Good Practices in the Use of ICT Equipment for Electricity Savings at a University Campus

Andreas Kamilaris, Dang Truong Hoang Ngan, Alexandros Pantazaras,
Balaji Kalluri, Sekhar Kondepudi and Tham Kwok Wai
Dallas, TX : Nov 3-5 2014

MELs account for more than 20% of the primary energy used in commercial buildings
and this is expected to rise to 40% by 2035.
MELs are transforming into dominant
electrical loads
As can be seen the electrical loads by
traditional uses is expected to decline,
while the same for MELs is increasing
rapidly.
3
© 2014 Sekhar Kondepudi

• A study measuring consumption of MELs in a controlled environment
in University of California in San Diego revealed that MELs category of
ICT equipment accounts for:
–70% of the electrical loads during peak hours
–80% of the electrical loads during off-peak hours
• Therefore energy audit focusing on ICT equipment is very important,
when minimizing the energy foot-print of a building.
4

• What are the different power (plug load) behaviors of different ICT devices ?
• What are the different ICT device classes ?
• Can these plug loads and their related parameters be characterized ?
• What is the transient behavior of these devices – moving from one state to
another?
• Are there similar patterns within a device class?
• How to manage increasing ICT loads in next-gen smart buildings ?
• Can we develop Predictive Algorithms for Disaggregating Multiple Loads from a
Single Measurement
5 © 2014 Sekhar Kondepudi

• Goal
–To develop Best Practices on the Use of ICT Devices in the University Campus
using the School of Design & Environment (SDE) as a proxy (3 Departments, 3
Buildings)
• Quantitative
–Detailed Inventory of ICT Devices
–Measurement of Individual ICT Devices
–Field Measurements & Monitoring
• Qualitative
–Surveys and interviews with users and facility managers
6

• Desktop PCs + Displays = 1300
• Imaging (Printers, Scanners, MFD) = 150
• VoIP Phones = 85
• Projectors = 44;
• Faculty offices = 108, predominantly in SDE1-L4&L5 then in SDE3-L2&L3
• Admin Staff = 104, predominantly in SDE1-L3&L5 then in SDE2-L1&L2
• Limited Laptops – Not permanently attached ( only 5 )
• Desktops: 41%
• Display Monitors: 41%
• Imaging equipment: 8%
• VoIP, projectors, external LCD screens:10%
7

• Energy Metering Hardware
Employed smart power outlets or smart plugs to sandwiched in the
middle of the socket and electrical appliance plug to measure their
consumption.
• These motes sample the current, voltage, active and apparent power of the
attached load.
• They include a low-power processor, radio and integrated antenna.
• Developed drivers in Java for parsing the measurements and storing them
in a database for statistical analysis, similar to smart homes concept.
8

Monitor Projector Printer Desktop Laptop
ON-Low Brightness OFF OFF OFF OFF
ON-Med Brightness SLEEP OFF – BOOT UP – IDLE OFF to ON OFF to ON
ON-High Brightness ON IDLE – PRINT – IDLE (6 Single sided) ON ON
STANDBY SLEEP TO ON IDLE – PRINT – IDLE (3 double-sided) ON-app ON-app
OFF ON TO SLEEP IDLE – SCAN – IDLE (3 page) ON to SLEEP ON to SLEEP
IDLE – COPY – IDLE (6 single-sided) ON-app to SLEEP ON-app to SLEEP
IDLE – COPY – IDLE (3 double-sided) SLEEP SLEEP
SLEEP - IDLE SLEEP-app SLEEP-app
IDLE SLEEP to ON SLEEP to ON
SLEEP SLEEP-app to ON SLEEP-app to ON
ON to HIBERNATE ON to HIBERNATE
ON-app to HIBERNATE ON-app to HIBERNATE
HIBERNATE HIBERNATE
HIBERNATE-app HIBERNATE-app
HIBERNATE to ON HIBERNATE to ON
HIBERNATE-app to ON HIBERNATE-app to ON
ON to OFF ON to OFF
ON-app to OFF ON-app to OFF
CHARGING

• Desktops
• Laptops
• Monitors
• Printers
• Scanners
• MFDs
• VoIP Phones

0.00
20.00
40.00
60.00
80.00
100.00
120.00
140.00
160.00
180.00
200.00
0 10 20 30 40 50 60 70 80 90 100 110 120
ActivePower(W)
Time (sec)
Active Power vs Time
Desktop 1 Desktop 2 Desktop 3
SLEEP to ON
0.00
20.00
40.00
60.00
80.00
100.00
120.00
140.00
160.00
180.00
200.00
220.00
240.00
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140
ActivePower(W)
Time (sec)
HIBERNATE to ON
0.00
20.00
40.00
60.00
80.00
100.00
120.00
140.00
160.00
180.00
200.00
220.00
0 10 20 30 40 50 60 70 80 90 100 110 120
ActivePower(W)
Time (sec)
Desktop 1 Desktop 2 Desktop 3OFF to ON

0.00
0.20
0.40
0.60
0.80
1.00
0 20 40 60 80 100 120
Current(A)
Time (sec)
Current vs Time
SLEEP to ON
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
0 50 100 150 200 250
Current(A)
Time (sec)
Current vs Time
HIBERNATE to ON
0.00
0.20
0.40
0.60
0.80
1.00
0 10 20 30 40 50 60 70 80 90 100 110 120
Current
Time
Current vs Time
OFF to ON

0.00
100.00
200.00
300.00
400.00
500.00
600.00
700.00
0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00
Power(Watt)
Time (sec)
Printer (MFD) - Idle State
Printer 1 Printer 2
0
10
20
30
40
50
60
70
5000 5200 5400 5600 5800 6000 6200 6400 6600 6800 7000
AveragePower(W)
Time (sec)
Spike every 40 seconds (keep the drum warm ?)
Spike lasts for 7-8 seconds
Consumes up to 500W during that small timeframe
Trend similar with Other MFD printer
Snapshot of Field Data
Captured at 15 sec intervals over multiple weeks
Range between 50 and 60 W
Energy Consumption Consistent with Detailed Per
Second Data
Assume 50 W for 12 hours a day X 365 Days X $ 0.25 / Kwh ~ $ 55.00 / year / printer
At least 3000 such printers on NUS Campus = $ 165,000 savings annually

• Laptops consuming 25% less power than desktops in ON mode and
50% less power during SLEEP mode.
• Our measurements show heat produced by desktops is 4 times more
than laptops. Each laptop needs 3000 btuh less than a desktop to
cool office space.
• Recommendation to procure Laptops when refresh time comes for
computers

• Wake-on-LAN : send packets on network to make machines sleep
on wake up depending on network activity.
• SleepServer : transition to low-power sleep while maintaining network
presence of all connected machines by a proxy mechanism on one
server.
• LiteGreen : virtualize the desktop environment, migrating it between
the user’s physical machine and virtual server.

• Assigning power settings, more suited to the intended use of the computing
devices.
• Many users of our building were not sure whether they should set their laptop in
hibernate or sleep mode when they had to leave for lunch or home.
• When ON, consumption is 34 times more than in SLEEP and 116 times more
than HIBERNATE.
• SLEEP consumes more power than HIBERNATE but enables a faster waking up
time of the desktop. However the difference is quite tolerable
• 20-65 sec, 0.46 Watts in Sleep and 40-80 sec, 0.08 Watts in Hibernate

• Laptop
Running NO applications. For less than 44 minutes and 30 seconds, it is better that a laptop is
in SLEEP. For longer, hibernate is preferred.
Running applications. For less than 59 minutes and 39 seconds, it is better that a laptop is in
SLEEP. For longer, hibernate is preferred.
• Desktops
The tradeoff (independent of running applications or not) is 126 minutes and 3 seconds. Less
than this time, it is better to put the desktop to SLEEP. More than this time, it is more practical to
HIBERNATE.
Dilemma – Due to a large trade off of over two hours, the user is better off
switching the desktop OFF when leaving it idle for over two hours.

SLEEP and OFF have nearly the
same power consumption.
Hence switch off monitor, whenever a user
puts their desktop in SLEEP.
Power consumed in IDLE is 15-22
times more than SLEEP.
Hence, set time to switch off display after
15 or so minutes of inactivity.

Adjusting brightness to 75% can
lead to 18% decrease in
consumption
Adjusting to 50%can lead to 30%
savings.
Recommendation: 65%-85%
brightness do not affect
productivity while saving
electricity.

• Common Printers & Multifunctional Devices
(MFDs) in labs as well as those in the
personal spaces of academic staff, remain
IDLE/ SLEEP at night time.
• Especially at Night, there is no need to have
the printers/ MFDs ready for tasks so these
devices should be powered off, after hours.
0.00
100.00
200.00
300.00
400.00
500.00
600.00
700.00
0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00
Power(Watt)
Time (sec)
Printer 1 Printer 2
Between $ 50 and $ 75 savings per printer per year

• Is double sided printing is more efficient compared , to single sided (in addition to
the savings of paper ?
• YES – Always better to print double sided
 Single-sided printing consumes 2.13 times
more power than double sided.
 0.124 Kwh for 3 double-sided pages
compared to 0.058 Kwh for 6 single-sided
pages.

 MFD
 Double sided Copying
 Time: 54 sec, Power: 0.209kWh
 Single Sided Copying
 Time: 34 sec, Power: 0.117 kWh
 Single-sided copying consumes
1.8 times less power than double-
sided copying.
 Hence, with regards to electrical energy
savings, it is better to copy single-sided.
 But there is a trade-off here, as single-sided
copying uses more paper.

• Is it better to Scan + Email or make a Physical Copy ?
• YES – Always better to Scan + Email : Energy + Paper savings
 Sample of 6 pages scanned vs. 3 double-
sided copies.
 Copying needs 9 times more energy and 3
times more time.

Projectors have highest power consumption compared to other ICT
devices. The projectors we tested consumes 220-285 Watts
 SLEEP mode: Power: 10-12 Watts. Time to start up
from SLEEP: 29 sec
 OFF mode: Power: 0 Watts. Time to start up from OFF:
56 sec
 Hence it is preferred to switch project OFF, as the 27
seconds saved in time, are not much compared to the
gain in energy savings.
 Projector Power consumption is directly linked to the
brightness. Therefore it is suggested that only the
needed LUMENS specifications must be installed.

We compared energy efficiency of an Energy Star labeled laptop and a
non-labeled Laptop in both IDLE and SLEEP modes.
 Energy Star Labeled Laptop consumes
 43% less power than a non-labeled Laptop in IDLE
mode.
 14% less power than a non-labeled Laptop in SLEEP
mode.
 Hence, we strongly suggest to purchase Energy
Star labeled ICT devices

Power consumption of VoIP phones is very low around 2.5 Watts for a
VoIP.
Incoming or outgoing calls do not have an impact on the consumption of
power.
0
0.5
1
1.5
2
2.5
3
3.5
1 21 41 61 81 101 121 141
Power(Watts)
Time (seconds)
VoIP IDLE
VoIP CALL OUT
VoIP CALL IN
 Even though VoIP usage is low, the
phones consume power at night
time when they are mostly idle.
 Cisco has introduced an Energy-
Wise feature, having the ability to
turn the VoIP phone off and on
based on the loads on the local
network.

An underestimated energy savings parameter is efficient and accurate
utilization of common PC labs.
In SDE, during class in PC Lab time, the PC utilization is more aggressive,
reaching 68%. This is still less to warrant a fully provisioned lab.
0
10
20
30
40
50
60
70
80
9:00 9:30 10:0010:3011:0011:3012:0012:3013:0013:3014:0014:3015:0015:3016:0016:3017:0017:3018:0018:3019:00
Occupancy(%)
Day Time
Tuesday Thursday
Friday
29
Class timings for the chart below:
Tuesday 1100-1300, Thursday 1000 -1400

Need to have Better Utilization
of Common PC Labs
• Students use different machines
each time.
• Students forget to switch them
off after each use.
• 22% of the machines remain
idle after use.
• 51% of the machines remain
idle after use after a class.
0
10
20
30
40
50
60
70
ON SLEEP OFF
Percentage(%)
Desktop State
Class No Class

Educate students about the importance of saving energy by
switching off the machines after use.
A Supervisor from students or staff, should make sure machines are
switched off.
Differentiate general computing labs with PCs to specialized
computing lab with PCs.
Specialized labs should only house as many students as course
registration.
Generalized lab may offer just basic computing facilities to a larger student
body.

Some desktops in common pc labs, run simulations for
hours or even a few days.
0 5 10 15 20 25 30
Friday
Thursday
Wednesday
Tuesday
Monday
Consumption (kWh)
SIMULATION
ON
SLEEP
OFF
NIGHT
 Desktops used for simulations
consume largest percentage of
electricity. More than 50% on all
weekdays.
 Increased consumption at night
time, due to desktops running
simulations. Left ON from previous
day.

• Almost $ 50K per year in School of Design & Environment
• University Wide – probably can extrapolate to $ 500 – 750 K per year

• Great Potential to implement Best Practices which not only save energy but also
money. Win-Win
• Areas of future work
Audit power consumption of ICT infrastructural devices
Increase the duration of the study for greater than 6 months to identify temporal patterns for
saving.
Associate user groups/profiles with use of ICT devices and try to develop more effective and
personalized strategies to encourage occupants to adopt greener use of office equipment.
• Still not clear whether to involve building users more for energy savings or use
automation. We support at least some education and training which is essential
for users to perceive how to use their ICT devices.

Prof. Sekhar Kondepudi, Ph.D.
sekhar.kondepudi@nus.edu.sg
+65 9856 6472
Dr. Andreas Kamilaris
kami@cs.ucy.ac.cy
The authors would like to acknowledge the support of the Ministry of Education, Singapore. Via an AcRF Grant for this project

Good Practices in the Use of ICT Equipment for Electricity Savings at a University Campus

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