A Peer-reviewed Official S Sci Design and Implementa Conditioning C Frezer Getachew 1 , Helen Yibe 1 Department of Computer Engineerin 2 Department of Computer Science Ab In order to transport temperature sensitive which demand high quality products, using sp facilities is mandatory. However, the cu dynamically controlled system as expected design, simulate and implement microcontro and control the Refrigerator temperature b sensor monitors the temperature of the ref value under the control of PIC016F877 temperature and the status of the heater, co The input temperature in the range of –55 t the user and if the temperature goes below heater and fan switch will be ON and compr predefined temperature value only fan switc value goes above, the fan and compressor o interfaced with the microcontroller in ord compressor switched ON/OFF. The simu correctness with the result of physically imple Copyright@2015 STAR Jo INTRODUCTION Air conditioning is the process of modifying the properties of air in the specifi case the refrigerator truck; the ultimate conditioning is to distribute the tempera comfortable conditions, typically with distributing the conditioned air to improve th and indoor air quality. Therefore, temperat is a process in which change of temperature an object or both is detected so that the energy into or out of the space is controlled to achieve a better and desired temperatu 2015). The existing traditional and mostly affo AC controlling system has lots of proble manually manipulated. As a result of this error. In addition to this, the measurement accurate and also the expected output is d analog display system. Beside this almost a existed refrigerator trucks are mostly comp cooling system. Therefore, this paper aim simulate and implement microcontrolle conditioning controller for refrigerator truck both the heating and cooling element and International Journal of Wollega University, Ethi DOI: http://dx.doi.org/10.431 ISSN: 2226-7522 (Print) and 2305- Science, Technology and Arts Resea i. Technol. Arts Res. J., Oct-Dec 2015, Journal Homepage: http://www.st ation of Microcontroller based Automa Control System for Refrigerator Truck n Nekatibeb 1 , Samuel Workineh 1 , TesfayeYitb eltalGelaye 1 and Taye Girma 2* ng, Microlink Information Technology College, Addis A e, St.Mary’s University, P.O. Box: 120611, Addis Aba bstract Articl agricultural or factory products for the markets pecial freight transportation like refrigerator truck urrently available refrigerator trucks have no d to be. Therefore, the aim of this paper is to oller based air conditioning controller to monitor by using a temperature sensor, LM35 and this frigerator based on the predefined temperature 7A microcontroller. The system displays the ompressor and fan as ON or OFF on the LCD. to +150°C is compared with the value stored by w the predefined point of temperature value, the ressor will be OFF; if temperature goes between ched ON, and when the predefined temperature only switched ON. A 24V of each three relays are der to make the respective fan, heater and ulation result is checked for consistence and emented refrigerator truck controller. Article Receiv Revise Accep Keywo Microc Air con Refrige Sensor *Corre Taye G E-mai tayegir ournal, Wollega University. All Rights Reserved. changing or ied area, in this e goal in air ature to more a target of hermal comfort ture controlling e of a space or e flow of heat d and adjusted ure (Wikipedia, ordable type of em since it is it is prone for is not as such displayed using all the currently plemented with med to design, er based air k by integrating d come up with ON-OFF type closed loop controlling s has an impact in the development ende MATERIALS AND METHODS Materials The following hardware and softw used in order to design and impleme based automated refrigerator truck AC Hardware Requirements Microcontroller (PIC16F877A): It is the system that controls the entire sys the input and output signals. It continu temperature signal from the sensor an information and decides based on the p of temperature condition. Temperature Sensor: The LM35 se integrated circuit temperature senso voltage is linearly proportional to the C with a gradient of 10mV/°C (Thein The Sooxma). This sensor is used to sen inside van temperature condition betwe o C and then transmit to the microco Original 131 iopia 14/star.v4i4.20 -3372 (Online) arch Journal 4(4): 131-137 tarjournal.org/ ated Air barek 1 , Ababa, Ethiopia aba, Ethiopia le Information e History: ved : 25-08-2015 ed : 10-11-2015 pted : 13-11-2015 ords: controller nditioning erator Truck r esponding Author: Girma il: [email protected]system which in turn eavor. ware resources are ent microcontroller- controlling system. the central part of stem by processing uously receive input nd then process the predefined set point eries are precision ors, whose output Celsius temperature ein Soe et al., 2014; nse the refrigerator een -55 o C and 150 ontroller for further Research
Transcript
A Peer-reviewed Official International Journal
Science,
Sci. Technol. Arts Res.
Design and Implementation of Microcontroller based Conditioning Control System for Refrigerator Truck
Frezer Getachew1, Helen NekatibebYibeltalGelaye
1Department of Computer Engineering, Microlink Information Technology College
2Department of Computer Science,
AbstractIn order to transport temperature sensitive agricultural or factory products for the markets which demand high quality products, using special freight transportation like refrigerator truck facilities is mandatory. However, the currently available refrigerator trucks have no dynamically controlled system as expected to be. Therefore, the aim of this paper is tdesign, simulate and implement microcontroller based air conditioning controller to monitor and control the Refrigerator temperature by using a temperature sensor, LM35 and this sensor monitors the temperature of the refrigerator based on the predefined value under the control of PIC016F877A microcontroller. The system displays the temperature and the status of the heater, compressor and fan as ON or OFF on the LCD. The input temperature in the range of –55 to +150°C is compared with the valuethe user and if the temperature goes below the predefined point of temperature value, the heater and fan switch will be ON and compressor will be OFF; if temperature goes between predefined temperature value only fan switched ON, and when the prvalue goes above, the fan and compressor only switched ON. A 24V of each three relays are interfaced with the microcontroller in order to make the respective fan, heater and compressor switched ON/OFF. The simulation result is checked correctness with the result of physically implemented refrigerator truck controller.
Copyright@2015 STAR Journal
INTRODUCTION
Air conditioning is the process of changing or modifying the properties of air in the specified area, in this case the refrigerator truck; the ultimate goal in air conditioning is to distribute the temperaturecomfortable conditions, typically with distributing the conditioned air to improve thermal comfort and indoor air quality. Therefore, temperature controlling is a process in which change of temperature of a space or an object or both is detected so that the flow of heat energy into or out of the space is controlled and adjusted to achieve a better and desired temperature (Wikipedia, 2015).
The existing traditional and mostly affordable type of
AC controlling system has lots of problem since it is manually manipulated. As a result of this it is prone for error. In addition to this, the measurement is not as such accurate and also the expected output is displayed using analog display system. Beside this almost all the currently existed refrigerator trucks are mostly complemented witcooling system. Therefore, this paper aimed to design, simulate and implement microcontroller based air conditioning controller for refrigerator truck by integrating both the heating and cooling element and come up with
Official International Journal of Wollega University, Ethiopia
DOI: http://dx.doi.org/10.4314/star.v4i4.
ISSN: 2226-7522 (Print) and 2305-
Science, Technology and Arts Research Journal
Sci. Technol. Arts Res. J., Oct-Dec 2015,
Journal Homepage: http://www.starjournal.org/
Design and Implementation of Microcontroller based Automated Air Conditioning Control System for Refrigerator Truck
, Helen Nekatibeb1, Samuel Workineh1, TesfayeYitbarekYibeltalGelaye1 and Taye Girma2*
Department of Computer Engineering, Microlink Information Technology College, Addis Ababa, Ethiopia
Department of Computer Science, St.Mary’s University, P.O. Box: 120611, Addis Ababa, Ethiopia
Abstract Article Informationtemperature sensitive agricultural or factory products for the markets
high quality products, using special freight transportation like refrigerator truck facilities is mandatory. However, the currently available refrigerator trucks have no dynamically controlled system as expected to be. Therefore, the aim of this paper is to design, simulate and implement microcontroller based air conditioning controller to monitor and control the Refrigerator temperature by using a temperature sensor, LM35 and this sensor monitors the temperature of the refrigerator based on the predefined temperature value under the control of PIC016F877A microcontroller. The system displays the temperature and the status of the heater, compressor and fan as ON or OFF on the LCD.
to +150°C is compared with the value stored by the user and if the temperature goes below the predefined point of temperature value, the heater and fan switch will be ON and compressor will be OFF; if temperature goes between predefined temperature value only fan switched ON, and when the predefined temperature value goes above, the fan and compressor only switched ON. A 24V of each three relays are interfaced with the microcontroller in order to make the respective fan, heater and compressor switched ON/OFF. The simulation result is checked for consistence and correctness with the result of physically implemented refrigerator truck controller.
Air conditioning is the process of changing or modifying the properties of air in the specified area, in this case the refrigerator truck; the ultimate goal in air
the temperature to more a target of
distributing the conditioned air to improve thermal comfort and indoor air quality. Therefore, temperature controlling is a process in which change of temperature of a space or an object or both is detected so that the flow of heat
or out of the space is controlled and adjusted to achieve a better and desired temperature (Wikipedia,
The existing traditional and mostly affordable type of AC controlling system has lots of problem since it is
of this it is prone for error. In addition to this, the measurement is not as such accurate and also the expected output is displayed using analog display system. Beside this almost all the currently existed refrigerator trucks are mostly complemented with cooling system. Therefore, this paper aimed to design, simulate and implement microcontroller based air conditioning controller for refrigerator truck by integrating both the heating and cooling element and come up with
ON-OFF type closed loop controlling system which in turn has an impact in the development endeavor.
MATERIALS AND METHODS
Materials The following hardware and software resources are
used in order to design and implement microcontrollerbased automated refrigerator truck AC controlling system. Hardware Requirements
Microcontroller (PIC16F877A): It is the central part of the system that controls the entire system by processing the input and output signals. It continuously receive input temperature signal from the sensor and then process the information and decides based on the predefined set pointof temperature condition. Temperature Sensor: The LM35 series are precision integrated circuit temperature sensors, whose output voltage is linearly proportional to the Celsius temperature with a gradient of 10mV/°C (Thein Thein Soe Sooxma). This sensor is used to sense the refrigerator inside van temperature condition between oC and then transmit to the microcontroller for further
g system which in turn has an impact in the development endeavor.
The following hardware and software resources are used in order to design and implement microcontroller-based automated refrigerator truck AC controlling system.
It is the central part of the system that controls the entire system by processing the input and output signals. It continuously receive input temperature signal from the sensor and then process the information and decides based on the predefined set point
The LM35 series are precision integrated circuit temperature sensors, whose output voltage is linearly proportional to the Celsius temperature
(Thein Thein Soe et al., 2014; This sensor is used to sense the refrigerator
inside van temperature condition between -55 oC and 150
C and then transmit to the microcontroller for further
Original Research
Frezer Getachew et al.,
processing (Tassou et al., 2006). The circuit connection for LM35 temperature sensor is also given in (Figure 1)(Thein Thein Soe et al., 2014).
Figure 1: Circuit connection of LM35 s
Liquid Crystal Display (LCD): Microcontroller interfaced LCDs are mostly used in many applications. These days, LCD replaced most of the LEDs in system design because of low power consumption and flexible graphics display. This intelligent LCD module can show 160 different characters (Thein Soe et al., 2014). It displays every
Figure 3: Power s Relay: is an electrical switch that opens and closes under the control of the microcontroller. Permanently the relays gets positive DC volt from the power supply and opposite DC from the microcontroller in order to amplify the respective subsequent refrigerator truck electromechanical system. Push Button: is used to RESET the system. Other Components: semiconductor and basic components such as diode, transistor, resistors and capacitors are also used during system designJames, 1959). Software Requirement
There are different ways to program PIC16F877A microcontroller either using a highly level programmilanguage like C or using an assembly language. In this project we used the procedural oriented language of to program the microcontroller. The C programming language has a lot of advantage compared to other programming languages: It has many libraries that provide built-in functions and possibilities for user to define arbitrary functions. The compiler optimize the code for faster execution, easy to learn syntax and easily portable
Sci. Technol. Arts Res. J., Oct-Dec
FEDABC
D2
9D1
8D0
7
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RW
5RS
4
VSS
1
VDD
2
VEE
3
., 2006). The circuit connection given in (Figure 1)
Circuit connection of LM35 sensor
Microcontroller interfaced LCDs are mostly used in many applications. These days,
EDs in system design low power consumption and flexible graphics
display. This intelligent LCD module can show 160 , 2014). It displays
condition of the microcontroller output based on ASCII standard set of characters and mathematical symbols. It is indicated in (Figure 2).
Figure 2: A 16 character x 2 lines LCD pin c DC Power Supply: stable DC voltage is needed for consistent operation for the entire circuit. The microcontroller needs +5DC volt, the three relays each (24DC volt), and other component in the system also need stable DC voltage. As can be shown below a variable regulator can be set to produce +5v and +24v by varying the output in order to obtain the desired DC output (Figure 3).
Power supply circuit for truck refrigerator controller
is an electrical switch that opens and closes under the control of the microcontroller. Permanently the relays
DC volt from the power supply and opposite DC from the microcontroller in order to amplify the respective subsequent refrigerator truck
is used to RESET the system.
semiconductor and basic electronics components such as diode, transistor, resistors and capacitors are also used during system design (Amos and
ways to program PIC16F877A microcontroller either using a highly level programming language like C or using an assembly language. In this project we used the procedural oriented language of (C)
The C programming language has a lot of advantage compared to other
libraries that provide in functions and possibilities for user to define
arbitrary functions. The compiler optimize the code for faster execution, easy to learn syntax and easily portable.
Proteus 8 professional and MPLAB IDE v8.92 are also used.
Methodology
To design, simulate and implement the microcontroller based automatic air conditioning control system for refrigerator truck the following procedures are followed, Identifying the Requirement
Identifying the Required Hardware
• Microcontroller (PIC16F877A), Resistor (10k(normal p-n and LED), DC power supply (5V, 12V, and 24V), Switch, Transistor, Relay (24V), LCD (LM016L), Temperature Sensor (LM35), and capacitors (1nf x4, 2.2nf) are used
Identifying the required Software
• C-Programming language to program the microcontroller
• Proteus 8 professional for circuit designing and simulation
• MPLAB IDE v8.92 for code development environment
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KJIHGF
D7
14
D6
13
D5
12
D4
11
D3
10
D2
9
condition of the microcontroller output based on ASCII set of characters and mathematical symbols. It is
A 16 character x 2 lines LCD pin configuration
stable DC voltage is needed for consistent operation for the entire circuit. The
DC volt, the three relays each in the system also
As can be shown below a variable regulator can be set to produce +5v and +24v by varying the output in order to obtain the desired DC output
Proteus 8 professional and MPLAB IDE v8.92 are also
To design, simulate and implement the microcontroller based automatic air conditioning control system for
llowing procedures are followed,
(PIC16F877A), Resistor (10kΩ), Diode n and LED), DC power supply (5V, 12V, and
24V), Switch, Transistor, Relay (24V), LCD (LM016L), Temperature Sensor (LM35), and capacitors (1nf x4,
g language to program the
Proteus 8 professional for circuit designing and
or code development environment
Frezer Getachew et al.,
Designing and System Modeling
• In this step the system flow diagram is developed to design and integrate each component to form the required system and C code is written to run the entire system.
Simulating the System
• Integrating the circuit design with the C-program code
• Based on each component specification interfacing with the microcontroller and then loading the program on proteus and on microcontroller.
Testing the System
• After loading the code on the Proteus and integration of the circuit design with the code the systested for its correctness and performance.
Physical Implementation and Experimentation
• After simulation and simulation testing, all components are tested for proper functionality and then soldered together to get system circuit.
Testing the Physical Implementation
• In this step, injecting the code to the microcontroller was performed and then testing was conducted to confirm the simulation result by physically implemented system.
System Design and Simulation The system design basically consists of microcontrollera central processor of the entire control operation. The temperature sensor gives the analog output voltage based on the temperature of the refrigerator truck room. This analog voltage is feed to the ADC (builtmicrocontroller). The ADC then converts the analog input voltage from the temperature sensor into equivalent
Figure 5: Circuit Diagram for
The PIC16F877A microcontroller receives information signal through LM35 sensor from external environment (level of temperature). The sensor checks the
Sci. Technol. Arts Res. J., Oct-Dec
In this step the system flow diagram is developed to each component to form the
required system and C code is written to run the entire
program code.
Based on each component specification interfacing with the microcontroller and then loading the program
After loading the code on the Proteus and integration of the circuit design with the code the system was tested for its correctness and performance.
Physical Implementation and Experimentation
After simulation and simulation testing, all components are tested for proper functionality and then soldered
In this step, injecting the code to the microcontroller performed and then testing was conducted to
confirm the simulation result by physically
The system design basically consists of microcontroller as a central processor of the entire control operation. The temperature sensor gives the analog output voltage based on the temperature of the refrigerator truck room. This
he ADC (built-in inside the microcontroller). The ADC then converts the analog input voltage from the temperature sensor into equivalent
binary bits. The converted binary data from the ADC is applied to microcontroller and then the microcontroller reads binary data from ADC. Finally, the microcontroller converts it to suitable form and performs different operations based on the value of temperature read from ADC. The LCD is used to display the data given by microcontroller. Microcontroller can turn on the rbased on the condition defined during initialization (set value). The system functional diagram for refrigerator truck controller is given in (Figure 4).
Microcontroller
LCD
Temperature
Sensor
Figure 4: Functional block diagram for refrigerator t
controller
Circuit Diagram for truck refrigerator controller result after RESET
The PIC16F877A microcontroller receives information signal through LM35 sensor from external environment
of temperature). The sensor checks the
environment in every five seconds. The microcontroller processes the digital signal and then transmits command to the respective relays based on the conditions
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binary bits. The converted binary data from the ADC is applied to microcontroller and then the microcontroller
nary data from ADC. Finally, the microcontroller converts it to suitable form and performs different operations based on the value of temperature read from ADC. The LCD is used to display the data given by microcontroller. Microcontroller can turn on the relay(s) based on the condition defined during initialization (set value). The system functional diagram for refrigerator
Relay 2
Relay 1 Fan
Relay 3
Heater
Compressor
block diagram for refrigerator truck
environment in every five seconds. The microcontroller processes the digital signal and then transmits command to the respective relays based on the conditions
Frezer Getachew et al., Sci. Technol. Arts Res. J., Oct-Dec 2015, 4(4): 131-137
134
predefined set value. If the checked set point of temperature is below 2
oC, the microcontroller commands
relay one and relay three turned ON- to make the fan and heater switched ON respectively; and relay two switched OFF- to make the compressor turned OFF. If the checked temperature is between 2
oC and 6
oC, the microcontroller
directs relay two and three switched OFF (compressor and heater) and relay one switched ON. If the temperature condition is greater or equal to 6
oC, the
microcontroller commands relay one (fan) and relay two (compressor) switched ON and relay three (heater) switched OFF. Relay one (fan) always switched ON to make the air diffused or balanced throughout the van of
cold truck. Whether each respective relays functions or not, that is enables the fan, compressor, and heaters switched ON is observed through the LEDs which are connected to the fun, compressor, and heater. Also if each respective LED’s are switched ON, the respective relays are function properly, and the push button is used to RESET and the system starts again. System Flow Diagram
The following flow chart illustrates the flow of operations of the overall automatic AC controller system for refrigerator truck. A C-programming code is employed to run the entire system.
Read Temp from temp sensor
Is
Temperature
Compressor
ON state
Heater
ON state
Compressor &
Heater OFF state
End
Fan Controller ON
Do untill
RESET
Display the status on LCD
No <=1.9oC Yes >=5.9
oC
Figure 6: System flow diagram for refrigerator truck controller
RESULT AND DISCUSSION
The sensor, LM35, checks the environment in every five seconds to collect information from the external environment so that microcontroller uses this information for generating commands to send to relays depending on the predefined conditions. Whether each respective relays connected to fan, compressor, and heaters are properly functioning or not are controlled through the LEDs which are connected to the fan, compressor, and heater. That means, if each respective LED’s are switched ON, the respective relays are working properly. The simulation of the system is performed based on the following conditions,
Condition 1: If the sensor finds temperature below 1.9oc,
the microcontroller commands relay one and relay three to be turned ON so that the fan and heater switch ON; and relay two switch OFF so as to make the compressor will turn OFF.
Below in (Figure 7), the sensor reads truck temperature of (T
oc = 0.8) as displayed in LCD. As the
result, the microcontroller commands the respective relays to turn ON so as to ON the fan and heater as indicated on the LCD and the respective LEDs (the red and yellow) has also switched ON.
Frezer Getachew et al.,
Figure 7: Refrigerator Truck Controller result when temperature is below 1.9 Condition 2: If the sensor senses a temperature between 2
and 5.9
oC, the microcontroller directs relay two and
three to be switched OFF (compressor and heater) and relay one switched ON.
Figure 8: Refrigerator truck c
Condition 3: If the sensor reads a temperature greater or equal to 6
oC, the microcontroller commands relay one
(fan) and relay two (compressor) to be switched ON and relay three (heater) to be switched OFF. Relay one (falways switched ON to make the air diffused or balanced throughout the van of cold truck.
Sci. Technol. Arts Res. J., Oct-Dec
Refrigerator Truck Controller result when temperature is below 1.9o
C
If the sensor senses a temperature between , the microcontroller directs relay two and
three to be switched OFF (compressor and heater) and
The sensor finds a temperature of 2.30on the LCD and microcontroller commands the faturned ON (red LED) and the other two LEDs are to be switched OFF state (compressor and heater). This is shown below in (Figure 8).
Refrigerator truck controller result when temperature is between 2oC and 5.9
If the sensor reads a temperature greater or
C, the microcontroller commands relay one (fan) and relay two (compressor) to be switched ON and relay three (heater) to be switched OFF. Relay one (fan) always switched ON to make the air diffused or balanced
If the sensor reads a truck temperature of 6.5displayed on the LCD, the microcontroller commands the fan and compressor to be turned ON (red and yellow LED) and this is depicted in figure 9.
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The sensor finds a temperature of 2.30oC as displayed
on the LCD and microcontroller commands the fan to be he other two LEDs are to be
switched OFF state (compressor and heater). This is
C and 5.9oC
If the sensor reads a truck temperature of 6.5oC as
displayed on the LCD, the microcontroller commands the turned ON (red and yellow
Frezer Getachew et al.,
Figure 9: Refrigerator truck c Condition 4: Reset Condition, when the refrigerator truck reaches its target destination, the entire system will be rested through re-setted button so that the system starts again. That means, the microcontroller command the LCD
Figure 10: Refrigerator
Sci. Technol. Arts Res. J., Oct-Dec
Refrigerator truck controller result when temperature is above 6oC
hen the refrigerator truck reaches its target destination, the entire system will be
button so that the system starts again. That means, the microcontroller command the LCD
to display the readiness of the system with the default temperature (T
oC = 0.00) and the status of fan and
heater to be on the ON state as it is indicated in f
Refrigerator truck controller result after RESET
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to display the readiness of the system with the default C = 0.00) and the status of fan and
ON state as it is indicated in figure 10.
Frezer Getachew et al., Sci. Technol. Arts Res. J., Oct-Dec 2015, 4(4): 131-137
137
Physical Implementation Once the simulation results are justified for its proper
operation of the system, the physical implementation of the system is performed as indicated in Figure 11. After soldering each component based on the circuit design, the resulting automated digital control board as it’s shown in figure below, the microcontroller is interfaced with the LCD and the relays through diodes and then transistors and also with external crystal oscillator, DC voltage source, and analog temperature sensor to get the desired output.
The PIC16F877A microcontroller accepts external
signal as an input +5V DC, 16MHz Clock frequency through pin OSC1 (CLKIN) and analog temperature through port-A (RA0/AN0) in order to produce output
signal through port B and D, i.e., the LCD is connected to the PIC pin RB0 –RB2 and RD0 – RD7; the three transistors are also connected to the PIC via pin RB3 – RB5.
The status of each condition is then displayed through
the LCD based on ASCII standard. On the other hand, the output of the microcontroller which directs the respective fan, compressor, and heater in order to regulate the van air condition of the truck. This output is checked in our digital board by assigning three LEDs for each respective fan, compressor, and heater. The digital controlling board has also reserved socket (Plug) to connect with the refrigerator truck’s electrical and mechanical controlling units, i.e., fan, compressor, and heater controlling boards.
Figure 11: Physical implementation of the system
CONCLUSIONS
Refrigerator truck has an aluminum shielded van which is used to transport easily perishable and temperature sensitive materials from place to place. In order to make the temperature balanced and stable, most of the refrigerator trucks, starting from their invention till present have mainly cooling related controlling mechanism.
By using easily affordable electronics components
PIC16F877A chip, LCD, relays, transistors, capacitors, resistors, diodes, and power supply and suitable programming code written in C programming language; an automated digital controller for refrigerator truck is designed, simulated and implemented. The controller controls the air condition of the truck’s van by processing the three states predefined using temperature range, i.e., below 2
oC, between 2
and 6
oC and above 6
oC and then
directs the respective fan, heater and compressor to turn ON/OFF. In this project the simulation result is confirmed with the physical implementation result for its correctness. However, this digital controlling system is properly working and useful when implemented as it is; it might also be possible to manage remotely by using remote sensing, communication and other relevant technologies.
Conflict of Interest Authors declared no conflict of interest.
Tassou, S.A., De-Lille., Lewis, J. (2006). Food Transport Refrigeration. Centre for Energy and Built Environment Research. School of Engineering and Design, Brunel University. http://www.grimsby.ac.uk/documents/defr/trns-refrigeenergy.pdf
Thein Thein Soe., Kyaw Soe Lwin., Zaw Min Naing., Aung Soe Khaing (2014). Design and Development of Microcontroller Based Air Conditioning System. International journal of Scientific Engineering and Technology Research 3(10): 2000-2004
Wikipedia (2015). History of Refrigerator truck, [Available: http://en.wikipedia.org/wiki/Refrigerator]
