Solar Conduction Dryer – Boon for Dehydrating Farm Produce


Author – Aritro Ghosh


Wastage of food has become a serious issue in India. Every year, large amounts of fruits and vegetables are wasted due to lack of storage facilities in India. This particularly happens since the transportation and storage facilities from the farm gate to the consumer still remains ramshackle and most farmers do not have the resources to invest in proper storage facilities. According to a recent estimate, 20-30% of 74 million tons of fruits and 143 tons of vegetables harvested every year in India are wasted due to post-harvesting mismanagement and lack of storage facilities. Due to this post-production handling mismanagement, the shelf life of fruits and vegetables is reduced and the nutritional value of the food is lost.

Countering the problem

Vaibhav Tidke, Shital Somani and Aditya Kulkarni, three graduates from the Indian Institute of Technology, Bombay, wanted to create an easy-to-use and cheap solution to solve this problem of food wastage. They realized that while there is a need for a proper post-production of fruits and vegetables, the stifling poverty of farmers prevents them from investing in expensive food preservation technologies. Most farmers use community or government provided electric dryers, which require electricity but power cuts over 8 hours are a common feature in rural India. What Indian farmers require is a low-cost food preservation system that can function without power. This was the main motivation for these IIT Bombay students to develop an eco-friendly innovative solution named ‘Solar Conduction Dryer’ (SCD).

The Solar Conduction Dryer Idea

Solar-Conduction-Dryer-India-2The dehydration process has been used over the centuries to preserve fruits and vegetables, which not only increase their shelf life but also maintains their nutritional value. All fruits and vegetables contain large percentage of water, which is the main cause for their spoilage over time. Dehydration basically absorbs the water and moisture content from the food material, which not only prevents its perishing, but also increases its economic value. Although dehydration leads to loss of some nutritional value, but it helps in preserving food for a longer time. Most modern dehydrators use a heating mechanism that is powered by electricity. These electric dehydrators use complex heat-transfer techniques, which are expensive and difficult to maintain.

The Solar Conduction Dryer (SCD) consists of a rectangular box, which has a black surface inside and a glass lid in the top. Sliced fruits and vegetables have to be kept inside the box and the box has to be placed in the sun to begin the dehydration process. The SCD works on the principle of heat transfer through radiation and convection. When the SCD is placed in the sun, solar radiation enters the box through the glass lid and heats up the air inside the box through ultraviolet rays of the sun, which are generated once the normal sunlight passes through the glass. The rectangular box has a black surface inside, which absorbs most of the heat. This retained heat is transferred to the air inside the box through convection. Thus the heat is trapped in the air inside the box through convection and radiation, which is utilized to absorb all the moisture and dry the fruits and vegetables.


The IIT students claim that their SCD is 25% more efficient than any other conventional dryers. Since SCD uses UV radiation for heating, it saves 45% more nutritional value in the edible fruits or vegetables as compared to other conventional dryers. It also is unique since it works completely on a renewable source of energy. The SCD is especially suited for Indian rural farmers as it requires no electricity at all.

The cost of an SCD will be around INR3000-3500, which is cost effective in comparison to conventional dryers. There is an immediate payback in terms of the profits that the farmer will earn by preventing spoilage of harvest. Further, SCD’s maintenance cost of is also negligent. SCD can also be utilized to preserve other harvests like fishes and marine produce too. Thus the SCD can be a boon for rural farmers and fishermen, as they live in similar conditions in Indian villages.

Limitations of SCD

SCD has a few constraints at present – the technology that SCD works on is quite new and is not patented yet. Further, the mass production of SCD requires considerable capital investment which can be a hindrance to its mass adoption. Another drawback is the lack of knowledge of its functionality among farmers which might make maintenance of SCD difficult.

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