Thermodynamic analysis of PID temperature controlled heat pump system

In the current research, a heat pump fluidized bed dryer a with PID temperature control was designed. Drying air temperature was determined as 40 °C and it was controlled through this system with ±0.36 °C uncertainty. The designed and manufactured PID controlled heat pump dryer was analyzed by drying the plants of mint, parsley and basil. These analyses included the energy analysis, energy utilization ratio, exergy analysis and uncertainty analysis. In this system, drying air velocity was changed depending on the set temperature. As the set temperature increased, drying air velocity decreased as well. Drying air velocity varied from min 1.01 to max 7.4 m/s. Therefore, energy utilization ratio (EUR) in the fluidized bed dryer was changed during the drying period between 16% and 90%. The whole system heating coefficient of performance (COPws) was calculated as an average of 1.91.