Partial cooling in a naturally ventilated building in the tropics.

The objective of this project was to provide cool working conditions for a small number of Customs Department staff in a turn-of-the-century heritage building in Town ville at 19° S latitude. A ducted air conditioning system was initially proposed but rejected as it would have been incongruent with the Victorian elegance of the space, as well as its high cost. As the working area in the three storey high space was surrounded by ornate timber counter and partitions, a scheme was developed using fan coil direct expansion units. These were located behind the counter to the public space. The jet of cooled air was directed toward a line approximately 2 metres above floor level along the opposite wall 5 metres away. Return air was drawn into the fan coil units near floor level. Entrance doors and selected windows to the space were kept open during office hours for natural ventilation and the cool air was retained by gravity behind the counter and partitions. The installation, which received an Australian Institute of Architects award, saved 85% of the original ducted system cost, and has been operating to the user's satisfaction for 2 years. Estimated savings in annual operating costs are around 15%.