PhD Oral Exam - François Tardy, Building Engineering

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

Planning for improving energy efficiency in infrastructure often requires investigations of the thermal performance of existing buildings. Current techniques, such as those found in standard ISO 9869, require that measurements be taken inside building spaces and directly on or through walls for periods lasting up to ten days. For this reason, a new approach that would allow reliable assessments with minimal intrusion over short periods of time would be beneficial in terms of cost, scope and applicability.

The present thesis provides a methodology that can be used to assess the thermophysical properties of a building envelope using outdoor envelope temperature measurements and meteorological data taken over a short period. Diffuse and direct solar radiation, longwave radiation in clear or cloudy skies, and convective and inner envelope heat transfer sub-models are combined in a comprehensive building energy model which contains both conventional and non-conventional evaluation techniques. A multivariable minimization algorithm is used to find optimal results over 24-hour periods. To verify the methodology, exterior building envelope walls are investigated in-situ in long and short-term experiments using different inputs, and best practices, limitations and accuracies are identified.

Finally, the present thesis examines how, with proper thermal and environmental modeling, infrared thermography can be used in place of heat flux meters in building envelope auditing standards such as ISO 9869, potentially saving time, effort, and costs as well as allowing broader and more widespread auditing activities to take place.