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Multizone Modeling of Three Residential Indoor Air Quality Control Options.


pdf icon Multizone Modeling of Three Residential Indoor Air Quality Control Options. (8009 K)
Emmerich, S. J.; Persily, A. K.

NISTIR 5801; 142 p. March 1996.

Sponsor:

Consumer Product Safety Commission, Washington, DC

Available from:

National Technical Information Service
Order number: PB96-165782

Keywords:

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

Abstract:

[*]Superceeds NISTIR 5346; NISTIR 5559; NISTIR 5712[*] The National Institute of Standards and Technology (NIST) performed a preliminary study of the use of central forced-air heating and cooling system modifications to control indoor air quality (IAQ) in residential buildings. The objective of this effort was to provide insight into the use of state-of-the-art multizone airflow and IAQ models to evaluate such modifications, the potential of these modifications to mitigate residential IAQ problems, the pollutant sources they are most likely to impact, and their potential limitations. This study was not intended to determine definitively whether the IAQ control options studied are reliable and cost-effective. Another important objective of the project was to identify issues related to the use of multizone IAQ models and to identify areas for follow-up work. This report summarizes the three phases of this effort, each of which consisted of three main tasks. The Phase I tasks included conducting a literature review, developing a plan for computer analysis, and holding a workshop to discuss the plan. The Phase II.A tasks included 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. The Phase II.B tasks included computer simulations of contaminant levels with IAQ control retrofits, evaluation of the effectiveness of the IAQ control retrofits, and development of recommendations for future research. This report is a consolidation of the three previous reports on the project: Emmerich and Persily 1994 on Phase I, Emmerich and Persily 1995a on Phase II.A, and Emmerich and Persily 1995b on Phase II.B. The multizone airflow and pollutant transport program CONTAM93 was used to simulate the pollutant concentrations due to a variety of sources in eight buildings with typical HVAC systems under different weather conditions. Three indoor air quality control technologies were incorporated into the 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. Simulation results indicate that the system modifications reduced pollutant concentrations in the houses for some cases. However, the heat recovery ventilator and outdoor air intake damper increased pollutant concentrations in certain situations involving a combination of weak indoor sources, high outdoor concentrations, and indoor pollutant removal mechanisms. In cases where the IQA controls reduced pollutant concentrations, they led to larger relative reductions in the tight houses than in the house with typical levels of airtightness, though the typical houses still had lower post-control concentrations. The controls had the largest impact on concentrations of non-decaying pollutant from a constant source. Limited system run-time under mild weather was identified as a limitation of IAQ controls that operate in conjunction with forced-air systems.