Monday, 26 January 2026

Design and Evaluation of a Passive Solar Dryer for Small-Scale Food Preservation | Chapter 5 | Atomic Absorption Spectroscopy and Physical Experiences in Morogoro, Tanzania

 

The use of solar energy has great potential for promoting energy efficiency and reducing the environmental impact of energy consumption in the environment. Solar drying is a very old but continuously explored technology that everyone can use to dry food products from meat, vegetables, cereals and dairy products. However, over time, with increased pollution to both the air and water, the sun drying has been deteriorating. Solar drying provides a safe and reliable environment for the quality of the dried products and their preservative duration. Despite the development of solar energy technologies, high costs and competition with inexpensive fossil fuels have historically limited their widespread adoption. Thus, interest was rekindled in the harnessing of solar energy for heating, cooling, the generation of electricity and other purposes. This study focuses on the design and construction of a solar dryer device intended for drying a variety of food products. The local and cheap materials were selected in the design so as to help local farmers reduce the cost of drying. The principle of the dryer allows lighter hot air to rise up the altitude and cool the surface. In the raising process, warm air comes in contact with the food slices and draws the moisture from them. The repeated cycle of this process makes it a very healthy, low-cost cost long-term drying mechanism. In thermodynamic terms, the sun’s power or heat is used to dry up the moisture content of the fruits or vegetables.  The construction materials were wood, polyurethane glass, mild steel metal sheet and the trays. The optimum temperature of the dryer was 75°C with a corresponding ambient temperature of 28°C. The rapid rate of drying in the dryer reveals its ability to dry food items reasonably rapidly to a safe moisture level. The capital cost involved in the construction of a solar dryer is much lower compared to that of a mechanical dryer. Also, from the test carried out, the simple and inexpensive solar dryer was designed and constructed using locally sourced materials. The temperature inside the drier was found to be about three times than that of the outside atmospheric temperature. As per our experiment the maximum peak temperature inside the drying chambers was 750C during the mid-day (1.00pm) and an average of 570C in a fully sunny day (from 10:00am to 5:00pm). In seven (7) hours continuous drying in one full sunny day under the same climatic condition and in the same time the solar drier can remove maximum moisture contents from the food contents inside the drier for low moisture content food products. Experimental observation shows that the solar drier can be used as an alternative in case of food preservation and the efficiency is also acceptable. The people can make it on their homes especially in the developing countries where the energy demand is high.This chapter of the book is significant because it advocates the sustainable preservation of food using renewable energy. The creation of a passive solar dryer provides a cheap and environmentally beneficial way to lower post-harvest losses. It promotes further research in sustainable energy and agricultural technologies and helps ensure food security.

 

 

Author(s) Details

Yusuf Ismail Koleleni
Physics Department, Muslim University OF Morogoro, P.O. Box 1031, Morogoro, Tanzania.

 

Please see the book here :- https://doi.org/10.9734/bpi/mono/978-93-47485-78-7/CH5

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