SEDL / STP / STP1002-EB / STP10175S

A Multiple Tracer System for Real-Time Measurement of Interzonal Airflows in Residences

Fortmann, RC
GEOMET Technologies, Inc., Germantown, MD

Rector, HE
GEOMET Technologies, Inc., Germantown, MD

Nagda, NL
GEOMET Technologies, Inc., Germantown, MD

Pages: 11    Published: Jan 1989

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Abstract

Airflows between different parts or zones of a residential dwelling may vary substantially over short time periods due to changes in meteorological conditions. HVAC operation, and occupant activity. The ability to measure interzonal airflows on a "real-time" basis can provide a realistic input for either predicting air pollutant concentrations at various locations within the dwelling or for modeling energy use.

An automated multiple tracer system that employs halocarbons and sulfur hexafluoride (SF⁶) as the tracers was tested in a bilevel, single-family research house. The system employs a constant injection system for halocarbon release in two zones. An automated system samples each zone in the house four times each hour. Halocarbons and SF⁶ are quantitated with a gas Chromatograph with an electron capture detector.

Airflow rates between the upstairs and downstairs of the research house ranged from 33 to 610 m³/h. The magnitude of the airflow rate was related to the percent of time that the furnace fan operated. Measurements of average interzonal airflow rates with PFTs were substantially lower than measurements with the halocarbon tracer system. Whole house air exchange rates calculated from the PFT and SF⁶ decay measurements were nearly identical. For periods with concurrent halocarbon measurements and SF⁶ decay measurements, whole house air exchange rates calculated with the halocarbons were lower than those calculated with the SF⁶, decay method.