Constructing a solar dryer for drying of pineapples : Implementing a solar dryer for sustainable development in Ghana

Abstract: Drying of fruits has been done for many years and different techniques have been developed. For preservation of fruit, drying is a good method for producing sustainable food products that avoids waste. The interest in producing sustainable food products that are nutritious and safe from bacterial growth has increased. In developing countries large amounts of food are destroyed, while many people are undernourished. Every year large amounts of pineapples are produced in Ghana. The pineapples are either being sold fresh or distributed to juice producers. To minimize the wastes and improve the economy in rural areas, drying is an interesting method. The unreliable power supply system is a problem in Ghana. Power failure is frequent. During dry season, sun drying is a suitable method for Ghana, which has a tropical climate with dry and rain seasons. A solar dryer for pineapples has been developed, constructed, modified, tested and implemented in the village Edumafa, in a rural area of Ghana. The only energy source that has been used to dry the pineapples is the sun. Before the trip to Ghana, drying tests were made in a laboratory in Sweden and a prototype of the dryer was built in the university workshop. This was done to facilitate the work in Ghana by gaining experience from drying and constructing. The prototyping also clarified which type of tools that would be needed so the tools could be transported from Sweden. The results from drying pineapple slices at 70°C in an oven in Sweden resulted in slices with hard shells and a soft, moist content (the moisture could not be removed since it became enclosed inside the slices).The conclusion was drawn that the pineapples cannot be dried in such a high temperature. Slices were in good quality when dried at 50°C. Since the citizens in the village Edumafa have never dried pineapples before, it is important for them to learn how to use the dryer and keep it in good working condition. During wet season it is important that the dryer is protected against rain. In the mid of a sunny day, when the temperature in the ambient air was 30°C, the temperature in the drying chamber could be around 50°C. Temperatures over 50°C were possible to achieve and there were no risk for getting to high temperature in the drying chamber. Therefore good drying temperatures can be achieved. To change the economy in considerable proportions for the citizens in Edumafa, a bigger dryer is necessary. The villagers need investment help to afford a bigger dryer of this type. The dryer can minimize losses of pineapples and create bigger incomes if the solar dryer is maintained in good condition and the villagers use it often to dry pineapples.