NUI Galway – UL Alliance First Annual ENGINEERING AND - ARAN ...

Formal calibration methodology for CFD model development to support
the operation of energy efficient buildings
Magdalena Hajdukiewicz, Marcus Keane
NUIG – College of Engineering and Informatics – Civil Engineering Department
Informatics Research Unit for Sustainable Engineering
E-mail: m.hajdukiewicz1@nuigalway.ie
Abstract
Computational Fluid Dynamics (CFD) is a robust tool
for modelling interactions within and between fluids
and solids. At every stage of the Building Life Cycle
(BLC), CFD can help understand and predict
phenomena that are difficult to test experimentally
leading to cleaner, healthier, and better controlled
internal environments. Previous research has focused
on developing and validating CFD models for different
internal and external environments. However, limited
work has been done in developing formal procedures
for calibrating CFD models. Once calibrated, these
models can be used to determine optimal physical
sensor positions, which can aid in improving
environmental and energy performance.
1. Introduction
CFD gives an opportunity to model interactions within
and between fluids and solids. This may lead to
improved prediction and understanding of phenomena
that are difficult to test experimentally. When used
appropriately, CFD may provide cleaner, healthier and
better controlled internal environments.
Previous research has described the use of CFD models
for various internal and external environments [1]; [2].
However, limited work has been done to develop
formal procedures for calibrating CFD models and to
use them to determine optimal physical sensor positions
so that both the environmental and energy efficiency
constraints are achieved.
2. Research goals
This project aims (i) to develop a formal calibration
methodology for indoor environments that require
specific conditions (e.g. office spaces, clean rooms,
etc.) and (ii) to determine the best position of sensors
controlling these environments.
3. Methodology
Using existing geometrical documentation and
real data gained from the on-site measurements,
a reliable 3D virtual model of indoor environment is
being developed. The CFD model is calibrated with real
data gained from a well-positioned wireless sensor
network and weather station. The reliable CFD model is
used to determine the best sensor position for
controlling internal environments. Figure 3.1 shows the
process of creating a reliable CFD model of internal
environment.
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Figure 3.1. Process of achieving a valid CFD
model of internal environment
4. Demonstrator
The demonstration building used in this research is
a 3 storey, (800 m 2 ) “Nursing Library” expansion to the
James Hardiman Library at the National University
of Ireland in Galway. The building is naturally
ventilated with the support of mechanical ventilation.
For the simulation of an internal environment, a CFD
model of one of the study rooms in the demonstration
building is developed. Data obtained from
the on-site weather station provide boundary conditions
for the CFD model. A well-positioned wireless sensor
network collects real-time data at multiple locations
within the indoor environment. The data are compared
with CFD model results and a calibration procedure is
being developed. The calibrated CFD model will be
used to optimise the positions of the physical sensors
for the control of the internal environment. This will
result in significant energy and economic savings by
providing a more accurately controlled internal
environment.
5. References
[1] J. M. Horan and D. P. Finn, “Sensitivity of air
change rates in a naturally ventilated atrium space
subject to variations in external wind speed and
direction,” Energy and Buildings, vol. 40, no. 8,
pp. 1577-1585, 2008.
[2] J. Srebric, V. Vukovic, G. He, and X. Yang, “CFD
boundary conditions for contaminant dispersion,
heat transfer and airflow simulations around
human occupants in indoor environments,”
Building and Environment, vol. 43, no. 3, pp. 294-
303, Mar. 2008.