Post on 21-Mar-2018
A Smart GUI Based Air-Conditioning and Lighting Controller for Energy
Saving in Building
M. F. ABAS, N. MD. SAAD, N. L. RAMLI
Faculty of Electrical & Electronics (FKEE)
Universiti Malaysia Pahang (UMP)
Lebuhraya Tun Razak, 26300 Gambang, Kuantan, Pahang
MALAYSIA
mfadhil@ump.edu.my, norhafidzah@ump.edu.my, noorlina@ump.edu.my http://www.ump.edu.my
Abstract: - This paper will concentrate on the algorithm and control strategies where the air-conditioners and lighting
system can be controlled using microcontroller; a microcontroller is chosen due to its low cost and high flexibility.
Conceptually, the controller is programmed with i9nternal timer and sensors to automatically switch off the power
supply to the air-conditioning and lighting units at pre-defined times, or when no user is detected in a room. The
working prototype of energy saving control system is developed with graphical user interface (GUI) embedded in
Graphic LCD in order to avoid the dependency of personal computer which consume a lot of energy. The system has
been built and tested in UMP lecture room. Based on our case study and energy audit, the prototype can achieve 35%
reduction in the energy consumption of the air-conditioning and lighting system in UMP lecture room. For market
potential, the control system can also be used in other places such as domestics, industrial and office building.
Key-Words: - graphical user interface (GUI), graphic LCD, energy saving control system, microcontroller
1 Introduction Energy is a part of everyday necessities which is
proportional to the cost which the supplier has endorsed.
Due to this fact, the energy usage must be used smartly
and efficiently. Currently, UMP has not applied energy
efficiency in its buildings. Thus excessive power usage
is used and hence billing is quite tremendous. These can
be seen in the monthly average electricity cost in UMP
from Year 2005 until Year 2008 as shown in Table 1
[1]-[4].
Table 1: Monthly Average Electricity Cost in UMP
Besides that, energy wasting occurrences in the
campus are significant, especially in the air-conditioning
and lighting system. A preliminary work was carried out
in UMP’s lecture hall (DK13) to study the consumption
and wastage of energy in the room. For the purpose of
the research, a three phase data logger (Elite Pro power
meter) was installed in DK13 for data collection
regarding energy consumption and energy wasting. We
found that the electrical equipments such as air-
conditioning and lighting system is always left ON with
no occupants which lead to energy inefficient and
energy wasting [4].
Clearly, a major energy saving can be obtained if the
air-conditioning and lighting systems can be made more
energy efficient through better control [5]-[8]. A smart
air-conditioning and lighting controller has been
developed based on a case study done prior to the
development. The case study has shown that numerous
air-conditioner and lighting have been left on without
any occupants. Based on this the control system has
been developed with the following characteristics:
• User can operate the lighting and air conditioner
via GUI embedded in graphic LCD and / or via
common switches.
• The controller is able to source or sink a
maximum current of 8A.
• Include PIR sensor to detect human presence. If
there is none after a predefined time then the
lighting and air conditioner will be
automatically switch off for energy saving and
can only be manually switch on.
• Three adjustable preset times is available to
allow the controller to turn off the air
conditioners and lighting system.
• A security password for setting preset time.
Conceptually, the control system is design with
internal timer and sensor to automatically switched off
the power supply of air-conditioner and lighting units at
three predefined time, or when the sensor detect no user
in the room. The air-conditioners and lighting system
need to be manually switched on if the room is in use
again. The GUI based controller is designed for setting
and switching of the control system. The setting of
internal timer can be changed in GUI setting menu via a
password.
YEAR 2005 2006 2007 2008
RM 160,000 183,000 209,000 302,000
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ISSN: 1790-5117 87 ISBN: 978-960-474-139-7
2 Hardware Development The hardware development comprises of two different
systems. The first part is the standalone user friendly
GUI embedded in the controller. Standalone means that
it is not using any personal computer since personal
computer consumes a lot of energy. The second part is
the air conditioner and lighting control unit which
controls the switching on and off of the peripheral. The
block diagram for both systems can be seen in Figure 1.
Figure1: System Block Diagram
2.1 Graphical User Interface (GUI) Control
Unit The schematic development of GUI control unit was
made using OrCAD 10.5. The schematic involve the
integration between the GUI controller
(microcontroller), small keypad and Graphic LCD.
The graphic LCD unit type LMG7420PLFC-X
(Hitachi) is connected to the GUI controller via 12 pins
and five pins for power. The intersystem communication
port and programming port is used to communicate
between the master (GUI Control Unit) and the slave
(Air conditioner and Lighting Control Unit). The
protocol for intersystem communication will be
explained in the firmware development. The fully
assemble of GUI control unit can be seen in Figure 2
and Figure 3 respectively.
Figure 2: Full Assemble GUI control Unit
Figure 3: Internal Circuitry of GUI Control Unit
2.2 Air-Conditioning and Lighting Control Unit The air-conditioning and lighting control unit schematic
consist of the current sensor schematic and the air-
conditioning and lighting controller with air-
conditioning control module and Lighting control
module. The current sensor used in the system is a hall-
effect based sensor ACS712ELCTR-05B-T (Allegro
MicroSystems Inc.). It can detect maximum current of
5A but the device can withstand up to 60A. The
connectors are used to connect in series with the power
line to the air conditioners or the lighting systems. The
sensor circuits are also connected to the control unit via
connectors.
Lighting control module consists of resistors, triacs,
optocouplers and connector which form two identical
circuits with one connectivity. The double circuits act
similar to a single-pole-double-throw switches. Triac
used in the circuitry could withstand a maximum current
of 12A. Optocoupler (MOC 3042) with an integrated
zero voltage crossing circuit is used for switching of the
lighting control module. There are four lighting control
module to cater for four lighting circuits and four sets of
air-conditioning control module thus enable the
controller to control up to four air-conditioners
simultaneously.
The air-conditioning control module consists of
resistors, diode, optocoupler, relay and connector. Here,
the optocoupler used are 4N25 which is not identical to
MOC3042 since it can only be used for dc voltage
circuitry. Connectors will be connected to the controller
of the air-conditioner. This will enable the system to
operate the air-conditioner safely without damaging or
reduce its life span. The full assembled of the control
unit can be seen in Figure 4.
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Figure 4: Full Assemble of air-conditioning and lighting
control unit
2.3 Smart Air-conditioner and Lighting
Controller The fully developed smart air-conditioner and lighting
controller is setup on a test bed inclusive of a single-
phase one horse-power air-conditioner and four light
bulb rated at 2 x 23W and 2 x 100W. The full system
can be seen in Figure 5 and Figure 6.
Figure 5: Smart air-conditioning and lighting controller
Figure 6: Smart air-conditioning and lighting controller
during operation
Figure 7: Program Flow
A/C and lighting
control unit
GLCD based GUI
control unit
4 x Proximity Sensors
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3 Firmware Development The firmware for the controller consists of the main
program with a number of subroutines to operate the
main program and link to each of the GUI windows. The
flow diagram of the program can be seen in Figure 7.
The full program and subroutines will not be explained
in this paper.
4 Graphic LCD Based GUI Control System
User can switch on or switch off the lighting and air
conditioner via the GLCD based GUI controller and / or
via common switches. The controller includes four PIR
sensors to detect human presence. If there is no user
after a preset delay time then the lighting and air
conditioner will be automatically switch off. The auto
off subroutine will send a command to the A/C and
lighting control unit to turn off all peripheral. Besides
that, three adjustable predefined timer can be set at the
GLCD based GUI controller to turn off the air
conditioners and lighting system at the setting time. For security, user needs to enter the password for setting
predefined time. The introduction window is depicted in Figure 8.
Figure 8: Introduction window of the controller
The main window consists of the ALL section which
enables the user to turn on or off all the air-conditioners
and the lightings. Besides that, the main window also
consists of an AIRCOND, LIGHTING and
CONFIGURE sections which if the user selects it, the
window will change to air-conditioners window, lighting
window and configuration window respectively. These
can be seen from Figure 9 to Figure 15.
Figure 9: Main window
Figure 10: Air-conditioner window
Figure 11: Lighting window
Figure 12: Password window for setting
predefined time
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Figure 13: Predefined time window of
internal timer
Figure 14: Predefined time window to
set internal timer
Figure 15: window to enter new
password
The window in Figure 13 can only be access via a
password. This page consists of the CHANGE CODE,
CHANGE TIME, SET PRETIME1, SET PRETIME2
and SET PRETIME3. CHANGE CODE if selected will
bring up the change code page which allows the user to
change the password. CHANGE TIME if selected will
bring up the change time window which will enables the
user to change the real time clock which is visualized on
the bottom left of the every page. PRETIME1,
PRETIME2 and PRETIME3 if selected will bring up the
respective pre-defined time page which will allow the
user to change the predefined time to automatic turn off
of all peripherals.
5 Analysis of energy consumption at
BK13 After the control system has been fabricated and tested,
it is installed for further analysis at UMP lecture hall
(BK13) which has maximum capacity of about 30
students. The energy consumed with and without the
control system is compared by using data logger (Elite
Pro power meter). Based on the data collected, the
energy saving can be measured.
The data was collected within five working days time
frame during semester session for both conditions; with
and without the controller which was taken from 2nd
February to 6th February 2009 (with control system) and
9th to 13th February 2009 (without control system).
Figure 16 shows the installation of the controller at sub-
switch board. The data of energy saving in BK13 is
depicted in Figure 17.
Figure 16: Installation of control system
at lecture room sub-switch board
Air-conditioners and
lighting Control unit
Lecture room sub-
switch board
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Figure 17: Power consumption in BK
13 with and without control system
From the graph, it shows that power saving at BK13
after installation of the control system is about 35%. The
calculation of power saving and simple payback period
(SPP) by using Malaysian low voltage industrial tariff is
shown below:
Simple payback period (SPP):
Cost of controller = RM 700.00
Saving per month (RM):
= (kWh (not install) – kWh (install)) x 0.38 x 4
= (130.754 – 88.22) x 0.38 x 4
= RM 64.65
Operation cost per month:
= kWh x 24 hours x 30 daysx0.38
= 0.02 x 24 x 30 x 0.38
= RM 5.47
Saving per year (RM):
= (64.65 x 12) – (5.47 x 12)
= RM 710.16
SPP = Cost of controller / Savings per year
= 700.00 / 710.16
= 0.986 years
The simple payback period of the control system will
reduce for application in large area compare to small
area since the savings per year will increase if the
control system is install in large area.
6 Conclusion A working prototype of smart graphic LCD GUI based
air-conditioning and lighting controller for building
energy saving has been designed, fabricated and tested.
Our achievement in this project is 35% reduction in the
energy consumption of the air-conditioning system in
small UMP lecture room with capacity of 30 students.
The controller can also be used for domestic application
as well as industrials and offices applications. The
simple payback period of the controller is less than one
year and for application in large area it will reduce since
the savings per year is increase.
References:
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Based Smart Control System for Energy Saving
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F. Abas, A. H. M. Hanafi and A. Walik, The Effect
of Using Timer to the Split Unit Air-Conditioning
Control in UMP’s Lecture Halls and Labs,
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Power Consumption Vs. Days
(2/2/2009 - 14/2/2009)
0.000
20.000
40.000
60.000
80.000
100.000
120.000
140.000
Days of The Week
Power Consumption (kWh)
kWh (install) 31.095 44.032 53.609 77.698 88.220
kWh (not install) 32.751 63.957 83.491 110.860 130.754
Mon Tue Wed Thurs Fri
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ISSN: 1790-5117 92 ISBN: 978-960-474-139-7