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.

Maintaining proper differential pressure in lab spaces is one of the most challenging tasks facing the environmental control engineer.

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.

There is a need to calculate root mean square (r.m.s.) pressures from the output of steady-state computer programs. We know much less about calculating r.m.s. pressures than about calculating r.m.s. velocities. R.m.s. pressures can be quickly estimated from calculated mean pressures, mean velocities and r.m.s. velocities using the equations in this paper. The equations have been used in \Mind Engineering but can be applied in any turbulent flow where pressures are required.

ln the paper a numerical program package is described to calculate incompressible, unsteady, three-dimensional, viscous and turbulent flow fields around sharp edged obstacle. By this the velocity and pressure distributions in the flow field and on the surfaces of square-formed bodies in a plane channel can be determined, as well as the frequencies of periodic vortex separations The channel consists of two plates extended to infinity. On the lower plate the square-formed body, which is identical with the building model, is placed.