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.

Direct capture efficiency of a local exhaust system is defined by introducing an imaginary control box surrounding the contaminant source and the exhaust opening. The imaginary box makes it possible to distinguish between contaminants directly captured and those that escape. Two methods for estimation of direct capture efficiency are given: (I) a numerical method based on the time-averaged Navier-Stokes equations for turbulent flows; and (2) a field method based on a representative background concentration.

Unique air flow windows and dual air-conditioning systems provide occupant comfort and energy conservation.

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.

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.

The objectives of this project were to develop and test a simplified duct-leakage measurement technique that could be used as part of both new-construction and retrofit DSM programs for residential duct systems.