In India, roughly $10 billion USD of perishable food items spoil each year because of the poorly developed cold supply chain and unreliable energy sources in rural areas. The dairy industry is particularly vulnerable to spoilage because approximately 80 percent of animals are kept on small farms scattered across rural India. This makes collecting quality milk time consuming and costly. Farmers can experience as much as 30 percent spoilage in the hot season.
Currently, to keep milk from spoiling before it reaches the dairy plant for processing, farmers can use specialized bulk milk chillers (BMC) to keep milk cool. However, the unreliable grid electricity supply in rural India means the refrigerators must operate using diesel-powered generators, which is an undesirable solution that increases capital and operating costs. Sorin Grama and Sam White, the founders of Promethean Power Systems, recognized these challenges and set out to design a milk refrigeration system better suited for remote, rural areas.
Developing a Rapid Milk Chiller
Grama designed a rapid milk chiller (RMC) for village-level collection centers that could consistently keep milk cool until it was picked up and transported to a dairy plant or a central collection center. However, a milk cooling system is a mission-critical application that must run 24 hours per day, 365 days per year, so they supplemented the poor grid infrastructure with a thermal battery for a superior system that can operate even during extended periods of power outage (Figure 1).
A key component of the system’s design was the control system that manages the operation of the entire system. It controls a refrigeration compressor that converts the electrical power to cooling power and stores the energy as thermal energy—a specialized ice tank. This ice is later used to cool the milk during the morning and evening collection times when grid power may not be available. The control system monitors and controls all temperatures, records data for food safety validation and communicates via SMS with a central facility if there are any emergencies. Grama knew he needed to design an embedded control system to perform these tasks, yet provide a very simple operating interface for the farmers, so they used the NI Single-Board RIO platform and the LabVIEW Real-Time Module as the heart of their system.
Benefits of the Rapid Milk Chiller
Capable of chilling up to 500 liters per collection, the RMC stores cold energy in the form of a thermal battery, providing farmers with the ability to chill and store milk even when the power is out. Using the stored energy, the RMC can cool raw milk to 4 °C in a matter of seconds, arresting bacteria growth and drastically improving milk quality. The system also creates more flexibility in the supply chain by eliminating the need to route milk through costly central chilling centers, which can reduce transportation costs by up to 40 percent. Furthermore, by eliminating the use of diesel generators the system can reduce operating cost by 50 percent. With the potential to install as many as 1000 milk chillers in the next 3-5 years, each new RMC system has the potential to impact more than 30-40 farming families thereby having a direct impact on approximately 30000 dairy farmers and 1 million milk drinkers in India. This will be achieved by eliminating large amounts of milk spoilage and providing higher quality milk.
The Benefits of Working with the Planet NI Program
The founders of Promethean Power Systems wanted to work with the Planet NI program because they knew the goals of the program are to nurture innovation and assist companies developing technologies that will have a social impact. Planet NI provided hardware and software for Promethean Power Systems to use to design, prototype, and deploy its RMC. As a result of the project, Indian village collection centers can now preserve the hundreds of liters of milk collected each day. Prior to the RMC, dairy processors had to quickly transport the milk to central chilling centers, and milk often spoiled because it could not reach these centers in time. Cooling the milk at the source results in premium-quality, healthier milk that can be used for higher value products like cheese and baby formula, which positively impacts the economies of small farming villages by providing higher revenues for dairy farmers.
Promethean Power Systems designs and manufactures rural refrigeration systems for commercial cold-storage applications in off-grid and partially electrified areas of developing countries. The company’s technology helps food suppliers reliably store and preserve perishable food items—such as milk, fruits, and vegetables—without the need for expensive diesel-powered generators
By Sorin Grama, Promethean Power Systems, USA