An Experiment with Hybrid Ventilation: A More Sustainable Approach to Thermal Comfort

Abstract

It has been observed that humans are comfort-seeking creatures with thermal comfort high on the list of priorities. Since the invention of mechanical refrigeration and particularly over the last half century we have come to depend more and more on mechanical systems for cooling, heating and ventilating buildings. Tight enclosures defy the outdoor weather. The indoor climate has little or no relationship with that outside the building. The cost is high in terms of consumed fossil energy. And it is becoming apparent that these artificial climates are less than fully satisfactory to many of their users. This paper presents some preliminary results from a study of a hybrid ventilation system aimed at providing improved thermal comfort with lower expenditure of energy. The study area consists of twenty five offices of academic staff in the Faculty of Architecture at Sydney University. The rooms are ventilated through operable windows and doors and have been equipped with supplementary reverse cycle refrigerated cooling and heating equipment which is used by room occupants to moderate severe conditions in hot and cold weather. The system has been in operation for nine months. Surveys before installation and recently indicate significant improvement in perceptions of thermal comfort and air quality since it was commissioned. Records of energy consumption indicate that it is between one quarter and one third of what would be expected for a conventional well designed centrally controlled mechanical ventilation, cooling and heating system for the same group of offices.