Energy-saving opportunities in Pumping Systems: Where they are and how to recognize them MAM-001aR1.

Energy-saving opportunities inPumping Systems:

Where they are and how to recognize them

MAM-001aR1

Big Picture Perspectives: Industrial Motor Systems

Industrial motor systems:

- are the single largest electrical end use category in the American economy

- account for 25% of U.S. electrical sales

Motor loads dominate industrial electrical energy consumption

ProcessHeating

Electrolytics

Motor-DrivenEquipment

Lighting& Other

Over 60% of industrial motor-system energy consumption involves fluid handling

Pumps24.8%

Fans13.7%

Compressed Air15.8%Refri

geratio

n

6.7%

Material handling

12.2%

Material processing22.5%

Other

4.3%

Just over 1/3 of themotor population

accounts for almost2/3 of the energy

A large portion arecentrifugal devices

A small fraction of the motor population is responsible for most of the energy consumption

0102030405060708090

100

> 10

00

> 50

0

> 20

0

> 10

0>

50>

20 > 5

> 1

Cumulative motor horsepower range

Pe

rce

nt o

f en

erg

y/po

pul

atio

n

Population

Energy10% population

uses 80% energy

Note the descending order (left to right)

Comparing life cycle costs: automobile and pump/motor combination

Common assumptionsDiscount rate = 8%Non-energy inflation rate = 4%Lifetime = 10 years

Item Automobile Pump & motorInitial energy cost rate $1.50/gal 5 cents/kWhrEnergy inflation rate 10%/yr 5%/yrOperating extent 12,500 miles/yr 7000 hr/yr (80%)

Life cycle cost - example automobileFull size vehicle, $28,000 price tag, 24 mpg

Purchase:51%

Maintenance, Insurance

31%

Energy16%

Miscellaneous2%

First year energy cost = $69,000First year energy cost = $69,000

Life cycle cost - 250-hp pump and motor$28,000 initial cost, 95% motor efficiency

First year energy cost = $69,000

Purchase3%

Maintenance, downtime

21%

Energy74%

Miscellaneous operations

2%

First year energy cost = $19,600First year energy cost = $19,600First year energy cost = $19,600

Higher first cost pump and motor ($56K),low service time (2,000 hrs/year)

Purchase20%

Maintenance

15%

Energy59%

Miscellaneous operations

6%

Pump and motor component efficiencies:Seventy+ years of progress

Pump MotorYear efficiency (%) efficiency(%)

1928 80 87.5

1955 85 90.5

2002 88 95.4

Achievable efficiency estimates for commercially available 75-hp pump and motor

What can you deduce about thesurroundings from this picture?

Are you in a lush forest?

Or the Badlands?

With pumping systems, motor and pump performance is just part of the bigger picture

The Pareto Principle or "the vital few and trivial many"

J. M. Juran, who first used the term "Pareto Principle" also coined a more descriptive phrase:

Input

20%80%

Output

20%80%

(Relatively few are responsible for relatively much)

"The VITAL FEW and the trivial many"

Prescreening to narrow the field of focus - i.e., to select the VITAL FEW for further review

All plantmotor systems

Policies andpractices bin

Filter 1

Seldom used,small loads

Big loadsthat run a lot

Filter 2

Big centrifugalloads that run a lot

Symptom orexperienced-based

segregationLarge non-centrifugal loads

* *

Moderatepriority

* Productivity/reliability-critical systems sent to higher priority levels

HighestPriority

• Look for:

– Throttle valve-controlled systems

– Bypass (recirculation) line normally open

– Multiple parallel pump system with same number of pumps always operating

– Constant pump operation in a batch environment or frequent cycle batch operation in a continuous process

– Cavitation noise (at pump or elsewhere in the system)

– High system maintenance

– Systems that have undergone change in function

Example symptoms in pumping systems that indicate potential opportunity

Many life cycle elements influence reliability, cost, and productivity of motor-driven systems

– Design– Procurement– Construction/Installation– Testing/Troubleshooting– Operation– Maintenance– Insurance– Regulations– Decommissioning– Down time– etc…..

Most of these elements are interdependent

AffectMaintenance

Design

ProcurementConstruction/InstallationTesting/Troubleshooting

OperationMaintenance

InsuranceRegulations

Decommissioning

Example: other factors do or may affect maintenance

Down time

Just like any stable control system, optimal asset management requires feedback

Maintenancedoes, shouldor may affect

Design

ProcurementConstruction/InstallationTesting/Troubleshooting

OperationMaintenance

InsuranceRegulations

Decommissioning

Unfortunately, feedback is often weak or non-existent

Down time

Life cycle elements are an integrated system, much like the physical systems themselves

• The elements can be treated as components

– For example, procurement can be on lowest first cost basis, without regard to the effect on maintenance or operations

• The elements can be treated as a system

– For example, procurement considers all the elements of cost and is based on lowest total life cycle cost

Ideally, all the life cycle elements could be analyzed with a single common denominator

– Design– Procurement– Construction/Installation– Testing/Troubleshooting– Operation– Maintenance– Insurance– Regulations– Decommissioning– Down time– etc….

Cost

When considering options, some elements can often be disregarded - even at the system level

• Insurance

• Regulations

• Decommissioning

Alternatives & supplements to life cycle cost analysis

• Probabilistic analysis of reliability & risk (commercial software is available)

• Engineering judgment

• Weighted/graded evaluation

• Sole-source contracting (initial selection would involve overall cost/reliability considerations)

• Outsourcing - shed some of the decision-making responsibility

Contingency planning - making the change when a failure occurs

• The alternatives evaluation picture changes dramatically when failures occur

• Changes that couldn't be justified when the system was functional may very well be after failure

• The alternative may actually be less costly than simple repair/replace of the existing component