Abstract

This thesis presents an assessment of different modeling methodologies for
developing dynamic thermal models for buildings and discusses the benefits of each for
model-based thermal control in buildings. The modeling section consists of two main parts:
(1) the development of a detailed dynamic thermal model by means of frequency domain
techniques and transfer functions (2) the development of low-order, grey-box, RC
(resistance-capacitance) thermal network models with parameter optimization. The models
are verified with experimental data from the Environmental Chamber (EC) test facility at
Concordia University. Environmental Chamber is an experimental facility that is designed
to test and calibrate building dynamic thermal models and technologies. The advantages of
each of the modeling approaches for understanding the thermal behavior of the
Environmental Chamber are discussed.
A detailed frequency domain model is developed from the application of first principle
heat transfer equations to study the thermal characteristics of the system. A
detailed lumped parameter finite difference model (LPFD) is used as a tool to calculate
required data for the frequency domain model that was not available through experiment.
LPFD model also provides significant insight into the actual behavior of the chamber under
transient conditions.
Then, the creation of low-order, grey-box, RC circuit model for the Environmental
Chamber is explained, as well as a methodology for optimizing the circuit parameters to
find the “effective” resistances and capacitances for a defined objective which is the fit
between measured and simulated air temperature. The challenges encountered while using
experimental data to perform optimization for the low-order RC circuits are discussed.
Such low-order models that capture the important physics of the problem are best suited to
real time MPC in building automation systems in which they can be actually implemented.
Finally, an analytical frequency domain model is developed for a thermal zone in
an experimental facility (one of Hydro-Québec's Twin Houses in Shawinigan). The effect
of different floor coverings on the thermal response of the zone is investigated by means
of the frequency domain model. Also, using the frequency domain model, the effect of
increasing the thermal mass and thermal conductivity of the materials used in the zone on
the thermal response of the zone is investigated. The importance of studying the magnitude
of the zone transfer function for effective thermal storage in the zone in an important certain
frequency range is demonstrated. The key advantage of frequency domain modeling for
evaluating design options without any need to perform simulation is presented.