The researchers compared the energy use and associated greenhouse gas emissions by modelling five scenarios with different combinations of fan and air conditioner use. This included situations with fans operating at different speed settings.
After logging data on the impact of the fans on human comfort levels before they begin to feel discomfort, the number of hours above the thermal comfort limit were calculated to determine air conditioner usage, and associated energy use and greenhouse gas emissions.
“To carry out this calculation we needed to process hourly temperature data for an entire year, for the entire continent on a 150,000-cell raster grid. We were able to do this using supercomputers,” said co-senior author Professor Manfred Lenzen of the School of Physics.
They found that operating fans with air speeds of 1·2 m/s with occasional air conditioner use, compared with air conditioners alone, resulted in a 76 percent reduction in energy use (from 5592 GWh to 1344 GWh) and associated greenhouse gas emissions (5091 kilotonnes to 1208 kilotonnes).
“We know that curbing greenhouse gas emissions is the only way we will limit future global warming,” says Professor Jay.
“By increasing indoor air movement with fans, you can feel the same at a higher temperature as you will do at a lower temperature using an air conditioning unit. This is a really easy thing that most people can do now to help reduce the prodigious emissions associated with cooling homes and indoor spaces in Australia.”