When we talk about refrigeration, naturally, it occurs to any Indian, in a powerstarved country like India, how we should provide the extra power that will be required to run the refrigerated plants that are essential components for any cold environment or facility (my focus is not only on cold stores, but also malls and other places where agri-products are kept long time, in its true sense). However, if we consider the fact that 40% of our agricultural produce is lost because of lack of appropriate refrigeration facilities in the country, when we look into the fact that the farmer’s suicide has increased 26% in 2014 over 2013 – definitely we all realise the need for a robust agri-cold-chain in our country. The cold chain is literally a long one that (in some cases) originates from the corn field and
ends at our dining table. However, here I am going to focus on the beneficial provisions for refrigeration within four walls only.
Now, coming back to the question of power supply: many of us already know that soon our
entire country is going to enter a new phase of metering, which is called ToD (Time of Day)
metering. A ToD meter is a device that records the time of using energy along with the amount of energy used. In many countries around the world, the power tariff is designed based on the time of the day when the power is consumed. Thus, using more power during peak load hours will cost more than using that during the off-peak hours. Also, if a consumer can produce some power at his premises – that also he may exchange during peak hours with the grid. For all these to be a reality an Advanced Metering Infrastructure (AMI) is required. In India, the first pilot AMI was installed at a small town near Chennai called Puducherry. The result is good, and by now everyone knows _ it works.
Next comes up the question: the refrigeration plant/system in a cold facility runs during 24 hours and its active hours mostly coincide with those of the peak load hours, then how to reduce the power bill?
Well, as the purpose of this article is to disseminate some of the good developments that are reality today, in the later portion of this article, I will focus on a few examples of best practices (developments) that are being followed in some countries (including India), which will address the above question.
Contextually, I would like to mention that although application of solar energy in refrigeration is no longer a new concept, it’s a pity that even being one of the most blessed countries of the world with plenty of sunlight, we are yet to exploit the full potential of the same in our country. Just to draw a reference of international progress in this field: way back in September 2011, SunDanzer Refrigeration Inc. obtained a non-exclusive license from NASA to patented battery-free solar powered refrigeration systems technology. It was originally developed by innovators at NASA’s Johnson Space Center who were investigating solar alternatives for cooling lunar bases. (Source: www.nasa.gov)
The technology can be used for a variety of purposes, including off-grid, battery-free refrigeration for food and drinks, air conditioning systems in remote locations such as field hospitals, and refrigeration of milk tankers and other transportation vehicles. By that time, SunDanzer was already using the technology to develop a battery-free solar powered refrigerator for storing vaccines and a refrigerated container for transporting food and beverages to remote military personnel.
Such provisions are very useful for our country’s rural areas, and although at a slow pace, the area of technology is drawing attention here too. Several Indian universities and research centres are also working on it.
By 2013, as part of their ‘eKOCool’ project, Coca-Cola India installed more than 1,000 solar coolers at shops in rural parts of India, where an estimated 60% of the population lacked electricity (and where those with access to the grid only had power a few hours each day). Rooftop solar panels were linked to the chest-style coolers installed inside the stores. (Source: http://www.cocacolacompany.com)
As per the company, the idea of the solar cooler was borne out of the realities of the Indian marketplace but chiefly a couple of factors (1) the need for safe hydration and packaged beverages as a safe, hydration option, when it is served chilled, and (2) the practical reality that most rural pockets in the country either have no or intermittent supply of electricity. The logistics for procuring ice, which the retailers use to chill the product, is cumbersome. Sometimes, the retailers have to fetch the ice from places as distant as 5 kms away and that too, the supply chain for ice is not reliable. Solar coolers, by harnessing sunlight, was a good solution to all this.
Describing the win-win outcome of the programme, Coca-Cola company states, the eKOCool solar cooler programme targeted expansion in rural markets. The capacity of the solar cooler was initially restricted to two cases keeping in mind the cost, available space at retail outlets and the potential for sales. The increase in sales has been such that retailers are demanding a cooler with higher capacity. The solar cooler is bringing in first time retailers who were not selling Coca-Cola products before _ as well as first time consumers who have never consumed Coca- Cola products due to unavailability of chilled beverages. The programme has thus been able to tap new rural markets for Coca-Cola. As the programme expands, the increase in sales from existing retailers and emergence of demand from rural markets will encourage new retailers to crop up and thus benefitting both _ retailers as well as Coca-Cola.
There are many references of good practices in this field, many companies are doing excellent projects throughout the world. As everything cannot be included in this small article, let me hereafter highlight a few projects from the journalistic angle, and obviously I will not go into the details of the technical sides of those _ as my purpose is just creating awareness among my community.
Refrigeration battery
Axiom Exergy Inc. is based in Berkeley, California. It is a firm equipped to deliver a cost-effective energy storage solution that meets the unique needs of individuals and organisations. Let us now see a bit of their system that is working for super stores.
In the USA, an average supermarket runs on a profit of 1.38% of total sales. But many items there need to remain cool throughout 24 hours. So, every supermarket needs a way to reduce consumption during afternoon which is the peak load time for them.
According to Axiom Energy, the refrigeration battery is a thermal energy storage retrofit for central refrigeration systems in supermarkets and other refrigerated facilities. The technology is very simple. They say, “Charge by freezing a tank of water with common additives at night, when electricity is cheap. Discharge by using the frozen tanks to provide refrigeration during peak hours, when electricity is expensive.”
The Refrigeration Battery System Integrator plugs into the central compressor racks as if it were a new refrigerated display case. It does not require physical changes or controls programming modifications to central refrigeration systems. The refrigeration battery’s thermal storage tanks are located in the warehouse or outside on a concrete pad. Their wireless sensors connect to the building’s existing electricity meter.
Rapid milk chiller
According to a case study from Promethean Power Systems – which designs and manufactures refrigeration systems for coldstorage applications in off-grid and partially electrified areas of developing countries, the collection centre in the village of Chetawala (Rajasthan, India) started operations in 1997 with 50 L of milk per day. It used to collect milk every morning and evening and dispatch it in cans to the nearest chilling point.
Over the years, milk procurement increased to 500 L per day, but that brought along many operational issues. High ambient temperatures in Rajasthan and large distances between villages, resulted in 5% milk spoilage. When the milk spoiled, collection centre had to bear the penalty.
In addition, collection vehicles had fixed time of arriving at the centre and only a few minutes to collect the milk and depart for the next centre. Such rigid schedule often led to losing out on milk delivered by distant farmers _ who could not reach in time. Moreover, erratic grid supply led to high dependence on diesel generators pushing up chilling costs. Such issues made 1000 L collection centres economically unviable to operate and less commitment of milk producers towards Jaipur Dairy. (Source: www.promethean-power.com)
Promethean installed a Rapid Milk Chiller (RMC) at Chetawala. The milk chiller can cool milk without a diesel generator at village collection centres. It can chill 1000 litres of milk per day _ even when there is no power during milk collection _ by using only 4 to 5 hours of intermittent grid power between each milking shift. By eliminating diesel, Promethean Milk Chiller (PMC) provides the most cost effective way of collecting top quality chilled milk from village milk collection centres where grid power is erratic.
Apartment building creates energy surplus
One of the six winners of the INTERSOLAR AWARD 2015 is an apartment owners building at Frankfurt’s Gutleutviertel. Their achievement shows that everything is possible through effort. If it is possible in Germany, why not in our motherland India?
The ‘Aktiv-Stadthaus’ (active house) (realised with the help of Solarnova Deutschland GmbH) generates more energy that the residents of the 75 apartments consume. Passive efficiency achieved by insulation and active electricity generation are optimally combined in this Effizienzhaus Plus (an efficient building pilot project initiated by the German government).
What makes this concept revolutionary is the fact that both the users’ energy requirements and urban integration were taken into account in the planning process. “The Aktiv-Stadthaus is a proof that the EU can achieve its 2020 energy efficiency target,” said the (Intersolar 2015) panel, explaining its reasons for presenting the project with the Intersolar AWARD 2015. (Source: http://www.intersolar.de)
Conclusion
I started with the challenge that how we can make best cold facilities (within four walls) in our power-starved country. The product and project references cited above are of selfexplanatory type, and show how some good projects or schemes are working in India and abroad. To stop loss of agri-products in our country, to increase the shelf-life of the perishable food items, to feed the nation at reasonable cost, we need to ponder on such innovative technologies and techniques.
