natural convection

The SOLVENT window is an innovative glazing system concept that involves the use of a rotating frame, an absorptive glazing and a naturally ventilated vertical channel, in order to improve the balance between the visual comfort and the energy efficiency of windows.

In the modem office environment there are numerous heat generating equipment. In addition there are loads from solar radiation and heat produced by people. Therefore, the loads will often exceed.the load the ventilation system can cope with. To meet this demand on extra cooling capacity the commercial market provides cooling ceiling panels and cooling beams. A literature review shows that until now the majority of the research has been focused on the cooling performance and only a minor part on the thermal comfort and air quality.

The buoyant plume characteristics of heat sources and their relation to geometric factors are of fundamental importance to the effectiveness of the displacement ventilation. The interactions in buoyant plumes from an array of horizontal line heat sources are investigated systematically with Mach-Zehnder interferometer. Based on the discussion about convective flow patterns of a single lime heat source, the characteristic velocity and temperature to character the accumulating buoyancy effects of an array of horizontal line heat sources are proposed.

This paper deals with the convective flow through a horizontal aperture connecting two superimposed large enclosures which are kept at different temperatures. The lower room is warmer than the upper room and this unstable thermal configuration generates a natural them1osyphon flow, between both volumes. This type of flow can occur inside buildings: stairwell flows or natural ventilation flows through horizontal openings. In the literature, very little information is available concerning this domain of applications.

The purpose of the presented investigation is the comparison between measured data of the laminar and turbulent mixed convection and their approximation by wall functions. New wall functions were implemented in a FVM-research-code using unstructured grids, which was developed by the author. Numerical results are compared with a turbulent closed cavity flow.

In order to give some guidance for the optimization of shop entrances regarding comfort and energy savings, a project was launched by the City of Zurich. The project covers field investigations in 12 shops with different entrance types, and analytical and numerical investigations (CFD)for complementary results. The emphasis of this work was on the interaction between the situation at the entrance for different technical local solutions with other factors of importance like building ventilation, building tightness and combination with other entrances.

In this paper the experiences carried out in a large church of Bologna equipped with a floor radiant panels heating plant are presented. High intensity air flows were measured not compatible with thermal comfort. Experimental data will form the basis for understanding and controlling thermal instabilities in very high halls.

The aim of this study was to ascertain the validity of using computational fluid dynamics (CFD) techniques to predict the behaviour of three dimensional gravity induced natural convection buoyant plumes from a vertical heated cylinder in a large quiescent enclosure. The calculated velocity distributions and turbulence quantities over the cylinder were compared to a wide range of experimental measurements. The laminar boundary layer on an isothermal vertical plate was also modelled. The CFX4.