The CCES Blog often contains tips to reduce your energy usage and therefore greenhouse gas (GHG) emissions as cost effectively as possible. Here’s another such tip. Take a hard look at your mechanical equipment, mainly pumps. If they are more than a decade old, they may well be oversized for its function, reducing energy efficiency and raising its costs rise.
There are certainly exceptions to the rule, but until recently most engineers oversize their design of pumps by 10-20% “just in case”. Add that to the equipment manufacturer recommending a model that may be oversized by an additional 10-20% (to better ensure it perform adequately at the customer’s facility) and you have a pump that is significantly overperforming its need. In addition, given decline in manufacturing rates, a pump may not need to operate at such a high rate anymore. In fact, there are many examples of pumps that operate flow controls to reduce the flow into it of the item to be transported to achieve the desired rate. However, the pump is still operating at full load. This is like having to use your brake to drive a car to get somewhere because the accelerator is too strong.
Not only is this a waste of electricity, but this also leads to greater costs in maintenance and potential replacement of the equipment quicker than planned.
There are three potential solutions to this problem. First, when replacing a pump, re-evaluate its actual needs given new plant realities and with less overdesign. Second, purchase as energy efficient a pump as available. Remember that a majority of its life cycle cost is the electricity it uses in your plant over a lifetime. Finally, purchase new a pump with a variable frequency drive (VFD). This allows you to operate the pump not only at its maximum frequency, but also at alternative (lower) ones, which, if they can do the job, will save you money. In addition, flow restrictors (which cause a pressure drop-caused loss of efficiency) would not be needed anymore. Industries are reporting savings of hundreds of kilowatt-hours and thousands of dollars per year by right sizing even a single pump and using a VFD. For certain industries that pump large quantities of liquids or solids for processing, this alone could result in a very large reduction in percent electricity usage.
CCES and our energy experts can help many types of facilities evaluate your energy usage and provide options to reduce energy usage and costs significantly.