Evaporative Cooling: Conclusions

Introduction | Status Quo | Alternatives | Requirements | Load Minimisation | Conclusions | Bibliography

The sources surveyed suggest that passive evaporative cooling systems are capable of high cooling efficiencies with minimal energy input, and that such systems could be adopted or adapted to provide feasible cooling alternatives for Alice Springs. In addition to reducing average annual household energy consumption by up to 850 kWh per annum, other benefits would include the greater amenity provided by quieter cooling systems.

Passive evaporative cooling requires a two-fold approach combining thermally efficient building design to minimise the cooling load in conjunction with the use of ventilation and evaporative cooling devices. It is clear that passive cooling systems are primarily architectural rather than technological in nature, with the building envelope itself effectively embodying the cooling system. Consequently, passive cooling is best integrated at the design stage, starting with good general thermal design to reduce heat gain. Nevertheless, the existing stock of residential housing also demands further investigation of retrofit solutions as well.

These conclusions are based on data that cannot be considered conclusive, and involve several assumptions based on generalisations and averages. There is a clear need for further research into most areas addressed above, and in particular for carefully controlled and monitored research using specific systems in specific buildings in specific locations. Areas requiring investigation include but are not limited to:

• Climate: seasonal wind patterns in Alice Springs, including direction and velocity, at the macro and micro levels.
• Water Delivery: optimal amount and manner of introducing water into airflow, and the possibility of dynamically matching this with changing temperature, humidity and wind velocity conditions.
• Aerodynamics: optimal wind-catcher, wind-escape and solar chimney configurations to maximise airflow.
• Architecture: traditional arid land architectural techniques and devices, which evolved prior to the development of active cooling technology and the widespread availability of grid electricity and embody a wealth of commonsense, efficient and sustainable cooling solutions.

Michael Hall
September 2007

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