1 color deterioration of green fruit during dehydration and 2 decomposition of residual chlorophyll in the tissue under direct solar radiation.
What are the advantages and disadvantages of solar crop dryers.
Uv protection of solar dryers maintains colors and nutrients of fruits and vegetables.
The basic components of a solar dryer are an enclosure or shed screened drying trays or racks and a solar collector.
The product is protected against flies pests rain and dust.
Less risk of spoilage because of the speed of drying.
In hot arid climates the collector may not even be necessary.
Its advantages are you have increased drying rate overall and drying capacity and increased energy efficiency.
A solar dryer in which solar energy collection and drying take place in separate units is known as a distributed solar dryer.
This type of solar dryer has two parts.
If the drying process is slow the fruit start to ferment and the product is spoilt.
Solar greenhouse dryers are available in different size and design and are used for drying various crops and.
The dryer consists of a parabolic roof structure covered polycarbonate sheets on a concrete floor.
Greenhouse solar dryer for drying macadamia nuts.
1 a flat plate air heater and 2 a drying chamber.
Air is heated in the flat plate heater placed on the roof of the building or on the ground.
Direct solar drying has some disadvantages concerning both quality and quantity due to losses attacks by insects etc thus in recent years direct sun drying is replaced by mechanical dryers heated indirectly by solar energy.
This technique changed very little from its early.
Drying is faster because inside the dryer it is warmer than outside.
More sophisticated solar dryers protect grain and fruit reduce losses dry faster and more uniformly and produce a better quality product than open air methods.
1 easy to assemble 2 cheap available materials can be used 3 simple to operate maintain and control and 4 light in weight.
It has also advantages that crop are protected from dust rain insects animals etc.
Relative advantages and disadvantages of cabinet type direct solar dryers are.
Pankaew abstract this paper presents experimental performance and modeling of a greenhouse solar dryer for drying macadamia nuts.
It is labour saving.
However this requires a great deal of management in maintaining the equipment and monitoring when the grain needs to be move from one dryer to the next and it also increases the grain handling that s needed.
Timber can be dried to any desired low moisture content by conventional or solar kiln drying but in air drying moisture contents of less than 18 are difficult to attain for most locations 2.