INVERTERS FOR FANS: HOW TO LOWER THE ENERGY CONSUMPTION FOR COOLING.
In this article we describe the project carried out in order to develop energy efficient cooling solutions.
As a scientific organization, we have made available our know-how for the management of the technical and design part.
The objective was to reduce energy consumption in fans (with consequent economic savings) and increase reliability.
Our added value
TECHNICAL SOLUTION: we decided to replace the typology of the fans.
We have replaced the traditional fans with AC motors with fans with EC motors, using very efficient brushless motors.
On a functional level, AC fans use asynchronous motors, while EC fans use synchronous (brushless) motors.
The difference between the two types is given by the rotor: in the EC synchronous motor the rotor is made of permanent magnets, while in the AC asynchronous motor the magnetization occurs at the expense of the electrical power supplied to the motor, with a higher energy consumption.
This is one of the reasons why EC fans, with the same performance, consume less energy than an AC fan of the same size.
This type of fan, which is becoming increasingly popular, has an electronic regulation system that automatically changes its rotation speed to adapt to the system’s pressure drop, thus guaranteeing the desired air flow at all times, regardless of the circuit’s pressure drop – provided that the latter is not higher than the maximum pressure value that the fan can offer.
The results obtained
The increase in Kw combined with the increase in the power factor, has allowed to obtain an energy saving of about 60% compared to the original AC fans.
This saving has translated into a lower cost of electricity.
Another fundamental advantage of the proposed solution is the reduction of noise and vibrations in the working environment.
In addition to this replacement, we have integrated on the fan + synchronous motor group the drive necessary to drive the electric motor in order to create a product consisting of the drive + motor + fan group, easy to purchase and to manage, as the time for installation and commissioning is greatly reduced, allowing reductions in space and wiring, because the drives are no longer on the panel and the related wiring from the panel to the fan group is reduced.
Benefits reported by this application:
⦁ Longer fan life
⦁ High efficiency
⦁ Reduced maintenance
⦁ Controllability of cooling capacity
⦁ Increased flexibility
⦁ Reduced footprint due to compact construction
⦁ Weight equivalent to about half of an induction motor
⦁ High power density
⦁ Eliminated drive configuration
⦁ Integrated monitoring functions with motor self-protection
⦁ Simplified electrical installation with easy installation and wiring with Plug&Play mode
⦁ Low speed torque
⦁ Connection options
⦁ Stock code reductions
⦁ Ease of maintenance
⦁ Noise reduction
⦁ Reduced overall costs
⦁ Reduction of the electric power committed of about 50% and therefore reduced consumption
The integrated electronics on board the motor manages the operating parameters and allows monitoring and control functions with constant traceability, even in modbus mode.
A few months after installation, the extra cost associated with the EC motor is in fact absorbed by the energy savings and the significant reduction in the components of the system which, when realized with this technology, does not require protection switches and speed controllers upstream of the fans.
A simplicity that also pays off, both in terms of wiring and in terms of safety/duration of operation.
CASE HISTORY DRIVE GROUP+ torque motor+ STRATIFIC FAN
These are helicopter blade fans that move large masses of air from top to bottom and implement a process of air exchange, mixing and redistribution, within the environment in which they operate.
The low speed of rotation of the blades produces a light and uniform breeze, which lowers the temperature perceived in the environment of installation and increases the well-being of those who are inside the structure.
They are supplied with reducer, or with permanent magnet motor depending on the use and preferences.
In the application of speed regulation on large fans to destratify the air in large halls, two solutions are normally used.
Asynchronous motor solution coupled on a gearbox, connected to the stratifier fan.
Speed regulation is carried out by a standard inverter positioned near the motor+ REDUCER+fan assembly.
The replacement of a fan with reducer, with a variable speed fan with everything integrated and positioned in a more rational way, allows these advantages:
⦁ Increased motor life expectancy
⦁ No physical and electromagnetic noise
⦁ Limited overall dimensions
⦁ Versatility in speed management during use
⦁ Lower consumption compared to the asynchronous equivalent.