How effective is the energy-saving performance of variable frequency drives in fan and pump applications?

Variable frequency drives (VFDs) are now widely used in various industries such as petroleum, chemical, light industry, papermaking, rubber, power, metallurgy, and more. The energy-saving effect of variable frequency speed control technology has elevated the level of processes, saving resources for enterprise production. It plays a crucial role in energy conservation and environmental protection and is essential for the transformation and updating of products in enterprises. The application of variable frequency drives in fans and pumps is outlined as follows:

Pump loads are typical quadratic torque loads. Usually, the type of pump load is selected based on the quantity required for full load operation. However, in practical applications, the pump does not operate at full load most of the time. Therefore, as long as the average speed decreases slightly, the load power will rapidly decrease, achieving energy-saving effects.

When the motor is directly started, as it cannot adjust the speed, often windshields and valves are used to regulate air volume or flow. This not only causes energy waste but also results in startup current surges affecting the power grid, equipment vibration, and water hammer phenomena.

When using variable frequency technology, it is convenient to control the speed according to the actual process requirements. For example, when the motor speed is 80% of the rated speed, the load power is the square of the rated power (80%, approximately 50%). This speed reduction of 20% saves more than 40% in energy. Simultaneously, closed-loop constant pressure control can be easily achieved, further enhancing energy efficiency.

After adopting VFDs for fans and pumps, it not only avoids the impact on the power grid during startup but also reduces equipment failure rates, eliminates vibration and water hammer phenomena, extends equipment life, and reduces power grid capacity requirements and reactive power