While pump system optimization has become much better understood and has grown in popularity over the last decade, it is still not used as much as one would expect based on the potential economic benefits. A number of issues constrain the adoption of pump system optimization practices, but understanding them can help end users overcome these barriers.
Pump system optimization is more difficult to implement than one might expect. From a historical perspective, pump system designs routinely included a safety margin, or more capacity to ensure that the system could deliver more head (pressure) and flow than required. This was a common-sense approach used in case the original design data did not cover the maximum case and to ensure enough capacity if the production rate increased.
In addition to rising energy and maintenance costs, the cost of process downtime resulting from pump system failures has steadily increased as profit margins have decreased because of global competition. Many plants must operate around 80 percent of the year just to cover fixed and variable costs in order to make a profit. With scheduled downtime requiring 3 to 6 percent of the remaining 20 percent of time for profitable operation, every increment of unscheduled downtime incurs significant cost.
Another barrier is high capital costs required for mechanical and control modifications to improve system efficiency and reliability, as well as process control improvements. While proper screening of pump systems, before selecting the highest value targets for study and implementation, will yield good opportunities with payback in six to 18 months, the capital costs for implementation are 0.5 to three times the pump system’s life-cycle cost.
For example, an optimization study of 20 pump systems could identify $400,000 to $800,000 in energy savings, not including maintenance savings, with total capital cost in the range of $600,000 to $2.4 million.
Pump system optimization is seldom a single system change. It often requires multiple changes at once that involve the piping, pump, valves and controls. There is rarely a silver bullet that will return the pump system to a higher-efficiency operation.
Historically, pump system components have been seen as items to be replaced when they fail and not as part of a system that needs to be tweaked or optimized. For this reason, most plants are not familiar with how to identify and implement the required changes to optimize a pumping system.
Today, there is a growing body of knowledge (BOK) that covers pump system optimization, and courses are being developed through industry trade organizations, such as the Hydraulic Institute and the British Pump Manufacturers Association. Pump and seal manufacturers also are starting to develop or add staff that are specialists in the emerging field of pump system optimization.
The growth of a pump system optimization BOK and associated practitioners is vital to move from awareness of the opportunity to implementation of system changes that provide major benefits to pump system end users.
In the future, pump system optimization should be viewed the same way as industrial plant owner/operators view lean manufacturing or International Organization for Standardization and American Society of Mechanical Engineers (ISO/ASME) quality improvements.
Studies have shown that 10 to 30 percent of installed pump systems are operating well below 40 percent efficiency. These systems represent a significant opportunity.
The future of pump system optimization is bright. It is time to make this strategy part of plant energy efficiency and reliability improvement programs.