aiming to improve the thermal performance of a direct solar dryer, a new technique of heat supply was proposed and investigated using a double level tubular heat exchanger with geothermal water, constructed in LENREZA laboratory. The heat exchanger was placed deliberately above the absorber plate facing the holes so as to enable the air penetration. The temperature of the circulating water was set to 70 degrees C analogically to that of geothermal water in southern regions of Algeria. The experiment was carried out in LENREZA laboratory, (laboratory of development of new and renewable energy in arid and Saharan zones), University of Ouargla, Algeria. Moreover, numerical simulation was carried out and results were compared with the experimental. The findings showed that the integration of heat exchanger improves significantly the solar dryer performance. By using heat exchanger, the lowest drying air temperature was found to be 46 degrees C, while the highest one was 58 degrees C. After sunset and throughout the night, the drying air temperature remains important and almost steady with an average value of 46 degrees C. The integration of the heat exchanger ensures the continuity of drying process at the night and even during cloudy days. (C) 2018 The Authors. Published by Elsevier Ltd.