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displacement ventilation

Impact of Clothing, Breathing and Body Posture on the Shaping of a Thermal Plume above a Human

The impact of clothing, breathing and body posture on the thermal plume above a thermal manikin was investigated. Measurements of air velocity and temperature above the manikin were performed at four different heights above a sitting and a lying manikin. The results obtained from tests above the sitting manikin show an inverse proportion between the thermal insulation of clothing and the air velocity in the thermal plume. Air velocity in the thermal plume with the breathing function switched on equalled 90-98% of the values obtained for non-breathing experiments.

Modeling human exposure to particles in indoor environments using a drift-flux model

This study developed a drift-flux model for particle movements in turbulent indoor airflows. To account for the process of particle deposition at solid boundaries in the numerical model, a semi-empirical deposition model was adopted in which the sizedependent deposition characteristics were well resolved. After validation against the experimental data, the drift-flux model was used to investigate human exposures to particles in three normally-used ventilation types: mixing ventilation (MV), displacement ventilation (DV), and under-floor air distribution (UFAD).

Numerical Simulation of Thermal Comfort Degree in Radiant Floor Cooling Room

As a comfortable and energy-efficient air conditioning system, the application of radiant floor heating system is increasing greatly used in the north of China. Now, more and more people begin to be aware of the problem of thermal comfort degree in radiant floor cooling room. This study aims at developing a radiant floor cooling system using the existing radiant floor heating system. Unlike an all-air cooling system, the radiant floor cooling system could remove the cooling by convection and radiation.

Comparison of displacement ventilation and mixing ventilation systems with regard to ventilation effectiveness in offices

Air quality in offices depends on the ventilation system ability to remove contaminants from the occupied zone. In a low polluted building air quality mainly depends on the human presence and carbon dioxide is normally used as indicator of human bioeffluents.

Influence of Partition Curtain on Vertical Profile of Temperature and Contaminant Concentration in Sickroom with Displacement Ventilation

For patients, the sickroom is a place where they receive medical treatment and also a living space where they spend most of time in a day. Therefore, good indoor air quality and comfort should be kept in sickroom. We propose to use the displacement ventilation as a means of obtaining high indoor air quality in sickrooms. The purpose of the study is to examine the validity of this system. This paper shows the experiment results and CFD analysis results to examine the effect of partition curtain in the displacement-ventilated room.

Year-round Energy Saving Potential for a Stratum Ventilated Subtropical Office

Stratum ventilation has been proposed to cope for elevated indoor temperature recommended by governments in East Asia. TRNSYS is used for computation of the space cooling load and system energy consumption. A typical Hong Kong office is investigated. Compared with mixing ventilation and displacement ventilation, stratum ventilation derives its energy saving potential largely from the following two factors: a reduced ventilation load and increased coefficients of performance (COP) for chillers.

Field Study Assessment of the Performance of Displacement Air Distribution in a Canadian School during the Heating Season

Stratified ventilation systems use a fundamentally different approach to supply heated or cooled air through a building than the ‘fully mixed and dilution’ ventilation systems found in the majority of non-residential buildings. Stratified air distribution creates a non-uniform environment in terms of temperature and pollutant distribution, and acceptable conditions in the occupied zone. Previous research has shown that this type of system works well for regions where buildings require year-round cooling.

An Energy Efficient Air Conditioning System using Displacement Ventilation and Chilled Ceiling for Modern Office Buildings

Thermal comfort and indoor air quality (IAQ) play a vital role in creating a pleasant and healthier indoor environment for occupants. The supply air conditions and the concentration of CO2 contaminant present in the supply air can decide the comfort level and purity of air in indoor environments. In this study, an effort was made to investigate the combined effect of a chilled ceiling and displacement ventilation (CC-DV) air conditioning (A/C) system that would possibly achieve good thermal comfort and IAQ in a proposed office building subjected to hot and humid climatic conditions.

3DFLOW Development and Validation for Three Cases - Downward Mixing, Partition and Displacement Ventilation

The 3DFLOW code has been developed based on:
· The standard three-dimensional K-epsilon two-equation turbulence model;
· A modification for buoyancy effects;
· Wall functions applied to deal with solid boundary conditions;
· An adaptation of the SIMPLE algorithm.
The representative indoor air flows in conditioned spaces, including downward mixing, partition and displacement ventilation cases, were simulated and analysed in detail using the 3DFLOW code. Good agreement was found between the numerical predictions and experimental data.

VERTICAL PROFILE OF CONTAMINANT CONCENTRATION IN SICKROOM WITH LYING PERSON VENTILATED BY DISPLACEMENT

In the sickroom, high indoor air quality and thermal comfort is essential for the treatment of patients.Therefore it is proposed to use displacement ventilation for the whole room ventilation and the radiantpanel for the thermal comfort of each bed. This study is intended to investigate validity of this system.This paper shows the experimental and calculated results of the displacement-ventilated room with onebed and one radiant panel. The vertical profile of contaminant concentration and temperature aremeasured and compared with the calculated ones.

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