Control your energy cost and improve system performance

Why fans and pumps are expensive to operate

Most equipment fans and pumps are selected to meet a maximum system demand or potential future demands. This means that most are oversized and rarely operating at their full design capacity. Variable frequency drives (VFDs) or adjustable speed drives (ASDs) provide an efficient flow control alternative by varying the motor’s speed. Controlling the speed/flow can significantly reduce energy use. One statistic from the U.S. Department of Energy reports that reducing the speed or flow by 20% can reduce energy use by up to 50%.

Evaluate your drives

Follow these steps to achieve the greatest cost savings opportunities:

• Start with the largest horsepower motors; then evaluate the motors that run the longest, and finally, determine where mechanical control devices are located.
• Determine potential turndown opportunities where motors might be over producing.
• Use fundamental engineering rules like the Affinity Laws to determine airflow (CFM), pressure (P) and horsepower (hp), which are all affected by most fan and pump speed changes.

Additional benefits

In addition to saving money, drives can also:

• Increase Comfort — greater control on HVAC systems allow more control over inlet/outlet throttling devices, bypass valves, and dampers that waste energy.
• Extend Equipment Life — the ability to precisely regulate speed may prolong component life (bearings, belts, etc.) and lower maintenance costs.
• Improve Reliability — the ability to fine-tune controls may result in more precise process operations.
• Increase Productivity — drives can also optimize performance and quality through programming and have the ability to communicate with other devices. Most drives come standard with hardware that allows for predictive maintenance to help save expensive equipment downtime.

Get Started

Call the Energy Efficiency Specialists at our Business Solutions Center at 1-800-481-4700. E-mail energyefficiency@xcelenergy.com or visit xcelenergy.com for more information.