This thesis consists of three major parts.
First, drying rate of radish pieces was measured under various drying conditions with a conventional dryer and as the results characteristic drying curve was obtained.
Second, with heat pump dryer which is carefully designed, drying performance was tested. Optimum operating point with respect to bypass ratio was obtained. At optimum point, bypass ratio was approximately 0.3 - 0.4.
Finally, computer simulation was performed. As the results, the optimum operating point was found with bypass ratio 0.3 - 0.4.
