Whilst Computational Fluid Dynamics (CFD) has been popularly applied in indoor air andventilation research, most Personalized Ventilation (PV) research is based on experiments.This study is an attempt to seek validation of PV experimental data with results fromnumerical models of Air Terminal Device (ATD), since the ATD is crucial in the simulation ofPV system.The CFD study involves a systemic study and comparison of various simulation methods ofPV ATD, aimed to develop PV ATD models for future whole room PV system simulation.Boundary Conditions (BC) are obtained from an elaborate set of me
Air supply diffusers used in air-conditioning systems can be classified as ceiling diffusers,side-wall diffusers, floor diffusers, jet nozzles and low velocity displacement diffusers. Fixedor adjustable slats are usually used to control airflow directions. Recently, swirling vanes areused in floor diffusers to create a swirling out-flow jet, so that more rapid mixing withambient air can be achieved.
The objectives of the present work are to use computational fluid dynamics (CFD) to studythe airflow pattern and to evaluate the effectiveness of the passive cooling design of theproposed Jurong General Hospital (JGH) using natural wind. The complex three-dimensionalCFD model is used to assess the environmental conditions at the deep podium inside the JGHcomplex with prevailing wind conditions in Singapore, corresponding to the monsoon(November-February) and hot (March-October) seasons.
In the indoor air quality (IAQ) assessment of ventilated enclosures it is useful to know therelative influence of key boundary conditions on the personal exposure and ventilationeffectiveness, for instance as a source of information on where to allocate the greatest effortin the design phase. CFD is used to predict ventilation effectiveness and personal exposure tocontaminant sources in a displacement ventilated room subject to variation of several keyboundary conditions.
This paper investigates the pollutant distribution patterns in a ‘negative pressure’ isolation room by means of objective measurement and CFD modelling. The isolation room has two air supply diffusers and two extract grilles mounted in the ceiling. Numero
Cavity wall is often proposed in the building envelope design as a solution for improving the thermal comfort of the inhabitants and reducing the adverse condensation effects on the building fabric. In order to evaluate the thermal effect of ventilated air gaps on building energy demand and comfort, an experimental ventilated cavity wall has been built and tested. The cavity wall separates two ambients at different temperatures that are assumed to be constant over the time required to perform the experimental analysis.
The airtightness of a building envelope impacts upon the magnitude of uncontrolled air leakage and associated ventilation energy losses. A building's airtightness can be assessed using a steady state fan pressurisation technique. This paper describes a study on the largest building in the UK ever to have had its airtightness tested. Power law regression analysis revealed a good correlation between flow rate into the building and observed pressure differentials.
Infiltration has traditionally been assumed to contribute to the energy load of a building by an amount equal to the product of the infiltration flow rate and the enthalpy difference between inside and outside. Some studies have indicated that application of such a simple formula may produce an unreasonably high contribution because of heat recovery within the building envelope. The major objective of this study was to provide an improved prediction of the energy load due to infiltration by introducing a correction factor that multiplies the expression for the conventional load.
The use of natural ventilation systems continues to be a popular feature in low energy, sustainable building design. One feature of natural ventilation is that, depending upon the prevailing climatic or thermal conditions, the airflow through a ventilator can be bi-directional. Aerodynamically, the ventilator, depending upon its construction, may not perform in the same way for the two different flow directions.
Condensation and mold problems have been identified as one of the severest IAQ problems in Japan. Especially in the wintertime, moisture condenses on cold wall surfaces where it can cause deterioration of the building materials and mold growth related to allergic symptoms. This paper discusses the possibility of using the CFD method to solve condensation problems.
Firstly, a CFD model for simulating condensation is developed, and then the validity of this model is examined experimentally.
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