For that study , measurements of carbon dioxide and ultrafine particles were carried out in four restaurants located in 2 different cities in northwest Ohio. In each city, one restaurant was smoke free and the other one had a dedicated smoking room. A smoke free office space was assessed as a reference site. The results of the measurements show that C02 levels were elevated in all 4 restaurants with an inadequate fresh air supply.
For that paper, a case study was conducted to compare the performance of two control methods in an office environment : conventional setpoint control and predicted mean vote (PMV) based control. To obtain the thermal environments created by the two control methods, computer simulations have been used. The results show that the conventional control caused a reduction in human productivity whereas the PMV control performed well for both human comfort and human productivity.
For the experiment detailed airflow fields were measured in three cases of ventilation air temperature : an isothermal case, a hot case and a cold case.The experimental data have been used to test four two equations turbulence models. And it appears that none of the models is reliable concerning the cold case whereas they all can predict reasonably the hot and isothermal cases global values of temperature and velocity. Those models are not able to predict the exact experimental velocity and temperature fields.
The numerical simulation results of the stack effect in medium-rise buildings in Harbin (cold region in China) are presented in that paper. The multizone ventilation model COMIS was used for the simulation. The effect of the wind speed velocity and the temperature of the stairwell on the pressure difference curves shape have been investigated. It appears that the wind speed velocity may have a strong effect on the pressure difference.
The aim of that research is to obtain contaminant concentrations in a room, to perform qualitative and quantitative comparison for a wall jet air inlet and a ceiling diffuser air inlet, and to determine more efficient inlet and outlet configuration. The effect of air inlet types in mixing ventilation was investigated in an experimental room under two conditions, with no occupant and with an occupant present north of the source. The results have shown that the air inlet type is an important physical determinant to the distribution of airborne contaminant concentrations.
How the contaminants disperse in a personalized ventilation room has to be studied carefully in so far the contaminant distribution determines IAQ. This paper deals with the investigation by CFD of the dispersion of particles in a room ventilated by a personalized ventilation system. In that aim a three-dimensional model is employed, airflow and temperature distribution is simulated after experimental validation. The results of the different simulations are presented.
The indoor air quality is influenced in the long term by the chemical contaminants emitted by dried building material. The aim of this paper is to simulate the indoor total volatile organic compounds (TVOCs) distribution emitted from a new floor along with the total TVOCs quantity inhaled by an occupant with the different fresh air ratios under a re-circulated ventilation system. The simulation results and analysis are a great help to design the indoor healthy occupant environment and to improve some features of the re-circulated ventilation system.
One of the common approaches for assessing indoor pollutant level is the continuous sampling. Alternative sampling schemes taking shorter measurements were proposed. For that study a year round indoor CO2 concentration at 17 locations in a typical office in Hong Kong was used to evaluate the probable errors using four sampling schemes :
A - a continuous sampling throughout the measurement
B - 2 sampling periods of 2 equal sessions of the measurement
C - 2 structural sampling periods of the 2 sessions of the measurement
A numerical study of assessment of the performance of a windcatcher using CFD is presented in this paper. A 500 mm square windcatcher system connected to the room has been modeled for different wind speeds in the range of 0.5-6 m/s and four different wind directions. The numerical results agree with the published experimental results of a wind tunnel experiment. The windcatcher system is found to be an efficient way to channel fresh air into the room.
In both airspeed and thermal fields, a scale-model study of an non-isothermal ceiling slot-ventilated enclosure was investigated. Semi-empirical prediction equations have been established. Results have also been compared with previous researches for the validation of the physical behaviour of air-jet. That analysis of airflow performance in a non isothermal condition makes progress in predicting air quality inside the enclosures and it guides the design concepts of ventilation system for an indoor environment.
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