This report is based on a pilot project for a large epidemiologic study of inner-city asthma, in which exposures to air pollutants will be related to both incidence and prevalance of asthma. Nitrogen dioxide concenmuions were measured in three rooms as well as outdoors in 44 inner-city apartments with gas cooking stoves. Fifty-two separate month-long series of 48-h time-integrated NO, sample. (Palmes tubes) were gathered from fall 1982 to spring 1984. The 48-h average N02 concentrations taken within homes frequently exceeded the U.S.
The pressure field in fluid systems reflects the flow configuration. Measurements of the pressure along the perimeter of a slot ventilated room have been conducted for different room sizes. The momentum of the jet at the end of the room is decreased with increasing room length. The impingement region (region where the influence of the opposing wall is present) starts, independent of room size, when the distance from the supply device is about 70% of the room length. Corner flows could not be predicted by CFD using the linear eddy viscosity or standard stress models. However.
Concrete may be cold and hard, but some energy- efficient builders have been warming to insulating concrete forms (ICFs). As ICFs become more common, home performance professionals need to know how they're built and how well they work
This paper presents a comparison of predictions from a duct efficiency model developed by the authors with measured real-time heating n, system efficiency measurements from six site-built residential homes with natural gas furnaces in the Puget Sound region. The model takes into account the interaction between supply and return side losses, the interaction between conduction and air leakage losses, the interaction rs between unbalanced leakage and natural infiltration, and the recovery of heat through the building envelope from ducts in various locations 1) within the home.
At present, Computational-Fluid-Dynamics (CFO) with the 'standard' k-e model is a popular method for numerical simulation of room airflow. The k-e model needs a lot of computing time and large a computer. This paper proposes a new zero-equation model to simulate three dimensional distributions of air velocity, temperature, and contaminant concentrations in rooms. The method assumes turbulent viscosity to be a function of length-scale and local mean velocity.
A pressure-equalized rainscreen (PER) wall is a multiple-line-of-defence approach to rain penetration control. This Update defines pressure equalization and discusses the various elements that must be incorporated in a PER wall to minimize rain penetration due to air pressure differentials.
Convective heat transfer from internal room surfaces has major effect on the thermal comfort, air movement and heating and cooling loads for the room. Recent studies have shown that the values of convective heat transfer coefficient used in building thermal models greatly influence the prediction of the them1al environment and energy consumption in buildings. In computational fluid dynamics ( CFD) codes for room air movement prediction accurate boundary conditions are also necessary for a reliable prediction of the air flow.