Looking for a simple way to reduce cost of operation?  Have you viewed your energy bill, lately?

The cost of energy has been skyrocketing.  Water and wastewater utilities are becoming aware of the large cost of energy bills as part of their bottom line.  Much of the cost of energy at these utilities is directly related to electric motors.

Here are statistics from the Department of Energy (DOE):

• Nearly 25% of all of the nation’s electricity demand comes from industrial motor systems
• Over 50% of pump “life-cycle-costs” result from energy and maintenance expense
• Less than 15% of pump “life-cycle-costs” are initial purchase costs
• Energy savings of 20% or more are possible with systems optimization

In addition, power and efficiency levels are defined – allowing comparison to published data for the pumps as installed.  It’s like having the DNA for pump/motor combinations in actual field conditions.  And, the data is now available for comparison to future measured values – tracking performance in a scientific approach to optimizing performance.

In addition to awareness of power consumption, operators/owners of utilities need to be aware of the quality of the power they are buying.  Quality of electric power includes variation in power across the legs of three phase lines and variation in the quantity of variability in the sine wave being provided (sometimes containing harmonic variations).  The consumer of electric power rarely knows the quality of power being purchased at his metered location.  The quality of power being provided will directly affect the life span and operating characteristics of machinery being operated in the consumer’s plant.

Fortunately, there are simple instruments which a consumer of electricity can use to make quality and quantity checks for the power being purchased. I recently had the opportunity to borrow a “power pad” by Rockwell Automation/Allen Bradley in conjunction with a pump station audit for the City of Mequon, WI. PowerPad offers a wide assortment of measurement parameters in one compact device. It can determine both quality and quantity of power being provided to the end user and provides both qualitative and quantitative metrics to offer ways to improve upon the effective use of power while minimizing consumption by measuring and reporting. A photo of a typical field set up – with laptop, PowerPad and whiteboard at Mequon is depicted in the photo at left.

City of Mequon, Wis. Pioneers in Defining Pumping Station Performance Metrics

The city of Mequon, WI – home of Allen Bradley’s Drives and systems division – elected to be pro-active in their defining the metrics of performance for their 21 wastewater pumping stations.  As part of their “metrics” project, they asked their consultant to provide energy consumption values for the pumps at their main pumping stations.  The Rockwell PowerPad portable power monitor was the perfect solution to their needs.  Each pump was run at design flow conditions and power curves were produced (an example of power/watts vs time for one pump cycle is shown in the graph) which defined energy consumption for the design conditions.

Thanks to Sean Schmelzer, P.E., Rockwell Automation, Allen Bradley Division for providing the PowerPad for this study at no cost.

Fred Schneeberg, Mequon Utilities Superintendent, for helping us through our first official pump station audit.

David Rice, Electrical Engineer, Port Washington, Wis. for sorting through the hardware and software to refine the field data.

Take care,
Don

Don Voigt, P.E.
Systems Engineer

April 1, 2009

Valuing “where to look” for solutions

Recently, I was visiting a customer’s plant as a follow up to earlier work.  In the general conversation, the customer had asked me a basic question as to the principals of operation of one of his process equipment units at his water treatment plant.  The question required a basic understanding of how his water filter operated and a related question as to the operation of his backwash pumps during the backwashing/cleaning of his filters.

Having been involved in both design and operation of the specific type of filter installed at his plant, I asked if we could go the filter building and observe the operation during backwash.  It turned out that, in doing so, I was able to help him understand how he could backwash without the need to operate a 40 hp backwash pump (the pump had been turned on for backwash for the entire plant history of more than 30 years) – thus, saving this energy and relevant costs and “demand” charges.

Since I was visiting the plant on my own volition, it seemed inappropriate to “invoice” for the solution I had just provided.  And, yet, I think that this is part of the “problem” with engineering…..it seems that many of the answers are simply practical and not theoretical or equation defined.  In other words, the supposition might be that any person could see the solution – given the same knowledge which I had acquired.  Yet, isn’t this the base of the conundrum which all engineers face….at any given time, we arrive at solutions which – in some circumstances and with some individuals – the answer could be provided by a casual observer or simple lay person or mechanic.

Now, this, I realize, sounds elitist but isn’t it the preparation, the background, the many hours at the drawing board, and even the mathematics in differential equations solutions which are embodied in such a solution?  The pump had run for 30 years – and survived the scrutiny of many previous witnesses and tours by dozens (hundreds?) of engineers and bystanders and no one “knew” what to look for.  My background and my arduous history of working in the internals of design and operation of this type of filter led me directly to the solution/resolution.  Luck?  I suggest that it is the embodiment of engineering knowledge that led me to the solution.  And, why do we feel that this is “un-billable work”….while we are so ready to pay an attorney’s invoice where she/he renders an opinion with much less productive results?

I don’t have the answer for this rhetorical question…perhaps you do?

Regards,
Don

In considering the more serious energy audits, the practitioner should be armed with a set of tools.  I’ve not seen a good practical list for this task so I thought it might be of value to begin a list, here.  Many of these tools are suggested in the many energy articles which have become prevalent in the trade journals.

My background is heavily oriented toward the water and wastewater markets – where I have spent the better portion of 35 years since college.  So, if you have a better list – based on your background – please add to this list with a comment below.

Here is a start:

• Amp probe or clamp on amp coils which fit around motor lead wires or lead wires leading to consumers of power.
• Watt meters – this is the logical next step up from amp meters and can be considered less popular due to costs and logistics of getting to a portable form of such watt meters.
• Flow meter – air and water flow meters are available from multiple rental sources.  GE rentals (a division of GE Company) have a number of models available for nominal rental fees.
• Pressure gages with snubbers (and diaphragm protectors) with ranges appropriate.  Such gages are now available in digital form and allow extensive recording/time tracking opportunities.
• Heat sensing imaging equipment (Fluke and others) which offer infrared images which can be timed to interface with other instruments in this family of devices.
• Digital cameras and video recorders – which record and date the data input/shown from the above family of devices
• Access to power company data for meters which are providing and recording power consumption at the sites being investigated.  Power companies have very detailed history for power being used at major meter locations – such as for a major pumping station and – for sure – at water and wastewater sites.

Of course, the next step is to actually compile the required data in a method which allows complete evaluation of efficiencies at a later date in another location (typically at an office the day or two after the data is compiled).  There are wonderful software tools to enable compiling and presenting the meaningful data which can – then – be made meaningful for those in control of making the necessary changes/investments to implement energy savings.

There are a few, select, engineers out there who can be of invaluable assistance in determining “what to measure” and “what to do with the data”. One of these would be the “Pump Guy”, Larry Bachus, who writes a regular column in Flow Control Magazine.

I’ll take this opportunity to put in a plug for the first Pump Guy Seminar, which will be held May 27-29, 2009 at the Astor Crowne Plaza hotel in New Orleans. You can learn more about it and register for the event on the Flow Control Network website.

Cheers,
Don

Over the years, I’ve read a number of articles in the popular water/wastewater trade journals – authored by the “Pump Guy” (Larry Backus of Backus Inc). Since he seems to have such simple answers to apparently complex problems, I recently jotted him an email – asking about his recommendations for “tools” for doing a pump survey for a typical client. Here is the dialog:

Dear Larry,
I really always appreciate your articles in the various technical journals in our industry. So practical and so unique in their perspectives.

The article in the August issue of Flow Control refers to the importance of “systems” in looking at “problems” and I agree 100%. Look at the following blog to see the name and the recent article:
http://equipintegration.com/wordpress/

On a related issue regarding pumps…..do you have a list of “recommended tools” for conducting field evaluations of pumps? Such as a vibration meter, an amp meter, watt meter, pressure gage, speed meter and the like? It would be nice to have a suggested list of tools with example manufacturers of the tools to help a person put together a kit.

Don

Hello Don,
Glad you like the Pump Guy articles. I enjoy writing the column.

As for the recommended tools;
I used to operate a pump rebuild shop. We had 3 pick-up trucks loaded with equipment and tools to attend to the process pumps and motors of our clients. We carried amp meters, alignment equipment, vibration meters, gauges, portable cranes, chain hoists, a complete set of air powered tools, lubricants, gaskets, spare bearings and seals, spare nuts and bolts, etc. to disassemble, repair, load, and off-load pumps and parts onto the trucks.

Today, I travel with my laptop, safety glasses and a hard hat. I visit a process plant or power station as a pump consultant. I tell the engineer to install his equipment (vibration meters, flow meters, gauges, amp meters ) on his problematic pumps. I observe. I can tell about his grasp (understanding) of the problem by his available equipment…and his dexterity handling his equipment and managing his men.

I find I am able to analyze most “pump” problems:
1. by observing, listening and talking with the operators and mechanics.

After analyzing the probable pump problem, I find I am able to resolve most pump problems with:
2. a set of pressure gauges (for the suction and discharge nozzles of the pump),
3. a clip-on flowmeter,
4. the pump performance curve, and sometimes
5 an amp meter.

Often the problem is not in the pump, but in the equipment leading to, or away from, the pump.

Last June, a chemical plant in the Caribbean contracted me regarding a critical pump. I was flown 1st class to the chemical plant 3 hours out of Miami, and put into a 5-star tourist hotel suite. The critical pump was vibrating. The bearings were overheating. The pump had been eating seals and bearings for 10-months.

The vibration technician, with his $60-k analyzer, couldn’t isolate and identify the vibrations. The pumped liquid was not really hot. But the axial roller bearing was hot, and the pump was quite noisy. The engineer wanted my opinion on a better mechanical seal and some synthetic lubricant.

I ordered to install 2 pressure gauges on the suction piping. One gauge was installed onto the exit nozzle of the tank being drained by the pump. The other gauge was installed onto the pump suction nozzle. We started the pump and observed the gauges.

The reading on the gauge at the tank exit nozzle didn’t match the elevation in the tank. The differential pressure was inadequate on the two gauges leading into the pump. We drained the tank.

A hard hat was lodged into the exit nozzle of the tank, preventing the free flow of fluid through the pipe leading to the pump.

We removed the hard hat, filled the tank, and started the pump. The pump vibrations and noise went away.
The hard hat had an ID number. The hat had been missing for a year. The hat had been checked-out to a young intern engineer last year who was cycling thru the Safety and Inspection Department. The intern had inspected the tank last year.

As he left the plant, the intern engineer told the guard he had left his hard hat in the cafeteria, or men’s bathroom.

The hard hat was never found, or turned-in to the guard shack.

Oh well!
Later,
Larry Bachus

Over the course of my experience in assisting owners and other designers toward efficient water and wastewater plant operations, I have noted one subtle and highly minimized factor….and, this is the lack of consideration of the “system” vs. the individual component.

A few examples might help, here:

1. One of the most troublesome devices – based on cost of equipment vs. problems occurring – is the common flow meter…anyone who has tried to have 3 flow meters on 3 lines add up to the combined total in the fourth meter knows exactly what I mean, here. Yet, we continue to design such systems in some hope that we will avoid the history of such systems.

2. Utilities install new side solids thickening devices and find that all sorts of new plant loads occur. Everything from the buildup of fines from centrifuges to the tremendous water demand placed on the plant due to wash water side stream needs….all part of the system needs but not so obvious at time of purchase.

3. Pumping equipment is often selected on the basis of published pump efficiencies…where, in fact, the total efficiency of a pump is the multiplied result of the efficiency of all moving items in the chain. This might be 30% or more poorer.

The point is…..believing that a simple change in the process of water and wastewater systems can be accomplished without a series of (multiple) subsequent implications is a perilous presumption. Beware the obvious solution. It is generally “not” (obvious) and is almost always going to have subsequent “collateral” affects. Or, look carefully, before you leap

Don