Use of Efficient Drives

The drive system often offers substantial opportunities to improve energy efficiency and to lower overall system operating costs. The direct drive systems, where the motor shaft is directly attached to the fan offer a high efficiency solution – particularly in cases where the motor can be located close to the fan and can benefit from the extra cooling it can provide. However, use of direct drives may be limited due to offering less flexibility with respect to speed adjustments (unless fitted with a variable speed drive system), due to lack of space or clean air.

Belt drives offer a key advantage to fan systems by providing flexibility in fan speed selection. In axial fans, belt drives keep the motor out of the airstream, which can be an advantage in high temperature applications, or in dirty or corrosive environments. There are several different types of belt drives, including standard belts, V-belts, cogged V-belts, and synchronous belts. While the V-belts are most commonly used, synchronous belts offer higher efficiency and over a longer time (see also "effcient transmission systems") . By switching over to a more efficient belt drive system can provide significant energy savings and reduce maintenance costs.

Development Status Products

Use of Efficient DrivesCosts & Benefits

Parent Process: Fan Systems
Energy Savings Potential

This measure is estimated to offer following improvement potentials (UNIDO, 2010):
• 4.5% for low efficiency base cases;
• 2.5% for medium efficiency bas cases;
• 0.5% for high efficiency base cases.

Electrical and primary energy savings potential of this technology for different countries is estimated as following (UNIDO, 2010):

  Final (GWh/y) Primary (TJ/y)
US 812 8913
Canada 149 1856
EU 573 5380
Thailand 84 844
Vietnam 38 548
brazil 153 1712
CO2 Emission Reduction Potential

Total emission reduction potential, as kt CO2/y for different countries are estimated as (UNIDO, 2010): 

US 490
Canada 74
EU 249
Thailand 43
Vietnam 19
brazil 22


Estimated typical capital costs of this measure for different system sizes (S) are:
• US $200  for S < 37 kW;
• US $750 for 37 kW < S < 75 kW;
• US $1000 for 75 kW < S < 150 kW;
• US $N/A for 150 kW < S < 375 kW;
• US $N/A for 375 kW < S < 745 kW; (UNIDO, 2010)

Cost of conserved energy, expressed as US $/MWh-saved, in different countries are estimated as following (UNIDO, 2010):

US 52.9
Canada 52.7
EU 49.6
Thailand 7.6
Vietnam 7.8
brazil 13.2

Use of Efficient Drives Publications

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24, 64-76

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