Transcript Slide 1

Welcome
Using Variable Speed Drives
to Save Energy.
•Dan Reilly
•June 22nd 2010
Welcome
(Lunch is now less than 90 min away!!)
Agenda
• Emerson Industrial Automation Overview
• Industry/Application Expertise
• Variable Torque Loads
– Pump Control
– Fan Control
– Energy Savings Calculator
• AC Drives Benefits
– Variable Frequency drive product features
• Product Solutions Overview
• Summary
Saving Energy with VFDs
• Over 50% of the electric energy consumed in the U.S.
is used by electric motors.
• Electric motors & systems account for almost 64% of
manufacturing sector electricity consumption. This
translates into $30 Billion annual energy cost.
• A heavily-used motor may cost six to ten times its
purchase price to operate per year.
Lifetime Costs of a 100HP Motor
**Over a 10 Year expected life cycle.
**Purchase price represents less than
1% of the lifetime cost.
What does a Variable Frequency Drive Do?
Motor Control Basics
Q: What is motor control?
A: Motor control is the means by which a motor’s speed, torque, or
position is determined in some form of a controlled manner.
Q: What is a drive?
A: A drive is a device that converts electrical energy into rotary
mechanical motion via a motor shaft.
Q: Why use a drive?
A: Lower costs through:
– Energy savings
– Reduced overhead
Better Performance:
– Increased productivity
– Higher throughput
What Differentiates Industrial VFDs?
ANY Motor
• Exceptional motor control
• Virtually any type of motor and feedback device
• Control Techniques performance delivers higher
throughput and quality
• Best product retrofit solutions on the market
AC Motor
Servo Motor
DC Motor
Industry & Applications
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Aerospace
Agriculture
Asphalt and Cement
Automated Assembly
Building Materials
Chemical
Centrifuges
Converting
Crane and Hoist
Energy Generation
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Extruders
Fiber and Wire
Food and Beverage
Heavy Moveable Structures
Life Sciences
Medical Devices
Mixing
Lumber and Timber
Pharmaceutical
Plastics and Rubber
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Pumps
Semiconductor
Specialty Machines
Stage and Theatre
Textiles
Water/Wastewater
Introduction
• Of all the applications for Variable Speed
Control, Centrifugal Pumps and Fans offer the
greatest potential for Energy Savings due to
the nature of the load.
• These loads are defined as Variable Torque.
• Variable Toque means that the load torque
requirement varies (increases) with speed.
Fan Affinity Laws
 Volume Flow is proportional to fan speed
 Pressure proportional to the speed squared
 Power used proportional to the speed cubed
 Audible noise proportional to speed to 5th Power.
Variable Torque Loads
• Load requires much lower torque at low speeds than at high
speeds.
• Fan and Pump loads obey the AFFINITY LAWS.
• Horsepower varies approximately as the cube of the speed,
and the torque varies as the square of the speed.
• If the motor speed is reduced 20%, motor horsepower is
reduced by a cubic relationship (0.8 x 0.8 x 0.8) = 51%.
• If the speed is reduced significantly and often the opportunity
for energy savings is great.
Variable Torque Load Characteristics
% HP and Torque
NOTE: At 80% Speed (Flow) the theoretical Power consumption is only 50% of rated.
100
90
80
70
60
50
40
30
20
10
0
HP
Torque
Flow
0
10
20
30
40
50
60
% Speed
70
80
90
100
VFDs and Pumps
• Common applications in Industrial Process
control, Building HVAC systems and
Water/Wastewater.
– Chilled Water Pumps
– Condensed Water Pumps
– Building Supply Pumps
– Chemical Dosing Pumps
VFDs & Pumps
• Typically sized for maximum
flow
• Systems typically operate at
less than designed levels
• Flow control is normally
achieved using an output
control valve
• Measured in GPM (this is
what we want to control)
VFDs and Pumps
• Control Pump Speed for
process control
• Regulate Flow
• Save Energy
• Payback periods of 8
months to 2 years
depending on:
– Duty Cycle
– Energy Costs
Typical Fixed Speed System
DUTY
REQUIRED
POWER INPUT
CONTROL
VALVE
Variable Speed Drive System
POWER
INPUT
DUTY
REQUIRED
VFD
Control Valve
Eliminated or
Locked Open
VFDs and Pumps
• Provide significant energy savings when:
– Pumps are operated at lower flow rates
– Existing system has bypass control
– System has low static head
– Local electricity costs are high
– Pump has steep design curve
VFDs and Pumps Additional Benefits
• Elimination of expensive valves and valve controls
• Reduces power surges and stress associated with across the
line starting
• Provides accurate flow control
• Longer Pump and seal life
• Reduced wear
• Less noise
A VFD is potentially the BEST way to regulate
flow and save energy
VFDs & Fans
• Common applications in
Industrial Process control
and Building HVAC
systems.
– ID (Induced Draft) and FD
(Forced Draft) Fans
– VAV (Variable Air Volume)
Fan
– Condenser Fans
– Fume Hoods
– Cooling Towers
VFDs &Fans
• Typically sized for maximum
flow
• Systems typically operate at
less than designed levels
• Flow control is normally
achieved using either an
output damper or inlet
guide vanes
Typical Fixed Speed System
DUTY
REQUIRED
POWER INPUT
OUTPUT
DAMPER
Variable Speed Drive System
POWER
INPUT
DUTY
REQUIRED
VFD
Damper
Eliminated or
Locked Open
Energy Savings Estimator
Owens Corning – Fan Drives
Owens Corning 500HP fans.
• 3 x 500HP fans on fiber glass production line.
• Changed from damper to variable speed control.
• VSD Installed cost - approx $390,000.
• Energy savings - $225,000 per year
• Payback period - 1 year 9 months.
• Increased equipment life.
• Reduced maintenance / noise / vibration
• $225k on the bottom line every year after payback!
Variable Frequency Drives
Fan and Pump Features
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Variable (Dynamic) Volts/Hz
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Maximizes Energy Savings
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Is selectable for application flexibility
Independent PID
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For stand alone process control of flow or pressure
Skip Frequencies
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For bypassing of mechanical resonance's
Variable Frequency Drives Fan and
Pump Key Features and Benefits
PROBLEM:
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Supply Dip Ride through
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The drive can automatically ride through momentary power dips by reducing
speed and then returning to set speed when the supply recovers without
tripping.
Load Speed
Supply Voltage
Time
Variable Frequency Drives Fan and Pump
Key Features and Benefits
PROBLEM:
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Skip Frequencies
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For bypassing of mechanical resonance's reduces wear on the system
Actual Drive
Frequency
jumps past
critical points
Actual Drive
Frequency
Skip Frequency 1
Skip Frequency 2
Set Point
Variable Frequency Drives Fan and Pump
Key Features and Benefits
PROBLEM:

Independent PID loops built into the VFD
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For stand alone process control of flow or pressure or level
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No need for external controller, save $$$
Level
Set Point
Reference
Level Transducer
Feedback
P
I
D
Output
Drive Frequency
Variable Speed Drive
Additional Benefits
• Electrical Supply Benefits = more cost savings
– Good power factor – approx. Unity.
– Reduced peak amps surcharges
• Comfort
– Reduced fan / pump noise
– Reduce water hammer and air duct rumble
– No light dimming on start up
• Maintenance
– Less stress on mechanical equipment
– Controllable via a DeltaV, PLC or fieldbus (Ethernet, DeviceNet,
Profibus, Modbus, & others) reduces the need for process adjustments
Variable Frequency Drives Fan and Pump
Key Features and Benefits
PROBLEM:
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Energy Metering and Operating Cost Indicator
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Power consumed, operating costs per hour, power up time log and
maintenance flags are all standard features providing free Asset Management
tools.
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ENERGY
kWh
Variable Frequency Drives
• World Class AC Drives are:
– Specifically suited to Centrifugal fans and pumps
applications
– Easy to set up and install
– Feature packed for maximum flexibility
– High Performance
– Going to save you money!
Saving Energy with VFDs
• Look for:
– Centrifugal fans and pumps
– Pump systems with a low static head
– Duty cycle 40hrs / week.
– Significant installed over-capacity.
• Variable Frequency Drives can:
– Assist with payback analysis
– Provide Fan and Pump drives, motors, systems, fieldbus interfaces,
fan/pump sequencing software.
Saving Energy with VFDs
• LOOK FOR “DUTY CYCLE”:
What if I don’t know what my duty cycle needs
to be?
How long does the motor need to run at 100%
speed?
How long does the motor need to run at 50%
speed?
How long does the motor need to run at a
minimum to keep the process running?
Control Techniques
• A Market Leader in Intelligent
Drives & Drive Systems
• Founded in 1973
• 1,500 Employees Worldwide
• Key Advantages
– Technology Leader
– Best Service and Support
– Best Value Solutions Provider
– Global Manufacturing facilities
(USA, UK, China, Mexico)
– Manufacture ~400,000 drives
annually
Energy Savings Demonstrator
Questions?
Please call…or email us
Visit www.emersonct.com
Dan Reilly
[email protected]
630-708-0037