1：Experimental Design and Method Selection:

The study investigated the thin layer drying behavior of lettuce leaves using an indirect pilot solar dryer with thermal energy storage in water, equipped with solar collectors and photovoltaic cells. The drying procedure involved shredded lettuce leaves at temperatures ≤ 52 °C, airspeed of 1.0 m?s?1, and process time ~10.0 h. Fifteen drying models were adjusted to the experimental data obtained.

2：0 m?s?1, and process time ~0 h. Fifteen drying models were adjusted to the experimental data obtained. Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Romaine lettuce (Lactuca sativa L. var. longifolia) leaves were selected from healthy and uniform leaves used for the drying experiments. They were stored at 8.0 ± 2.0 °C prior to the drying process.

3：0 ± 0 °C prior to the drying process. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: The experimental equipment mainly consists of a pilot solar dryer of indirect operation using thermal energy storage in water and equipped with solar collectors (U‐pipe) for converting the solar irradiance in heat energy and photovoltaic cells (monocrystalline) for converting the solar irradiance in electricity. This equipment has two drying chambers that operate in series, and each has three trays to put samples on.

4：Experimental Procedures and Operational Workflow:

The drying evaluations took into account the following considerations: (a) lettuce var. longifolia as vegetable leaves with high humidity, (b) exposure to dry form: shredded; (c) constant velocity of the drying air, 1.0 m?s?1; (d) inlet drying air temperature ≤ 60 °C; the drying process was conducted using the pilot solar dryer in the beginning summer in the southern hemisphere, December 2016–January

5：0 m?s?1; (d) inlet drying air temperature ≤ 60 °C; the drying process was conducted using the pilot solar dryer in the beginning summer in the southern hemisphere, December 2016–January Data Analysis Methods:

2017. 5. Data Analysis Methods: Statistical parameters, R2, SSE, RMSE and, χ2, were used to determine the goodness of fit of the drying curves of the fifteen models studied. The determination coefficient (R2) was the primary criterion for selecting the most suitable equation to describe the drying curves of shredded lettuce leaves in the solar dryer.