Cold Chain Cooling

During my first travels to India some 30 years ago, if I were to capture my initial impressions in one word, it would be “diversity” – diversity in culture, diversity in food and diversity in geography.  In recent years I have had the privilege to reacquaint myself with this wonderful country, augmenting my initial impressions with further diversity – diversity in innovative business.

Representing a Canadian company that manufactures vapour absorption chillers, my exposure to Indian business is linked to the cooling industry.  I am greatly impressed by many innovators who are developing solutions to address one of India’s greatest needs – cooling.  Today’s musings aren’t focusing on Thermalfrost’s core competency, but rather innovations I have been introduced to by Indian entrepreneurs, with an emphasis on Phase Change Materials (PCM) and their role in Thermal Energy Storage (TES).

In District Cooling plants, known benefit of TES is taking advantage of time-of-day electricity rates and the reduction of capital expenditures on equipment like chillers.  In the latter, TES can address peak cooling load allowing for chillers of lower cooling capacity to be installed.  Moreover, chillers operate at highest efficiency when providing a level cooling load spread over time, as opposed to riding the roller coaster of peaks and valleys to meet typical cooling demand.  In my observations, this feature of being able to spread the cooling load over time can have more application in India.  For example, rather than dairy farms purchasing a large chiller to rapidly cool milk twice daily, why not install a small chiller operating at a constant level mode to charge TES?   The TES can be discharged rapidly, cooling milk from 32°C to 4°C in less than 30 minutes.

Gurugram based PLUSS, a materials research company, is doing terrific work on advanced PCMs that can offer precise evaporation temperatures over a wide range of temperatures.  Changing the physical state of materials (like liquid to solid) enables a lot more energy storage for a given volume.  Water is an excellent PCM, with an evaporation temperature of 1°C.  However, for many cooling applications, a different temperature is ideal.  PLUSS can provide deep freezing PCMs suitable for many applications, including flash freezing of produce.  At the other end of the temperature spectrum, sometimes higher temperatures are desired, like in the case of milk, or sometimes fruit at 12°C or 18°C.  In addition to regulating temperatures at the desired level, TES in PCMs with higher phase change temperatures than water can raise the efficiency of chillers because instead of expending the energy to freeze water, they can change the physical state of a material (“freeze”) at a higher, less demanding temperature.

I have had the privilege of visiting many farms across India and have been treated to organically grown vegetables immediately upon harvest – the freshness is palpable.  I have learned the most important stage in the food cold chain is the immediate four hours upon harvest.  For smaller farms, it is impractical and not economical to install a chiller on site, especially if electricity is unavailable or unreliable.  Is this a potential application for TES?  Companies like Pune based Absolute Cold and Global Cold Chain Solutions in Ahmedabad, make TES boxes of various sizes that can hold precise temperatures for long lengths of time.  Commonly these boxes are used in the pharmaceutical industry to transport goods in a controlled environment. Might this be an economical solution for refrigerating produce immediately upon harvest? Farmers can store their harvest in these boxes, and when they take their produce to the local mandi might they fetch a better price?  I see an opportunity for entrepreneurs who can supply farmers with these boxes and every time they return to the mandi with produce, removable PCM cartridges can be swapped with newly charged ones and the farmer can repeat the cycle. The business model can be flexible, and with increased quality in terms of the freshness of the produce, I see plenty of potential margins for mutually beneficial operations.  Additionally, if a suitable buyer is unavailable, might the same entrepreneur be able to cold store the produce for sale on a future day?  The same chillers used to charge the PCM cartridges, can be used to provide cold storage until a suitable buyer arrives, preserving the food cold chain.  For refrigerated transport of the food from mandi cold storage to larger scale more centralized cold storage, PCM Trucks, like those used by Pune based Promethean can be used.  These innovative trucks don’t require a diesel consuming compressor on-board and can move the food long distances.  There is no concern for chiller mechanical failure, not uncommon for journeys on long bumpy roads.

An important aspect behind these thoughts is the importance of TES for successful and efficient implementation of renewable energy.  Pune based Ecozen have developed portable cold storage rooms driven by solar energy – charging in the daytime and able to keep produce fresh 24/7. Mysuru based Implantaire as well as Physiz from Mumbai, are investigating different PCMs that can be used for similar cold storage and providing cooling for controlled environment agriculture.  For solar thermal, or other heat sources, Physiz is implementing control systems to manage interoperability between thermal chillers, TES, and various heat sources for diverse cooling applications.  One such heat source is waste heat harnessed from the process of biomass power generation.  In conjunction with Punjab Renewable Energy Services Private Ltd. (“PRESPL”), and Thermalfrost, Physiz is implementing a control system to manage the interoperability between PRESPL and Thermalfrost equipment with various cooling environments, including District Cooling and Cold Storage.  By collecting crop stubble which in the past would have been burned in open fields polluting our air, PRESPL is turning this negative into a positive by controlling this burn to generate power.  This “green” initiative will be enhanced by making more use of the generated heat to produce cooling.  As these biomass plants get more portable for distributed applications, like a mini biomass plant being developed by Sersa based Nano-Bio Graphite, the need for TES becomes even more important.

To continue with the idea of PCM boxes in which farmers bring their produce to the mandi, I believe a real business and environmental argument can be made for new cold rooms, that also charge the PCMs to return to the farmer, to be operated with chillers driven by renewable energy.  Whether it is at a mandi, or another community/co-op based location, imagine solar or crop stubble being used to generate electricity with the waste heat used to provide cooling, reducing food spoilage and improving its quality.  Is there a better path to doubling farmer’s income by 2022!

An underlying benefit to creating frameworks that take advantage of TES is the obvious impact on reductions in air pollution and GHG emissions, both directly and indirectly.  Just the GHG emissions associated with replacing the global food supply lost to spoilage due to a lack of refrigeration exceeds the total emissions of the largest emitting countries in the world.  Directly, facilitating the use of renewables reduces our dependence on fossil fuels and GHG emissions associated with our electricity grids.  Perhaps most importantly, as an enabler for renewable energies, TES makes distributed energy more feasible.  When we generate power, most of the consumed energy is lost in the form of waste heat.  When power is generated centrally, finding a purpose for this waste heat is difficult.  Distributing power generation to points in proximity to where it is being used (our communities, schools, hospitals, and industrial parks) facilitates combined heat and power, enabling us to make use of this waste heat, decreasing electrical consumption and raising efficiency.

As we all rethink what our new world will be like post-pandemic, the distributed models, like working from home or our energy solutions, make even more sense! With its richness in diversity, including innovative leading-edge businesses, I believe India is well positioned for this new world.

Steven Donaldson
Steven Donaldson
President, Thermalfrost Intl. Inc.
Innovators in Thermal Cooling.