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Visar resultat 1 - 5 av 103 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Potential of Ventilation Radiators : Performance evaluation by numerical, analytical and experimental means

   Författare :Jonn Are Myhren; Sture Holmberg; Per Olaf Tjelflaat; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ventilation radiator; thermal comfort; exhaust ventilation; CFD; energy saving; convection fin; low temperature heating; Building engineering; Byggnadsteknik;

   Sammanfattning : Energy consumption for heating and ventilation of buildings is still in 2011considered far too high, but there are many ways to save energy and construct lowenergy buildings that have not been fully utilised. This doctoral thesis has focused onone of these - low temperature heating systems. LÄS MER

3. 2. Ventilation Performance in Operating Rooms : A Numerical Assessment

   Författare :Cong Wang; Sture Holmberg; Sasan Sadrizadeh; Anna Bogdan; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; operating room ventilation; bacteria-carrying particles; laminar airflow; mixing ventilation; temperature-controlled airflow; computation fluid dynamics; Lagrangian particle tracking; Civil and Architectural Engineering; Byggvetenskap; Strömnings- och klimatteori; Fluid and Climate Theory;

   Sammanfattning : Surgical site infections (SSIs) remain one of the most challenging postoperative complicationsof healthcare and threaten the lives of millions of patients each year. Current evidence hasshown a positive relationship between the airborne concentration of bacteria-carryingparticles (BCPs) in the operating room (OR) and the rate of infections. LÄS MER

4. 3. A Ventilation Strategy Based on Confluent Jets : An Experimental and Numerical Study

   Författare :Setareh Janbakhsh; Bahram Moshfegh; Alexander Zhivov; Linköpings universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Multiple interacting jets; round jets; confluent jets; wall jet; ventilation strategy; air distribution system; air supply device; ventilation performance; thermal comfort; energy-saving potential; measurement; numerical predictions; RANS turbulence models; renormalization group RNG k– ε ; realizable Re k– ε ; and shear stress transport SST k– ω ;

   Sammanfattning : This study presents air distribution systems that are based on confluent jets; this system can be of interest for the establishment of indoor environments, to fulfill the goals of indoor climate and energy-efficient usage. The main objective of this study is to provide deeper understanding of the flow field development of a supply device that is designed based on wall confluent jets and to investigate the ventilation performance by experimental and numerical methods. LÄS MER

5. 4. Modelling of Turbulent Flow and Heat Transfer for Building Ventilation

   Författare :Peng Shia-Hui; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; large eddy simulation; turbulent buoyant convection; ventilation performance assessment; purging flow rate; SGS modelling; ventilation flow; stochastic Markov chain model; turbulence modelling; LRN k-w model; two-equation models; building ventilation; transfer probability; transition regime; modified SGS buoyancy model; energy backscatter;

   Sammanfattning : This thesis contributes to studies on the assessment of building ventilation performance and the development of turbulence models accounting for Low-Reynolds-number (LRN) effects and buoyant convection with heat transfer. Assessments of building ventilation performance are discussed with respect to indoor air distribution and passive contaminant dispersion. LÄS MER

7. 5. Performance-based design of ventilation systems. Potential and limitations regarding indoor air quality

   Författare :Ragib Kadribegovic; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; ventilation; prescriptive design; indoor air quality; air cleaning; energy efficiency; performance-based design; recirculation;

   Sammanfattning : It has been increasingly common to design for increased ventilation rates above legislative requirements specified in building codes and other norms as the most optimum way to improve indoor air quality. However, this concept has recently been challenged, for example, by studies demonstrating that the emissions or pollution from used traditional particle filters increases proportionally with air flow through the filter. LÄS MER