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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2003.

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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