The International Journal of Engineering and Science (IJES) || Volume || 10 || Issue || 1 || Series I || Pages || PP 18-23 || 2021 || ISSN (e): 2319-1813 ISSN (p): 20-24-1805 DOI:10.9790/1813-1001011823 www.theijes.com Page 18 Construction of Solar Dryer for Drying Agricultural Produce: Tomato Slices Abdullahi Zubairu Abdulhamid 1 , Ado Yahaya Sumaila 2 , Inuwa Aliyu Faragai 3 and Sani Garba Durumin-Iya 4 Turado Surajo Abubakar 5 1235 Kano University of Science and Technology, Wudil, Kano State, Nigeria,. 4 Sule Lamido University Kafin Hausa, Jigawa State, Nigeria, -----------------------------------------------------------ABSTRACT------------------------------------------------------------- This research dwells on the construction and performance evaluation of mixed-mode solar dryer for Tomato Slices at Kano University of Science and Technology, Wudil. A mixed-mode solar dryer utilizes direct solar radiation from the sun as well as inputs heat from the solar collector inlet which is directly connected to the dryers and at the same time the drying cabinet absorbs solar energy directly through the transparent glass. The results obtained during the test period revealed that the temperature inside all the dryers was much higher than the ambient temperature during most hours of the day-light. However, the temperature risen up inside the drying cabinet was up to 63.1°C with one inlet and also 68.8°C with two inlets occurred within the hour immediately after 12.00 noon. The capacity of the dryer is 0.2kg of products per tray while the inlet temperature is identified to play a crucial role in the solar dryer performance. Keywords: tomato slices, solar energy, dryer, mixed mode, performance evaluation. --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 28-12-2020 Date of Acceptance: 09-01-2021 --------------------------------------------------------------------------------------------------------------------------------------- I. INTRODUCTION The use of solar energy to dry crops is nothing new in the tropics as many edible and even cash crops such as cocoa, and coffee beans have traditional been dried on racks placed in sun .Although the traditional sun drying process is common and widely embraced by all, however, the process is shown and sometimes incomplete under unfavourable climate condition (Abdulelah All Al-Jumaah, Abdullah Mohamed Aslri, 2010). Often the drying products are subjected to noxious effects of dust, dirt, and insect infestation. As a result of inadequacies of the open sun drying process, research effort on drying agricultural produce have been on the increase over the years in order to develop and produce an economical effective and systemized method of drying (A. Salaudeen, 2015). Owing to the higher level of exhaustion in the conventional energy sources such as: chemical energy, thermal energy and petroleum energy, solar energy is rapidly becoming the main alternative source of energy. The availability and accessibility of the solar energy has greatly assisted in improving the techniques for the preservation of agricultural products. (E.K. Akpinar and F. Kocyigit 2010) Drying is a simple technique for preserving crops at a very low cost that might be otherwise spoilt. Although, the solar air collector is a very important component in the solar drying system, much attention has not been drawn during dryer design previously. In principle, the performance of solar dryer depends on the several operating conditions such as the climate condition, collector orientation, the thickness of the cover material, wind speed, length and depth of the collector, and the type of material used for the absorbers (E.K. Akpinar and F. Kocyigit 2010)For this reason, this research has dealt with the optimization of the design, material selection, and required parameters to enhance the efficiency of the designed solar dryers. Tomatoes dried using solar dryer is good in test, color and ordor over tomatoes dried in an open air (S. Tabassum et al.,2019). In this paper we used two dryers one with one collector and the other with two collectors and analysed the results. II. MATERIALS AND METHODOLOGIES The drying chambers consist of chimney, tray and transparent glassing. The drying cabinet alongside the structural support of dryer was built from wooden materials which could withstand the unfavourable weather condition. Glass was selected as the glazing material for additional heating at the drying chamber because of its high transitivity to short wave radiation. Tomato samples were selected randomly from market and sliced with a sharp knife. The slices were cut to a thickness of approximately 0.02 m and 0.01m by using a vernier. From