05
2020

Using the Pump Performance Curve to Increase Pump Efficiency & Save Energy

Our industrial pumps are wasting far more energy than we know – an estimated $10.2 billion/year! But by carefully watching and addressing pump efficiency, your facility can get control of these energy losses. In this post, we’ll look closer at what causes pump efficiency issues and specific steps for improving pump performance.

Pumps & Energy

In 2015, the US industrial sector consumed 800.7 million megawatt hours of electricity at a total cost of $56.4 billion. The pump portion of this is an estimated $10.2 billion of industrial expense.

Energy used by pumps tends to be an “invisible cost,” often buried in other expense lines. The reality is that improving the efficiency of a pump can have an enormous impact on increasing the return on investment (ROI) of each pump in your operation.

The lifetime energy costs to run a pump can dwarf the initial capital outlay for the pump itself (depending on the type of pump and how often it is running). These costs can be exponentially higher if a pump is operating far from its optimal efficiency point – often to the tune of tens of thousands of dollars across all the pumps at a single facility.

The Impact of Pump Efficiency

Plant managers are often surprised at the widespread nature of under-performing pumps. Several years ago, a Finnish research center* evaluated 1,690 pumps at 20 process plants. They found that the average pumping efficiency was below 40%, and that over 10% of the pumps were running below 10% efficiency.

To check whether your pump is operating efficiently, measure the power it consumes and check it against the pump’s performance curve. The pump curve will specify how much power you should be using at the pumps generated flow and pressure. You can then identify the specific energy savings that can be achieved by addressing inefficiencies. Your local power company may also be willing to provide energy audits as a means to save energy and lower peak loads.

Wear rings

Some pumps are designed with enclosed impellers and wear rings. Wear rings are designed as a sacrificial component to inhibit re-circulation from the high pressure area of the impeller to the low pressure pump suction. If the mounting surfaces are corroded, the fluid will take the path of least resistance around the wear ring and flow into the pump suction, reducing performance. Pump manufacturers can mitigate these issues by using materials which are corrosion and erosion resistant. Slurry pump manufacturers often offer very hard casing and impeller material or rubber linings to prevent erosion.

Summary

With a little pro-active, scheduled checking of a pump’s performance curve, you can take a big step in reducing issues and energy costs. If you are interested in a plant audit or would like more information, contact our Ask the Expert desk.