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Hand-powered cooler developed by students

By Sharon Omahen
University of Georgia

University of Georgia engineering students have developed a cooling system that could help farmers in developing countries get more milk to the market.

"Small dairy farmers in countries like Uganda and Kenya are literally throwing away half of their milk because they don't have the means to get it to market," said William Kisaalita, an engineering professor with the UGA College of Agricultural and Environmental Sciences.

No more wasted milk

"The prototype cooling system our students developed," he said, "would allow them to cool their evening milk and double their production."

Using funds from a U.S. Department of Agriculture Challenge Grant and the Engineering Information Foundation, Kisaalita has led classes of cross-disciplinary student teams for the past two years. During the spring-semester class, the students work on projects like the milk cooling system.

"First I identify a problem overseas that affects a large population," he said. "Then the capstone-class students work as a team to solve the problem."

In this case, the problem affects small dairy farmers in Uganda, Kenya, Tanzania, Zambia and Malawi. In Uganda alone, more than 2 million farmers could benefit from the cooling system, Kisaalita said.

"The problems farmers face in cooling their milk is very well known in these countries," said Kisaalita, a native of Uganda.

Small dairy farmers there milk their cows in the mornings shortly before the milk buyer picks it up. The problem is with the evening milkings.

"The farmers' evening milk isn't picked up, and they have no way of keeping it cool until the buyer comes back the next morning," Kisaalita said. "These farmers are losing half of their production."

Hand-driven, vaccum cooled

As a solution, Kisaalita and his students developed a vacuum-driven cooling system. It's hand-driven, and ice created under vacuum cools the milk.

"We took the traditional, large, metal milk containers and built a second container that wraps around it," he said. "Then the vacuum is used to create ice that lowers the milk's temperature."

So far, the system has lowered the milk's temperature by 5 degrees centigrade and kept it there for 10 hours, he said.

"The milk comes out of the cow at 37 degrees C," he said. "If we can drop it to 4 to 8 and keep it there, that would be a fantastic feat."

The cooling system still has some kinks. "It hasn't worked perfectly yet, but we're working on it," Kisaalita said. "It should take another year or two to make all the improvements we need to make."

Unit would quickly pay for itself

Once completed, the cooling system should cost around $800. Kisaalita says the system would pay for itself through increased production in eight months to a year.

"If a farmer couldn't afford a unit on his own, he could partner with two or three nearby farmers and they could share the cost," he said. "Or there are milk buyers who are willing to lend the farmer the money to buy the system. Then the farmer pays the money back in milk."

Kisaalita says the UGA project has attracted interest from both Heifer International and Land O' Lakes, Inc.

"These groups are very supportive of the project and have voiced interest in helping fund future work," Kisaalita said. "And the farmers I have spoken with are eager for us to finish. They say they wish we had it ready for them now."

Besides its use with milk, Kisaalita sees other applications for the cooling system.

"It could be used to carry perishable vaccines into villages," he said. "And there are vendors who would like to use it to cool fresh fruit juices."

In the United States, the system has much more competition.

"We haven't found a market for it here because there are many more economical options," he said. "But I could see a special interest group, such as people who like to conserve energy, being attracted to it."

(Sharon Omahen is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.)

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