Thermal energy storage is a great interest for solar dryer as the availability of solar resource is intermittent. In this paper, we present an experimental work on a new mixed mode solar greenhouse drying system with and without thermal energy storage unit by Phase Change Materiel (PCM). In fact, The experiments were carried out simultaneously and the focus area is to investigate the effect of paraffin wax as a PCM on drying efficiency of red pepper. The drying system consists of two solar greenhouses, a storage unit and two identical solar air heaters. The experimental results show that air temperature inside solar greenhouse with PCM is higher than other driers by about 7,5 degrees C during all night period. The relative humidity in the drying chamber with PCM is lower by about 18,6% than the ambient relative humidity after sunset. The moisture content has an effective reduction of 95% in 30 h for dryer with PCM, whereas it took 55 h in dryer without PCM and 75 h in open sun. Ten thin-layer mathematical models were fitted to the drying data to select a suitable drying equation. The Midili et al. and the Two-term were found to be the best models respectively, in solar greenhouse with PCM, for both solar greenhouse without PCM and open sun dryer. The use of PCM in solar greenhouse dryer was found to be a promising alternative to enhance the drying process efficiency. (c) 2019 Elsevier Ltd. All rights reserved.