Pump Guy Article – October 2014 – Issue 34 – The War on Energy

“The War on Energy”

There’s a war going on. No, I’m not talking about that war. I’m talking about the struggle in every conscious mind and soul to conserve energy and insure an existence for future generations.

Almost everyone I know has done something to use less energy, like consolidating numerous daily trips in the family car into one well-planned, organized trip. Every little bit helps.

Many people want to do more. But, the economics of paying triple the price for an electric auto mobile with limited public places to recharge the batteries seems too much for “Joe the office worker”. And, how can you justify trading the family sedan for something that looks like a glorified roller skate? It’s a difficult decision and hard to justify.

I work as a pump consultant and trainer. I normally attend to sick pumps. But recently, I’ve met with managers charged with reducing the operating costs.

25-years ago, managers were ordered to produce more with less people. This meant mechanization, more machines, assembly-line robots, servo-motors, more electricity and hydraulic power drives.

Now, those same managers are charged with producing more at lower energy cost. But, there is no one left to downsize. Maybe the company should fire the robots?

The best way to reduce operating costs is to improve efficiency. This will be reflected in the monthly electric bill.

Maybe 10-years ago, I heard someone say that industrial pumps consume 20-25% of the world’s available energy. At first, I thought those numbers were exaggerated. Then, I looked around my house.

I opened the refrigerator. I saw milk, OJ, yoghurt, cheese, beer, water, soy sauce, peach chutney, mayonnaise, peanut butter, ketchup, hot sauce, etc. Industrial pumps bottled these liquids and made those sauces possible.

I went to the bathroom and looked into the closet. I saw soaps, shampoo, hair rinse, toothpaste, mouthwash, cough syrup, rash ointment, body lotion, ear drops, nose drops, deodorant, hair spray, hair removal cream and other assorted bottled and tubed liquids. Industrial pumps filled these containers and made these medicines and creams possible.

I looked into the utility closet. What did I see? Paints, glues, laundry soap, fabric softener, dish soap, caulk, penetrating oil, drain pipe cleaner, window cleaner, bug spray, lawn fertilizer, weed killer, motor oil, the list goes on and on. Industrial pumps make these products possible.

Then, there is water pressure, waiting 24-hours a day at each faucet in the front yard, back yard, the kitchen, laundry room, bathroom and shower. Industrial pumps provide that water pressure. And, other industrial pumps carry-away the liquid and solid waste from our homes.

I convinced myself it isn’t an exaggeration. Pumps consume about 20-25% of the world’s available energy.

For most chemical process pumps, the pump’s efficiency is determined by two factors. One factor is the pump’s duty coordinates (head and flow) on the performance curve. I frequently write about the operator’s contribution to reliability in controlling the pump to best efficiency duty coordinates.

The other factor is the gap (space) between the impeller wear band and the casing wear band. The gap tends to open with time and erosion. The pump loses about 2% efficiency for every 0.025-mm in excess gap beyond the original factory setting. Replacing worn bands is a maintenance function when the pump is in the shop.

Shop Fitters often wonder why the electricians earn more money. The Mechanical Engineers are perplexed because the Electrical Engineer’s salary is slightly higher.

There is a simple explanation for this. Electrical types support their arguments with kilowatts. Mechanical types support their arguments with time and labour. Consider the following example:

“Hey Boss, that operation requires 2 hours of downtime. If you let me buy this new gadget, I can perform that operation in 1-hour!” This argument is supported with a saving in time.

“Hey Boss, that task normally requires four labourers. Let me buy this gadget and we can perform that task with only two workers!” This request is supported with a savings in labour.

The company accountants don’t understand this. The accountants think the mechanic wants to take a longer lunch break, or leave work early. So, the requisition for the new gadget gets filed in a stack of dead paperwork.

The electrical types support their proposals with kilowatts. The company accountants understand kilowatts because the accountants pay the monthly electric bill.

If you work with pumps and electric motors, here is a formula to help you push your projects through purchasing.

Operating (Electricity) Cost per Year =

Head = total dynamic head in metres
Flow = liquid flow in cubic metres per hour
Sp. Gr. = Specific Gravity
R/kWh = cost in Rand per kilowatt hour
8,760 = total hours in a year (can be adjusted to actual operating hours)
367.7= conversion factor
eff. pump = pump efficiency (see the pump curve)
eff. motor = motor efficiency (see the motor specs)

Consider a newly installed pump in a properly designed system, with the following values:
Flow is 260-cu.m./hr.
Head is 200-m. Sp gr. is 1.0.
Electricity Cost R-1/kWh.

The pump runs 24-hrs per day or 8,760 hours per year. The pump is 78% efficient. The motor is 92% efficient.

The yearly operating cost is R-1,726,108.
Calculation 2
After 6 months of service, the pump is disassembled and measured for erosion. The gap in the wear bands had opened an additional 0.100-mm beyond the original factory setting. The pump lost about 8% efficiency through the gap. The pump is now 70% efficient. The energy to operate this pump for a year increases to R-1,923,648.

Calculation 3

The 0.100-mm additional wear in the wear bands costs the company an additional R-197,540 per year in energy for this one pump. The wear bands for this pump might cost R-5,000 to purchase and install in maybe 3 to 5 hours of time and labour for a back pull-out process pump.

You can use this same “Yearly Electricity Cost” formula in other energy issues regarding process pumps and electric motors. Let’s say you plan to lay some pipe for a cooling tower modification at work (or pipe the plumbing under your hunting cabin in the bush).

You need 300-m. of schedule 40 pipe. Projected flow is 200-cu.m/hr. at 16-hrs/day (5,840-hrs. per year). You want to use 200-mm pipe. The purchasing agent wants to buy 125-mm pipe because it is cheaper to purchase.

You consult a pipe resistance chart and learn:
The friction loss (Hf) at 200-cu.m/hr. thru 300-m. of 125-mm pipe is 33-m.
The friction loss (Hf) at 200-cu.m/hr. thru 300-m. of 200-mm pipe is 4.8-m.
You will purchase a pump for this application that is about 80% efficient.
The motor is 90% efficient.
Electricity in your province is R-1/kWh. 300-m of 125-mm pipe will cost the company R-145,614 per year in electricity to overcome the friction losses through the pipe.

Calculation 4

The energy cost to overcome the friction of cooling tower water moving through 300-m of 200-mm pipe will cost the company R-21,180 per year in electricity.

Calculation 5

You can say to the purchasing agent, “I understand that 125-mm pipe costs less to purchase than 200-mm pipe. However, in this application, the energy to overcome the friction losses through 125-mm pipe will cost the company R-145,614 each year in electricity. The energy to overcome the friction losses through the 200-mm pipe is only R-21,180 each year in electricity”.

You go on to say, “I calculate the larger pipe will pay for itself in energy from friction losses in about 26-months, 42-months, or whatever. The cooling tower modification has a projected life of 20-years. After the 200-mm pipe has returned the investment in cost difference, the remaining 16 years will actually earn the company R-xxx,xxx in energy savings. After 20-years, the 125-mm pipe will actually cost the company R-XX,XXX,XXX in excess energy.”

How can the purchasing agent (or VP of Finance) say no to this information? You can push your projects through purchasing if you support your position with kilowatts and Rand.

People, you could change the standard incandescent light bulbs to energy efficient lighting in every home in your entire neighbourhood. You won’t produce the savings that you could realize with one or two small pumps at work.

Learn to support your arguments and proposals with kilowatts and Rand. It’s the language of the bean counters. We’ll win the energy war and secure the future for our kids.

Or you could write your elected official! Maybe he’ll listen. Yeah right!