The energy performance of a fan system is influenced by a number of factors. These typically include the fan efficiency, which depends on the type of fan (i.e. forward curve, radial blade, backward inclined or airfoil fan), the air flow rate (e.g. variable vs. constant), the type of air flow control (i.e. variable speed, discharge damper, inlet damper or inlet guide vane) and the number of hours that the fan is operating. Other factors also include the motor efficiency at full load, which depends on the type of motor (i.e. standard efficiency, energy efficient or premium efficiency), the motor capacity, and the load factor (i.e. the ratio of the average load during operating hours over the full load capacity). Refer to the Fan-Motor System Schematic for more information.

Software & Data
The RETScreen Software Fan Model can be used worldwide to evaluate the energy use and savings, costs, emission reductions, financial viability and risk for fan energy efficiency measures. The software can model a wide variety of projects in commercial and institutional buildings and industrial facilities ranging from replacement of inlet guide vanes with variable speed drives (VSD), to improved fan system designs including system resistance reduction, fan operation time reduction, improved fan efficiency, correctly sized fans and motors, and fan operation at their best efficiency point (BEP). The model also calculates the cross-effects of other energy efficiency measures employed in the facility (e.g. heating and cooling impact of installing premium efficiency motors). The software (available in multiple languages) also includes product, project and climate databases, and a detailed user manual.

Click here to download RETScreen 4 (36 MB).

Training material
Fans and Blowers - UNEP - Presentation slides (2.57 MB)
Fans and Blowers - UNEP - speaker's notes (34 KB)
Fans and Blowers - UNEP - Workshop exercise (20 KB)
Fans and Blowers - UNEP - Quiz (20 KB)

e-Textbook / Guides
Fans and Blowers - UNEP - Guide (606 KB)
Energy-Efficient Motor Systems Assessment Guide (4.78 MB)
Fans and Pumps - Guide (3.44 MB)
Premium-Efficiency Motors - Technical fact sheet (195 KB)
Use of Variable Frequency Drives for Fan and Pump Control - Technical fact sheet (267 KB)

Case studies / Templates
Energy efficiency - Commercial - MNECB
Energy efficiency measures - Industrial - Fans
Energy efficiency measures - Industrial - Fans - Variable speed / UK