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With recent hikes in prices of energy and electricity, companies are seeking avenues toreduce the cost of goods and services in order to remain competitive. Energy assessment is animportant tool for companies to uncover the areas energy cost could be saved. This paperoutlines lean six-sigma approach to conducting an industrial energy assessment in a facility.This approach is based on the internal energy assessment within an industry. This paperfocus on five major steps: define measure, analyze, improve and control. It is worthy to notethat for a company to conduct internal energy assessment, it must have an energymanagement team in place. The energy management team is to comprise of top management,energy management champion, energy management team.This paper provides a lean six-sigma approach to conduct energy assessment in order toidentify areas to reduce waste in energy, productivity and also a reduction in carbonfootprint. This guideline can be used as part of the procedure for developing an energymanagement plan.
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Lean Six-Sigma Approach to Industrial Energy Assessment
Abiodun Babalola*
Department of Mechanical Engineering, University of Louisiana at Lafayette, USA
*Corresponding author: University of Louisiana at Lafayette , P.O. Box 44170, Lafayette,
LA 70504. Tel.: (01) 337-326-0075. E-mail address: [email protected].
Abstract
With recent hikes in prices of energy and electricity, companies are seeking avenues to
reduce the cost of goods and services in order to remain competitive. Energy assessment is an
important tool for companies to uncover the areas energy cost could be saved. This paper
outlines lean six-sigma approach to conducting an industrial energy assessment in a facility.
This approach is based on the internal energy assessment within an industry. This paper
focus on five major steps: define measure, analyze, improve and control. It is worthy to note
that for a company to conduct internal energy assessment, it must have an energy
management team in place. The energy management team is to comprise of top management,
energy management champion, energy management team.
This paper provides a lean six-sigma approach to conduct energy assessment in order to
identify areas to reduce waste in energy, productivity and also a reduction in carbon
footprint. This guideline can be used as part of the procedure for developing an energy
management plan.
Keywords: Energy assessment, lean six-sigma, energy efficiency, energy management
1 Introduction
Increasing energy demand and cost has necessitated research into ways of reducing
energy consumption and waste. Industries are faced with an increasing cost of energy and
this has been transmitted to the cost of operation. In the past, companies do consider energy
cost as a normal operating cost which is been considered as normal cost of doing business.
Now everyone is being sensitive to energy cost and ways of reducing it.
In the recent past, companies and organizations have all been under great operational and
environmental pressure. Being economically competitive in the global market and meeting
increasing environmental standards to reduce air and water pollution have been the major
driving factor in most of the recent operational cost and capital cost investment decision for
organizations [1]. Most companies and organization depend on energy for their operation and
this can be a major operational cost to the company, whichever line of business they may be
engaged in. Environmental cost can also be attributed to energy by the emission of
greenhouse gases which deplete the ozone layer, cause acid rain and invariably cause climate
change.
In order to improve organization profitability and environmental sustainability, it is
essential to improve energy conservation and efficiency. This is the simplest way to
minimize emission of greenhouse gas and other air pollutant that causes acid rain [2]. Rising
energy prices and increasing awareness of the environmental problems coincident with
energy use have highlighted the importance of research that investigates the economic
efficiency of energy production and consumption.
Energy management is a tool that helps companies to meet these objectives. Energy
management is described as a standardized way of managing energy [3]. Energy
management has been identified as business management which possesses a framework for
encouraging companies, suppliers and customers to control their energy in a better way, and
thus they can promote energy efficiency through supply chain. For successful
implementation of energy management systems (EMS) there is the need of top
management’s involvement and leadership. An effective energy management commences
with an assessment of the energy systems in the facility [4]. This results in cost savings and
protection of the environment as proposed in the recommendation of the energy assessment
report.
Energy efficiency activities are those sets of activities embarked upon by a company or
industry in order to reduce energy waste. Asides from the reduction in energy waste, energy
efficiency reduces greenhouse gas emission by decreasing energy consumption and peak
demand, thereby delaying or avoiding capacity upgrades [5]. Energy efficiency is enhanced
when an economizer is installed in a boiler in order to reduce the energy required to convert
water into steam. Energy efficiency is improved when a photo sensor or occupancy sensor is
installed to control the switching on and off of the lighting when it is daylight or night and
when there is no occupant in a room
Six-sigma is a well-established approach that seeks to identify and eliminate defects,
mistakes or failures in processes or systems by focusing on those process performance
characteristics that are of critical importance to customers [12]. The main focus of six-sigma
is to reduce potential variability from processes and products by using a continuous
improvement methodology [13]. This methodology employs define, measure, analyze,
improve and control phases. This is known as DMAIC (‘Duh-MAY-ick’) methodology and
is employed in existing processes or products.
Lean manufacturing is the elimination of waste which forms the core of the Toyota
Production System [14]. Waste elimination is one of the most effective ways to increase the
profitability of any business [15]. During operation in a facility, process is either value added
or non-value added. There are seven wastes identified by lean, which are: (1) overproduction,
(2) large inventory, (3) excess motion, (4) waiting, (5) transportation, (6) over-processing,
and (7) defects. All the identified wastes contribute to an increase in the consumption of
energy in a facility. By overproducing products and having large inventory, energy is used up
in production and in some instance used to prevent the excess inventory from perishing (if
perishable). Excessive motion and transportation increases the fuel consumed by the forklift
or leaving the machine on to get the product to another product line. Energy that can be used
to produce one product will be used for rework and over processing. All these are energy
waste and result in an increased energy cost.
Lean six-sigma is the integration of lean manufacturing and six-sigma in a process. The
integration of lean and six-sigma is important because lean alone cannot bring process under
control and six-sigma alone cannot eliminate waste from a process [16]. Lean six-sigma
drives the elimination of defects and waste from a systematic analysis of processes based on
facts [17].
This paper focuses on the use of lean six-sigma approach to conduct industrial energy
assessment. It focuses on the use of internal energy management team to conduct energy
assessment as the employees assigned to the team know that it is part of their job
responsibilities. The flow chart for the lean six-sigma approach is shown in Figure 1 Energy
Assessment Flow Chartand the major steps discussed in the following sections are: (1) Define
team and level of assessment, (2) Measure the facility energy use, (3) Analyze energy data,
(4) Improve and recommend, and (5) Control.
Figure 1 Energy Assessment Flow Chart
2 Define Team and Level of Assessment
In conducting an effective and efficient industrial energy assessment, the first thing is to
define the team and the level of assessment. This is the planning stage of the energy
assessment and lots of hours should be spent at this level to ensure an effective and efficient
assessment. This is important as this will form the yardstick for measuring the success or
failure of the energy assessment. The flowchart for the define stage is shown inError!
Reference source not found.. The energy assessment team should consist of five to seven
people. This team can further be subdivided into the basic energy consuming equipment in
the facility. Examples include; lighting team, motor driven system team, HVAC team, infra-
red survey team and air compressed system team.
2.1 Create Energy Assessment Team
The energy assessment team is needed in performing all the activities involved in the
energy assessment. These activities include energy data collection, analyzing of energy data,
Define team and
level of assessment
Control
Improve and
recommend
Measure facility
energy use
Analyze energy
data
plant survey. The size of the team is dependent on the level and scope of the energy
assessment. The size of the company to be assessed could also be a determining factor. The
energy assessment team can be drawn from a cross functional group. The production and
maintenance staffs that are familiar with the facility [4] can also be part of the team. This will
allow for varying skills and experience. An effective energy assessment team may take many
forms [18]:
A stand-alone group, or be distributed among existing job functions
Many people, just a few, or a single individual
Entirely internal, or make extensive use of consultants and contractors.
Figure 2 Define Team and Level of Assessment Flowchart
The team should be subdivided according to the various energy systems to be assessed.
Examples are lighting team, HVAC team, air compressor team, motor driven system team
and infra-red survey team. The responsibilities of the energy management assessment team
are; (1) Conduct energy assessment audit, (2) Identify the sources of energy procurement, (3)
Identify activities, equipment and human activity which affect the energy consumption and
contribute to CO2 emission and (4) Identify and prioritize for opportunities for improvement.
Create Energy
Assessment Team
Lighting
Team
Motor Driven
System Team
Infra-red
Survey Team
HVAC
Team
Air Compressed
System Team
Train Team
Pre-Assessment
Data Collection
Define Level and
Scope of Assessment
Start-up Meeting
Facility Survey
Team member roles and responsibilities should be documented using the assignment matrix.
This gives the team members a clear understanding of their responsibilities in conducting the
energy assessment. In assigning responsibilities to the team members, it is essential to assign
the right person to the right task.
It is important to have the commitment of the higher management. The higher
management should have a representative in the energy management team. This
representative is called an energy management champion whose responsibilities are; (1)
Direct activities of the energy management team as well as the organization as a whole, (2)
Report to top management for the energy management system improvement, (3) Assign
responsibility for energy management systems in organization and cooperate within
organization, and (4) Monitor implementation and make sure for continuous improvement.
The top management serves as a source of the voice of customer (VOC). A one on one
interview should be conducted with the energy champion to figure out the level of
management’s commitment to energy efficiency. A summary of the energy management
team responsibilities are summarized in Table 1.
Table 1 Energy Management Team Responsibilities
Energy Management Team Responsibilities
Top Management
Allocating Resources.
Defining and creating the energy policy.
Energy Management Champion Directing activities of the team.
Assign responsibilities to the energy management team.
Monitor implementation of recommendations.
Reporting improvement to top management.
Energy Manager Performs training for the energy management team.
Oversees the activities of the energy management team.
Energy Management Team Conduct energy assessment.
Identify sources of energy consumption
2.2 Train Team
The energy assessment team should be trained on how to assess the various forms of
energy systems within the facilities. This is where the role of the energy manager comes in.
As it is expected, the energy manager must be knowledgeable of what energy assessment
entails, must be fully informed of the technicality involved, and must understand the impact
of a successful assessment to the goals, growth and development of his company. These
trainings should include safety procedure while conducting the assessment, how to conduct
leak test, how to measure with basic assessment tools like the lux meter, ammeter, infra-red
cameras etc. Some simple tools needed for a successful energy assessment are listed below:
Lux-meter: The lux-meter is a simple hand held tool used to measure light
illumination levels during energy assessment. This instrument measures in foot-
candles and the value is compared with the illumination levels specified by the
Illuminating Engineering Society (IES). This comparison allows the team to make
recommendation like reducing the number of lighting, replacing lamps with efficient
ones.
Thermometer: This tool is used to determine the temperature of offices, working
areas and other equipment within the facility. In measuring temperature, the auditor is
able to determine the quantity of energy and lost in different ways. More often, air,
gas and surface temperature are measurement carried out in energy audit. Different
types of temperature tools can be used, the common being thermocouple is used
because of its efficiency in providing a more adequate range of 392 degrees
Fahrenheit to 272 degree Fahrenheit and a high reading accuracy.
Wattmeter: This tool measures voltage and current using a clip-on current
transformer. A typical wattmeter is capable of measuring 600volts systems up to a
maximum of current of 200 amps. This tool is often most effective in performing
measurement on a balance 3-phase power system even though it is primarily intended
for measuring in a single phase power systems. It captures the maximum current
values and its best utilized by measuring values using shorter intervals.
Combustion analyzer: This is an electronic instrument used in measuring the
combustion efficiency of furnace, boiler and other equipment with a fuel combustion
system. Its major aim is to ensure that the optimum air to fuel ratio is used. The
efficiency of’ the combustion analysis is derived by different analysis which includes
stack temperature and the composition of stack gas. Its use cuts across many
industries using combustion equipment. Its main function in ensuring efficiency is
dependent on its level of air ratio of optimization to fuel.
Tape measure: Tape measure is used to measure the dimension of ceilings, walls,
windows and generally the distance between two points on equipment. For example,
it can be used to measure the length of the hot water outlet pipe on a steam boiler in
order to know the quantity of lagging material it would require.
2.3 Pre-Assessment Data Collection
Information of the facility should be collected and analyzed before survey of the facility.
This information is to give the team the current state of energy health of the facility. Sources
of data include electricity bill, water bill, and natural gas bill, number of lighting fixtures,
number of HVAC units, Chillers, cooling towers, compressors, and productivity data. Pre-
assessment forms as shown in Table 2 can be used to collect basic information about the
facility to be assessed. The utility bills should be between 12 months to 36 months.
The utility bills should be analyzed using a statistical tool like run-chart or performance
metrics to get a visual understanding of the energy consumption profile of the company as
shown in Figure 3. The figure shows a twelve months energy consumption pattern, in July,
2010, the energy use was the highest. July can serve as a for cost reduction by analyzing all
the energy consuming equipment used. The Pareto chart is another important six-sigma tool
which provides information on the few energy systems consuming the highest energy as
illustrated in Figure 4. From the figure, it can be observed that the boiler and compressed air
system energy cost is about 80% of the total energy cost. This shows a high potential for
energy savings from the assessment of these equipment. The analyzed bill should also be
verified to ensure that the company is billed at the approved commercial or industrial rate. It
is also important to compare current company’s utility rate with other utility companies to
determine the cheapest rate.
Table 2 Pre-Assessment Data Sheet
Assessment Date: 10/01/2013
Company Name: ABC Chemical Company
Company Address: 3217 US 90,Broussard, LA70518
PPE for Assessment Steel toe, hard hat, safety glasses
Contact Name:
Name: Smith Jack
Contact Title:
Plant Manager
Email:[email protected]
Phone:
337-326-0137
SIC: 3225 No of Employees: 320 Plant Area: 650,000 sq.ft.
Gross Annual Sales:
$ 120 million
Annual Production:
900,000 Tons
Principle Product:
Chemicals
Total HP
Capacity: 1700
Largest Motor HP: 450 Power Factor: 2.0
Operation Hours Days/Week Weeks/Year
Shift 1 8 5 50
Shift 2 8 5 50
Production Lighting Hours 24 7 52
Office Hours 10 5 50
Office Lighting Hours 10 5 50
Figure 3 Energy Consumption Performance Metrics
Figure 4 Pareto Chart of Energy Cost by Energy System
Utility bills have three basic charges and these are:
Customer Charge: this is a flat fee charged to the customer irrespective of the energy
use. This charge ranges from zero to $25 for residential customers to thousands of
dollars for commercial and industrial customers. The energy assessment team should
explore different utility providers to determine the cost effective charge as this char
varies from one utility provider to the other.
Energy Charge: energy charge measured in dollars per kilowatt-hour ($/kWh) of
electricity or dollars per cubic foot ($/ft3) is the charge for energy use. This is
dependent on the amount of electricity or the quantity of gas used for the month. The
charge varies with seasons and the cost of generating electricity or the price of gas.
500
600
700
800
900
1,000
Oct-09 Jan-10 May-10 Aug-10 Nov-10
Ele
ctri
cal E
ne
rgy
Usa
age
(kW
h)
Tho
usa
nd
s
Energy Use UCL LCL Mean
0
20
40
60
80
100
120
$-
$20.00
$40.00
$60.00
$80.00
$100.00
$120.00
Pe
rce
nta
ge (
%)
Ene
rgy
Co
st (
$/y
r)
x 1
00
00
Energy System
Demand Charge: This charge is measured with the demand meter and usually applied
to commercial and industrial customers. The demand meter measures the minimum
demand and maximum demand in any 15, 30, or 60 minutes time increment in the
billing period.
Some basic six-sigma tools like performance metrics, histogram, pie-chart, and run chart
can aid in the analysis of these data. Abnormal spikes in the chart should raise concern to the
team on the possibility of abnormal energy charge or usage. The plant energy profiler (PEP)
an online software tool provided by DOE can be used by the energy management team to
profile the facility’s energy use and consumption [8]. The data gathered are input into the
software and a report is generated to show the details of purchased energy, consumed energy
and possible areas of energy cost savings. This will provide the current state of the facility
and aid the team to know where to focus their attention during the facility assessment and
also the extent or level of the assessment.
2.4 Facility Survey
During the facility survey, the energy management team walks the entire facility to list
the building envelope (roof, windows, etc.), the heating, ventilation, and air conditioning
equipment (HVAC), the lighting equipment, boiler, conveyors other facility specific
equipment. A plant survey identifies:
Areas of energy waste,
Areas that require repair or maintenance work, and
Areas that require capital investment to improve energy efficiency.
With a facility survey, the energy management team would have better understanding of
how each facility is used, operated and the level of deterioration. This survey will identify
activities that require kaizen, 5S projects that can be carried out in order to reduce energy
consumption thereby reducing cost. For example on a facility survey of one of the sites
visited, the condenser (Figure 5) was discovered to be covered with dust. In recommending
this type of observation, the energy management team can recommend a 5S project for the
condensers in the facility. 5S is a lean tool which is the foundation for continuous
improvement and cost reduction through employee involvement [19]
The facility survey also enables the team to collect voice of employee (VOE). Collecting
VOE enable the team to identify the likely areas of energy cost savings since the employees
are the ones using the energy system. The VOC can be collected by face to face interviews
and surveys.
Figure 5 Example of finding from a facility survey
2.5 Define the Level of Assessment
After all the steps listed above have been completed, then the team would be able to
define the level of assessment. There is no agreed definition for the types of energy
assessment in an industry. Different bodies classify energy assessment based on different
factors such as; size, function and operations in the industry, level of detail needed and scope
of the energy assessment. CIPEC [6] identifies two types of energy assessment based on the
level of details needed. These are:
1. Macro Energy Assessment: with this type of energy assessment, the entire facility is
assessed in an effort to identify energy saving opportunities. It involves a broad
physical scope and less detail.
2. Micro Energy Assessment: this type of energy assessment is energy system specific,
it usually start with the macro energy assessment. For example, a boiler identified for
possible energy saving opportunity in the macro audit is further analyzed. This type
of energy assessment is of less scope and broad details.
2.5.1 Create an Energy Assessment Plan
The energy manager is responsible for creating the energy assessment plan with input
from the team. This is a document which outlines the approach and strategy for carrying out
the energy assessment. The energy assessment plan ensures that the energy assessment is in
consistent with what it was intended to achieve and serves a guide for the energy
management team to ensure consistency, effectiveness and completeness in use of allocated
resources. The energy assessment plan should provide the following [6]:
The energy assessment charter and scope,
Where, when and duration of the energy assessment,
High priority activities of the energy assessment and timeline to completion,
Names of the energy management team conducting the energy audit, and
Energy audit report format, contents, deadline for completion and circulation
2.5.2 Develop Energy Assessment Charter and Scope
The energy assessment charter is the most important output of the define phase. It
summarizes the main focus of the assessment and the time frame for the completion of
assessment. In developing the scope of the assessment, the persons involved are considered.
In most cases, it should be decided early if carrying out the assessment will involve working
with in-house expertise alongside the external energy auditor. The internal auditor needs to
be part of the process from the beginning even though the bulk of the assessment procedure
is coordinated by the energy manager who should be independent of any bias in order to
achieve a credible result. Also of consideration is the content of the assessment which will in
most case refer to the energy systems to be assessed, as well as the reporting, format of
findings reporting, circulation of reports. In all of these, the time frame for completion is
highly crucial and must be stated. In summary, the details involved in the assessment define
the scope.
In order to effectively define the energy assessment scope, Plant Energy Profiler (PEP)
can be used. The PEP is an online or offline software provided by DOE that can be used by
the energy manager to quantify energy purchase and use in a facility. It also helps to identify
energy cost savings potentials. Energy managers can download the software from the DOE
website.
2.6 Start-up Meeting
Once the scope of assessment has been established, the next step is the start-up meeting.
This meeting informs all stakeholders involved in energy assessment of the procedure
involved in in terms of manpower, technicality which will include instrumentation and the
expected outcome of the assessment. It will also allow for specific role identification and
equally give room to obtaining other needed information on the assessment. In most cases,
the start-up meeting gives information such as: (1) the need for the energy assessment, (2)
Those involved in the assessment, (3) resources available for the assessment, (4) duration of
the assessment, and (5) expected results and their effect on the energy system or plant. The
meeting can also be an avenue to gather useful existing information and identify loop-holes
or areas of interest to be considered in achieving overall success of the assessment
3 Measure the Facility Energy Use
A basic understanding of energy measurement techniques and equipment is needed for a
successful energy assessment. Both correct tools and its use are fundamental in obtaining
useful measured data. Knowledge of energy measurement makes it easy to measure the
energy in terms of how much energy is consumed by each energy system, and how all the
units add up to equal the energy use of a facility. In measuring energy use in a facility, you
might want to consider answering the following questions: (1) which energy systems
consume energy? (2) how much of energy is consumed and at what rate? And (3) what
activities are carried out with the energy systems or within the facility?
Giving specific answers to the questions will invariably help to locate where energy is
overused or underuse making it easier to identify areas in which energy saving opportunities
abound. Figure 6 is a flowchart of the activities involved in measure the facility energy use
and this include (1) Measure the baseline, (2) Conduct energy assessment of facility, (3)
Gather data, and (4) conduct analytical assessment.
3.1 Measure the Energy Baseline
The energy baseline of the company should be measured. This can be done by analyzing
the energy sources used by the facility. These sources include electricity, propane, and
natural gas. This baseline is important in order to compare the facility to other facilities of
the same capacity thereby evaluating the facility’s energy consumption. Examples of energy
baseline parameters are energy use index, energy productivity index and the energy cost
index.
3.2 Conduct Energy Assessment of Facility
Having gathered information and data needed by measuring the energy use of the facility
and the energy baseline as well as other information deem useful from equipment and facility
operation, the next step is to be considered is conducting the energy assessment of the facility
as planned. An energy assessment should be carried out during normal operation period as
this affords the team the opportunity to speak with plant supervisor and some other facility
employee who are in a technical position. As already suggested, facility operation period is
the best time for assessment since it is the time the equipment are in use even though some
other equipment might be used after normal operation hours.
Figure 6 Measure the Facility Energy Use
To ensure a successful assessment, further information of the facility and energy systems
should be gathered while engaging in this assessment. In most cases, specific information
pertaining to different energy system of the facility will be made available by the employee
(VOE) operating the energy system. Most likely, a maintenance supervisor will provide
information on the performance and the problem areas of energy systems such as lighting
system, motor driven system, HVAC system, air compressors. The data gathered from the
interview with the employee can lead to the identification of energy savings opportunities. In
gathering the data, the team should look at the areas in which energy savings opportunities
appropriate for the facility can be achieved. Below are some energy systems to consider:
Measure Energy
Baseline
Conduct Energy
Assessment of Facility
Compressed
Air Systems
Lighting
Systems HVAC
Systems
Motor Driven
Systems
Infra-red
Survey
3.2.1 Lighting System
In order to conduct an effective lighting assessment, the lighting team needs to have a
lighting inventory data sheet in place for taking data readings as shown in Table 3 and lux
meter for measuring the light illumination. Inventory on the number of each type of light,
light wattage and the hours of operation of each type should be recorded. Readings of the
light intensity of each area putting into consideration of the activities carried out in each area
should be noted. The team should be able to identify areas of potential energy saving
opportunities by considering where light is in excess, looking at such factors as: the type of
light being used, the number of each type used, the size and wattage of lighting used, hours
of operation of each type and the area light is used in terms of activity carried out.
In order to control lighting inefficiency, these recommendations should be considered:
Offices and areas which are less frequently used should be checked for availability of
occupancy sensor control, where not available installation of such should be
recommended.
Offices and common areas where daylight can serve as an alternative source of light
will require less energy consuming light type.
Table 3 Lightening Inventory Sheet
COMPANY NAME ABC Chemical company
Lighting Summary
No Room Name Type Size Units Wattage
(TX)
Recommendation Lux
Reading
1 Rm202 F 4X2 18 T8 R.O 450
2 Rm203 F 4X4 8 T8 O 330
3 Rm204 F 4X2 14 T8 P,R 450
4 Rm205 F 8X2 6 T8 O 247
5 Rm206 F 4X2 24 T8 P,R 436
Legend
Type Size Recommendation
Incandescent (I) 4 foot 2 bulbs (4x2) (R) Reduce lighting
Fluorescent (F) 4 foot 4 bulbs (4x4) (O) Occupancy Sensor
Metal Halide (MH) Bright
white
8 foot 2 bulbs (8x2) (P) Photo Sensor
Operation floor with more than the recommended light intensity should be checked
with the lux meter and compared with the recommended illumination levels specified
by the Illuminating Engineering Society (IES). Recommendation should be made for
the reduction of the excessive light.
It is important to have a photo sensor lighting control installation control in place
especially in operation areas where daylight serves as an alternative source of light
during the day since the sensor is capable of measuring a drop in the intensity of light
and automatically turns on the light at night when daylight is not available.
Operation floors with the recommended light during hours of operation should be
checked after hours of operation and the light possibly turned off or switched to a
lighting type adequate enough for an off operation period.
3.2.2 Motor Driven Systems
An inventory of all motor should be taken with data sheet providing information on
motor size, hours of operation, usage, age and model. Recordings on motors that are less
frequently used measurement of voltage, current and other power related factors of motors
should also be considered.
Some of the most commonly used motor driven systems in facilities include fans, pumps,
compressors, blowers, and conveyors among others. Electric motors account for over 60% of
electrical energy used in facility [20], as a result of this; great potential energy savings can be
identified in energy efficient motors. The energy assessment team should consider paying
attention to pumps and fans as they account for the highest number of energy system using
motors in most facilities for potential energy saving opportunities. The team should be able
to identify areas of possible energy savings by checking the output level of the machines and
taking note of the speed of the motors. In most cases, a variable speed drive (VSD)
installation should be done. The VSD reduces the output of the machine by controlling the
motor speed. Often times, oversize motors capable of handling maximum load demand which
are hardly reached at demand, in this case, the VSD controls the speed of the motor to that
needed.
In order to achieve motor driven system efficiency, the following should be
recommended:
Old motors with high usage time should be replaced with new high efficiency ones.
A VSD installation should be checked and installed in motors in which they are
unavailable. This is to reduce machine output by controlling the speed of the motor.
Oversized motors should be replaced with optimum sized motors.
3.2.3 HVAC
The HVAC system comprises of the heating equipment, cooling equipment and
ventilating equipment. Heaters and air conditioning systems inefficiency are sources of
waste heat as a result much attention needs to be given to it since the wasted heat can be
recovered and used as part of the heat needed for efficiency. The temperature of these
sources of waste heat should be taken, also the air velocity should be measured as this will
enable for discovery of air leaks.
Most facility do not condition or heat operation areas, the most conditioned and heated
areas are offices and common areas. In identifying possible areas of energy savings the
condition of the evaporators, air filters, condensers and insulation should be examined. The
structural and architectural features of the facility such as the walls, ceiling and ceiling
heights should be considered. Most non-air conditioned operation floors with large number
of ventilating fans are usually left running all year round especially in facilities with high
heats and in location experiencing mild weather making them areas of possible energy saving
opportunities
Inventory of heating, air conditioning and ventilating equipment should be recorded in a
data sheet. Information like the model number, size, type of equipment, age, operating hours,
should be recorded on a data sheet. The team should consider the following when conducting
assessment on the HVAC system:
1. Office and rooms that are not occupied should be checked to confirm that the rooms
are not being conditioned. When such is discovered, recommendation should be made
for the discontinue condition of the room or space.
2. The team should compare the space cooling or heating rate during operational hours
to non-operational hours to ensure energy is not being wasted via cooling during non-
operational hours.
3. Installation of programmable thermostat should be checked on the HVAC system,
where this is not installed, it should be recommended.
4. The team should check the HVAC system and ensure that dirty or hot air is not being
introduced into the system as this would reduce the efficiency of the system.
5. The team should check the maintenance record of the system to ensure proper
maintenance is done on the system which includes changing of the air filters and
some 5s operations on the condensers.
6. The distribution piping of the HVAC system should be checked for insulation. Where
insulation is not effective, replacing of the insulating material should be
recommended.
3.2.4 Compressed Air Systems
Compressed air is an indispensable tool [21]; it is considered as the fourth most used
utility after electricity, natural gas and water in manufacturing companies. It is use ranges
from simple hand tools, HVAC control systems, to pneumatic robots in car assembly.
Compressed air is one of the most expensive utilities in manufacturing facilities [22]. Most
energy use in the air compressor ends up as heat which is wasted and also causes an
increased load for the HVAC system. Air leaks in compressed air system are the significant
source of waste and it results in 20% - 30% of the air compressor’s output [23].
Compressed air leaks is also associated with problems resulting in the operation of the
system which include; (1) increased in compressor pressure which results in increased cost of
operation, (2) fluctuation in system pressure which results in inefficient and ineffective
operation of air tools and other air operated equipment, (3) increased in maintenance cost of
the system and a reduced service life. Common areas of air leakage are hoses, couplings,
fittings, tubes, pipe joints, valves, flanges to mention a few.
Ultrasonic detector is the best tool to detect compressed air leakage. Other method
includes the use of soapy water to the suspected areas but this can take some considerable
amount of time and energy. The energy management team must be knowledgeable in the use
of both methods to detect air leakages and should use it to detect air leakages. The team
should also check the air compressor’s pressure to be sure it is at a minimum set pressure of
100 psig (114 psia) as leakage accounts for pressure drop in the system.
3.4.5 Infra-red Survey
The electrical system in the facility should be scanned for heat emission which is as a
result of loose connection. This can be achieved by using an infrared camera to detect the
heat emitted from the system. The benefits of an Infrared survey [24]:
Help prevent emergency, unscheduled maintenance
Fewer interruptions to production – Greater uptime
More efficient energy usage
Reduction in potential damage to equipment and the facility from fire
4 Analyze Energy Assessment Data
Energy data gathered from the measure stage are analyzed by the team to identify energy
savings opportunities abound in the facility. The energy savings opportunities are converted
to equivalent dollar amount understandable by the management. At this stage, economic
analysis is performed to estimate the energy cost savings, implementation cost and the
payback period. Figure 7 is a flow chart of the analyze stage. The result of this is used in
formulating the recommendations needed to be taken by the facility in order to reduce energy
waste and cost.
Figure 7 Analyse Energy Data
4.1 Analyze Energy Data
With the completion of the facility or system survey assessment as per plan, the next step
is the analysis of all collected data. These data should be organized, examined and reviewed
to ensure that all data needed for significant assessment is collected. Often times even before
the assessment is conducted, a good knowledge of different energy efficiency measures that
can bring about energy savings must have been identified as it enables the team to determine
areas of potential energy savings from analyzing the data got from the actual assessment
conducted on the systems and facilities. For example, old motors or motors with high time
usage are potential energy saving opportunity for high efficiency ones. Over lighting in an
area signifies potential energy savings in light change or removal. A cause and effect
diagram can aid in analyzing the cause of the energy waste.
In performing an assessment analysis, the team aims at determining the cost and benefits
of the potential energy savings opportunities that is cost effectiveness. There are three
Analyze Energy
Data
Compute Energy
Savings
Energy Cost
Savings
Implementation
Cost
Pay Back
Period
commonly used medium for measuring cost-effectiveness: payback-period, discounted
benefit- cost ratio, and life cycle cost (LCC) approach. Most facilities look for a payback-
period of two years or less [10], this is derived by dividing the initial cost by the annual
savings. Another method of measuring is the discounted benefit-cost ratio which is derived
by adding up the future discounted annual savings to find the present value of annual savings
over a period of time and then dividing it by the initial cost, a ratio more than one signifies
great savings. The third relevant medium is the life cycle cost approach which focuses on the
savings accumulation and its relevance on the present savings to future savings and costs,
this approach gives a better evaluation of long term effects on energy savings. Another focus
of the analysis is in giving a valid and assured judgment on the cost-effectiveness of a
potential energy savings opportunity by computing cost savings and implementation savings.
5 Improve and Recommend
At this stage in the energy assessment process, the recommendations are developed and
evaluated; the initial draft of the assessment report is written and reviewed with the energy
management champion. Once all the recommendations are agreed on, the report should be
signed, distributed and a copy achieved with the energy management team for future
reference. Figure 8 is a process flow chart for improve and recommend stage.
Figure 8 Improve and Recommend
5.1 Develop and Evaluate Recommendations
The recommendations are developed from the analyzed data gathered for the assessment.
Table 4 is a summary of the recommended savings based on the assessment carried out in a
sugar mill by the IAC, Louisiana [25]. The recommendations are further evaluated to by the
energy manager to identify alternative method of energy cost reduction.
Develop and Evaluate
Recommendations
Draft Initial
Assessment Report
Review Draft
Assessment
Report
End of Improve
phase
Table 4 Recommendation Description, Resource Savings, Energy Cost Savings,
Implementation Cost and Payback Period
s/n Recommendation
Description
Resource
Savings
(/yr)
Energy Cost
Savings
($/yr)
Implementation
Cost
($)
Payback
Period
(month)
1 Install back pressure
turbine
8,600,000 kWh
electricity $ 573,937.00 $ 2,150,000.00 45
2 Repair steam leaks 120,454 MMBtu gas $ 69,765.00 $ 12,567.00 2
3 Install economizer 63,000 MMBtu gas $ 31,500.00 $ 21,500.00 8
4 Improve power
factor
$8,829.67 Power
factor $ 8,829.67 $ 4,602.34 6
5 Install photo sensor 38,753 kWh
electricity $ 37,535.46 $ 270.00 0
6 Repair pump seal 12,347 kWh
electricity $ 1,912.00 $ 756.00 5
7 Reduce number of
lights
$117.84 service
charge $ 117.84 $ - 0
8 Insulate surface of
pipes 66 MMBtu gas $ 304.50 $ 442.08 17
Total $ 723,901.47 $ 2,190,137.42 36
5.2 Draft Initial Assessment Report
A draft assessment report should be written to summarize the findings of the industrial
energy assessment. The facility assessed, level and type of assessment will determine the
length and content of this report. This report will have a summary of the energy sources and
use in the facility, the cost of the energy, the major energy consuming equipment,
recommended energy savings, implementation cost and the payback period on the
investment. An outline of an energy assessment report is shown Table 5 [26].
Table 5 Assessment Report Outline
Executive Summary
A brief summary of the recommendations and cost savings
Table of Contents
Introduction
Purpose of the energy assessment
Need for a continuing energy cost control program
Facility Description
Product or service, and materials flow
Size, construction, facility layout, and hours of operation
Equipment list, with specifications
Energy Bill Analysis
Utility rate structures
Tables and graphs of energy consumptions and costs
Discussion of energy costs and energy bills
Energy Conservation Opportunities
Listing of potential ECOs
Cost and savings analysis
Economic evaluation
Action Plan
Recommended ECOs and an implementation schedule
Designation of an energy monitor and ongoing program
Conclusion
Additional comments not otherwise covered
5.3 Review Draft Assessment Report
The drafted assessment report should be reviewed with the energy management
champion to obtain his reviews on the energy assessment conducted in the facility and the
recommendations made. His observations should be noted and incorporated into the energy
assessment report. Once all stakeholders involved with the assessment are satisfied with the
report, the report should be signed and distributed to the top management for their further
action. A copy of the assessment report should be archived by the energy management team
for future reference. This is important for future assessment as the report would serve as a
reference material for the energy management team.
6 Control
The control phase is outside the scope of the energy assessment as this is particular to the
top management. This includes procedure that can be taken to ensure implementation of the
recommendations from the energy assessment report in the industry in order to reduce energy
cost. The energy management team should also include actions that can be taken by top
management in order to implement the recommendations. Such actions include the
development of an energy management plan (EMP), and energy policy. EMP is an approach
of reducing energy consumption and operating cost simultaneously. Energy assessment is a
continuous improvement tool and should also be included in the EMP. Further research on
EMP was conducted by Lee, Yuvarmitra, Guiberteau and Kozman [27] and Osho [28].
7 Conclusion
This paper developed a lean six-sigma approach to conduct an industrial energy
assessment in a facility. The procedure is developed based on an internal energy assessment.
The following information was provided by this paper:
1. The procedure is based on internal energy assessment which is an employee based
type of energy assessment.
2. The procedure involves developing a procedure for conducting industrial energy
assessment based on the DMAIC approach.
3. This approach was implemented in a manufacturing industry and has yielded a 19.7%
reduction in energy savings.
4. This approach provides employee participation in energy assessment of the facility.
5. Developing an energy management plan and energy policy, which is the control
phase of this approach, would ensure continuous improvement in energy waste and
reduction.
It is not intended to claim the insignificance of the IAC but to show how the integration
of the internal energy team and lean six- sigma can bring about energy cost savings
opportunities. This approach also ensures continuous energy savings through implementation
of energy management plan and energy policy.
The lean six-sigma approach discussed in this paper can be employed in other manufacturing
industries for conducting industrial energy assessment. Further research should be done on
investigating the energy saved from the energy assessment conducted by an external auditor.
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