In this experimental study, it proportional integral derivative (PID) controlled heat pump dryer wits designed and manufactured. Heat pump dryer was tested drying of hazelnut and energy analyses were made. Drying air temperatures were changed as 50,45 and 40 degrees C in the drying system. Drying air velocities were changed as 0.25 m s(-1) for 50 degrees C, 0.32 m s(-1) for 45 degrees C and 0.38 m s(-1) for 40 degrees C. Heating coefficient of performance of whole system (COPws) of the heat pump dryer was calculated its 1.70 for 50 degrees C, 1.58 for 45 degrees C and 1.40 for 40 degrees C drying air temperatures. Energy utilization ratio changed between 24 and 65% for 50 degrees C, 17 and 63% for 45 degrees C and 14 and 43% for 40 degrees C drying air temperatures in the heat pump dryer. Copyright (C) 2008 John Wiley & Sons, Ltd.