Solar fruit drier developed
Jan 11, 2005
A new highly effective solar drier to help reduce the massive post-harvest losses of fresh produce has been developed.
By Kikonyogo Ngatya
A new highly effective solar drier to help reduce the massive post-harvest losses of fresh produce has been developed.
The rocket elbow solar drier dries fruit chips to 11% water content, thereby limiting the rotting of products. Unlike other driers, it takes less time and energy consumption.
It has been developed by the Uganda Industrial Research Organisation with support from the German Technical Cooperation and the Ministry of Energy an Mineral Development.
The drier can be used to dry pineapple, banana, pawpaws and other fruits to increase on their shelf life.
Uganda experiences some of the highest losses in the agricultural sector in Africa due to poor post-harvest handling technologies. About 30% of the produce is lost annually.
Doron Callies, a solar drying engineer with GTZ, said the drier uses both solar and wood energy.
He said due to variations of temperatures, solar alone may not be enough in drying produce at some seasons during the year.
Callies said the drier can dry a tonne of fresh fruits, using only 40 kilogrammes of wood in about 12 hours. Saw dust can also be used.
The drier has about 15 square metres of drying area, with wooden trays where the fruits are put for drying. The drier can be constructed using locally available materials. Callies said it would cost about sh5m to construct. “This is a permanent structure. It would need someone in the export business or drying fruits on a regular basis,†he said.
The drier has an absorber for the sunlight with a black surface filled with black paste. The absorber is covered with a clear glass to allow sunlight heat the black paste. When the air is heated, it is sucked inside by a fan in the middle of the stove.
The air will then move over heated pipes and reaches the fruits being dried before evaporating into a furnace at the top of the dried produce. The drier heats to about 800 degrees centigrade.
Callies said it was important to heat the pipes so that the hot air reaching the fruits can dry the chips faster.
“The fan is always on to push the air to the heat exchanger with pipes that are heated by hot exhaust gases from the stove,†He noted.
He said the drier heats the fruits to refined export quality levels.
“No smoke would mix up with the fruits,†he said. The researchers said they wanted to make air distribution inside the drier even all the time.
Charles Kirumira, a technician with Amfri, a dried fruit exporting company based in Ntinda, Kampala said the drier works well.
He noted that some of the fruits had been dried using the new solar, which he said would be adopted by their contact farmers
A new highly effective solar drier to help reduce the massive post-harvest losses of fresh produce has been developed.
The rocket elbow solar drier dries fruit chips to 11% water content, thereby limiting the rotting of products. Unlike other driers, it takes less time and energy consumption.
It has been developed by the Uganda Industrial Research Organisation with support from the German Technical Cooperation and the Ministry of Energy an Mineral Development.
The drier can be used to dry pineapple, banana, pawpaws and other fruits to increase on their shelf life.
Uganda experiences some of the highest losses in the agricultural sector in Africa due to poor post-harvest handling technologies. About 30% of the produce is lost annually.
Doron Callies, a solar drying engineer with GTZ, said the drier uses both solar and wood energy.
He said due to variations of temperatures, solar alone may not be enough in drying produce at some seasons during the year.
Callies said the drier can dry a tonne of fresh fruits, using only 40 kilogrammes of wood in about 12 hours. Saw dust can also be used.
The drier has about 15 square metres of drying area, with wooden trays where the fruits are put for drying. The drier can be constructed using locally available materials. Callies said it would cost about sh5m to construct. “This is a permanent structure. It would need someone in the export business or drying fruits on a regular basis,†he said.
The drier has an absorber for the sunlight with a black surface filled with black paste. The absorber is covered with a clear glass to allow sunlight heat the black paste. When the air is heated, it is sucked inside by a fan in the middle of the stove.
The air will then move over heated pipes and reaches the fruits being dried before evaporating into a furnace at the top of the dried produce. The drier heats to about 800 degrees centigrade.
Callies said it was important to heat the pipes so that the hot air reaching the fruits can dry the chips faster.
“The fan is always on to push the air to the heat exchanger with pipes that are heated by hot exhaust gases from the stove,†He noted.
He said the drier heats the fruits to refined export quality levels.
“No smoke would mix up with the fruits,†he said. The researchers said they wanted to make air distribution inside the drier even all the time.
Charles Kirumira, a technician with Amfri, a dried fruit exporting company based in Ntinda, Kampala said the drier works well.
He noted that some of the fruits had been dried using the new solar, which he said would be adopted by their contact farmers