To study the drying of red pepper in mixed mode and open sun solar drying system experiments at Bahir Dar climatic conditions were carried out. The solar dryer consists of a double pass solar collector integrated with aluminum cans, transparent glass, and insulated by timbered wood connected with the greenhouse drying chamber covered by polyethylene plastic cover. An experiment was conducted to study the drying characteristics of red pepper. A total dying period of red pepper in mixed mode greenhouse dryer takes less time than open sun solar drying system. The temperature range is 30.9oC to 54oC in mixed mode drying chamber over an ambient temperature range of 22.6 oC to 28.2 oC at a maximum value of recorded solar insolation of 973 W/m2, minimum solar insolation was 220 W/m2, and 0.0383𝑘𝑔/𝑠 air mass flow rate. Performance of a newly designed mixed-mode and the traditional open sun was 46% and 28% efficient and the drying times to reach the desired moisture content of 11% (on a wet basis) were 45 and 81h respectively. The drying rate for mixed-mode solar dryer and open sun solar dryer system 3.395 𝑥 10−4 𝑘𝑔/𝑠 and 3.65 𝑥 10−5 𝑘𝑔/𝑠 respectively. The dyer is composed of solar collector, greenhouse drying chamber, and air flow systems. The double pass solar collector integrated with aluminum cans has a surface area of 2m2 and is enclosed airspace with the upper side covered with a transparent glass which allows the solar energy into the solar collector. The absorber plates has aluminum cans 1.2mm and 2mm thickness respectively and cans dimeter has 50mm. The sides of the collector are made of wood which acts as solar insolation. All the sides and the underside of the collector are covered with 18 mm thick layer of wood as an insulating material, this helps to minimize loss of thermal energy. The air gap in above and bottom of absorber plate has a 100 mm. The duct is made of flexible hose which used for hot air passes to drying chamber. The dimensions of dome shape greenhouse drying chamber measures 1.3m height, 2.3m width and 3m length. It accommodates six drying trays made from perforated mild steel sheet which act as the holding compartment of the red pepper to be dried. An experimental study was performed to determine drying characteristics in a mixed-mode solar dryer with forced convection and under open sun dryer with natural convection of red pepper. Forced convection solar drying system consisting of a double pass solar air collector and polyethylene transparent greenhouse drying chamber was used in the experiments. The drying data were fitted to eleven different mathematical models. Among the models, the logarithmic model for ix mixed-mode and open sun solar drying system was found best to explain the behavior of red peppers. The performance of these models was investigated by comparing the maximum value coefficient of determination (R2) and minimum value reduced chi-square (x2) and root mean square error (RMSE) between the experimented and predicted moisture ratios. Keywords: Mixed-mode, Solar dryer, Greenhouse, Drying rate, Moisture, Mathematical model