Thesis Abstract

Abstract
This research project focuses on the design and manufacture of a natural convection solar dryer that requires minimal to no maintenance. The goal is to create a sustainable and efficient drying system for agricultural products that harnesses solar energy for the drying process. The proposed solar dryer aims to reduce post-harvest losses, improve product quality, and enhance food security in rural communities. The design of the solar dryer incorporates natural convection principles to promote air circulation and facilitate the drying of various agricultural products such as fruits, vegetables, grains, and herbs. By utilizing solar energy, the system eliminates the need for electricity or fossil fuels, making it environmentally friendly and cost-effective. Key considerations in the design process include the selection of appropriate materials that are durable, weather-resistant, and readily available. The solar dryer features a transparent cover to allow sunlight to enter the drying chamber while preventing dust and pests from contaminating the products. Additionally, vents and air outlets are strategically positioned to optimize air flow and heat distribution within the dryer. To ensure minimal maintenance requirements, the components of the solar dryer are designed to be robust and long-lasting. Regular cleaning and inspection are recommended to maintain optimal performance, but the system is engineered to operate efficiently with little intervention. By reducing maintenance needs, the solar dryer offers a practical solution for small-scale farmers and producers with limited resources and technical expertise. The manufacturing process involves assembling the components according to the design specifications and conducting quality control tests to validate the performance of the solar dryer. Field testing will be conducted to evaluate the effectiveness of the system in different climatic conditions and to gather feedback from end-users. In conclusion, the development of a natural convection solar dryer with minimal maintenance requirements has the potential to empower rural communities by providing a sustainable solution for food preservation and income generation. By harnessing the power of the sun to dry agricultural products efficiently and economically, this innovative technology can contribute to reducing food waste, improving livelihoods, and promoting environmental sustainability.

Thesis Overview

INTRODUCTION

1.1 BACKGROUND TO THE STUDY

Drying is one of the oldest methods of food preservation. For many years, people have been preserving agricultural products by drying until caning was developed at the end of the 18th century (Ekechukwu and Norton, 1999). The importance of dried foods cannot be overestimated as the kitchens and food stores in any country will confirm the quantity and diversity of dried food in use. Drying is essentially a process of moisture removal due to simultaneous heat and mass transfer. It is a classical method of food preservation which provides longer shelf life,lighter weight for transportation and small space for storage. Drying could be of various methods such as open sundrying,direct and indirect solar drying etc.

Open sundrying which is the most commonly used method to preserve agricultural products like grains, fruits and vegetables in most developing countries. Such drying under hostile climatic conditions leads to severe losses in the quantity and quality of the dried product .This losses related to contamination by dirt, dust, bird droppings and infestation by insects, rodents and animals as well as the quality of the products being degraded due to uncontrolled heat in sundrying even up t the extent that the food products are inedible (whitefield, 2000). Therefore the introduction of solar dryers in developing countries can reduce crop losses and improve the quality of the dried product significantly when compared to the traditional methods.

Solar dryers could be either Natural convection of forced convection solar dryers. The Natural solar dryer is such that it controls the drying process and protects the agricultural produce from contamination by insects, dust, bird droppings, invasions by animals, and in comparison to Natural solar dryers, it generates higher temperatures, lower relative humidity, lower produce moisture content and reduce spoilage during drying process in addition, it takes less time and is relatively inexpensive when compared to artificial mechanical drying method (Ged-Gujur at Energy development Agency, 2003, www.geda.com). Dried foods using natural convection solar dryers are quality products that can be stored for extended nutritive values.