English

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.