Natural ventilation and mixed mode climate control
Design investigations of thermal comfort were completed during the design development phase of the Chancellery to determine which passive design and natural ventilation strategies achieved the least number of hours of discomfort each year and thus reduced annual hours where air conditioning would be needed. It was determined that the use of 24 hour ventilation through night purging, combined with the use of exposed thermal mass, cross ventilation for teaching rooms and ventilating skylights and clerestories in public areas, would achieve the best thermal comfort conditions.
A combination of simple horizontal and vertical solar shading, internal blinds, thermal mass and night time purging maximise the period of the year during which natural ventilation can provide adequate cooling and thereby minimise the use of air conditioning.
Offices and tutorial rooms are designed to operate with a mixed-mode changeover capability. Each room is provided with natural cross ventilation by means of operable sliding windows to the outer wall and an exhaust damper located at high level to the wall adjacent to the breezeway. Sun hoods are designed to provide weather protection so that windows can remain open during summer rain.
If desired by the occupants doors can be left open when rooms are in natural ventilation mode. Individual fan coil units provide heating and cooling from locations above doorways. Fresh air intake is provided from the naturally ventilated breezeways immediately adjacent to the fan coil units by means of high-level anodised aluminium grilles.