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Pergola cooling

Human Kinetics, the book distribution company, in 1996 converted for their office use an existing vacant Lower Mitcham church originally built in the 1870's.

With occupation, staff assessment of comfort highlighted that the stone building was:

  • cold in winter through warmth rapidly leaking out through the stone walls
  • prone to heat accumulation inside in summer through gradual solar heat absorption by the stone walls, and limited in-built ventilation paths inside the building and to the outside.
A retro-fit scheme was subsequently developed which:-
  • re-opened the existing cornice line ceiling vents
  • installed roof ridge ventilators
  • grew rising climbing plants on a trellis on the sunward north facing stone wall to act as part insulation from direct solar gain
  • installed a pergola with climbing vegetation and water spray in the southern shade side courtyard
  • installed full height louvres in the church slit windows facing the shade side courtyard
  • installed up and downthrust ceiling fans in the interior
The result is summer cooling with modest energy use.
This is achieved through pre-cooled air being created in the courtyard.

The shade space holds air at less than ambient temperature, the water spray humidifies the air, and this is drawn into the church space by downflow in the height between vine pergola covering and building floor level.
This air is downthrust inside the building to people level by the fans.
Cross ventilation occurs through warm air extract through the ventilated ceiling and roof.
Ceiling fans also operate in winter.
The winter heating is enhanced by gas fired heating, circulated by the spatially offset and mutually reversed direction rotating fans.

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