The Amazing Milk Chiller

When the United Nations (UN) made the sustainable development goals to finish what we started with the Millennium Development Goals, they knew it would be no easy feat. One of the most challenging goals would be to end world hunger by 2030 because 690 million people go to bed hungry each night! Our problem lies mainly in Asian and African continents, primarily countries like India, South Sudan, Syria, Yemen, Ethiopia, Afghanistan, and Madagascar. According to the World Food Program, 135 million suffer from acute hunger because of conflicts, climate change, and economic downturns. The COVID-19 pandemic has further aggravated this situation.

India is the largest producer and consumer of milk in the whole world! Approximately 180 million metric tons (MT) of milk are produced annually by India's rural farmers. Sadly, 30% of this is wasted because of improper storage systems and the inability to reach markets on time. So how do we solve this?

When Soren Grama, a man with a passion for engineering, graduated with a master’s degree in engineering and management from the Massachusetts Institute of Technology (MIT) in 2007, he co-founded 'Prometheus Power Systems' (PPS) with his partner Sam White, who had a marketing and business development background. Grama and his partner first started developing a solar-powered cooling system for milk intended to use in India. When Grama and his team moved to India and consulted the local farmers, they realized their product was bulky and not cost-effective. As a result, it would not fit their purpose. After consulting the local users and trial and error, they changed their design for a thermal battery and used local materials. Grama was the principal inventor of PPS's thermal battery: Rapid Milk Chiller (RMC). This energy storage device instantly cools milk from 35 degrees Celsius to 4 degrees Celsius without a diesel generator! The system can cool 1000 liters of milk a day.

The thermal battery is a tank that stores energy and then discharges it to cool the milk. The system is ideal for rural areas where the grid power is erratic. When available, the battery draws electricity from the grid, stores it, and releases it rapidly to chill the milk. How cool is that! Dairy farmers in rural India, where grid power is not reliable, were facing the problem of keeping the milk fresh until transported to the markets. Milk can effectively be kept fresh for about four hours before it goes rancid, especially in tropical climates like India. Grama and White's RMC have changed all of that. Indian milk farmers in several states of India are now using this cost-effective chiller to chill their milk at village collection centers before the milk is distributed, thus eliminating the waste of spoiled milk. The use of this system has spread now to countries like Tanzania, Sri Lanka, and Bangladesh. The company is said to be improving the product to include two batteries and improving their design to work on solar power!

Farmers manage crops and reach markets quickly using modern technology in more advanced countries. They have access to detailed weather forecasts, computerized systems, intelligent and efficient farm machinery, drip irrigation systems, advanced storage systems, access to markets by improved infrastructure, and timely market information through digital media technology. In less developed countries, satellites, the internet, and smartphones have helped farmers, too. The facts above illustrate how engineers have already helped us solve a fraction of world hunger and can soon help us eliminate it. Furthermore, engineers have a big part to play to attain sustainable development goals and are here to stay! As Van Gogh said, "Great things are done by a series of small things brought together." Therefore, it is not just engineers; we must all do our part and work together for something as big as the sustainable development goals!