Ontario Centers of Excellence
DynaPlas Ltd:
Green Plant Project
by
Mashal Kara
A thesis submitted in partial fulfillment
of the requirements for the degree of
BACHELOR OF APPLIED SCIENCE
Supervisors:
W.L Cleghorn
J.K. Mills
Rick Packer
Robert Kuhi
Department of Mechanical and Industrial Engineering
University of Toronto
Executive Summary
DynaPlas Ltd is an injection-molding manufacturer that caters to the automotive
industry in North America. As the current economic crisis caused the big North
American automotive manufacturers to reduce production, DynaPlas was forced
to lay off 75% of their full time staff due to production losses in the past year and
a half. As production decreases, the plant’s overhead costs begin to weigh more
on the product pricing thus affecting DynaPlas’ ability to remain competitive.
In the year 2007-2008, DynaPlas spent M$ 980 in electricity and natural gas. The
purpose of this project was to reduce the energy consumed by the plant while
maintaining or improving production quality and working conditions. We focused
the scope of the project on the natural gas usage by and attempt to reduce the
quantity of outside air we need to heat and introduced into the plant.
Currently, the plant is exhausting a lot more air than it is forcing in to make sure
all fumes are exhausted. The suggested system captures fumes from the source
of the emissions allowing us to reduce the plant’s air changes per hour thus
reducing the natural gas consumption. Implementing this system at DynaPlas will
cost M$ 115 and will generate M$ 185 in energy savings every year thereafter.
This project’s payback period of 0.62 heating seasons makes it highly feasible
and we would recommend DynaPlas to go ahead with the work in early fall.
Although this project was designed to be implemented at the DynaPlas injectionmolding facility, it can be repeated at any other manufacturing plant having a
large volume of exhaust.
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Acknowledgments:
This project was accomplished with the support of DynaPlas Ltd and The Ontario
Centers Of Excellence.
Throughout the project, we appreciated the help of Rober Kuhi, Rick Packer,
Ronnie Fong, Stephanie Ruthard and Johann Schimd without whom we would
not have been successful.
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Table of Contents
Executive Summary ................................................................................................................. 2
Acknowledgments: .................................................................................................................. 3
Table of Contents ...................................................................................................................... 4
i. List of Figures: ........................................................................................................................ 5
ii. List of Tables.......................................................................................................................... 6
iii. Project Charter .................................................................................................................... 7
1. Motivation: ............................................................................................................................. 8
2. Energy Usage in the Plant............................................................................................... 10
2.1 Electrical usage: ........................................................................................................................ 10
2.2 Natural Gas Usage:.................................................................................................................... 12
3. Background information ................................................................................................ 14
3.1 Make Up Air Unit (MUA): ....................................................................................................... 14
3.2 General Room Exhaust Fan: .................................................................................................. 14
3.3 Unit Heater: ................................................................................................................................ 15
4. Current situation ............................................................................................................... 16
5. Proposed Solution: ........................................................................................................... 20
6. Cost/Benefit Analysis ...................................................................................................... 22
6.1 Baseline costs: ........................................................................................................................... 22
6.2 Benefits of Proposed Solution: ............................................................................................ 23
6.3 Installation Costs: ..................................................................................................................... 24
7. Problems encountered: .................................................................................................. 26
8. Conclusion: .......................................................................................................................... 28
Appendix A: Union gas calculator .................................................................................... 29
Appendix B: Quotes............................................................................................................... 30
B-1: PlymoVent Quote: ................................................................................................................... 30
B-2: Lincoln Electric Quote ........................................................................................................... 32
B-3: Tin Knockers Quote: .............................................................................................................. 33
Appendix C: Movable arm data sheet ............................................................................. 34
Appendix E: Updated Plant shutdown procedures .................................................... 41
Appendix F: Electrical usage .............................................................................................. 43
Appendix G: Natural gas usage.......................................................................................... 44
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i. List of Figures:
1. Control chart KWh/kg of material melted…………………………………….......11
2. Control chart m^3 of natural gas/kg of material melted…………………...13
3. Roof map of HVAC equipment……………………………………………………………16
4. Location of all Unit heaters in the Plant……………………………………….....…16
5. Current exhaust strategy…………………………………………………………………..19
6. Point source exhaust system……………………………………………………………..20
7. Proposed Location of all Unit Heaters in the plant…………………………….21
5
ii. List of Tables
1. Equipment Volumetric Flow rate………………………………………………………17
2. Electrical benefits……………………………………………………………………………..24
3. Total implementation costs………………………………………………………………25
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iii. Project Charter
Project name: Green Plant Project
Problem statement: In 2007-2008, DynaPlas spent M$ 980 in energy costs; as
production is reducing, the overhead costs are weighing more on the plant’s
ability to remain competitive.
Project Goal: Reduce the overhead costs by reducing the amount of energy
used at DynaPlas’ facility while maintaining or improving production quality and
working conditions.
Scope of the project: Electricity and natural gas usage.
Project Leader: Mashal Kara
Team: Mashal Kara, Rober Kuhi, Rick Packer, Jamie Waduck, Kevin Jenkins
Customer Critical To Quality’s: Employee comfort and good production quality
Defect: Energy consumption
Cost of Poor Quality: $ 0.10 per kWh, $0.73 per m3 of natural gas
7
1. Motivation:
DynaPlas is an injection molding company that caters to the automotive industry.
Over the last few years as the big North American automotive companies have
been reducing their production and sending more of their business to China,
DynaPlas as most other manufacturing facilities were forced to make production
adjustments that affect the way they run their plant. In the past they would run
24hrs a day and 7 days a week but due market changes they have been reduced
to 5 days a week leaving the plant idle on weekends. In the last year and a half,
they have laid off about 75% of their full time staff due to production losses.
The reduced production causes DynaPlas’ overhead costs to carry more weight
on the price of their products thus impacting the competitiveness of the company.
A big part of the plant’s overhead is in their energy usage, which will be the main
focus of this project.
In the year 2007-2008 the plant used 7.4 million kWh of electricity and 330
thousand cubic meters of natural gas a year to run their equipment and maintain
their buildings. This usage leads to total energy spending of $ 980,000. It has
been noticed that energy is being wasted in many areas of the plant and it is in
need of a study to determine which opportunities are the most feasible and
attempt to implement a sustainable solution.
8
Reducing the plant’s energy consumption will reduce its overhead costs thus
allowing DynaPlas to offer more competitive prices to their customers and gain
more business. This project aims to reduce the plant’s environmental footprint
allowing the company to better market its products as the World’s population
becomes more conscious of the industry’s environmental impact. This will also
make government grants and subsidies available to reduce the investment costs
needed to complete the project.
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2. Energy Usage in the Plant
At DynaPlas, as in many other manufacturing plants, the main sources of energy
are electricity and natural gas. In this section we will analyze where these two
sources of energy are being used to determine where our opportunities lie.
2.1 Electrical usage:
DynaPlas pays 10 cents for each KWh consumed. In the fiscal year 2007-2008,
the plant used 7.5 million KWh thus spending M$ 750 in electricity.
When scoping the plant we found that electricity was being used for the following
purposes:
Injection molding machines: The machines use electrical current to control
the heat load used to melt plastic pellets before they are extruded into the
molds. This process is highly sensitive and needs to be precisely
controlled thus cannot be performed using any other energy source.
HVAC equipment: There are many fans and blowers in the plant used to
circulate and temper the plant’s ambient air. These equipments contain
motors that are all electrically operated.
Air Compressor: Compressed air is used to cool the molds and plastic
parts after they are formed. The plant has an air compressor that cycles to
maintain a specific pressure in the plant’s piping.
Offices: Computers, printers, photocopying machines and other office
equipment also consume electricity.
10
Lighting: All plant and office lighting.
The assumption was made that most of the electrical load was from running the
injection molding machines thus assuming that electrical usage in the plant was
correlated with production. In order to prove the above assumption, we used the
amount of kg of material melted in a month as a metric to represent production
and divided it by the total KWh consumed in a month. If the assumption above
were true our ratio would yield a constant. The data was then entered in MiniTab
to obtain the following control chart:
Figure 1: Control chart KWh/kg of material melted
From Figure 1, we can see that this process in under control thus the assumption
made earlier is valid: Electrical usage is strictly correlated with production.
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2.2 Natural Gas Usage:
DynaPlas pays 73 cents per cubic meter of natural gas. In the fiscal year 20072008 the plant used 330 thousand cubic meter of natural gas thus spending
M$275.
The plant was also scoped to determine where natural gas was being used. We
learned that natural gas was not used in any production equipment and its sole
usage in the plant was for space heating and employee comfort. We then made
the assumption that the amount of natural gas used depended on the outside
temperature.
To prove the above assumption we used a metric called a Degree Day. A Degree
Day is a measure of heating or cooling by measuring the difference in
temperature from the heating set point (usually 18 degrees C). We then divided
the total cubic meters of natural gas used in a month by the total Degree Days in
that time period. If the assumption made above is true, the ratio would yield a
constant. The data was then entered into MiniTab to obtain the following control
chart:
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Figure 2: Control chart m^3 of natural gas/kg of material melted
Observing Figure 2 we can see that this system is under control thus the
assumption made earlier has been verified: Natural gas usage depends on the
outside temperature.
Knowing where each energy source is being used and the factors that control
their demand we were able to narrow the scope of our project. We decided to
focus on reducing the plant’s natural gas usage in the winter since it did not
affect production and is a main contributor to the overhead costs.
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3. Background information
DynaPlas owns and uses different HVAC equipment such as Make Up Air (MUA)
units, General Room exhaust fans and Unit Heaters. In this section we will be
giving a brief background on each of these units.
3.1 Make Up Air Unit (MUA):
The primary reason for using Make Up Air units is to prevent negative pressure
from building up inside the building. They take air from outside, pass it through a
burner in the winter and deliver ambient temperature air into the plant. Since
there is no heat exchanger MUA units introduce CO2 into the building thus should
not be operating without adequate exhaust for the safety of the plant employees.
3.2 General Room Exhaust Fan:
General Room Exhaust fans take air from the plant and deliver it into the
atmosphere. They are positioned on the roof, which makes them very cost
effective at removing heat from the building in the summer. When an injectionmolding machine jams up, it burns plastic and generates some fumes. These
fumes can be harmful to the plant’s employees. In the winter, the creation of
fumes is the only reason why these exhaust fans are running.
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3.3 Unit Heater:
Unit Heaters are used to increase the plant’s ambient temperature. They recycle
air from within the plant, heat it by passing it through a heat exchanger and
redeliver it into the plant. The use of a heat exchanger ensures no products of
combustion enter the plant and makes the unit more efficient by not introducing
cold outdoor air.
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4. Current situation
The plant currently owns three (3) MUA units, seven (7) general room exhaust
fans and six (6) unit heaters, see figures 3 and 4 for their locations in the plant.
Figure 3: Roof map of HVAC equipment
Figure 4: Location of all Unit heaters in the Plant
All the injection-molding machines are located on the left side of the building; the
right side is used for storage and has no air exchange with the environment.
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In the past production had been consistently running 24/7 thus the heat
generated by the injection molding machines, the MUA units and employees
present was sufficient to keep the building temperature at reasonable levels
without the use of the Unit Heaters in the winter. Because of the busy production
schedule, maintenance for the unit heaters was neglected therefore most of them
stopped working and some have also been removed.
The purpose of the seven (7) general room exhaust fans is to remove heat from
the building in the summer and to remove some fumes generated by the injection
molding machines during production. Currently, all exhaust fans remain on during
production and idle shifts.
To balance all the exhausted air in the plant, all three (3) MUA units also run
continuously. Table 1 shows the volumetric flow rate of each fan:
Table 1: Equipment Volumetric Flow rate
Exhaust
fans
1
2
3
4
5
6
EF1
MUA
1
2
3
CFM
hp
10,000.00
10,000.00
10,000.00
10,000.00
10,000.00
10,000.00
17,000.00
77,000.00
4
4
4
4
4
4
7
CFM
(15,000.00)
(15,000.00)
(17,000.00)
(47,000.00)
hp
15
15
17
17
The 30,000 CFM imbalance created by the excess exhaust forms a partial
vacuum in the plant. The natural forces attempt to balance inside and outside air
pressure by pulling in replacement air from doors, windows and holes in the
building construction. This leads to uncomfortable drafts, stagnant air pockets,
cold offices, and reduces the efficiency of the plant’s ventilation equipment.
Given the current settings, the plant undergoes 8 air changes per hour. In the
winter all the air brought into the plant needs to be tempered thus reducing the
number of air exchanges would reduce the natural gas usage. The reason for
these many air exchanges is to remove the fumes generated by the injection
molding machines. Figure 5 represents the current exhaust strategy:
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Figure 5: Current exhaust strategy
Currently, the exhaust fans are twenty (20) feet above the source of the fumes.
This process of exhaust is highly inefficient and requires a lot of exhaust
capacity.
19
5. Proposed Solution:
To reduce the amount of air exhausted we decided to replace our current
exhaust system with a point source system. This will allow us to capture the
fumes at the source of emission thus reducing the required flow rate. Figure 6
below is a schematic representation of the proposed system.
Figure 6: Point source exhaust system
The arms will need to be flexible to accommodate machine attendants when a
mold needs to be changed (See Appendix C). We would like to have this system
implemented on forty-one (41) machines along three lines. Each line will have a
circular trunk duct go across the plant and finish at the roof to exhaust the fumes
out to the atmosphere. The arms will be branching off from the main truck duct as
it goes over each machine.
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We have also selected three (3) fans so that the volumetric flow rate at each unit
will be around 250 cfm (See Appendix D). The size of the ducts was determined
from the convention of having a flow velocity of 3000-4000 feet per minute.
This system would reduce our required exhaust flow rate to less than 15,000 cfm,
allowing us to permanently shutdown two (2) out of the three (3) MUA units. In
the winter, during production we would have one (1) MUA unit and our new
exhaust system running, this will balance the air exchanges in the building and
not create any negative air pressure buildup. On idle shifts, all ventilation
equipment will be turned off and the plant’s unit heaters should sustain the
building heat. To make sure the plant temperature remains reasonable on the
weekends, we would need to repair all damaged unit heaters and install three (3)
additional ones as shown in figure 8.
Figure 7: Proposed Location of all Unit Heaters in the plant
We have updated the plant shutdown and startup procedures to make sure the
settings remain consistent regardless of the operator (See appendix E).
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6. Cost/Benefit Analysis
This project suggests different settings on production (weekdays) and idle
(weekends) shifts. We will first calculate the estimated costs of our current
baseline and compare it with the data collected from DynaPlas’ energy bills to
validate our calculations. We will use the same methodology to calculate the
expected savings on weekdays and weekends. Then we will discuss the cost
associated with this project and analyze its feasibility.
The Natural gas costs were estimated using a calculator produced by Union Gas
(See Appendix A) based on the following equation:
6.1 Baseline costs:
For out baseline we inputted the following data:
Flow rate: 47,000 cfm
Supply air temperature: 75 F
Average outside temperature: 35 F
Number of hours in heating season: 5300 hrs
Number of hours of operation per week: 168 hrs/week (24/7)
Incremental natural gas rate: 0.73 $/m3
The calculator outputted the Cost of operation: $225,167
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The actual total cost of natural gas as reflected on DynaPlas’ bills amounts to M$
275, which including office heating. It can thus be assumed that the calculator
provides an accurate estimate and that M$ 50 a year is spent to heat the offices.
6.2 Benefits of Proposed Solution:
The following data was entered in the calculator as the improvement made to the
case above:
Flow rate: 15,000 cfm
Supply air temperature: 75 F
Average outside temperature: 35 F
Number of hours in heating season: 5300 hrs
Number of hours of operation per week: 168 hrs/week (24/7)
Incremental natural gas rate: 0.73 $/m3
The calculator returned the following output:
Average annual cost saving: $ 173,837
Implementing these changes will reduce the plant’s natural gas bill by M$ 174 a
year.
As a result of this project, we have been able to reduce the plant’s electrical load
in the winter by 38 hp. The electrical savings need to be calculated based on the
25 week heating season this project will be affecting. Table 2 summarizes the
calculations made:
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Table 2: Electrical benefits
hr/week
# of weeks
HP
kW/HP
Load Factor
Before
168
25
78
0.746
0.75
After
120
25
40
0.746
0.75
kW
kWh
43.641
183,292.20
22.38
67,140.00
This project will reduce the plant’s load by 116,000 kWh per year saving an
additional M$ 11.6
The total energy savings for this project will be M$ 185.6 per year.
6.3 Installation Costs:
After finalizing the design, we contacted a list of suppliers to purchase and install
the equipment. PlymoVent and Lincoln Electric provided the following quote (See
Appendix B-1 and B-2):
Material (41 hanging arms, 41 extension columns, 3 fans): $45,965 $90,920
Installation and ducting: $55,882 - $56,000
We also acquired quotes for the additional Unit Heaters from the Tin Knockers
(See Appendix B-3) at $4,500 each.
Other internal costs will be associated with the electrical installation to finalize the
job and the completion of a Certificate of Air Emissions. Being an energy saving
initiative, this project would qualify for many government grants and incentives
24
available to reduce the investment costs. Table 3 illustrates all the costs
associated with this project.
Table 3: Total implementation costs
Material
Ducting
Unit Heater
$45,965.00
$55,882.00
$13,500.00
$115,347.00
Given the costs and benefits described above, this project will yield a payback
time of 0.62 heating seasons or less than 16 weeks. It is financially worth
completing this project given high benefits and low payback period. It would be
recommended to begin the installation in early fall, before the heating season
begins to minimize the payback time.
In addition to financial benefits, this project will have solved the negative air
pressure problem within the plant. The building being balanced will have not
have any drafts from windows, doors and holes in the building structure. As a
result, employees will be more comfortable and the exhaust system will be able
to better capture fugitive fumes from the injection molding machines.
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7. Problems encountered:
In this section, we will talk about some of the obstacles we encountered and what
we did to over come them.
Given the nature of the project, many employees will be affected by the changes
made. When scoping the plant, it was very difficult to obtain real information
because each employee had a different understanding of the process.
Information was initially gathered from many different employees then verified
physically by following pipes, conduit and looking at technical drawings. Given
the large scope of the project, there were many factors to consider thus
lengthening the task of gathering information. As the project progressed, we
became familiar with each employee’s area of expertise and knew what
information they could each produce accurately.
Many times, instructions were sent to machine attendants or mechanics through
their supervisors and miscommunications occurred or feedback was not
conveyed back to the project leaders. To bridge these lapses and build trust with
all the employees affected, we spent a lot of time communicating the goals and
progress of the project with all employees. This also helped us get the
employees buy-in on the project and they communicated directly with us when
issues arouse.
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Six (6) months into the project, one of our industry supervisors, Robert Kuhi was
laid off as the business was going through some difficult economic times. Robert
was our main contact person at the plant and his removal made completing the
project more difficult. In the early stages of the project, Robert had introduced us
to all the plant’s key employees and explained to us what their area of expertise
was. Knowing where to get the information needed, we were able to continue the
project without losing a significant amount of time.
As we gathered quotes for the installation of the system, suppliers were not
consistent in how they quoted the job making the comparisons more difficult. We
were obliged to thoroughly review each quote to make sure they were identical.
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8. Conclusion:
Implementing this project will significantly reduce DynaPlas’ energy consumption
and save M$ 185.6 every year there after. This cost reduction will allow the
company to be more competitive as it reduces its overhead thus increasing
market share. This initiative will also create a new marketing strategy by
becoming a greener plant. These increases in sales will allow DynaPlas to re-hire
some of the employees laid off earlier this year and help the company survive
through the current economic crisis.
This project, although specific to DynaPlas can be repeated in other
manufacturing facilities that exhaust large amounts of air due to their process.
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Appendix A: Union gas calculator
29
Appendix B: Quotes
B-1: PlymoVent Quote:
30
31
B-2: Lincoln Electric Quote
32
B-3: Tin Knockers Quote:
33
Appendix C: Movable arm data sheet
34
35
Appendix D: Exhaust fan data sheets
36
37
38
39
40
Appendix E: Updated Plant shutdown procedures
41
42
Appendix F: Electrical usage
43
Appendix G: Natural gas usage
44