Low power factor is expensive and inefficient. Energy utility companies often charge additional fees to large commercial, institutional, and industrial clients when their power factor drops below 0.95. Understanding power factor and knowing how to measure it and improve it generates significant energy savings for very little cost.
Mike Wrinch, P. Eng. presented an informative 45 minute webinar on understanding, measuring, and improving power factor to reduce energy bills in buildings and facilities. Mike’s presentation included:
* An explanation of power factor and how it affects energy bills and electric systems' distribution capacity
* An overview of the hardware and software needed to measure the power factor in buildings
* Solutions to improve a building’s power factor
2. Go To Webinar Control Panel
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questions!
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3. Power Factor Agenda
• Background on Electricity
• What is Power Factor?
• What it can cost you
• How it effects your buildings
• How to fix it
• Case Study
• Software Demo
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5. Electricity Basics
Cars Speed Road Traffic
Amps * Volts on Wire = Watts
A V W
An amp is a
measurement of
many electrons
per second!) Traffic per hour
Watt-hour, Wh
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6. Traffic and Toasters
V*A=W
• Drive too fast: Car Crash (sparks)
• Too many cars = A crash. We prevent it by: __________
Bigger Roads/
(Wires)
EXAMPLE: Take a Toaster – 1000 W, Plug Voltage is 100 V,
running for 1 hour.
How many Watt-hours (Wh) of Energy ? ______________
1000 Wh or 1 kWh
How many Amperes (A) of current ? ______________
1000/100 = 10 A
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7. Unfortunately,
this is not completely true….
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8. Electricity
Is MORE like traffic in a City !
Flow (Amps) is delayed from speed (Volts) by city traffic
lights etc.(motors) the delay is a utilization of energy with
no work – it is called “imaginary”, Reactive Power or VARs.
The total of Watts and VARS is called APPARENT POWER
or VA. They are related by: VA W 2 VAR 2
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9. Apparent Power
City Traffic
Cars Speed Road
Apparent
Amps * Volts on Wire = Power
A V VA
Traffic per hour
is still: Watt-hours (Wh)
(We use expensive energy metersofto figure this out)
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10. Traffic and Fans/Motors make VARs
• Most Common Sources of VARs: Motors
(ie:Fans/HVAC), and Computer power supplies.
• VARs are BAD because they increase the amps but
they produce no real work ! (i.e. cars are now stuck in
traffic revving engines but not moving, (Do we need
to make the road bigger? OR Fix the traffic lights?)
• So: V*A=W is now: V*A=VA –> Apparent Power
• EXAMPLE: Take a Fan – 1000 VA, 900 W, Plug Voltage
is 100V, running for 1 hour.
• How many Watt-hours (Wh) of Energy ? ________ ??
900 Wh
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11. Power Factor – making power Super easy!
• POWER FACTOR (PF) was created
so power engineers do not have to think much!
• Power factor is the ratio of Watts to Apparent Power
or: PF=W/VA.
• EXAMPLE: If a Fan delivers 100 W
and uses 120 VA,
the Power Factor is: 100/120 = 0.833.
• SIMPLIFYING: Turn VA, VAR and
W into one number ! PF
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13. Why a Low Power Factor is a BAD Thing
Low Power Factor (PF) will force you and the Utility to
upgrade power lines to bigger wires. The Utility charges
their customers for low power factor. EXAMPLE:
% Inc.
W VAR VA pf V A
of A
100 0 100 1 1 100 100%
Wow!
60 117 0.86 1 116.6 117%
120 156 0.64 1 156.2 156%
180 206 0.49 1 205.9 206%
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14. Why Would You Have a PF Issue?
• Competitive bidding: will commonly leave out power
factor correction kits as it adds to the cost of
construction (and your monthly power bill).
• Building Improvements: may not take into
consideration the additional VARs. Examples include
heat pumps and geothermal upgrades
• Old buildings: with malfunctioning, inappropriate or
non existent power factor correction systems.
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15. How Do You Know if You Have a Problem?
• It will show up on your electricity bill as “Power Factor
Charges”.
• Charge Examples:
– BC Hydro: penalty charge on monthly PF average. Penalty
ranges from 2% to 80% of your kWh charge. Starting at PF
less than 0.9.
– California PG&E: charges on monthly PF average. Ranging
from +1% credit to a -2.1% penalty of your kWh charge.
Penalty starts at PF less than 0.85.
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16. Case Study: Community Center
• New community center on British Columbia coast
• Yearly energy bill: $100,000
• Power Factor averaged: 0.70 resulting in 24% penalty
charge (approximately $20,000/yr)
• Using Pulse Energy Management System to view the
real time demands, a $10,000 power factor correction
kit was specified and installed.
• Payback period of 6 months.
• NPR over 25 yrs of $390,000 !
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17. How You Can Identify and Correct for PF
1. Identify if you have a power factor issue by looking
at your energy bills.
2. Power Factor charges greater than $100/month are
worth addressing
3. In Pulse Software, Create a power factor and a kVAR
chart.
4. Show this to an Electrical Contractor who will then
work with you to select the right size of power factor
correction kit.
– The kit size is typically 75% the maximum kVARs and ordered as a
static or variable size. A static power factor correcting kit poses a risk
of over correcting which can damage a building – use variable.
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20. Example - Software
MAX PF = 0.81
Penalty Range:
Average PF = 0.71
MIN PF = 0.6
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21. Example - Software
MAX kVAR = 90
Solution: Variable PF correction
kit: 80,60,40,20 kVAR steps.
MIN kVAR = 50
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22. Summary
• Watt-hrs are the amount of watts used for one hour
and we pay for kWatt-hours (kWh = 1000 watt-hrs)
• VARs are caused by motors, HVAC, and computers
and cause excessive current in power lines.
• Low PF: can result in costly penalties seen on your
electricity bill. Caused by excessive VARs.
• PF: can be corrected with the right tools and can
reduce energy bills typically around 24% !
• Pulse Energy Management Software is an effective
tool for identifying VARs and managing your day to
day energy.
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41. Thank you!
Additional questions?
Contact Pulse Energy at: 1-877-331-0500 or at
info@pulseenergy.com
Look for future and archived webinars on our website:
www.pulseenergy.com/resources/webinars
Look for the webinar summary and further discussion on our
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