Fuel cells and thermal batteries power refrigeration

Refrigeration has a key role to play in the transportation of perishable goods. Implementing effective refrigeration schemes in developing (and hot) countries like India presents particular challenges, but even in developed countries, where refrigeration is taken for granted, there is always room for improvement.

Speaking earlier this month at NIWeek, Sorin Grama, president of Promethean Power, explained that in India, refrigeration problems begin before perishable goods get near a truck that can take them to the point of consumption. In India, he said, $10 billion worth of perishable foods go to waste because of a lack of refrigeration along the supply chain.

Electricity is unreliable he said, with rural areas lucky to get 10 to 15 hours of service per day. Individuals and families learn to cope, but it presents significant difficulties for businesses, especially ones like dairies that deal with perishable items such as milk—a commodity of significant nutritional and cultural importance in India.

His company, he said, started up in 2007 to address the $10 billion in annual losses. The company, he said, conducted market studies and field trials to get a handle on the problem. India, he said, has hundreds of millions of individual farmers in remote areas who might have one or two cows that produce 5 or 10 l of milk per day. Typically, 30 to 40 farmers near the village will bring the milk twice per day to a collection center near their homes, where it will be trucked twice per day to a chilling center.

Twice per day trucking imposes high transportation costs, and the 5-hr. spoilage time limits trucks' ability to reach areas distant from the chilling center. The few villages with chilling capabilities, because of the regular power outages, tend to use diesel generators, which impose high capital and operating costs while creating noise and pollution.

Promethean Power's solution was to build a thermal-battery-powered refrigeration system to cool and store raw milk at the villages where the milk is produced, which cuts both transportation and chilling costs for dairy farmers. The thermal batteries could be “charged” when electricity becomes available. The system employs the NI Single-Board RIO platform and the LabVIEW Real-Time Module for control and data logging—the latter being important for food safety validation.

You can see Grama's NIWeek presentation here or read more about the application here.

Even in the U.S., where refrigeration is taken for granted, there is always room for improvement. To that end, researchers at the U.S. Department of Energy's Pacific Northwest National Laboratory are overseeing a project in which tractor trailers whose refrigeration units are powered by fuel cells will deliver perishable foods to grocery merchants in Texas, California and New York.

“This is a great application for a fuel cell,” said Kriston Brooks, the PNNL researcher leading the project. “A trailer refrigeration unit traditionally is powered by a small diesel engine or electric motor that drives compressors to provide cooling to the cargo. A fuel cell can potentially provide a clean, quiet and efficient alternative by powering the electric motor.”

As part of the project, Two fuel-cell manufacturers, Massachusetts-based Nuvera and Albany, NY-based Plug Power Inc., will each receive $650,000 from the DOE's Office of Energy Efficiency and Renewable Energy.

Estimates are that the fuel cells will save 10 gallons of fuel per day per unit.