The passive cooling techniques such as night time cross ventilation is potentially an interesting strategy to provide substantial cooling energy savings in warm climates. The efficiency of the night cooling ventilation is determined by three main factors: the external air flow rate in the room, the flow pattern and the thermal mass distribution. Most of the software used to simulate building thermal performance assumes natural convection in the enclosure; therefore the convective heat transfer coefficients for internal room surfaces are underestimated.
This paper investigates the effectiveness of a Purging System in a high-rise office building in Singapore with the aim of improving indoor air quality. The study initially adopts a continuous monitoring concept to investigate the impact of a daily purging operation on pollutant concentration levels at the low, middle and high floors of the office building. Pollutants investigated include formaldehyde, carbon dioxide, carbon monoxide and total volatile organic compounds (TVOC).
This paper sums up the results of a study on the internal partitioning with its effects on the room air quality along with the ventilation performance. Physical tests and numerical modeling for a CFD simulation were used to evaluate different test conditions that employed mixing ventilation from the ceiling.
In Hong Kong, design and construction of new operating rooms and upgrading of older ones have been based on the UK Health Building Notes. In a case study, field measurements showed that the airflow and some design features did not tally with the specifed requirements.
As the risk of contamination in an operating room can be minimized through appropriate filtration and air distribution scheme, a CFD analysis was carried out with the simulation of the temperature distribution, airflow pattern and the contaminant dispersion.
The use of a combined methodology of wind tunnel experiments and CFD simulations in order to study the potential of using active stack to enhance natural ventilation in residential apartments in Singapore is demonstrated in this paper. Comparison between the results obtained from the experiments and those from the simulations has been made.
The purpose of the present study was to evaluate the possibility to reproduce heat and air flowcharacteristics in a machine room where high heat generating systems and devices are installed. For this purpose, in an experiment room was air-conditioned by double floor air supply on the assumption that the machine room, data were selected such as air flow rate of the systems and various boundary conditions were elected. Further, double floor supply air flow rate distribution, and heat and air flow distribution in the room were measured.
We performed numerical simulation of the inflow characteristics at an opening by using LES,the standard k- emodel, and the improved k- emodel that was applied Durbins limitation (hereafter, it is described as Durbins k- emodel in this paper). As a result of this simulation, Durbins k- emodelreproduced the experiment result fairly well as in case of LES. Accordingly, by using Durbins k- emodel, the analysis was carried out on the air flow characteristics at some openings. As a result, the static pressure increase was induced by the collision of the air flow with the leeward opening frame.
This study presents the results obtained when Computational Fluid Dynamics is applied tocalculating the flow in a domestic kitchen hood at operating conditions. Special emphasis has been placed on parametric modeling of the geometry to permit the rapid modification of fundamental parameters, such as the number of blades and the twisting angle. The governing equations (mass, momentum, energy and turbulence) have been solved using the commercial code, Fluent.
The method of exposure prediction using the scales of accessibility of supplied air (ASA) and the scales of accessibility of contaminant source (ACS) is presented in this paper. The spreading performance of supplied air and indoor pollutants can be figured out by CFD simulation and then used for the prediction of contaminant dispersion. For the validation of the model, a traver gas measurement was conducted.
The paper presents an extension of a two-equation turbulence model to predict the airflow fordisplacement ventilation systems. First, every flow effect is investigated separately natural convection along a vertical wall and above a person as well as mixed convection at the floor. Second, a CFD analysis of a test room is compared to full scale measurements. The modified two-equation turbulence model leads to a good agreement of the measurements and the calculations.
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