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Indoor Air Quality Impacts of Residential HVAC Systems. Phase II.A Report: Baseline and Preliminary Simulations.

pdf icon Indoor Air Quality Impacts of Residential HVAC Systems. Phase II.A Report: Baseline and Preliminary Simulations. (4910 K)
Emmerich, S. J.; Persily, A. K.

NISTIR 5559; 77 p. January 1995.


Consumer Product Safety Commission, Washington, DC

Available from:

National Technical Information Service
Order number: PB95-178893


air flow modeling; building technology; heating; ventilation; air conditioning; computer simulation; filtration; heat recovery ventilator; indoor air quality; infiltration; residential buildings; ventilation; quality control


NIST has completed Phase II.A of a project to study the impact of HVAC systems on residential indoor air quality and to assess the potential for using residential forced-air systems to control indoor pollutant levels. In this effort, NIST is performing whole building airflow and contaminant dispersal computer simulations with the program CONTAM93 to assess the ability of modifications of central forced-air heating and cooling systems to control pollutant sources relevant to the residential environment. This report summarizes the results of Phase II.A of this project, which consisted of three major efforts: baseline simulations of contaminant levels without indoor air quality (IAQ) controls, design of the IAQ control retrofits, and preliminary simulations of contaminant levels with the IAQ control retrofits. In Phase II.B of the study, all of the baseline cases will be modified to incorporate the IAQ control retrofits. The retrofit results will then be compared to the baseline results to evaluate the effectiveness of the retrofits. The pollutant concentrations in a building depend on many factors including the configuration of the building zones, the air leakage of the building envelope and of interior partitions, wind pressure profile on the building envelope, pollutant source strengths and temporal profiles, heating and cooling system airflow rates, furnace filter efficiency, characteristics of reversible pollutant sinks in the building, individual pollutant decay or deposition rates, and ambient weather and pollutant concentrations. This report describes the input data used to model the baseline houses with CONTAM93 and presents the resultsof the baseline simulations in the form of the transient pollutant concentrations for selected simulations and a summary of peak and average concentrations for all baseline simulations. Three indoor air quality control technologies were then selected for incorporation into the baseline house models to determine their effectiveness in controlling the modeled pollutant sources. The technologies include the following: electrostatic particulate filtration, heat recovery ventilation, and an outdoor air intake damper on the forced-air system return. Selected baseline cases were then modified to implement these indoor air quality control retrofits, and preliminary simulations were performed to demonstrate the ability of the program to model the control techniques.