Improving efficiency through VFD's

Just over a decade ago VFD may as well have stood for Very Foolish Decision. Their cost could not justify their installation and were often viewed as an afterthought to oversized equipment. The 21st century welcomed vast improvements in the reliability, pricing and understanding of the technology turning VFDs into a leading weapon in the arsenal of energy cost reduction.

Many of the first and second generation VFDs still lurk in your mechanical rooms taking up wall space. Our experience has been that most are either disconnected or in permanent by-pass mode. This is not a surprise considering the early versions had no protection against power strikes or brown outs which caused routine failures. Failures cost money and embarrassment and so goes the equipment back into full output mode never to be returned to VFD control.

The next generation of VFDs is here. They cost half of what they did a decade ago and are produced by more than 10 major manufacturers. However, price is irrelevant if we’re buying the same ineffective product. Fortunately, the increased competition has created demand for built in features such as power transient protection, harmonic reduction and built in control sequences.

VFDs have become one of the standard features in our design and implementation of HVAC systems today. Old school ideas commonly called for back up or redundant equipment to ensure continuous operation. We have seen that it is frequently more economical to operate both pumps at reduced flow. Data shows that the power requirement can be reduced by over 30%.

Why limit VFDs to pumps? They are also big savers on cooling towers, chillers, air handling units, all types of centrifugal pumping, air and refrigerant compressors and exhaust fans. If the energy saving isn’t enough incentive to add VFDs to your facility, consider the reduction in wear on the motors, gears and belts from reduced speed and torque.

With reduced costs, utility rebates, and significant energy savings, VFD’s offer a quick payback on your investment.