Modeling the Performance of a Naturally Ventilated Commercial Building With a Multizone Coupled Thermal/Airflow Simulation Tool.
Modeling the Performance of a Naturally Ventilated
Commercial Building With a Multizone Coupled
Thermal/Airflow Simulation Tool.
(952 K)
Axley, J.; Emmerich, S. J.; Walton, G. N.
HI-02021-4;
ASHRAE Transactions 2002 Annual Meeting. Proceedings.
2002, Honolulu, HI, 1-16 pp, 2002.
ASHRAE Transactions, Vol. 108, No. 2,
Keywords:
calibration study; night cooling; natural ventilation;
multi-zone model; envelope
Abstract:
Naural ventilation systems have long been employed in
European residences to control indoor air quality and
provide thermal comfort. European building designers
have turned to natural ventilation to control air
quality and cool commercial and institutional buildings
as well, hoping to take advantage of the potential of
natural ventilation systems to conserve energy
associated with mechanical cooling and fan operation.
Encouraged by the early successes of the past decade,
European building designers have advanced natural
ventilation technology, introduced promising hybrid
ventilation technologies that combine mechanical and
natural means, and developed analytical tools for the
design of these systems. These systems may be adapted to
the North American context, but much work will need to
be done to realize the full potential natural
ventilation may offer to North America. The needed work
includes modeling studies which may require advanced
modeling tools to adequately model the complex coupled
thermal and airflow dynamics. A modeling study of a
representative naturally ventilated building recently
constructed in The Netherlands is presented. A multizone
coupled thermal/airflow simulation tool CONTAM97R is
used to investigate the performance of this building in
two challenging North American climates. Comparisons of
measured and predicted performance of this building in
its native climate were performed as a validation
exercise and to calibrate the building models used for
subsequent analytical studies. Three models of a
five-story segment of this building were formulated-a
single-zone model with detailed representations of
ventilation inlets and exhausts, a highly detailed
31-zone model accounting for all purpose-provided and
infiltration flow paths, and a moderately detailed
11-zone model falling between these two extremes. The
moderately detailed 11-zone model was then used to
demonstrate the application of macroscopic coupled
thermal/airflow performance evaluation to the design
development of night ventilation cooling systems for the
Enschede Tax Office placed in a hot-arid North American
location-Los Angeles, California. Following a trial and
error procedure using the overheated degree hour ODH
performance metric, component sizes were adjusted to
achieve the night cooling objective. This modeling
effort demonstrated that a macroscopic tool like that
provided by CONTAM97R provides essential spatial and
temporal details that can guide system design relating
to both whole-building and inter-room air distribution
and thermal performance. In some cases, greater
intra-room detail may be required. In these cases,
performance evaluation would reasonably proceed to
detailed computational fluid dynamic studies of
individual rooms.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899