• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 515
  • 382
  • 239
  • 185
  • 157
  • 44
  • 21
  • 15
  • 15
  • 15
  • 15
  • 15
  • 15
  • 14
  • 12
  • Tagged with
  • 1997
  • 489
  • 405
  • 358
  • 297
  • 275
  • 254
  • 228
  • 169
  • 167
  • 156
  • 149
  • 148
  • 137
  • 136
  • 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.
321

Energisystemåtgärder i fastigheter : en stadsdelsförnyelse

Broberg, Per January 2011 (has links)
Detta arbete beskriver möjligheten att renovera och energieffektivisera fyra fastigheter i stadsdelen Sätra i Gävle. Den totala ytan på alla fyra huskroppar är ca 4200m2. Ägare till fastigheterna är Gavlegårdarna AB och arbetet utförs åt Tema-gruppen som har ansvar för bland annat energiavsnittet i restaureringen.   Målet med renoveringen var att sänka energiförbrukningen med ca 60 % samt att byta fastigheternas energilösning, både för uppvärmning och tappvarmvatten. Den planerade renoveringen kan sedan fungera som en vägvisare för övriga fastighetsbolag vilka kan dra nytta av resultaten i detta projekt.   Arbetet omfattar även teoretiska beskrivningar på funktionen hos olika system som tas upp som intressanta för projektet, såsom olika ventilationslösningar, funktionen hos en värmepump, energilager samt hur solens strålar påverkar energibalansen i en fastighet.   Olika åtgärder för energibesparing och energiproduktion som inte är planerade för detta projekt, men som skulle kunna appliceras även här, har också tagits upp för att ge en större bild av hur mycket som finns att åtgärda på gamla hus när det gäller energibesparing. Förslag på extra åtgärder är: energibesparing vid byte av belysningskällor, återvinning av gråvatten, byte av cirkulationspumpar, injustering av värmesystemet samt egen produktion av el från vinden.   Resultatet av detta arbete visar att det är fullt möjligt att, efter att de presenterade åtgärderna verkställts, minska energiförbrukningen med de 60 % som målet var. Detta ger självklart en lägre driftkostnad för fastighetsägaren, men huruvida installationskostnaden överstiger de besparingar som görs tas ej upp i denna rapport. Resultaten visar således på en tydlig energibesparing vilket innebär minskad belastning på vår miljö.
322

Analysis of a Mechanically Ventilated Multiple-skin Facade with Between-the-Panes Venetian Blinds

Nemati, Omid 01 April 2009 (has links)
A Building Integrated Photovoltaic/Thermal (BIPV/T) system that consists of a mechanically ventilated, multi-skin facade, a between-the-panes venetian blind layer, and a between-the-panes Photovoltaic (PV) panel is considered. Ambient air is drawn in and forced to flow upward through the system. As air moves through the system, it is heated by the blind layer, the glazing layers, and the PV panel. This BIPV/T system is especially attractive because it can produce electricity and thermal energy in the form of preheated fresh air and allow for adjustable daylighting. There is a need to understand, design, and optimize BIPV/T systems. The velocity and temperature fields around the blind slats were experimentally and numerically studied. Experimental observations and numerical models are essential in understanding the complex fluid dynamical and thermal system and providing design and optimization guidelines. Solar-optical and Computational Fluid Dynamics (CFD) models were developed and validated at various blind slat angles and flow mean speeds. Particle Image Velocimetry (PIV) and temperature measurements were taken inside the ventilated facade. A simple empirical one-dimensional (1–D) model was developed, based on average surface temperatures and heat transfer coefficients, to quickly calculate average surface temperatures and heat flux rates. Between-the-panes convective heat transfer coefficients were obtained from CFD and used in the 1–D model. Despite high vertical temperature stratifications along the glazing, shading, and air layers, the 1–D model can predict the surface temperatures accurately and allow for future optimization and inclusion in building energy simulation software.
323

Application Analysis on Ventilation Operation Strategy of Fixed Guideway System

Chuang, Yung-chun 06 July 2010 (has links)
Underground fixed guideway system has become an important solution to alleviate over-crowded population problems , especially in urban areas. During the planning stage, the station and the underground tunnel formed an enclosure which necessitated environmental control in order to facilitate thermal comfort and safety in case of fire. In this study, SES program has been utilized as a tool in evaluating the performance of the tunnel ventilation system under normal, congestion , and emergency operation modes, using an actual railway underground project as an example. Conclusions has been drawn that safety criteria can be met successfully, following the SES simulation results with recommendations made to facilitate successful ventilation modes.
324

Air jets in ventilation applications

Zou, Yue January 2001 (has links)
<p>The purpose of air distribution systems for HVAC is tocreate proper air quality and thermal conditions in an occupiedzone. In mixing type air distribution systems air is suppliedinto a room through various types of outlets and distributed byturbulent air jets. These air jets are the primary factorsaffecting room air motion. The ASHRAE handbook recognises fourmajor zones of maximum velocity decay along a jet.</p><p>Although numerous theoretical and experimental studies havebeen conducted to develop turbulent air jet theory from the1930's, air jet performance in the further field from theoutlet is still not well understood.</p><p>Many studies were therefore carried out, and the followingconclusions can be drawn from them:</p><p>    The end centerline velocities of zone 3 for both "free"jet and wall jet could strongly depend on the outletvelocities and room size.</p><p>    The<i>K</i>-value of wall jets could be a function of bothoutlet velocities and outlet size.</p><p>    It is very important to choose suitable sampling time toevaluate jet performance.</p><p>    CFD can not always be used to predict jet behaviour,especially for the jet with low outlet velocity and in thearea far away from the outlet. However, for a two-dimensionwall jet, CFD could be a powerful tool for designers.</p><p><b>KEYWORDS</b>: air jet, centerline velocity,<i>K</i>-velocity, air diffuser, ventilation, measurement,CFD</p>
325

Prévention des infections liées aux soins en réanimation

Girou, Emmanuelle Brun-Buisson, Christian. January 2007 (has links) (PDF)
Thèse de doctorat : Sciences de la vie : Paris 12 : 2003. / Version électronique uniquement consultable au sein de l'Université Paris 12 (Intranet). Titre provenant de l'écran-titre. Bibliogr. : 135 réf.
326

Optimisation de l'humidification des gaz au cours de la ventilation mécanique

Lellouche, François Brochard, Laurent. January 2008 (has links) (PDF)
Thèse de doctorat : Biomécanique : Paris 12 : 2007. / Titre provenant de l'écran-titre. Bibliogr. : 285 réf.
327

Insuffisance respiratoire aiguë hypercapnique de l'enfant bases physiopathologiques et implications pour la ventilation mécanique noninvasive /

Jacoupy-Essouri, Sandrine Fauroux, Brigitte January 2007 (has links) (PDF)
Thèse de doctorat : Médecine : Paris 12 : 2007. / Titre provenant de l'écran-titre. Pagination : 63 p. Bibliogr. : 92 réf.
328

Influence de la géométrie d'une source thermique sur le développement du panache

Blaise, Jérôme Devienne, René. Fontaine, Jean-Raymond. January 2008 (has links) (PDF)
Thèse de doctorat : Mécanique et Energétique : Nancy 1 : 2008. / Titre provenant de l'écran-titre.
329

Assessment of energy recovery technology in China : mechanical ventilation system with energy recovery /

Piippo, Kaj. January 2008 (has links)
Master's thesis. / Format: PDF. Bibl.
330

Improvement of indoor air quality through the development of polymeric microfibrous material

Luna, Eric Amor. Tatarchuk, Bruce J. January 2009 (has links)
Dissertation (Ph.D.)--Auburn University, 2009. / Abstract. Includes bibliographic references (p.163-175).

Page generated in 0.111 seconds