In the present work, the drying behavior of grapes under open sun and into indirect solar dryer was studied. The indirect solar dryer was designed in the Solar Energy and Environment Laboratory of Mohammed V University, Rabat, Morocco. It consists of a solar collector, a heat exchanger, a water storage tank and a drying chamber. Results show that during off sunshine hours, the heat transfer from the water storage tank kept the grapes temperature higher than ambient temperature. Drying results indicated that the times required for drying grapes starting at the initial moisture contents of 79.8% (w.b.) till final moisture contents of 20.2% (w.b.) were 120 h and 201 h in indirect solar and open sun drying, respectively. The drying data were fitted to 10 thin-layer drying models to describe and compare the drying characteristics of the grapes. Comparisons were based on the coefficient of correlation (R), root mean square error (RMSE) and reduced chi-square (χ2). Midilli et al. model is found to best depict grapes drying behavior in both indirect solar and open sun drying. The evaluated values of the effective moisture diffusivity of grapes sun drying and grapes indirect solar drying when applying the Fick's diffusion model were 2.34 × 10⁻¹¹ and 4.08 × 10⁻¹¹ m²/s, respectively.

在目前的工作中，研究了葡萄在阳光直射下和在间接太阳能干燥器中的干燥行为。间接太阳能干燥机是在摩洛哥拉巴特的穆罕默德五世大学太阳能与环境实验室设计的。它由一个太阳能收集器，一个热交换器，一个储水箱和一个干燥室组成。结果表明，在阳光不足的时候，储水罐的传热使葡萄的温度高于环境温度。干燥结果表明，在间接日光干燥和晴天干燥下，从初始含水量79.8％（wb）到最终含水量20.2％（wb）干燥葡萄所需的时间分别为120 h和201 h。将干燥数据拟合到10个薄层干燥模型，以描述和比较葡萄的干燥特性。比较基于相关系数（R），均方根误差（RMSE）和简化卡方（χ2）。Midilli等。发现该模型可以最好地描述葡萄在间接日光干燥和阳光直射下的干燥行为。使用菲克扩散模型时，葡萄晒干和葡萄间接晒干的有效湿气扩散系数的评估值为2.34×10^-11和4.08×10 ^-11  m ² / s。