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Are Belt Driven AHU's Going To Phase Out With Emerging EC Technology ??

Are Belt Driven AHU's Going To Phase Out With Emerging EC Technology ??
The global air handling unit market is estimated at USD 6.93 Billion in 2016, and is projected to reach USD 12.91 Billion by 2026, at a CAGR of 5.7% from 2016 to 2021.The rising usage of air handling units across various application sectors such as commercial buildings, hospitals, industries, universities, data centers, and server rooms is expected to fuel the growth of the air handling units market. This shows the importance of considering energy efficiency in AHU’s.

Most of the AHU’s were belt driven previously where the motor exists independently of the fan blades and at least one belt or sometimes more connects the motor to the fan’s impeller.This type of belt configuration is used to match the speed requirement of fan with motor as per required application. Speed adjustment for belt driven fans is performed by adjusting of sheaves and pulleys. These type of AHU’s were cheaper and silent in operation and enjoyed greater share in the market till recent days.

But recently after entire world started chanting “ Energy Efficiency ” mantra, neglected belt driven AHU’s energy losses came in to the picture. If we consider an entire system of Ahu from electrical wire to fan blade tip the losses can be categorized as below

There are inherent losses like
  • Motor iron & Copper Losses
  • Motor bearing losses
  • Belt transmission losses
  • Impeller losses
  • & VFD Losses if separate speed control is employed

But now a days there emerged a technology called electronically commutated brushless direct driven fans where in the losses at every stage has been reduced considerably making the unit 20% more efficient than the belt drive.

Due to advancements in chilling systems and controls, requirement for AHU speed control became necessary. Initially VFDs were used to control the speed where its own losses got added up along with existing losses.

Later emerged a new technology called electronically commutated direct driven fan where in the above mentioned losses are eliminated to the maximum extent and proved more efficient.

Previously DC machines were considered best in terms of performance because of their good speed torque characteristics. Later due to heavy wear and tear of brushes in DC motor, it has been replaced with AC induction motor. But with the advancement of power electronics, invention of commutation without brushes but with electronics has been invented. This again got back these DC motors in to the industry. As a whole emerging new EC AHU's has many advantages over belt driven drives like:

1. No or low transmission losses due to elimination of belt completely
2. Use of permanent magnet for flux generation in motor making motor ultra efficient
3. Use of electronic commutation which itself can control the speed of motor without any use of external VFD
4. In built protection mechanism
5. Almost Zero maintenance

Above mentioned features have brought down the energy consumption of AHU’s to 20% lesser and are emerging as the game changing technology. Recent advancement was done even in the fan design where in the centrifugal fans were replaced with axial fans where in the efficiency improved further. In some cases replacement of old belt driven centrifugal fan with permanent magnet electronically commutated axial fan has recorded more than 30% savings. At a energy cost of Rs 6 – 9 per kWh return on investment for replacing belt driven AHU’s were typically in the range of 2 – 2.5 years. With increased awareness, increased competition may be the prices for the same may come down in near future.

Replication potential of this technology is increasing gradually in other applications like cooling tower fans  and other cooling fans running with gear or belt.                                        

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