Multizone Modeling of Three Residential Indoor Air Quality Control Options.
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.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899