in order to provide designers with practical information about the performance of MLW in the control of natural ventilation inside the room. Some initial studies suggested the significance of adjustable horizontal louvered windows, or the MLW as they are referred to in this research, as an effective technique for the control of natural ventilation beside the other Environmental issues. In Jeddah, Saudi Arabia, the shelter adaptation to the hot-humid climate was achieved by employing a number of passive solutions, one of which, the MLW constructed in the Rowshan, was considered a main elevation treatment. The Rowshan, a projected window bay, covered in this study is constructed with adjustable louvers in a number of sashes arranged in rows and columns to control and alter breeze to the desired level inside the room. The Rowshan is also credited with controlling other environmental factors and is supposed to reflect social necessities. This thesis has investigated the airflow characteristics of the MLW with reference to the Rowshan of Jeddah, Saudi Arabia. After reviewing the previous efforts and prediction techniques concerned, the research has conducted a series of experiments including laboratory and computation fluid dynamics (CFD) appraisal stages. The laboratory stage included the evaluation of the pressure drop (L1J') and the velocity drop (v/ve%) characteristics across the MLW. The pressure drop was examined under various airflow rates (Q) using the depressurising test chamber technique. The velocity drop (v/ve%) was examined under various prevailing wind conditions using the test chamber technique. This appraisal stage covered also the room configuration and its contribution to this effect. On the other hand, the CFD measurement has examined the viability of CFD coding to simulate airflow around the reviewed MLW. The predicted results obtained from CFD were compared against those obtained from the laboratory. Consequently, an intensive evaluation of airflow patterns of the common Rowshan configurations, including the plain and projected Rowshans, employed in leddah in conjunction with various outlet types was conducted. From the literature review, it has been concluded that the MLW played a major role in the provision and the control of natural ventilation in the traditional architecture of leddah, Saudi Arabia. The various appraisal stages showed that parameters such as louver inclination, aperture between louver blades and the free area of the MLW were more significant variables than the depth of louver blades. Nevertheless, the major pressure and velocity drops were not due to individual variable but rather to the combination of variables that would comprehensively describe M and v/ve% across the MLW. Practically, the design of the modulated louvered windows must give consideration to those variables that play an important role in altering airflow characteristics inside the room. It should also have an element of flexibility as this enables designers to approach their window treatments with a number of choices whilst retaining similar ventilation performances. Airflow velocities in a room containing an MLW result from an interaction of louver geometry, room geometry and prevailing wind conditions. As far as the Rowshan configuration was concerned, the plain Rowshan was generally better than the projected Rowshan. Yet the flow in the living zone could be enhanced by correctly sizing the projected Rowshan. Finally, CFD analysis has been successfully used to predict air velocities in the region close to the MLW side.

Simulation of FtX ventilation technique in a typical Swedish house

Ferreras Pascual, Adrián January 2010 (has links)
<p>This project discusses the effect of reducing the amount of fresh air supplied mechanically to a typical Swedish house, remaining constant the amount of air removed from the building. The new ventilation technique studied through this project is used by the so-called FtX ventilation systems, whose main difference comparing to FTX ones is that the supply airflow rate is reduced.</p><p>This reduction of the supply airflow rate is simulated by means of commercial software called IDA Indoor Climate and Energy, which provides the energy consumption in the dwelling so as the temperature in the building and the different airflows. Firstly, the model of the house is built in IDA taking into account the regulations established by the Swedish Building Code and the materials and size of a typical construction in Scandinavian region. The building is located in Bromma, near Stockholm. The reason to situate the building in this place is that IDA ́s database contains the meteorological data registered in this location during a whole year, so yearly simulations can be carried out using real meteorological data.</p><p>After simulating every model, results are gathered and compared. On the one hand, an energy study is carried out for a whole year in order to determine the optimal quotient between the supply airflow rate and the exhaust airflow rate which minimizes the energy consumption. This study indicates that when the supply airflow rate is 0.95 times the exhaust airflow rate, the energy consumed by the building is minimal. On the other hand, an economical study is done. To calculate the economical cost of the energy purchased by the building, the tariffs of a company which sells district heating and electricity in Stockholm are used. Considering these data and the energy consumption for the whole year, it is calculated the economical cost in each case. The optimal ventilation rate, in monetary terms, is (Qs/Qe) ≅0.9. In this case, the energy cost amounts to 13,880 SEK.</p>

Kombinerat system för ventilation och rumsuppvärmning : Parameterundersökning i simuleringsmodell för takvärmesystem

Wegner, Robin January 2013 (has links)
A large amount of our time is spent indoors in an artificial climate. To make the experience pleasant there are requirements on the ventilation and the heating system. At the present time the most common form of heating is a radiator system complemented with a ventilation system. A ceiling heating system with combined heating and ventilation can replace the two separated systems. The benefit with a ceiling heating solution is that it saves space since the radiator system is no longer needed. This report aim to evaluate if it is possible to replace a radiator system with a ceiling heating system and maintain a pleasant indoor climate. The ceiling heating system is designed as a comfort module that blows air in four directions, the module is placed in the centre of the ceiling and is heating the room with warm air. The aim of this report is to evaluate which parameters that affects the indoor climate and how these are to be set to make the climate most pleasant. A comparison between the energy efficiency of a radiator system and a ceiling heating system is made. By using the simulation program COMSOL is it possible to evaluate the ceiling heating system and see how the: the angel of which the air enters the room, area of the module that distribute the air in to the room and the temperature of the air entering the room. The climate is evaluated by a number of key numbers which indicates how many of the individuals that feel discomfort for different module set ups. These numbers are plotted with the temperature and different design on the comfort module. The key numbers that will be used is PPD-value, PD-value, radiation asymmetry on a plane and the temperature difference between ankles and head. To be able to compare the ceiling heating systems energy loss through the façade with the radiator systems energy loss a simulation model with a radiator as heating solution were also created. To be able to verify the simulation a lab was executed under similar conditions. The simulations shows that a good indoor climate based on PPD-value is achievable for all different designs of the comfort module with a difference of what temperature that was necessary to achieve PPD=5 %. A problem with the ceiling heating system is that the air does not stir as well as it does when using the radiator system and that the PD-value is too high. There’s a very small difference in energy efficiency between the radiator and ceiling heating system. / En stor del av vår tid spenderas inomhus i ett artificiellt klimat. För att göra upplevelsen behagligt ställs krav på ventilationssystemet och på uppvärmningen. Idag är den vanligaste formen av uppvärmning ett radiatorsystem vilket kompletteras med en ventilationslösning. Genom att kombinera uppvärmningen med ventilationen i ett takvärmesystem kan detta ersätta de två separerade systemen. Fördelen med en takvärmelösning är att det sparar plats i lokalen då radiatorn inte längre behövs. Denna rapport syftar till att undersöka om det är möjligt att ersätta radiatorsystemet med takvärme och bibehålla ett behagligt inneklimat. Takvärmesystemet fungerar genom att en fyrvägsblåsande komfortmodul placeras mitt i taket och skickar in varmluft i lokalen. Denna rapport har som mål att svara på vilka parametrar som påverkar inneklimatet och hur dessa ska justeras för att ett behagligt inneklimat ska uppnås. Vidare jämförelse mellan radiatorsystemet och takvärmesystemet har som mål att undersöka om energieffektiviteten skiljer sig åt mellan dessa uppvärmningslösningar. Genom att använda simuleringsprogrammet COMSOL kan takvärmesystemet undersökas och parametrarna inblåsningsvinkel, inblåsningsarea och inblåsningstemperatur kan varieras för att visa på samband mellan dessa och det upplevda inneklimatet. Klimatet värderas genom ett antal nyckeltal som anger andel missnöjda personer vid olika förutsättningar. Sammanställningen av dessa plottas mot temperaturen på luften in i rummet för olika utformning på komfortmodulen. Nyckeltalen som kommer att användas är PPD-värde, PD-värde, strålningsasymmetri mot ett plan samt temperaturskillnad mellan anklar och huvud. För att kunna jämföra takvärmesystemets energiförluster med radiatorsystemets förluster konstrueras en simuleringsmodell med en radiator som uppvärmningslösning. Vidare gjorde en laboration som verifierades mot en simuleringsmodell uppbyggt efter laborationsrummet för att ge en bild över hur verklighetstrogna simuleringsresultatet blir. Resultatet visar att ett bra inneklimat sett till PPD-värde går att uppnå med alla utformningar av komfortmodulen men en skillnad ligger i vilket temperatur som krävs på inluften för att uppfylla detta. Problem med takvärmesystemet är luftomblandningen som inte blir lika bra som vid användning av radiatorsystemet samt att PD-värdet blir för högt. Väldigt liten skillnad mellan de olika systemen erhölls vid jämförelse mellan energiförluster genom fasaden vilket visar på att inget system är bättre än det andra sett till energieffektivitet.

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