Simulations of Indoor Air Quality and Ventilation Impacts of Demand Controlled Ventilation in Commercial and Institutional Buildings.
Simulations of Indoor Air Quality and Ventilation
Impacts of Demand Controlled Ventilation in Commercial
and Institutional Buildings.
Persily, A. K.; Musser, A.; Emmerich, S. J.; Taylor, M.
Ventilation, Humidity Control and Energy Proceedings.
Air Infiltration and Ventilation Centre (AIVC)
Conference and Building Environment and Thermal Envelope
Council (BETEC) Conference, 24th. Proceedings.
(International Energy Agency (IEA) Energy Conservation
in Buildings and Community Systems Program. Annex V: Air
Infiltration and Ventilation Centre.) October 14, 2003,
Washington, DC, 229-234 pp, 2003.
commerical buildings; institutional buildings;
ventilation; simulation; indoor air quality; carbon
dioxide; energy efficiency; volatile organic compounds
This paper is a shortened version of NISTIR 7042. The
original abstract follows. Carbon-dioxide (CO2) based
demand controlled ventilation (DCV) offers the potential
for more energy efficient building ventilation compared
with constant ventilation rates based on design
occupancy levels. A number of questions related to
CO2-based DCV exist regarding potential energy
efficiency benefits, optimal control strategies for
different building types, and sensor performance and
deployment. In addition, questions have been raised
concerning the indoor air quality impacts, primarily
with respect to contaminants with source strengths that
are not dependent on the number of occupants. In order
to obtain some insight into the issue of IAQ impacts of
CO2-based DCV, a simulation study was performed in six
commercial and institutional building spaces using the
multizone airflow and IAQ model CONTAMW. These
simulations compared six different ventilation
strategies, with four of them using CO2 DCV, the
simulations, performed for six U.S. cities, were used to
compare ventilation rates, indoor CO2 levels, indoor
concentrations of a generic volatile organic compound
(VOC) as an indicator of non-occupant contaminant
sources, and energy impacts. The results indicate that
these impacts are dependent on the details of the spaces
including occupancy patterns, ventilation rate
requirements in the relevant standards and ventilation
system operating schedule as well as the numerous
assumptions used in the analysis, including contaminant
source strengths and system-off infiltration rates. For
the cases studied, the application of CO2 DCV resulted
in significant decreases in ventilation rates and energy
loads accompanied by increased indoor CO2 and VOC
concentrations. The increases in CO2 were not
particularly significant, in the range of 100 ppm (v).
The indoor VOC levels increased by a factor of two or
three, but the absolute concentrations were still
relatively low based on the assumed emission rates. The
annual energy load reductions due to the use of CO2
control were significant in most of the cases, ranging
from 10% to 80% depending on the space type, climate and