ABSTRACT

Supriadi, The Cold Storage Temperature Control System Automatization   (supervised by Rhiza S. Sadjad and Zahir Zainuddin).

This is a design project to implement a certain kind of  automatic temperature control scheme in a cold storage system. For the design purpose, a scale model of the cold storage has been developed. 

The real cold storage system is located at the Makassar Industrial Estate (PT. KIMA) Makassar, INDONESIA. Its physical size  is ...... m x ..... m x..... m (l x w x h). By manually switching the cooler machine ON and OFF every period of 6 (six) hours, the temperature of the storage is maintained between - ...... oC to - ......... oC. The scale model is built at the laboratory, the physical size is reduced to ...... cm x ...... cm x ....... cm (l x w x h). The cooler machine is modelled by a fan, while a 100 Watt light-bulb raises the temperature. By adjusting the window opening, the temperature of the model can be maintained between +30oC to +45oC by switching manually the fan and the light-bulb ON and OFF every period of ........ minutes.

At the model, a personal-computer replaces human to monitor and control the temperature. An LM335 temperature sensor produces the analog voltage linearly proportional to the temperature. This voltage is converted into digital data by an Analog to Digital Converter (A/DC) and sent to the RS-232 port of the computer through a AtMega8535 Microcontroller. If the temperature is higher than a certain maximum value, a command is sent through the microcontroller to switch the fan ON and the light-bulb OFF. At the opposite, if the temperature s lower than a certain minimum value, a command is sent through the microcontroller to switch the fan OFF and the light-bulb ON. The temperature variation can be easily reduced to as small as 5oC so that the model temperature can be maintained between +35oC to +40oC (which is in reality equivalent to - ....oC to -.....oC), and the time period is reduced to ..... minutes (which is in reality equivalent to ...... hours).

The automatic cold storage temperature control system can be extended into a web-based temperature information system accessible via Internet by including a database system connected to a web-server.