Design and Implementation of Microcontroller based Automated Air Conditioning Control System for Refrigerator Truck

Abstract

In 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 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. The input temperature in the range of –55 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.