Farmers find it extremely possible to process and preserve high moisture content crops by normal open sun drying

1. NATURAL CONVECTION
SOLAR DRIYER
By
SATHISHKUMAR G
(sathishsak111@gmail.com)

2. TOPICS TO BE DISCUSED
• Abstract
• Dehydration
• How to dry
• Temperature of drying
• Determination of dryness
• After drying
• Advantages
• Application
• Reference and Conclusion

3. ABSTRACT
• Farmers find it extremely possible to
process and preserve high moisture
content crops by normal open sun drying.

4. Dehydration
• One of the oldest methods of preserving
food
• Alternative to canning & freezing
• Simple, safe and easy to learn
• Can dry year round
• No refrigeration needed
• Takes little space

5. How Drying Preserves
• Removes moisture from food so bacteria,
yeasts & molds can’t grow and spoil food
• Slows down action of enzymes but doesn’t
inactivate them

6. Temperatures for Drying
• Optimum temperature for drying food is
140°F
• If higher temps are used, food cooks
instead of drying
• Avoid “case hardening” – dried outside
and moisture is trapped inside – mold
results

7. Drying Out-Of-Doors
• Sun Drying
– Dry fruits, high sugar & acid make them safe
– Don’t dry vegetables or jerky/meat outdoors
– Need hot, dry, breezy days
– Temp of 85ºF. or higher, for several days with
humidity below 60%
– Need to cover, watch materials used and
control for insects and pests

8. Out-Of-Doors
• Solar Drying
– Need to make a dryer
– Need to stir and turn food several times a day
– Need several days…
• Vine Drying
– Dry beans, lentils and soybeans
– Leave bean pods on vine until beans inside rattle
– If not dried can dry further in oven or dehydrator

9. Drying Fruit
• Preparing the Fruit – wash fruit and core, if
needed
• Fruits can be halved or sliced and some left
whole
• Thin, uniform, peeled slices dry fastest
• Apples can be cored and sliced - wedges, rings
• Bananas can be sliced
• If fruit dried whole, “check” or crack the skin to
speed drying – cranberries – place in boiling
then cold water to “check”

10. Drying the Fruit
• Place fruit in single layer
• Follow directions given
• Follow approximate drying times given
• Watch food as it dries much faster at the
end of drying period

11. Determining Dryness of Fruit
• Most fruit – should have 20% moisture
content when dried
• Cut several cooled pieces in half…should
be no visible moisture and should not be
able to squeeze any moisture from fruit
• Not be sticky or tacky
• If piece folded in half, shouldn’t stick to
itself

12. After Drying…
• Cool fruit 30-60 minutes before
packaging…don’t pack too soon or
moisture buildup could occur…don’t wait
too long or could pick up moisture

13. ADVANTAGES
• Low cost
• It is suitable for all drying items

14. APPLICATION
• - fruits: apples, apricots, grapes, pineapples
and banana (taste great when dried), melon,
plums, beets, mangoes, dates, figs.
• - vegetables (cabbage, broccoli, peppers,
herbs, onions, squash, tomatoes, asparagus,
celery, potatoes, peas, carrots, peppers, yams,
red cedar)
- corn, maize, rise, cassava, cocoa

15. APPLICATION
• - Fish
• - Meat
• - mushrooms (may be can be cultivated in the
dryer as well with a plastic-foil on the button)
• - spices (dried chili, peppers, garlic)
• - Medical plants
• - tea, coffee, cacao, tobacco, cashew and
macadamia, milk, hay, copra (kernel of the
coconut)

16. Samples
Ready dried spices
dried apples
Mixed dried food

17. Samples
Bread with dry-fruits, very delicious!
Muesli in the morning with dry-fruits.
Can the day begin with something better?
Storage of dried fruits

19. CONCLUSION
• When the usage of forced convection solar
drying will increase the production ,reduce
the cost , time saving , reduce the
electrical energy usages ,prevention of
health.

20. Thank you