The purpose of this research paper is to perform experimental analyses of system in drying of various agricultural products under different climatic conditions. The secondary goals are to keep a constant drying air temperature with PID, to obtain a homogeneous temperature in the drying chamber to determine the effects of PID control on the system, and to evaluate the drying behavior of various products at 50 C a with variable mass flow rate for a drying analysis. Heat energy requirements were provided with new type double-pass solar air collector (DPSAC) and the heat pump (HP) unit while electricity energy requirements were provided with a photovoltaic (PV) system. The coefficients of performance of the whole system (COPws) for experiments of tomato, strawberry, mint, and parsley were calculated as 1.96, 2.27, 2.28 and 2.17, respectively. The average thermal efficiency of DPSAC was between 16% and 79%. Specific moisture extraction ratio value for the whole system (SMERws) was varied between 0.03 kg/kW h and 0.46 kg/kW h for the products. Energy utilization ratio (EUR) was obtained between 0.19 and 0.48. Results demonstrated that the HP unit, DPSAC, PV unit and PID control system can work in coordination with each other and was obtained dried products having good physical properties at the same time. (C) 2014 Elsevier Ltd. All rights reserved.