English

Air flow conditions at the supply opening, which are used as boundary conditions in a numerical simulation, must be applied in order to proceed with the numerical solution of the air flow within a room. Among the conditions usually specified are the turbulence parameters, including the turbulence kinetic energy or the turbulence intensity and turbulent kinetic energy dissipation rate. Investigators have used a variety of expressions to estimate these quantities. A review of these expressions is presented in this paper.

A sudden contamination of the outdoor air by some toxic gas can have several causes. To find out the protection afforded by sheltering indoors was the primary goal of the investigation. The object of the computational approach was a single family house with 2 floors. Three different models were utilized to calculate the infiltration air flows, the contaminant transport inside the building and the temperature decay of the building.

ASTM has recently standardized a methodology for measuring the leakage of residential air distribution systems to unconditioned zones. The standard includes two alternative leakage measurement techniques, one of which requires only a blower door, whereas the second technique requires a flowcapture hood as well as a blower door. This paper reports on the results of field measurements in 30 houses using both measurement techniques, and analyzes the relative strengths and weaknesses of the two techniques.

There are many unanswered questions about the typical effects of duct system operation on the infiltration rates and energy usage of single-family residences with HVAC systems in their basements. In this paper, results from preliminary field studies and computer simulations are used to examine the potential for improvements in efficiency of air distribution systems in such houses. The field studies comprise thermal and flow measurements on four houses in Maryland. The houses were found to have significant envelope leakage, duct leakage, and duct conduction losses.

This paper describes a framework for a figure of merit by which the energy performance of thermal energy distribution systems (e.g., duct systems) in residences could be characterized. The proposed figure of merit is designed to be incorporated into design guides, state energy codes and/or utility DSM programs.

This handbook describes the use of tracer-gas techniques for measurement of airflow in ducts. Initial measurements were carried out in the laboratory to examine the accuracy of these techniques. The mixing of tracer gases (eg, sulphur hexafluoride, SF6) in ducts of various shapes and sizes was examined using different types of tracer injector. Airflow estimated using tracer-gas techniques (eg, constant-injection, pulse-injection) was compared with measurements made with traditional instrumentation such as pitot-tubes and hot-wire anemometers.