Knowledge of room air distribution, including its flow and temperature characteristics, is very important to HVAC engineers. This study numerically predicts the air distribution in a room with differentially heated vertical walls. The Rayleigh number in the room is around 2.6-3x 10¹⁰. Time averaged equations of continuity, momentum, and energy are numerically solved by the finite volume method. Three turbulence models, the "standard" k-E model, and two low-Reynolds-number k-E models, are employed to simulate turbulent natural convection in the room.

A three-dimensional, large eddy simulation (LES) model developed for studying the transport of smoke and hot gases during a fire in an enclosure is described. The model uses finite difference techniques to solve the Navier-Stokes equations with an approach emphasizing high spatial resolution and efficient flow-solving techniques. The model uses the Smagorinsky subgrid-scale model. The LES model with Smagorinsky subgrid-scale model was applied to ventilation aiiflow in a three-dimensional room.

The airflow in buildings involves a combination of many different flow elements. It is, therefore, difficult to find an adequate, all-round turbulence model covering all aspects. Consequently, it is appropriate and economical to choose turbulence models according to the situation that is to be predicted. This paper discusses the use of different turbulence models and their advantages in given situations. As an example, it is shown that a simple zero-equation model can be used for the prediction of special situations as flow with a low level of turbulence.

Experts on animal production housing design were surveyed to determine current knowledge, identify potential control measures, and define research and development needs on indoor air quality in production animal facilities. Results indicated that for larger, more mature animals, properly designed and controlled natural ventilation systems are effective in providing good environments. For colder climates and more sensitive animals, a combined system with mechanical ventilation for cold weather and natural ventilation for warm weather works well.

This paper reviews several aspects of the performance of displacement ventilation: temperature distribution, flow distribution, contaminant distribution, comfort, energy and cost analysis, and design guidelines. Ventilation rate, cooling load, heat source, wall characteristics, space height, and diffuser type have major impacts on the performance of displacement ventilation.

This paper reports on the analysis of historical wind data from 239 stations in the United States and 146 stations in Canada to derive design wind speeds (95%, 97.5%, and 99%) for the design of smoke control systems. As part of the analysis, the data were thoroughly checked for missing observations, internal consistency, and uniformity of location and measurement height.