A solar dryer

Introduction
Meaning
Classification
Need for solar dryer
Pictures
Principles
Advantages
Working of solar dryer
Improvements'
Limitations

1. A Solar Dryer Under the guidance of : SUNDAR B N Asst.Prof.and Course Co-ordinator GFGCW , PG Studies in Commerce Holenarasipura Presented by : PREETHI Y R 1 st M. Com

2. Content : Introduction Meaning Classification Need of Solar Dryer Solar Dryer pictures (for examples) Principle of Solar Dryer Advantages of Solar Dryer Working of Solar Dryer Improvements/Advancement in Solar Dryer (with Cost estimation) Limitation of Solar Dryer

3. Introduction: Solar Dryers are devices that use Solar energy to dry substances, especially food . Solar Dryers are used to eliminate the moisture content from crops , vegetable's , and fruits . The solar dryer consists of a box made up of easily available and cheap material like cement , galvanized iron, brick and plywood . The top surface of the dryer is covered by transparent single and double- layered sheets.

4. Meaning: Solar Dryers are devices that use Solar energy to dry substances , especially food. Solar Dryers use the heat from sun to remove the moisture content of food substances. Classification of solar Dryers: There are two general types of solar Dryers: 1. Direct 2. Indirect

5. Direct solar Dryers: Direct solar Dryers expose the substance to be dehydrated to direct sunlight . They have a black absorbing surface which collects the light and converts it to heat; the substance to be dried is placed directly on this surface . These driver’s May have enclosures glass covers and/or vents to in order to increase efficiency.

6. Indirect solar Dryers: In indirect solar Dryers, the black surface heat’s incoming air, rather than directly heating the substance to be dried. This heated air is then passed over the substance and exits through a chimney, taking moisture from the substance with it.

7. What is the need of solar Dryers: In rainy season and winters due to presence of moisture a foul smell develops in food grains and there is full possibility of development of pests. It can also be used as filter. It make up rid of spreading food grains which was required earlier at regular period of time . Drying in the direct Sun has the risk of damaging the complete harvest by rainfall . Dehydration of fruits, potatoes , onions and other vegetable's. Seasoning of wood and timber.

8. Solar Dryers:

9. Principle of solar Dryers: Our solar Dryer is based on two principles : Conservation of energy in which one from of energy is covered into other form of energy. Black body which absorbs the heat of the incident sunlight and makes the temperature of chamber more than the surrounding temperature.

10. Advantages: Protection of rain. Protection of pollution by dust etc .. Protection of the wind which can blow away the food. Much less time is required for drying as compared to direct drying because of black body . Protection of the drying products from insects but, also from bird’s , dog’s, especially for drying meat and fish. The product is hygienic because micro-organisms, insects and flies are killed.

11. Fruits solar Dryers :

12. Vegitables solar Dryers :

13. Working of solar Dryers: Sunlight falls on whole apparatus . Solar energy is converted into electric energy by solar panel and this electrical energy is converted into mechanical energy by electric motor which rotates the rod. (Conservation of Energy) Wooden chamber absorbs the sunlight and generates the heat and after some time inner temperature becomes much larger than the outer temperature. Covering glass restrict the flow of heat outside. (Black Body) It can also be used as filter by which dirt , sand, mustard seeds can be removed and can be collected in a plastic box below .

14. Improvement / Advancement in Solar Dryer : Solar panel can be censored to the movement of Sun as Sunflower so that. Automatic refilling of container. The electrical energy produced by solar panel can be stored in a battery which can be used when sunlight is not available. Temperature censor can be used which can control over heating of food grains.

15. Construction of solar Dryer: Solar panel : 12volt and watt Electric motor : 150 rpm Black absorbing wooden chamber Glass cover : traps the heat generated and act as insulator Electric bulb(denoting sun ) : 200 watt Plastic container : To collect sand , pebbles, impurities .

16. Cost Estimation : 80 ft. Length 26 ft. Width Total 2080 sq. ft. 95 rs. For 1 sq. ft.

17. Limitations of solar Dryer: Not working at Night. Efficiency decreases to alarge extent on cloudy days. Over heating may occur if regular attention is not paid. Due to over heating it can decrease the quality of food . Change in taste and flavour of food may occur if regular monitoring is not done. We cannot get the accurate amount of sun rays and heat .

18. Develop a passion for learning if you do,you will never cease to grow - PREETHI Y.R