Inducting zero energy cool chambers in Meghalaya

By K.N. Kumar

Losses due to spoilage of fresh horticultural produce between harvest and market can be as high as 30%. Post-harvest losses depend upon the season, distance to the markets, condition of the roads and the nature of the commodity. Leafy vegetables like Spinach perish faster than layered vegetables like Cabbage. A farmer from South-West Khasi Hills district may be worse off than a farmer from Mawphlang if they both desire to sell their produce at the Shillong market. So how can a farmer minimize his post-harvest losses is one question that has been an evading answer in our state for long.
Cold storage prolongs the life of fresh produce, but the available technologies being costly and energy-intensive, farmers can neither mobilize the capital nor afford the maintenance costs of such units. Uninterrupted supply of power is a sine qua non for these units, but erratic power in rural areas is usually a deterrent. Solar-based cold-storage technologies are still not sufficiently commercialized, and the private sector is hesitant to step in because the scale of the operations, and the volumes are still uncertain. Cooperatives or FPCs may, if prodded, venture into establishing cold storage units, but we are aware that they are not primed yet for such investments in Meghalaya. So, what is the way forward? Even when we are confident that cold storage units, if set up at the household level, can prevent anything between 20-30% of a farmers’ loss, it has to be conceded that our search for low-cost technologies has not been successful. So far, that is!
We now have a ray of hope in the Zero Energy Cool Chambers (ZECC) about which technology I want to highlight in this article. The ZECC technology, developed by the Indian Agricultural Research Institute, New Delhi and customized by the Assam Agriculture University, Jorhat, has been in existence in the country for a while, though it has not yet reached out to our farmers for whatever reasons.
It is now clear that we should only explore low-cost and decentralized solutions that are easy to set up by the farmer himself. The technology should not be capital intensive, nor should it burn up energy but must still give a reasonable storage time. These criteria fit the ZECC model that functions on the thermodynamics principle of passive evaporative cooling without any external energy – electrical or mechanical. Evaporative cooling occurs when dry air passes across any wet surface. The ZECC is a semi-underground chamber of brick, mortar, and sand. It is a double-layered structure about five feet long and four feet wide. The height may vary depending on the local situation, but it is usually about 2.5 feet high. The cavity between the two layers is filled with sand, and the chamber walls are soaked in water from an overhead tank. The bricks and sand absorb water that evaporates slowly and lowers the temperature within the chamber. The ZECCs can bring down the temperature by 10-15 degrees C and maintain about 90% Relative Humidity. The faster the evaporation, the greater is the cooling. It is an environmentally sustainable model because it uses local construction materials. In sum, it fits the farmers’ requirements in that it can store up to 200 Kgs. of the fresh farm produce at a time and can be easily set up with a cost of about Rs.10,000/-.
So, the Farmers’ Commission decided to pilot this technology through the KVK, at Nongshillong, in the erstwhile Mairang sub-division, with a specific mandate to facilitate the construction of 100 ZECCs in the farmers’ fields. The approved construction cost was Rs.10,000/- per unit, of which the farmer’s contribution was limited to Rs.2.000/-. As I write this article, sixty ZECCs have already been constructed by the farmers and are being used. The balance work of forty ZECCs will be completed by the end of January 2022. Seeing the utility of these ZECCs, the Squash farmers of the South-West Khasi Hills district have approached the Commission for one hundred more such ZECCs in their district. Squash, as we know, is highly vulnerable to market price fluctuations, with the prices ranging from Rs.2/- per Kg. to Rs.25/- per Kg, depending upon the season. And the South -West Khasi Hills farmers are heavily dependent upon Squash cultivation, so they will stand to gain immensely if they can arrest the perishability even by three to four weeks. By the accounts of the farmers, the quality of the vegetables, even of flowers is retained, and better price realization is taking place. So far, so good!
Since the farmer feedback is encouraging, the Commission intends to deepen its involvement with this technology. The studies indicate that Potatoes can be stored for 90 days in a ZECC while at room temperature; the shelf life of potatoes is 46 days. Likewise, tomatoes stay well-preserved in ZECC for 15 days while they spoil within seven days at room temperature. At times of distress sale, even a two-week extension in the storage time could be a lifesaver for the farmer. The ZECCs can store up to 200 Kgs. ZECC capacity can go up to one tonne or more, depending upon the quantum of the produce and the affordability of the farmer; however, the Commission wants to limit its support to 200 Kg structures for the present.
Meanwhile, just for academic curiosity, let us do a simple math – one hundred ZECCs store 20 tonnes of Squash for an extra two-week period. I am assuming that the price difference between the distress sale and average sale is about Rs.4/- per Kg. If so, just one hundred ZECCs would have helped the farmers get an additional income of Rs.80,000/- per cycle. There could be at least three such cycles during a squash season. That would mean an additional income of Rs. 2.4 lakhs. We can install at least one lakh ZECCs in the state over the next two years (very much possible), which will amount to an additional gross income of Rs.24 crore per season to one lakh farmers. If we include other perishable items like Tomato and commercial flowers, the savings could be even higher. In fact, the practical applications can be so many that the benefits are incalculable.
It is time for the Department of Agriculture and Farmers’ Welfare to conceptualize a scheme for inducting the ZECCs in Meghalaya. Apart from the farmer who may construct a ZECC in his backyard, a string of commercial-sized cool chambers can also be constructed in the wholesale markets. Further improvements could be made to reduce the cost and enhance the storage time. The ZECCs may also be useful for mushroom cultivation, something we will have to experiment further with. I request the scientific community of the ICAR to look at this technology afresh and find a way to enhance the storage time. I will also seek private participation in widening the reach of the technology to all the villages and farmer households of the state. It is a commercial possibility better left for young entrepreneurs of the state.
(The writer is Chairman, Meghalaya Farmers’ (Empowerment) Commission)


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