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- Energy management
- Introduction
- Global warming
- Australia's greenhouse gas emissions
- Drivers for change
- Key policy & regulations
- Industry leadership
- Energy management principles
- Energy measurements
- Collecting energy data
- Transmission & distribution loss factors
- Calculating greenhouse gas emissions
- Key energy use areas
- Energy efficient methods
- Safety
- Motors, pumps and fans
- Energy efficient lighting
- Heating, cooling and solar
- Acknowledgements
Fans
3. Power requirements for airflow control |
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Each method of airflow control imposes an energy loss burden or energy losses. You can manage the energy wastage by the proper choice of airflow control. The effects are different for each airflow control as seen in the figure.
Example calculation: Compare the power savings of using VSD to drive six (6) 1kW fans. The fans feed into identical systems of duct work and fixtures. Calculate the power requirement if the airflow is halved (1/2) using either system. Solution: |
Fan and system curves to show the
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To achieve half the air flow in the non VSD system simply requires the plant to switch off half of the fans, therefore power consumption is 3 x 1kW = 3kW. Using the affinity law or fan law the VSD solution can be seen to consume 0.75kW compared to the non VSD system that consumes 3kW. See the diagram below:
Comparison of VSD and non-VSD control for multiple fans. |
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