The term system optimization is widely known, but how many people truly understand what it means? Total system efficiency has been a real challenge for the industrial sector to embrace.
Lack of Standards Hinders Configuration
Except for a few standards for package boilers, there are no system standards. What does this mean, and how does this impact your plant bottom line? Anyone can design, configure and specify a pumping system, but no one can say it is incorrect without a system standard (ASME, ISO, ANSI, HI). In my 45+ years in the pump industry, I can count on one hand the number of pump systems that were properly configured.
Given the focus on energy efficiency and sustainable growth in today’s industry, system optimization should be addressed in every pump system specification in some way, shape or form. The Hydraulic Institute defines system
The process of identifying, understanding and cost effectively eliminating unnecessary losses while reducing energy consumption and improving reliability in pumping systems, which while meeting process requirements, minimizes the cost of ownership over the economic life of the pumping systems.
Why Focus on Pumping Systems?
A pumping system’s efficiency is highly influenced by the system it is supplying; therefore improving pump or motor efficiency will do little to reduce pump energy use. The focus must be on the entire system because the motor and pump react to the system (see Figure 1).
The motor has a wide operating range maintaining high efficiency to as little as 50 percent load. The pump has a rather narrow operating range (depending on specific speed) and will lose efficiency quickly.
Unfortunately, total system efficiency is rarely addressed when specifying a new system. The first focus is typically on cost, which is not the most cost-effective approach when specifying a pumping system. Consider the life cycle cost of a typical 75 horsepower pumping system (see Figure 2).
The operating costs, which include electric and maintenance costs, far exceed the initial cost and installation cost. The lowest initial cost will not provide the desired long-term results that are critical to sustainable growth and profitability of the industrial sector.
Chances are high that the existing pumping systems in your plant are less than optimal. There is a very simple process for identifying “bad actors” by following The Hydraulic Institute’s six step action plan for evaluating existing pumping systems:
1. Screen and prioritize your pumping systems to identify good performance improvement candidates.
Working as a team (operations, maintenance engineering, purchasing), identify pumps that have required an excessive amount of maintenance or resulted in lost production, as well as systems that require further analysis. Hydraulic Institute has a pre-screening form that you can download from their website to assist in the screening process. Priorities for detailed investigation include:
- systems that are controlled by throttling valves
- systems where several pumps are normally run in parallel
- systems with frequent on/off cycling of a pump in a continuous process
- systems with no flow, pressure or power indication
- pump systems with high energy use (large motors that run continuously or frequently)
Now rank pumps with opportunities for performance improvement. Focus on energy use, those with maintenance problems, etc. You now have a list of pump systems and solutions that can be implemented immediately without further analysis, as well as a list of pump systems that need further analysis.
2. Get management support for improving the highest priority pumping systems.
Now that you have identified opportunities, present your findings to management for support in proceeding with further analysis.
3. Work with appropriate pumping system specialists or an in-house team to gather and analyze additional data.
Review the plant staff’s ability to collect additional data and provide solutions. You may want to consider using an outside pump system specialist or contact your electric utility, but make sure the specialist is qualified to perform this service.
4. Identify, economically validate and implement performance improvement opportunities.
There are many tools available for performing a system assessment. Many experienced assessors have developed their own Excel spreadsheets for performing the analysis. Hydraulic Institute has a list of available tools, both commercial and free, on their website.
During the assessment process, look beyond energy savings. Energy savings are important, but in many cases, the non-energy benefits outweigh the energy benefits. To financially justify an improvement, you often need to include the total cost of ownership. That’s why speaking the language of management is so important.
Some improvement opportunities may not require a great deal of work or cost, such as eliminating unnecessary pump uses or improving operations and maintenance practices.
5. Document actions and report results to management.
This is a critical step. Failure to identify and present positive results to management is a typical mistake, but remember that management has skin in the game. They approved the funding, and their superiors expect results.
6. Repeat Action Plan process for other good candidate systems.
If you have followed the process correctly, step six should be easy since management will be asking you to look for additional systems to evaluate.
If you want to improve your pumping systems, follow the plan. Know how much these systems are costing you. Look beyond energy savings. Many pumping systems are not well designed or controlled. Efficiency and reliability go together. Screening provides valuable information on how many systems should be further assessed. Build a business case and speak the language of management with bottom line results.