PID temperature controlling of thermoelectric based cool box

In this study, PID controller instrument design for controlling the input current to thermoelectric cooler (TEC). For cooling process, we used thermoelectric type of 12706 with active material of Bi2Te3. The instrument was tested by comparing the cooling process with and without PID control. Without PID control, the TEC modules cooled the temperature down to 11 “C within 6538 seconds. This temperature was obtained within 2060 seconds when PID control was applied. This finding showed that PID control could accelerate three times faster the cooling process. The best parameters for controlling were Kp =8.5, Ki =1.9 and Kd =0.4. In addition, we observed that two serial modules of TEC with current input of 2A could reach a set point of 11 °C. This result was better than a cooling process using three individual TEC modules in which each module was driven by 6A current. Our results showed that beside the number of TEC modules, the heat distribution also played important role in cooling process. Since two serial modules dissipated less power than three individual modules, the heat distribution became more effective and similar temperature could be achieve.