Integration of zero energy cold rooms in Meghalaya


By KN Kumar

Losses due to the deterioration of fresh horticultural products between harvest and market can reach 30%. Post-harvest losses depend on the season, distance to markets, road conditions and the nature of the product. Leafy vegetables like spinach perish faster than layered vegetables like cabbage. A farmer in South-West Khasi Hills district may be worse off than a farmer in Mawphlang if they both want to sell their produce at Shillong Market. So how can a farmer minimize post-harvest losses is a question that has long been eluded in our state.
Cold storage prolongs the shelf life of fresh produce, but the available technologies are expensive and energy intensive, so farmers cannot raise capital or bear the costs of maintaining such units. Uninterrupted power supply is a prerequisite for these units, but erratic power in rural areas is usually a deterrent. Solar energy-based cold storage technologies are still not sufficiently commercialized and the private sector is reluctant to step in as the scale of operations and volumes are still uncertain. Cooperatives or FPCs can, if prompted, venture into establishing cold storage units, but we are aware that they are not yet ready for such investments in the Meghalaya. So what is the way forward? Even when we are convinced that cold storage units, if installed at the household level, can prevent something between 20 and 30% of a farmer’s losses, it must be admitted that our search for low cost technologies does not was not successful. So far it is!
We now have a silver lining in the Zero Energy Cool Chambers (ZECC) on the technology that I want to highlight in this article. ZECC technology, developed by the Indian Agricultural Research Institute, New Delhi and customized by Assam Agricultural University, Jorhat, has been around the country for some time, although it has not yet reached our farmers for whatever reason.
It is now clear that only inexpensive and decentralized solutions should be explored, easy to implement by the farmer himself. The technology should not be capital intensive or consume energy, but should still offer a reasonable shelf life. These criteria correspond to the ZECC model which operates on the thermodynamic principle of passive evaporative cooling without any external energy – electrical or mechanical. Evaporative cooling occurs when dry air passes through a wet surface. The ZECC is a semi-underground chamber made 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 is typically around 2.5 feet tall. The cavity between the two layers is filled with sand, and the walls of the chamber are soaked in water from an aerial tank. The bricks and sand absorb the slowly evaporating water and lower the temperature inside the chamber. ZECCs can lower the temperature by 10 to 15 degrees C and maintain around 90% relative humidity. The faster the evaporation, the greater the cooling. It is an environmentally friendly model because it uses local building materials. In short, it meets the requirements of farmers in that it can store up to 200 kg. fresh from the farm at a time and can be easily put together with a cost of around Rs.10,000 / -.
Thus, the Farmers ‘Commission decided to pilot this technology through the KVK, in Nongshillong, in the former district of Mairang, with a specific mandate to facilitate the construction of 100 ZECCs in farmers’ fields. The approved construction cost was 10,000 rupees / – per unit, of which the farmer’s contribution was limited to 2,000 rupees / -. As of this writing, sixty ZECCs have already been built by farmers and are in use. Balancing work on forty ZECCs will be completed by the end of January 2022. Seeing the usefulness of these ZECCs, squash growers in the South-West Khasi Hills district approached the Commission for another hundred such ZECCs in the area. their district. As we know, squash is very vulnerable to market price fluctuations with prices ranging from Rs.2 / – per kg. at Rs. 25 / – per Kg, depending on the season. And the farmers of southwest Khasi Hills rely heavily on squash cultivation, so they stand to gain a huge amount if they can stop perishability even within three to four weeks. According to farmers’ accounts, the quality of vegetables and even flowers is maintained, and better price realization is underway. So far, so good!
As farmers’ feedback is encouraging, the Commission intends to deepen its involvement in this technology. Studies indicate that potatoes can be stored for 90 days in a ZECC at room temperature; the shelf life of potatoes is 46 days. Likewise, tomatoes keep well in ZECC for 15 days while they spoil in seven days at room temperature. In times of distress selling, even a two-week shelf-life extension could be a lifeline for the farmer. ZECCs can store up to 200 Kgs. The capacity of the ZECC can be up to one tonne or more, depending on the quantity of produce and the affordability of the farmer; however, the Commission wishes to limit its support to 200 kg structures for the time being.
Meanwhile, just for academic curiosity, let’s do a simple math – one hundred ZECCs store 20 tons of squash for an additional two weeks. I guess the price difference between distress sale and average sale is around Rs. 4 / – per kg. If this were the case, only one hundred ZECCs would have helped the farmers to obtain an additional income of Rs.80,000 / – per cycle. There could be at least three such cycles in a squash season. This would mean additional income of Rs. 2.4 lakhs. We can install at least one ZECC lakh in the state over the next two years (very possible) which will add up to Rs. 24 crore gross income per season for one lakh of farmers. If we include other perishable items like tomato and commercial flowers, the savings could be even greater. In fact, the practical applications can be so numerous that the benefits are untold.
It is time for the Department of Agriculture and Farmer Welfare to conceptualize a scheme for integrating ZECCs in Meghalaya. Besides the farmer who can build a ZECC in his garden, a series of commercial-sized cold rooms can also be built in wholesale markets. Other improvements could be made to reduce cost and increase storage time. ZECCs can also be useful for growing mushrooms, which we will need to experiment with more. I ask the ICAR scientific community to review this technology and find a way to improve storage time. I will also seek private participation to expand the reach of the technology to all villages and farming households in the state. It is a business opportunity that is best left to young entrepreneurs in the state.
(The author is chairman of the Meghalaya Farmers (Empowerment) Commission)


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