D. Tech. Mechanical Engineering, Mechatronics and Industrial Design / Heat pump drying (HPD) is a proven efficient method in food drying industries and more efficacious than traditional South African industrial and agricultural drying methods, providing high energy efficiency with controllable temperature, air flow, air humidity and large energy saving potentials. In the last decade the market of heat pump (HP) systems for water heating and space cooling/heating has been well developed in South Africa, but the development of heat pumps (HPs) for industrial and agricultural drying has been very slow. In the case of optimization of HPD systems, most literature studies concentrate on optimization of the drying parameters; however it is important to note that the overall performance of the HPD system, which consists of two subsystems, the HP and drying system, depends on working conditions and the two subsystems interact with each other. It is therefore important that the HP and the dryer should not be examined or optimized separately. Therefore, in this study, an air source heat pump system was designed, constructed, installed and analysed as a single integrated unit for drying fruits. The main objective of the study was to carry out experimental investigations on optimization of an air source heat pump for drying South African fruits.