Dynamic thermal comfort conditions in architecture

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. Conference theme: Architecture and the environment