The goal of this work was to assess the performance of two common ventilation systems, an exhaust and an exhaust supply system, in Swedish apartment buildings. Since correct air-exchange and interzonal airflows are important for removing contaminants and improving indoor air quality, these airflows were analyzed by systematic computer calculations when selected input parameters were varied around their default values.
To remedy comfort problems in a 99,000 fi2 (9,200 m2) office building, the total airflow rate was reduced by 35%, and the total outside airflow was reduced by 86% in four multi-zone air-handling units that serve the office building. After the airflow reduction, the peak room relative humidity level was reduced from 70% to 55%, and cold and hot deck reset schedules were implemented. These improved operating practices reduced building energy consumption by 27%.
This paper considers the numerical modeling of room airflows and illustrates the usefulness of computational fluid dynamics as a design tool for ventilation systems. A computer code, which simulates steady, buoyant, turbulent, three-dimensional flows in Cartesian coordinates, was developed. The time-averaged equations for conservation of mass, momentum, and energy are solved. A low Reynolds number kE model is used to simulate the turbulent transport. The code was validated by comparing it to benchmark data for both liddriven and buoyancy-driven cavity flows.
This study established a research facility where airflow velocities, temperature, and differential pressures could be measured at the ridge of an attic. Following the construction of a test building, sensors were constructed, calibrated, and installed inside the attic. Paired tests were performed for three different ridge vent treatments; two were rolled type vents and one was a baffled vent.
Rapid activation of fire protection systems in response to a growing fire is one of the important factors required to provide for life safety and property protection. Airflow due to the heating, ventilating, and air-conditioning (HVAC) system can significantly modify the flow of smoke along the ceiling and must be taken into consideration when a particular system is designed. At present, the standards used to guide the design of fire protection systems contain very little quantitative information concerning the impact of airflow produced by HVAC systems.
The relationships, in courtyards, between wind flow pattern and temperature distribution have been studied. Thus, in the first part of this study a dimensionless temperature based on the exchange of heat by convection is defined. Then, using the ratio of depth to width (Aspect Ratio) as the main parameter, we are able to explain the curious behaviour observed. Finally, courtyards are divided into several zones in order to separate the different heat sources in each one, allowing us a stratification study.
Confronting the high density of town planning, architects and towr1 planners are led to design mall outdoor places which are inserted into the city but offer specified properties: serenity, calmness, unusual surrounding ... Within the framework of the CERMA laboratory, we are looking for reference architectural examples likely to meet such needs and transposable into a contemporary architectural project.
In equatorial warm humid climates, ventilation has been largely adopted as a major strategy for natural passive cooling. In those climates the use porous elements are common to allow for permanent ventilation as temperature rarely drops below 20°C. Nevertheless, the performance of many building components has not been thoroughly determined, making it difficult to predict buildings performance as ventilation rates, estimated in most simulation codes are often based on apertures typologies from temperate and cold regions.
Results of an investigation of the effects of window position on the airflow characteristics for a typical bedroom setting in Taiwan are presented. Four different window positions were examined in the experiment which used a full-scale laboratory bedroom model with a single bed. A three-dimensional ultrasonic anemometer was used to measure airflow distribution and the results of flow measurements at two height levels are presented. Computer simulation of the airflow distribution was performed using the standard k-e turbulence model.
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