Interactive Socio-Technical Practicum

Preservation of Perishable Agricultural Food Produces Using a Solar Food Dryer

Students: Maeghel Puri, IIT; Sachin Dhariwal, IIT; Arpit Karwasara, IIT; Prashant Mundotia, IIT.
Advisors: Dr. Tushar Jain, IIT; Dr. Dhiraj Patil, IIT; Dr. Satvasheel Powar, IIT; Professor Fabio Carrera, WPI; Professor Svetlana Nikitina, WPI.

In rural India the major population is into Agriculture, which forms a great part of the country's economy. The harvest produced has to be dried for further processing or preserving. The current methods for drying are inefficient and time consuming. We focused on un- derstanding the types of available perishable food produces, quantum of perishable food to be preserved, currently employed methods, time taken for drying, wastage due to existing methods, and so on. We then interviewed stakeholders and collected data and developed a prototype of a solar food dryer and tested it for reduction in drying time and prevention of wastage. It is a portable and very cheap device which can be scaled for larger purpose. It can also be used as a solar cooker for boiling rice or dal (pulses).

Project Outcomes

The project led us to make a prototype which can be used to solve major problems faced by the local farmers of Himachal Pradesh while drying their crops after harvesting. We made our prototype using metal sheets in order to make it cheap, light weight and foldable. In our first prototype we designed the angles of the walls in such a way that maximum heat can be received from the sun irrespective of the sun location. But the heat input we received in our first prototype was less because of poor reflection from walls due to metal sheet surface and less absorption of heat on base. In our version 2 of prototype (figure 17) we painted the base of dryer black in order to absorb more heat and covered the walls of the dryer with aluminum foil for better reflection of sunlight in the middle of the dryer. These two modifications increased the input heat and the efficiency of our dryer. To minimize heat loses from the dryer we also covered the base with the fibre glass so that minimum heat is lost from the base.

This prototype is able to protect the crops from bad weather conditions as well as factors like monkeys, cows etc. due to which every year a large portion of crops was getting damaged. The project is fully cost efficient so that a local farmer can afford to buy it and once set up it requires no additional cost to run or maintain it. The number of days taken for drying are significantly reduced by using the solar dryer instead of using open sun drying technique.

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