Design & Engineering Services
Assessing the Demand Response Capability
of a Remotely Controlled, Stepped Dimming
Lighting System
Demand Response Emerging Markets and Technologies Program
Prepared by:
Design & Engineering Services
Customer Service Business Unit
Southern California Edison
March 15, 2006
Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
Acknowledgements
Southern California Edison’s Design & Engineering Services (D&ES) group is responsible
for this project in collaboration with Tariff & Program Services (TP&S). It was developed
as part of Southern California Edison’s Demand Response, Emerging Markets and
Technologies program under internal project number DR 05.01. D&ES project manager
Doug Avery conducted this technology evaluation with overall management by Carlos
Haiad of D&ES and Lauren Pemberton of TP&S. For more information on this project,
email doug.avery@sce.com or carlos.haiad@sce.com.
Disclaimer
This report was prepared by Southern California Edison and funded by California utility
customers under the auspices of the California Public Utilities Commission. This work
was performed with reasonable care and in accordance with professional standards.
However, neither SCE nor any entity performing the work pursuant to SCE’s authority
make any warranty or representation, expressed or implied, with regard to this report,
the merchantability or fitness for a particular purpose of the results of the work, or any
analyses, or conclusions contained in this report. The results reflected in the work are
generally representative of operating conditions; however, the results in any other
situation may vary depending upon particular operating conditions.
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
Table of Contents
Executive Summary........................................................................................ 1
1.0
Introduction .................................................................................................. 4
1.1 Background ............................................................................................. 4
1.2 Project Goals and Objectives ...................................................................... 4
1.3 Market Potential ....................................................................................... 5
2.0
Technical Approach ........................................................................................ 6
2.1 Equipment Description............................................................................... 6
2.2 Test Procedures...................................................................................... 10
2.3 Data Collection / Monitoring ..................................................................... 11
3.0
Results .......................................................................................................
3.1 Data Analysis .........................................................................................
3.2 Discussion .............................................................................................
3.3 Prior Work .............................................................................................
4.0
Conclusion .................................................................................................. 25
5.0
Bibliography ................................................................................................ 26
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Design & Engineering Services
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15
15
24
24
Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
Abbreviations
ADM
DR
EMS
FC
GE
kW
kWh
MCC
MW
Rms
Vdc
MHz
ADM Associates. Inc.
Demand Response
Energy Management System
Foot-candles
General Electric
Kilowatt
Kilowatt-hour
Motor Control Center
Megawatt
Root-mean-squared
Volts direct current
Megahertz
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Design & Engineering Services
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
Figures and Tables
Figure ES-1.
Lighting Breaker #3 Load Profile During Test 1 ....................................... 2
Figure ES-2.
Light Level and Power Measurements Charted Against Light Level Settings . 2
Figure 2-1.
Lighting on Third Floor of Test Building.................................................. 6
Figure 2-2.
Chiller in Basement of Test Building ...................................................... 6
Figure 2-3.
Internet Software Control Center for GE Wireless Energy Management....... 7
Figure 2-4.
Zone Control Web Page for Test Building Which Allows Control
of Lighting and Chiller Routers ............................................................. 7
Figure 2-5.
Load Profile of Chiller as Measured and Logged by GE Wireless Meter Data
Processor .......................................................................................... 8
Figure 2-6.
Lighting Router .................................................................................. 9
Figure 2-7.
Lighting Router and Ballast Controller ................................................... 9
Figure 2-8.
Chiller Router .................................................................................... 9
Figure 2-9.
Antenna for Wireless Chiller Router....................................................... 9
Figure 2-10.
Wireless Meter Data Processor ............................................................10
Figure 2-11.
Third Floor Lighting Panel ...................................................................12
Figure 2-12.
Third floor Lighting Plan .....................................................................13
Figure 2-13.
Close Up of Monitoring Equipment, Current Transducers and Loggers
in 3rd Floor Lighting Panel ...................................................................14
Figure 2-14.
Logger Monitoring Chiller in Motor Control Center ..................................14
Figure 3-1.
Baseline Load Profile of Lighting Panel on 3rd Floor .................................15
Figure 3-2.
Baseline Load Profile of Indoor Lighting on 3rd Floor ...............................16
Figure 3-3.
Lighting Panel Load Profile during Test 1...............................................17
Figure 3-4.
Lighting Panel Load Profile during Test 2...............................................18
Figure 3-5.
Lighting Panel Load Profile during Test 3...............................................19
Figure 3-6.
Light Level and Power Measurements Charted Against Light Level Settings 21
Figure 3-7.
Baseline Chiller Load Profile as Monitored by the GE Wireless System .......21
Figure 3-8.
Baseline Chiller Load Profile as Monitored by ADM..................................22
Figure 3-9.
Live Test Turning Chiller Off and Back On .............................................23
Table ES-1.
Demand Reduction per Fixture Referenced to 70% Level Setting...........…..2
Planned Lighting Test Schedule and Location of Actual Test Command. .....11
Table 2-2.
Sequence of Events ...........................................................................11
Table 2-3.
Third Floor Lighting Panel Load Description by Breaker ...........................12
Table 2-4.
Number of Dimmable Light Fixtures per Phase.......................................13
Southern California Edison
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
Figures and Tables, continued
Table 3-1.
Response Times during Lighting Test 1............................................... 17
Table 3-2.
Response Times during Lighting Test 2............................................... 19
Table 3-3.
Response Times during Lighting Test 3............................................... 20
Table 3-4.
Light Level and Power Measurements at Various Light Level Settings...... 20
Table 3-5.
Response Times during Chiller Test.................................................... 23
Table 3-6.
Demand Reduction per Fixture Reduction Referenced to Normal Operation
.................................................................................................... 24
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
Executive Summary
In this project, a GE wireless energy management system was installed in an office
building to evaluate the demand response effectiveness of this technology. The building
is located on the LA County Internal Services Division site. Installation and field testing
for this project was completed in October 2005. This project was performed under the
Southern California Edison Emerging Technologies Program, which investigates products
that have potential to reduce electric demand, particularly during peak use periods.
Most energy management systems currently in use are hardwired to all the loads being
controlled in a facility, including the command center. By contrast, the GE wireless
system investigated in this project is installed in modular components that communicate
at 418 MHz and can be activated by either the customer or the utility through any
computer connected to the internet.
This newly available product was installed to verify that the technology works and to test
it in real world conditions. Two types of load, lighting and a chiller, were controlled as
part of this project. Dimmable ballasts for fluorescent ceiling lighting were installed that
could be controlled by the GE wireless energy management system. The internet
software allows the authorized user to change the lighting level from Full Off to Full On
in 10% increments. An on/off control was installed on the chiller to signal the existing
chiller controls.
On-site verification and monitoring of the loads proved that the remote control of the
lighting and chiller worked effectively. The lighting system was tested at three different
times of the day over a pre-selected range of settings. Synchronized tests for the
lighting system produced response times ranging from 2 to 12 seconds from the time
the command was remotely issued and when the lighting load actually changed.
Response times for the chiller ranged from 50 to 80 seconds because the chiller control
system implemented the final turn off and on order.
During the testing, data were logged every 2 seconds. A sample of one of the tests is
shown in Figure ES-1. The commands to lower the lighting level were given at 13:00:00
(1:00 P.M.), 13:10:00 (1:10 P.M.) and 13:20:00 (1:20 P.M.) and lighting was reduced
to 60%, 50% and 30% levels, respectively. The new lighting system that had been
installed in this facility was dimmed by the occupants to 70% total light output,
providing the desired level of illumination in the space. This test demonstrated the
potential for significant Demand Response savings from a lighting system that has
already been tuned for optimal energy usage and occupant comfort. The demand
reduction per two-lamp fluorescent ceiling fixture measured at this facility is provided in
Table ES-1. The reduction is 22.7 Watts per fixture when the level setting is changed
from 70% to 30%.
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
Level: 70%
70%
60%
70%
50%
70%
30%
70%
70%
70%
0.5
Phase B, kW
0.4
kW
0.3
0.2
0.1
13:40:00
13:35:00
13:30:00
13:25:00
13:20:00
13:15:00
13:10:00
13:05:00
13:00:00
12:55:00
12:50:00
0.0
Figure ES-1 - Lighting Breaker #3 Load Profile During Test 1
Table ES-1
Demand Reduction per Fixture Referenced to 70% Level Setting
Level Setting
70%
60%
50%
30%
Reduction per
Fixture (Watts)
0.0
5.0
9.6
22.7
Light meter readings and measured lighting load from the 29 dimmable fixtures are
plotted in Figure ES-2. Note that this chart shows that the relationship between light
level settings by the control system are not linear with power usage or light output.
Further investigation into the dimmable ballasts used in this test are needed to quantify
savings based on level settings alone.
70
1.4
Light illumination, fc
60
1.2
50
1.0
40
0.8
30
0.6
20
0.4
10
0.2
0
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
Power (kW)
Light Level (foot-candles)
Dimming Lights, kW
0.0
100%
Light Level Setting
Figure ES-2 - Light Level and Power Measurements Charted Against Light Level Settings
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The chiller control test shed 37.5 kW. This shed load was exaggerated because the
chiller was turned completely off. Normally a chiller would be controlled by reducing the
thermostat set point, thus reducing the load demand, not by turning it off completely.
The ability to remotely control any number of loads throughout SCE service area from a
computer connected to the internet provides great potential for peak demand reduction.
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
1.0 Introduction
This project evaluates the demand response effectiveness of the GE wireless energy
management technology. This product is being prepared for the commercial market,
and Southern California Edison has the opportunity to test it before it becomes publicly
available. A GE wireless system was installed at an office building to verify the
technology works and to test it in real world conditions. This demand response
technology can be activated by either the customer or the utility through the internet.
1.1 Background
The electric utility industry in California is operating under mandates to reduce peak load
demand for electricity. Peak demand must be cut by 4% of annual system peak during
2006 and by 5% in 2007. Peak electricity load has been controlled by various programs
such as very large customer participation in Demand Bidding, Critical Peak Pricing and
Interruptible rate programs, Time-Of-Use rate structure for large commercial customers,
and residential air conditioning cycling programs. SCE is looking toward demand
response technologies to provide new opportunities to reduce the peak electric system
load.
Stress to the electric grid occurs when demand for electricity nears the capacity of the
available power generation. Hot summer afternoons are historically the time for the
most stress to the grid. Weather forecasts are used to predict when demand reduction
tactics will need to be used and provide a degree of planning for electric load
curtailment. Power generation or electric grid malfunctions result in an immediate need
to reduce electricity consumption.
Southern California Edison will benefit from technologies that allow the utility to reduce
loads upon command. Fast responding systems provide the flexibility to be the most
useful. The larger the load that can be controlled the more useful. Large load reduction
can be achieved by a few major facilities or by smaller load reductions at many facilities.
Technology is providing ways to coordinate larger groups of customers to participate in
organized demand reduction programs.
1.2 Project Goals and Objectives
SCE tested the implementation of a GE wireless energy management system to control
lighting and a chiller at a pilot test facility. The system controls the level of dimming in
dimmable ballasts in fluorescent ceiling lighting. The system also controls a chiller by
turning it on or off.
The project had four main objectives:
A. Determine if SCE could control external load from our facilities
B. Determine if this approach would work for lighting and chiller loads.
C. Determine how long it takes from the time the command is given until the load
responds.
D. Determine how much load is shed.
The lighting system tested has 2-lamp fluorescent recessed ceiling fixtures. The LA ISD
building employs an EMS that turns lighting off after hours. The building EMS controls
contactors that provide power to the lighting. The project installed dimmable ballasts
and T8 lamps in the ceiling light fixtures. The dimmable ballasts are now controllable by
the new GE wireless energy management system allowing various lighting levels to be
selected.
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
The building EMS also controls the chiller. The new GE wireless energy management
system was wired into the chiller control system to send the unit a signal to turn the
chiller off or on. Generally a chiller is not given these commands because there is a
sequence of events that should occur when turning a chiller on or off. Pumps for the
chilled water and condensate loops must be staged on before the chiller can be turned
on. A similar reverse process is used when shutting down a chiller. Because of this the
facilities management has installed a hardwired lockout switch that will only allow the
chiller to be turned off or on by the wireless controller when the override setting of the
lockout switch is manually changed.
1.3 Market Potential
The commercial sector uses 44.5% of the energy in SCE’s service area. Lighting makes
up 24% of the electric end-use load in commercial buildings in SCE territory. If demand
response programs could reduce power usage by 25% from just one quarter of the
commercial lighting fixtures in SCE territory, there would be a 577 MW reduction in load
during the peak demand period. Air conditioning makes up approximately 27% of the
electric end-use load in commercial buildings in California. If 5% of the commercial air
conditioning load in SCE territory could be reduced by demand response programs that
would represent a 462 MW reduction in load during the peak demand period.
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
2.0 Technical Approach
The test building for this project was the Los Angeles County Internal Services Division
(ISD) building at 1100 N Eastern Ave., Los Angeles, California. It is a three-story office
building. The third floor of this facility houses the facility maintenance offices and has
less square footage than the first or second floors. The test included lighting fixtures on
the third floor and the chiller, which is located in the basement. The chiller in this test is
less than a month old. Figures 2-1 and 2-2 show the lighting system and the 50-ton
chiller.
Figure 2-1. Lighting on Third
Floor of Test Building
Figure 2-2. Chiller in Basement
of Test Building
A GE wireless energy management system was installed to control over half of the
lighting fixtures on the third floor and the chiller. Data loggers were installed to collect
baseline electric load profile data and to measure response time during the synchronized
tests.
2.1 Equipment Description
The control system, which was installed and operated by Power Web Technologies, Inc.,
had these components:
1.
2.
3.
4.
5.
6.
7.
GE wireless energy management internet software
GE wireless lighting router
GE wireless ballast controllers
GE wireless chiller router
GE wireless power controller
GE wireless meter data processor
Sylvania Powersense T8 Dimming ballasts and lamps
The components work together to allow a remote operator to dim lighting or turn the
chiller off or on. Care must be taken so that all components are installed so they are
powered continuously.
The GE wireless energy management internet software was administered by Power Web
Technologies, Inc.. Internet software was set up to give the building facilities
department as well as SCE the security clearance necessary to change settings on the
control system for the test building. Figure 2-3 shows the internet page after logging
onto the system. The zone control option brings the user to the web page that provides
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
access to control the lighting or chiller routers. (See Figure 2-4). Lighting levels can be
set from FULL ON to FULL OFF and all 10% power increments in between.
Figure 2-3. Internet Software Control Center for GE Wireless Energy Management
Figure 2-4. Zone Control Web Page for Test Building
Allows Control of Lighting and Chiller Routers
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
The system was installed to meter the chiller and the 3rd floor lighting panel. A separate
watt-hour transducer was installed on the loads and connected to the GE wireless meter
data processor. A sample of the electric load profile collected from the chiller is
displayed in Figure 2-5. No load data was available at this time on the lighting panel
power because the current transformers on the transducer are oversized.
Operation of the system starts when a user issues a command using the Internet
Software. A wireless tower then transmits a signal to the routers. The router receiving
the coded message sends a signal on the wireless network to the ballast or power
controller. The controller then executes the command to change the power setting on
the load equipment.
Figure 2-5. Load Profile of Chiller as Measured and Logged
by GE Wireless Meter Data Processor
The wireless router for controlling lighting is located above the false ceiling near an air
register. The lighting router can send the control message to any ballast controller. A
ballast controller can serve up to 50 dimming ballasts by using a wire loop to supply a 0
– 10 Vdc signal to the dimming ballasts. There were three ballast controllers for this
installation. Figures 2-6 and 2-7 show the lighting router and a ballast controller.
Sylvania T8 fluorescent lamps and Powersense dimming ballasts were installed to allow
variable lighting levels.
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
Figure 2-6. Lighting Router
Figure 2-7. Lighting Router
and Ballast Controller
The wireless router for controlling the chiller was installed in the basement near the
chiller (Figures 2-8 and 2-9). The wireless power controller for the chiller does not
directly turn the chiller off or on. The power controller is tied into the EMS controls for
the chiller and provides an on/off signal so that the chiller is shut off by its own
controller. The facilities management has installed a hard-wired lockout switch that will
only allow the chiller to be turned off or on by the wireless controller when the override
setting of the lockout switch is changed manually. Normally the way a chiller would be
controlled to reduce peak demand would be to lower the thermostat set point, thereby
reducing the cooling load. The facilities personnel wanted this installation to have that
option, but it would have required an additional control option for the existing EMS
system. This was not added.
Figure 2-8. Chiller Router
Figure 2-9. Antenna
for Wireless Chiller Router
A GE wireless meter data processor (Figure 2-10) was installed to document the load
reductions. The finest time resolution on the electric load data is 15-minutes.
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
Figure 2-10. Wireless Meter Data Processor
2.2 Test Procedures
Test procedures were designed to control the loads at several different times. This was
a way to simulate different conditions that the system may experience during actual
operation. During all testing an engineer from ADM was on site, while personnel from
SCE initiated the test commands from a remote office. At different times test
commands were issued from three different locations via computers connected to the
internet. The computers from which commands were issued were located at SCE’s
office, at a home office and at ADM’s office. All computers, equipment and watches
were synchronized to NIST clocks on Pacific Time. (Note that daylight savings went into
effect on October 30, 2005.) The clocks were synchronized using the following web link:
http://nist.time.gov/timezone.cgi?Pacific/d/-8/java.
The lighting tests were scheduled to occur at three times during the day:10:00:00,
13:00:00 and 16:00:00 (i.e., 10:00:00 A.M., 1:00:00 P.M. and 4:00:00 P.M.).
Prescheduled times were chosen so that everyone involved with the tests would know
exactly, to the second, when the testing was to occur and would be prepared to observe.
The tests were conducted on two separate days, a Thursday and the following Monday.
The lighting level was changed to three different settings. A field engineer monitored
the changes as an eye witness and took measurements. Initially the settings selected
were 10%, 25% and 50% below maximum power settings. However, because of
complaints that it was too bright when lighting was at full on, the facility personnel set
the normal lighting power setting at 70% after the dimming ballasts were installed. The
wireless control system only allows changes in lighting power level settings at 10%
intervals. It was decided to use the normal setting for the lighting as the base case and
that power levels would drop from there. This meant that lighting tests would be
conducted at 70%, 60%, 50% and 30% of the maximum power settings. After each
drop in lighting power, the lighting power setting was raised back to 70% before the
next reduction. Each setting lasted for 5 minutes. Table 2-1 shows the planned
schedule of the lighting tests. Note that on the last test the lighting level was also
increased from the normal setting.
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
Table 2-1.
Planned Lighting Test Schedule and Location of Actual Test Command.
Lighting Level
Setting
60%
70%
50%
70%
30%
70%
80%
90%
100%
70%
Oct. 27
13:00:00
13:05:00
13:10:00
13:15:00
13:20:00
13:25:00
Oct. 27
SCE
SCE
SCE
SCE
SCE
SCE
16:00:00
16:05:00
16:10:00
16:15:00
16:20:00
16:25:00
ADM
ADM
ADM
Hm Off.
Hm Off.
Hm Off.
Oct. 31
10:00:00
10:05:00
10:10:00
10:15:00
10:20:00
10:25:00
10:30:00
10:35:00
10:40:00
10:45:00
SCE
SCE
SCE
SCE
SCE
SCE
ADM
ADM
ADM
ADM
The chiller test was planned as a single test because of the sensitive nature of the load.
The actual switching of the chiller was tested during the installation of the wireless
control system, so this was to be the first time the hardware had been tested. Originally
the chiller was to be tested on a Friday afternoon, but the office is closed on Fridays and
nobody would be available to open the doors for the eyewitness to the event. On short
notice the plan was changed to 12:15 noon on Thursday. When the command was
given for the chiller to go to FULL OFF, the chiller router went off-line. It took some time
to identify the problem, but no identifiable cause for the chiller router going off-line was
determined. To get the router back on-line, power to the router had to be turned off
and on to reboot it.
A chronological sequence of events and activities that took place at the facility is
provided in Table 2-2. The chiller router had gone offline on October 21 also. No reason
was known. It was pointed out that this building is next door to the emergency fire and
police response station with two large microwave towers. Any connection at this time is
speculative.
Table 2-2.
Sequence of Events
Date & Time
10/12/05
10/20/05
10/21/05
10/24/05
10/25/05
10/27/05 12:15
10/27/05 13:00
10/27/05 14:00
10/27/05 16:00
10/31/05 10:00
10/31/05
Activity
Installation of GE wireless control system complete
ADM installs loggers on lighting and chiller
Chiller router went off-line
Chiller router back on line
ADM visit site to collect baseline data from loggers
Attempt of First test of chiller controller. ADM on-site
First synchronized test of lighting controller
Actual test of chiller controller
Second synchronized test of lighting controller
Third synchronized test of lighting controller. ADM on-site.
ADM removed data loggers
2.3 Data Collection/Monitoring
The electric lighting load was monitored from the lighting panel located in the third floor
hallway. (See Figure 2-11.) This lighting panel powers 29 2-lamp 4-foot T-8 fluorescent
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
fixtures with dimming ballasts installed. These ballasts are actively connected to the GE
wireless control system. The panel also powers 5 fixtures with T-8 lamps and 14
fixtures with T-5 lamps that are not actively controlled by the wireless system. There
are two fixtures in the open office area that are not working (e.g., either burned out
bulbs or no control signal connected to the dimming ballast). The total daytime lighting
load on this panel not controlled by the system adds up to 1.10 kW. Table 2-3
describes the various loads powered through the panel.
Figure 2-11. Third Floor Lighting Panel
Table 2-3
Third Floor Lighting Panel Load Description by Breaker
A
# of
Dimmable
Fixtures
8
# of
Other
Fixtures
1 off
2
A
6
14 all T5
3
B
7
1 off
5
C
6
2
6
C
2
5 + 2(2’)
9
11
Total
B
C
0
0
29
?
?
21 + 2
off +
2(2’)
parking
Breaker
#
Phase
1
Southern California Edison
Design & Engineering Services
Location / Description
4 fixtures in open office area, 3 fixtures
in private office, 1 fixture in copy room. 1
fixture in open office is not working.
12 fixtures w/ T5 lamps in conference
room, 2 fixtures w/ T5 lamps in small
office. 6 dimmable fixtures in private
office.
7 fixtures in open office. 1 fixture in open
office is not working.
6 fixtures in open office, 2 by elevator
not dimmable.
2 fixtures in hall are dimmable, 1 fixture
at end of hall not dimmable, 4 fixtures in
restrooms (not dimmable) and (2) 2’
non-dimming fixture in restroom.
Parking Lot Lights
Parking Lot Lights
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
The number of dimmable lighting fixtures on the 3rd floor controlled by the wireless
system are summarized in Table 2-4. A layout of the lighting on the third floor is
provided in Figure 2-12.
Table 2-4.
Number of Dimmable Light Fixtures per Phase
Phase
A
B
C
# of Dimming
Fixtures
14
7
8
Copy
M RR
W RR
Room
Office
nc
nc
nc
Office
Open Office
Conference Rm
nc
Office
Elevator
Stairs
nc
nc
Third Floor
4 Ft 2 lamp Fixture
nc
Non-Working Fixture
not to scale
N
4 Ft T5 2 lamp Fixture
nc
Non Controlled Fixture
24/7 Fixture
nc
Room Not Controlled
Figure 2-12. Third floor Lighting Plan
For the monitoring, three loggers were used in the lighting panel, one for each of the
three voltage phases. The data loggers used are StowAway loggers manufactured by
Onset Computers. They are small (2”x2”x1/2”) battery operated loggers. They interact
with a laptop computer using an interface cable and BoxCarPro software. The StowAway
loggers (see Figure 2-13) accept the 0 – 2.5 Vdc output of the 30 Amp split-core current
transducers. These loggers effectively record the current load of the electric panel. The
data from the loggers was complemented with a series of one-time power
measurements taken using a portable power meter (AEMC model 3910). The power
meter has a digital display of voltage, current, true rms power (kW), and power factor.
The loggers will hold 16,000 data points in memory. With a storage interval set to 30
seconds they can hold over 5 days of data; set to a 2-second storage interval they will
hold over 8 hours of data. The data storage interval value used as the launch parameter
for the testing was determined by averaging data sampled every half second. A 30second time interval was set on the loggers to collect baseline data for the lighting and
the chiller. However, the data storage interval on test days (10/27 and 10/31) was set
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to 2 seconds in order to capture the fast response of the control systems. At 2-second
intervals, extended data can not be collected.
Figure 2-13. Close Up of Monitoring Equipment,
Current Transducers and Loggers
in 3rd Floor Lighting Panel
Lighting level measurements were made to quantify the dimming settings. The
measurements were made with an A.W. Sperry light meter. The measurements were
made 45 inches above the floor and documented in foot-candles. The human eye has a
non-linear response to lighting level. Light level measurements were taken to verify the
eyewitness observations that the light levels had changed at the assigned test times.
The logger used to monitor the chiller (see Figure 2-14) is the same type as was used to
monitor lighting (i.e., a StowAway) but uses a 400 Amp current transformer. One phase
was monitored for the chiller since the phases are approximately balanced and the
currents stay in ratio across the phases. The logger measurements were again
complemented by one-time power readings from the portable power meter.
Figure 2-14. Logger Monitoring Chiller in MCC
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3.0 Results
This section presents and discusses the data that was collected from the monitoring of
the 3rd floor lighting and basement chiller. Charts and tables showing response time are
presented for the three lighting tests. A correlation of lighting power and light intensity
versus lighting level settings is also provided.
3.1 Data Analysis
The baseline lighting load of the third floor lighting panel from October 20th to 31st is
shown in Figure 3-1. The night-time parking lot lighting is evident from this chart. The
monitored data identified the parking lot lighting load to be 2.23 kW.
5.0
3rd Flr Lighting Panel, kW
4.5
4.0
3.5
kW
3.0
2.5
2.0
1.5
1.0
0.5
10/20/05 14:00
10/20/05 20:00
10/21/05 02:00
10/21/05 08:00
10/21/05 14:00
10/21/05 20:00
10/22/05 02:00
10/22/05 08:00
10/22/05 14:00
10/22/05 20:00
10/23/05 02:00
10/23/05 08:00
10/23/05 14:00
10/23/05 20:00
10/24/05 02:00
10/24/05 08:00
10/24/05 14:00
10/24/05 20:00
10/25/05 02:00
10/25/05 08:00
10/25/05 14:00
10/25/05 20:00
10/26/05 02:00
10/26/05 08:00
10/26/05 14:00
10/26/05 20:00
10/27/05 02:00
10/27/05 08:00
10/27/05 14:00
10/27/05 20:00
10/28/05 02:00
10/28/05 08:00
10/28/05 14:00
10/28/05 20:00
10/29/05 02:00
10/29/05 08:00
10/29/05 14:00
10/29/05 20:00
10/30/05 02:00
10/30/05 07:00
10/30/05 13:00
10/30/05 19:00
10/31/05 01:00
10/31/05 07:00
0.0
Figure 3-1. Baseline Load Profile of Lighting Panel on 3rd Floor
To see the baseline indoor lighting load of the third floor, the parking lot lighting load
was deducted. The indoor lighting load profile from October 20th to 31st in Figure 3-2
confirms that Fridays are not a work day in this office.(see 10/21/05 and 10-28-05
data). The indoor lighting load typically peaks at over 2.5 kW.
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3.0
3rd Floor Indoor Lighting, kW
2.5
kW
2.0
1.5
1.0
0.5
10/20/05 14:00
10/20/05 20:00
10/21/05 02:00
10/21/05 08:00
10/21/05 14:00
10/21/05 20:00
10/22/05 02:00
10/22/05 08:00
10/22/05 14:00
10/22/05 20:00
10/23/05 02:00
10/23/05 08:00
10/23/05 14:00
10/23/05 20:00
10/24/05 02:00
10/24/05 08:00
10/24/05 14:00
10/24/05 20:00
10/25/05 02:00
10/25/05 08:00
10/25/05 14:00
10/25/05 20:00
10/26/05 02:00
10/26/05 08:00
10/26/05 14:00
10/26/05 20:00
10/27/05 02:00
10/27/05 08:00
10/27/05 14:00
10/27/05 20:00
10/28/05 02:00
10/28/05 08:00
10/28/05 14:00
10/28/05 20:00
10/29/05 02:00
10/29/05 08:00
10/29/05 14:00
10/29/05 20:00
10/30/05 02:00
10/30/05 07:00
10/30/05 13:00
10/30/05 19:00
10/31/05 01:00
10/31/05 07:00
0.0
Figure 3-2. Baseline Load Profile of Indoor Lighting on 3rd Floor
Lighting Test 1 started at 13:00:00 on October 27th. The initial lighting level before the
start of the test was 70%. Figure 3-3 shows the monitored electric power of all three
phases separately and combined. The displayed lines on the chart show data that was
collected at 2 second intervals. The lighting power level setting for each of the 5-minute
blocks on the chart is displayed across the top of the chart. When the lighting level was
at 60%, 50% or 30%, corresponding drops in power usage are seen on all three phases.
Electric phases A and C power light fixtures that were not part of the dimming control
test, but could not be excluded. Normal activity in the office continued through all the
test periods. Restroom lights (phase C) were turned on just before the test began and
were turned off about two minutes later. The same lights were turned on again for a
couple minutes after the test was complete.
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Level: 70%
70%
60%
70%
50%
70%
30%
70%
70%
70%
2.5
2.0
3rd Flr Lighting Panel, kW
Phase A, kW
Phase B, kW
Phase C, kW
kW
1.5
1.0
0.5
13:40:00
13:35:00
13:30:00
13:25:00
13:20:00
13:15:00
13:10:00
13:05:00
13:00:00
12:55:00
12:50:00
0.0
Figure 3-3. Lighting Panel Load Profile during Test 1
The response times of the control system during Test 1 are shown in Table 3-1. The
first column shows the lighting level setting command issued remotely via the internet
software. The second column shows the time the command was initiated (i.e., when the
‘Set Level’ button clicked). The third column is the time stamp in the monitored data
when the lighting level had fully changed. The last column is the time difference
between the third and second columns. The response time for the six different lighting
level changes ranged from 6 to 12 seconds.
Table 3-1
Response Times during Lighting Test 1
Command Setting
Lighting
Lighting
Lighting
Lighting
Lighting
Lighting
60%
70%
50%
70%
30%
70%
Time Command
Initiated
13:00:00
13:05:00
13:10:00
13:15:00
13:20:00
13:25:00
Time Lighting
Responded
13:00:12
13:05:08
13:10:08
13:15:06
13:20:06
13:25:06
Response Time
12 seconds
8 seconds
8 seconds
6 seconds
6 seconds
6 seconds
Lighting Test 2 was the same as Test 1 but started at 16:00:00 on October 27th. The
initial lighting level before the start of the test was 70%. Figure 3-4 shows the
monitored electric power of all three phases separately and combined. When the
lighting level was at 60%, 50% or 30%, corresponding drops in power usage are seen
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on all three phases. Restroom lights on phase C are evident and were turned on and off
just before and after the test but not during the test.
Level: 70%
70%
60%
70%
50%
70%
30%
70%
70%
2.5
2.0
3rd Flr Lighting Panel, kW
Phase A, kW
Phase B, kW
Phase C, kW
kW
1.5
1.0
0.5
16:35:00
16:30:00
16:25:00
16:20:00
16:15:00
16:10:00
16:05:00
16:00:00
15:55:00
15:50:00
0.0
Figure 3-4. Lighting Panel Load Profile during Test 2
The response times of the control system during Test 2 are shown in Table 3-2. During
Test 2 there were a few departures from the original test plan but they did not seriously
impact the test results. The scheduled level increase from 50% to 70% occurred one
minute early. The setting scheduled for 16:20:00 was 30% but was accidentally set to
70% (no change); this mistake was quickly realized and the command for 30% reentered. The response time for the five different lighting level changes with available
data ranged from 2 to 12 seconds.
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Table 3-2
Response Times during Lighting Test 2
Time Command
Initiated
16:00:00
16:05:00
16:10:00
16:14:00
16:20:00
16:20:26 *
16:25:00
Command Setting
Lighting 60%
Lighting 70%
Lighting 50%
Lighting 70%
Lighting 70%
Lighting 30%
Lighting 70%
* Estimated time
Time Lighting
Responded
16:00:08
16:05:06
16:10:12
16:14:02
n/a
16:20:30
16:25:02
Time Delay
8 seconds
6 seconds
12 seconds
2 seconds
n/a
n/a
2 seconds
Lighting Test 3 started at 10:00:00 on October 31st. Test 3 was similar to the previous
two tests but was extended to increase the lighting level settings. The initial lighting
level before the start of the test was 70%. Figure 3-5 shows the monitored electric
power of all three phases separately and combined. More unintended lighting activity
occurred during Test 3 than during the other tests and included lighting fixtures on
phase A and C.
Level: 70%
70%
60%
70%
50%
70%
30%
70%
80%
90%
90%
70%
70%
3.0
2.5
3rd Flr Lighting Panel, kW
Phase A kW
Phase B kW
Phase C kW
kW
2.0
1.5
1.0
0.5
10:55:00
10:50:00
10:45:00
10:40:00
10:35:00
10:30:00
10:25:00
10:20:00
10:15:00
10:10:00
10:05:00
10:00:00
9:55:00
9:50:00
0.0
Figure 3-5. Lighting Panel Load Profile during Test 3
The response times of the control system during Test 3 are shown in Table 3-3. Test 3
was an extended test with plans to set the lighting level all the way to 100%. The data
that was collected did not register that the full on command was received. The
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response time for the nine different lighting level changes with available data ranged
from 2 to 8 seconds.
Table 3-3
Response Times during Lighting Test 3
Time Command
Time Lighting
Time Delay
Initiated
Responded
Lighting 60%
10:00:00
10:00:04
4 seconds
Lighting 70%
10:05:00
10:05:04
4 seconds
Lighting 50%
10:10:00
10:10:08
8 seconds
Lighting 70%
10:15:00
10:15:02
2 seconds
Lighting 30%
10:20:00
10:20:02
2 seconds
Lighting 70%
10:25:00
10:25:04
4 seconds
Lighting 80%
10:30:00
10:30:06
6 seconds
Lighting 90%
10:35:00
10:35:02
2 seconds
Lighting 70%
10:45:00
10:45:08
8 seconds
During Test 3 light level measurements were made directly under one of the dimmable
light fixtures using a light meter. These light meter readings, which are measured in
foot-candles, are provided in Table 3-4. The base load of the non-dimming fixtures was
deducted from the panel power measurements to provide the power to the 29 dimmable
light fixtures.
Command Setting
Table 3-4
Light Level and Power Measurements at Various Light Level Settings
Level
Setting
70%
60%
70%
50%
70%
30%
70%
80%
90%
70%
Time
9:56
10:02
10:08
10:12
10:17
10:23
10:27
10:32
10:37
10:52
Light Level
Foot-candle
48.2
40.9
47.8
33.3
47.8
15.5
48.0
55.7
57.9
47.9
Dimming
Lights kW
1.231
1.086
1.229
0.951
1.227
0.572
1.235
1.313
1.371
1.227
The light meter readings from Table 3-4 are charted in Figure 3-6. The measured
lighting load power of the 29 dimmable fixtures is also plotted in Figure 3-6 using the
secondary y-axis on the right-hand side of the chart. Note that this chart shows that the
relationships between light level settings by the control system are not linear with power
usage or light output. This relationship is most likely a result from the type of dimmable
ballast. Further investigation into the dimmable ballasts used in this test are needed to
verify this claim.
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70
1.4
Light illumination, fc
60
1.2
50
1.0
40
0.8
30
0.6
20
0.4
10
0.2
0
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
Power (kW)
Light Level (foot-candles)
Dimming Lights, kW
0.0
100%
Light Level Setting
Figure 3-6. Light Level and Power Measurements Charted Against Light Level Settings
The baseline chiller load was monitored by two different meters and data logging
systems. An extended history of the chiller load is available via the GE wireless internet
software. Figure 3-7 shows the data from October 17th to 31st. ADM monitored the
chiller from October 20th to 27th using a StowAway logger with much finer time
resolution for the time response testing. This data is shown in Figure 3-8. The chiller
typically runs between 35 and 40 kW.
50
45
Chiller, kW
40
35
kW
30
25
20
15
10
5
10/17/05 00:00
10/17/05 12:00
10/18/05 00:00
10/18/05 12:00
10/19/05 00:00
10/19/05 12:00
10/20/05 00:00
10/20/05 12:00
10/21/05 00:00
10/21/05 12:00
10/22/05 00:00
10/22/05 12:00
10/23/05 00:00
10/23/05 12:00
10/24/05 00:00
10/24/05 12:00
10/25/05 00:00
10/25/05 12:00
10/26/05 00:00
10/26/05 12:00
10/27/05 00:00
10/27/05 12:00
10/28/05 00:00
10/28/05 12:00
10/29/05 00:00
10/29/05 12:00
10/30/05 00:00
10/30/05 12:00
10/31/05 00:00
10/31/05 12:00
11/1/05 00:00
0
Figure 3-7. Baseline Chiller Load Profile as Monitored by the GE Wireless System
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50
45
Chiller kW
40
35
kW
30
25
20
15
10
5
10/27/05 14:00
10/27/05 08:00
10/27/05 02:00
10/26/05 20:00
10/26/05 14:00
10/26/05 08:00
10/26/05 02:00
10/25/05 20:00
10/25/05 14:00
10/25/05 08:00
10/25/05 02:00
10/24/05 20:00
10/24/05 14:00
10/24/05 08:00
10/24/05 02:00
10/23/05 20:00
10/23/05 14:00
10/23/05 08:00
10/23/05 02:00
10/22/05 20:00
10/22/05 14:00
10/22/05 08:00
10/22/05 02:00
10/21/05 20:00
10/21/05 14:00
10/21/05 08:00
10/21/05 02:00
10/20/05 20:00
10/20/05 14:00
0
Figure 3-8. Baseline Chiller Load Profile as Monitored by ADM
A two hour load profile of the chiller is charted in Figure 3-9. For this test the data were
recorded and displayed in 2-second intervals. Prior to the test, the chiller load was
modulating in about half hour cycles and averaging 37.5kW. When the chiller received
the Full Off command it did indeed turn completely off. The chiller was off
approximately a quarter hour before it was turned back on. A 54 kW spike in the
demand lasting 2 seconds was recorded when the chiller was turned back on. The load
increased a few minutes after the chiller came back on line. This is expected because
the chiller must make up for the rise in the building temperature while it was off.
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60
50
kW
40
30
Chiller, kW
20
10
10/27/05 13:00:00
10/27/05 13:04:00
10/27/05 13:08:00
10/27/05 13:12:00
10/27/05 13:16:00
10/27/05 13:20:00
10/27/05 13:24:00
10/27/05 13:28:00
10/27/05 13:32:00
10/27/05 13:36:00
10/27/05 13:40:00
10/27/05 13:44:00
10/27/05 13:48:00
10/27/05 13:52:00
10/27/05 13:56:00
10/27/05 14:00:00
10/27/05 14:04:00
10/27/05 14:08:00
10/27/05 14:12:00
10/27/05 14:16:00
10/27/05 14:20:00
10/27/05 14:24:00
10/27/05 14:28:00
10/27/05 14:32:00
10/27/05 14:36:00
10/27/05 14:40:00
10/27/05 14:44:00
10/27/05 14:48:00
10/27/05 14:52:00
10/27/05 14:56:00
10/27/05 15:00:00
10/27/05 15:04:00
10/27/05 15:08:00
0
Figure 3-9. Live Test Turning Chiller Off and Back On
The response times for the chiller during the test are shown in Table 3-5. During the
chiller test there was an irregularity in that the scheduled turning back on occurred two
minutes later. A repeated Full Off command was accidentally given at 14:15. The Full
On command was given at 14:17. The command to turn the chiller on or off is indirect
because it must relay through the chiller control system. The response time for turning
the chiller off was 80 seconds and 50 seconds to turn it back on.
Table 3-5
Response Times during Chiller Test
Command Setting
Chiller Full OFF
Chiller Full OFF
Chiller Full ON
Time Command
Initiated
14:00:00
14:15:00
14:17:00
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Design & Engineering Services
Time Chiller
Responded
14:01:20
n/a
14:17:50
Time Delay
80 seconds
n/a
50 seconds
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Assessing the Demand Response Capability of a Remotely Controlled, Stepped Dimming Lighting System
3.2 Discussion
It is anticipated that the lighting level reductions for demand response customers would
be 10, 25 or 50 percent depending on the needs at the time. For the test facility this
actually translates to lighting level settings of 60, 50 and 30 percent. The demand
reduction per fixture measured at this facility is provided in Table 3-6. The reduction is
22.7 Watts per fixture when the level setting is changed from 70% to 30%.
Table 3-6
Demand Reduction per Fixture Reduction Referenced to Normal Operation.
Level Setting
70%
60%
50%
30%
Reduction per
Fixture (Watts)
0.0
5.0
9.6
22.7
The facility allowed the installation of the system to test turning the chiller on and off,
but does not intend to allow the chiller to be controlled this way for demand response
purposes. This would be an unusual installation for demand response purposes.
Normally the thermostat set point would be changed as part of a chiller application on a
demand response program.
3.3 Prior Work
For most research work electric loads are monitored on 15-minute intervals. When
more time detail is wanted the monitoring interval will drop to 5-minutes. For this
project, loads needed to be monitored in seconds. Two-second intervals were selected
for the testing based on monitoring equipment capabilities and expected time resolution
needed.
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4.0 Conclusion
The GE wireless energy management technology holds promise for being a part of the
strategy to reduce peak demand for SCE. The objectives of this test program were
successful. The four objectives and results are outlined here.
A. Determine if SCE could control external load from our facilities. Yes, the project
verified that the loads could be controlled from multiple remote locations.
B. Determine if this approach would work for lighting and chiller loads. The tests for
the lighting and chiller were successful.
C. Determine how long it takes from the time the command is given until the load
responds. The response time for lighting level changes ranged from 2 to 12
seconds. Chiller on and off response was 50 and 80 seconds respectively.
D. Determine how much load is shed. For two-lamp, four-foot T-8 lighting fixtures,
22.7 Watts per fixture were shed when the level setting was reduced from 70%
down to 30%. The chiller shed 37.5 kW.
The response time for the lighting system control is very quick. The response time for
the chiller is longer because it must interact with the chiller controller. The chiller load
shedding is exaggerated because normally a chiller would be controlled by reducing the
thermostat set point, thus reducing the load demand, not turning it off completely.
Three issues came up during this study that warrant further study.
1.
One issue pertains to power measurement versus lighting level setting. Results
from this testing suggest that the response of dimming ballasts to signal levels
may not be linear and could lead program operators to assume the wrong amount
of power is being reduced. Further testing may be warranted to measure control
system signal level to dimming ballasts.
2.
A second issue pertains to testing chiller control when thermostat set point can be
changed. Measurable savings via this approach would require longer data
collection during summer-like conditions.
3.
Finally, the architecture of the existing software only permits dimming of the
lighting system in 10 percent increments, (i.e.) from 70% to 60%. Typically SCE
will contract with a customer for a certain percentage of load reduction, based on
the actual load being used. In the case of Los Angeles County, the existing
lighting load was set at 70% of total system power. A 10 percent reduction signal
should have dropped the lighting system to 63% rather than the 60% level
demonstrated in this study.
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5.0 Bibliography
Rulemaking
California Public Utilities Commission, Decision 05-01-056 January 27, 2005, Rulemaking
02-06-001, “Opinion Approving 2005 Demand Response Goals, Programs And Budgets.”
(IOUs peak demand must be cut by 4% of annual system peak during 2006 and by 5%
in 2007.)
Press Release
Edison International Reports Financial Results for Third Quarter 2005, November 4,
2005.
(3rd quarter Commercial sales of 11,044,615 kWh, Total sales of 24,837,592 kWh =
44.5%)
Annual Report
“Southern California Edison 2004 Annual Report”, P. 93
(Operating data for 2004 reported peak demand of 20,762 MW.)
Report Reference
ADM Associates, Inc., February 1990, “End-Use Metered Data for Commercial Buildings
– Annual Report 1988-1989”, prepared for Southern California Edison
(Report lists monitored Air Conditioning and Lighting end-uses as a percentage of total
building load for summer weekdays for major commercial building types.)
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