Extract

ABSTRACT: In response to Hornsby Shire Council’s desire to promote sustainable building
technology, CSIRO has developed an innovative combined power, heating and desiccant cooling
(trigeneration) system which has been installed at the Hornsby Central Library. The system uses
exhaust from a 60kW micro-turbine to directly regenerate a desiccant wheel, enabling fresh air
dehumidification and both direct and indirect evaporative cooling. In conjunction with the cogeneration
system, the building management system (BMS) has been upgraded to allow building temperatures to
fluctuate in response to seasonal conditions, providing adaptive thermal comfort. This has lead to a
significant reduction in the electricity consumption of this building and a reduced CO2 footprint.

Having both a conventional and desiccant cooling system installed in this building has provided a
unique opportunity to compare user comfort under different air-conditioning regimes. For each system,
library staff and patrons were surveyed to determine perceptions of thermal comfort and air quality.
Results of the survey show that the cogeneration system has maintained thermal comfort levels for
staff while library users perceived an improvement. We are able to conclude that the trigeneration
system has been able to achieve improved thermal comfort while reducing primary energy use.

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