Ventilation Performances of Mixing, Displacement, and Impinging Jet System under Different HVAC Scenarios : Part I

In most conditioned spaces, the Mixing Jet Ventilation (MJV) systems are commonly installed. Relying on turbulent mixing, MJV homogeneously controls the room environment. However, Indoor Air Quality (IAQ), draft, and noise can sometimes be drawbacks of MJV systems. In late the 70s, Displacement Ventilation (DV) was first introduced. By supplying low supply velocity air from the floor or lower wall, a stratification zone is formed which forces pollutants to be collected near the ceiling and allows clean air to remain in the breathing zone.

Pedestrians’ Comfort Index in Urban Settlements Using CFD Analysis

Application of scale models along with the use of wind tunnel testing facility have been the primary tool used in building aerodynamic studies by architects and planners. Problem areas in a given airflow study could be identified by an experience wind engineer; however, the timely sharing the results with the design team becomes essential for a successful project.

Improvement of Indoor Air Environment in a Large Welding Factory by Displacement Ventilation

The design of ventilation equipment is important because it affects the ventilation performancedirectly. To improve the ventilation efficiency of the displacement ventilation, a new ventilation system was proposed in this study. The experiment was performed to measure the fume concentration and the visibility at four points under working conditions. In experimental results, the concentration of dust with a new ventilation system was decreased by about 42-60% compared to that of the existing system. The visibility was increased by about 11-18%.

CFD Modeling of Heat Convection in a Large Cross-section Earth-to-Air Heat Exchanger

An Earth-to-Air Heat Exchanger (ETAHE) is a low energy cooling and heating technology for buildings. It uses the ground’s thermal storage capacity to dampen ambient air temperature oscillations by delivering outdoor air to indoor through a horizontally bu

A computational fluid dynamics study on airflow patterns in an indoor gymnasium.

Airflow pattern in an indoor sports hall of 17,325 m3 located in the sports complex of City University of Hong Kong has been investigated by computational fluid dynamics technique. The turbulence flow was taken into account by using Renormalisation Group method (RNG) k-e model. The objectives of this study are to obtain a preliminary understanding of the airflow pattern and evaluate the badminton 'playing zone' within which there should be no disturbance to the badminton shuttle behaviour.

Use of computational fluid dynamics to aid studies of room air distribution: a review of some recent work.

Computational fluid dynamics has a wide range of application in the study of room air distribution. The application is providing valuable guidance for those interested in such areas as comfort, productivity and sick building syndrome. This paper gives a comparative review of some of the work undertaken in the field and highlights some of the modelling assumptions noted within the literature.

Predicting breathing zone concentrations of aerosols dispersed in a time dependent airflow using vortex methods.

When a person works facing a local exhaust ventilation (LEV) hood, it may be possible to obtain higher concentrations of aerosols in the breathing zone (BZ) than without the hood because recirculating eddies form downstream of the body. These eddies shed periodically in an alternating pattern called vortex shedding, which is thought to be a primary determinant of contaminant transport in and out of the breathing zone (1, 2, 3). Previous computational fluid dynamics (CFD) studies have explored the effect of timedependent airflow on occupational exposure to gaseous contaminants (2, 3).

Evaluating uncertainties in computational fluid dynamic simulations of human exposure to paint-spray aerosols.

Preliminary numerical simulations of human exposure to paint-spray aerosols demonstrate the ability of computational fluid dynamic (CFD) software to discriminate between two different orientations of spraying a flat plate in a cross-flow ventilated spray booth. To conduct exposure-scenario simulations using CPD, a conceptual model of reality must be created that is compatible with the computer code. If this conceptual model is not a sufficient representation of reality with regard to the desired outcome, then no matter how accurate the simulation, the results will be of limited value.