Dynamic thermal comfort conditions in architecture
Authors: Drake, Dr Scott
ABSTRACT: This paper will outline a research project currently being undertaken at The University of
Melbourne aimed at developing a dynamic model of architectural comfort.
Much of the energy used in buildings goes to providing suitable levels of environmental provision – light, heat
and air – for building occupants. In terms of thermal performance, the levels have been determined principally
through research by air-conditioning engineers (ASHRAE), and are based largely on the steady state
equations of thermal comfort established by P.O. Fanger in Denmark. Steady state conditions are not only
expensive to maintain in terms of energy costs, they also underestimate human adaptability to indoor climate
and fail to respond to local climatic variation. They are also inconsistent with current office design, where
increased mobility resulting from computer and telephone technologies has led to models of space provision
that allow for worker movement between workstations, meeting areas, and other formal and informal spaces.
The aim of the project is to investigate preference for, and tolerance of, ‘dynamic’ comfort conditions in
buildings, ie variation to temperature and wind speed resulting from inhabitant activity, such as moving to
another space (indoor/outdoor), opening or closing windows, or adjusting temperature settings. By correlating
thermal comfort data with user behaviour, it is hoped that a more comprehensive picture of thermal comfort
will be developed, taking into account frequency distributions and rates of change of temperature and air
movement, that will assist in the implementation of natural ventilation systems. The project will explore the
degree to which spatial and temporal variation correspond with natural variation due to external weather
conditions, and in doing so, will attempt to develop a model of comfort that more accurately reflects the human
need for variation in sensory experience.