The Chimney Effect
1st exhibition: MacLaren Art Centre, Barrie, Ontario,
February 26 – May 29, 2011
The Chimney Effect harnesses a particular phenomenon of thermal movement known generally as the “stack effect”*, where buoyant air rises and falls in a vertical enclosure according to fluctuations in pressure, density, temperature and moisture.
A steel and glass box is placed in front of a fireplace so that an airtight fitting is achieved. This casing becomes a musical instrument with six taut harpsichord strings that catch naturally-occuring drafts in or out the narrow upper vent of the box. The air movement generates vibrations in the strings, which are amplified by contact to the steel casing.
The Chimney Effect is a self-contained version of an Aeolian harp. You can hear subtle changes in overtones, some self-generated, others set off by outside conditions, the modulating force of the flames in the fireplace or the opening and closing of the entrance door to the exhibition space.
* The Stack Effect is the movement of air into and out of buildings, chimneys, flue gas stacks, or other containers, and is driven by buoyancy. Buoyancy occurs due to a difference in indoor-to-outdoor air density resulting from temperature and moisture differences. The result is either a positive or negative buoyancy force. The greater the thermal difference and the height of the structure, the greater the buoyancy force, and thus the stack effect. The stack effect is also referred to as the ‘chimney effect’, and it helps drive natural ventilation and infiltration. en.wikipedia.org
©Gordon Monahan 2011