Empowering Pump Systems: The Key Role of VFDs in Energy Conservation

People often choose to use VFDs because of their expected energy savings. However, they offer many more benefits that can improve system reliability and efficiency.

For example, a VFD can reduce power demands during pump start up. This can help eliminate water hammer damage to pipes and pumps. The ability to adjust the speed of your pump also helps you optimize system performance.

Energy Efficiency

VFDs are a proven energy-efficient technology. They help manage wasted power by adjusting pump speed to match process demands. They also reduce energy costs by reducing the need to run pumps full load.

The may bom chim nuoc thai ebara can adjust their speed to maintain a constant pressure, eliminating the need for pressure reducing valves. This helps to eliminate waste and extends the lifespan of water system components.

To enable a market-wide determination of an energy efficiency index, standardized load-time profiles have to be established for specific applications. Those profile types are supposed to represent typical applications well enough to allow comparisons between different pump units without considering physical and technical particularities. However, such profiles are difficult to create and expensive to determine. To reduce the effort involved, semi analytical models of the pump and interpolation procedures for losses of the power drive system have to be used.

VFD Water System Benefits

A VFD controls the way a pump responds to changing demand. Unlike constant speed systems, it can control the system response by modifying the system and pump curves. This ultimately saves energy, reduces wear and improves process control.

VFDs may also offer features such as deragging that rotates the motor backwards to dislodge solids and stringy material. They may also include field-adjustable ramp up and down functions that reduce inrush current, reducing the stress of stopping and starting on the motor/pump.

Because pump performance changes with speed, a VFD can adjust the operation of the pump on the fly to match system conditions without interrupting use. This prevents energy waste during periods of varying operational load. It also eliminates water hammer in the system, which can damage an aging piping infrastructure and cause premature failure.

Water Pump System Retrofitting

In pump systems, VFDs can make a real difference in energy savings. This is especially true for sludge or slurry pumps. These materials can be abrasive and have high viscosity. A pump laboring to push a thick, heavy mixture will need much more power than one that’s just pushing water.

VFDs can manage this by controlling the power delivered to your motor. This makes it possible to reduce energy use without the risk of damaging your system.

VFDs also offer a constant pressure controller that takes the AC power from your utility and re-inverts it to the correct frequency for your pump. This eliminates the issue of poor quality power and allows your expensive pumps to operate at their designed maximum efficiency. This also minimizes mechanical stress.

Water Pump Performance Optimization

The power consumption of pumps is a significant percentage of the overall electricity usage at many industrial, water and wastewater facilities. Pump energy optimization reduces this cost and offers significant environmental benefits.

Replacing pumps with new equipment designed for higher production rates can provide the most immediate capacity gains. However, this option will typically require downtime and a major capital expenditure.

VFDs can offer a retrofit solution that provides the same increase in capacity, but with lower capital and annual energy costs. This is possible by re-sizing the original pump cartridge and retaining existing pipework, site critical interfaces, lube systems and mechanical seal ancillaries. This enables a new, more efficient multiple pump operation that stages and destages pumps only when required. This significantly decreases the average operating time per pump, which increases energy efficiency and reliability.

Reducing Water Hammer

In addition to providing a more energy efficient operating point, VFDs can help eliminate water hammering in pumps. These hydraulic shock waves can cause damage to piping and valves, and they typically happen when an open check valve suddenly closes. A VFD’s ability to gradually ramp up and down speeds can extend the closing time for a valve, decreasing the occurrence and intensity of these pressure changes.

VFDs can also make control valves more open during periods of low demand, eliminating the need for a minimum flow orifice and its accompanying energy usage. This is particularly beneficial for multistory apartment buildings and hotels that experience varying use patterns.

Although it would be ideal, a load-time profile that perfectly represents the specific application of a pump unit is costly to determine. In such cases, standardized load-time profiles are often used for energy efficiency index determination.