Campus News

Professor gets $1M to design milk cooler for dairy farmers

William Kisaalita

Keeping milk safe and healthy to drink is a challenge in areas around the world without electricity. 

A UGA engineer received $1 million to continue working on a milk cooler designed to help dairy farmers, particularly those in sub-Saharan Africa, who lack access to refrigeration. 

Currently, dairy farmers may lose as much as 50 percent of their daily milk due to inadequate cooling technology. 

The milk cooler, developed by William Kisaalita, a professor of biological and mechanical engineering in the College of Engineering, uses the principle of evaporative cooling to quickly bring the temperature of milk to a safe holding temperature.

“It’s the same phenomenon that occurs when you jump into a swimming pool and then you come out on a windy day,” Kisaalita said. “If there’s water on your skin, you will feel cold. This same principle is applied in chilling the milk.”

Kisaalita recently received $1 million from the U.S. Agency for International Development in partnership with the Swedish government, Duke Energy Corp., the German government and the Overseas Private Investment Corp. Kisaalita’s was one of 12 international projects selected from 475 applications to share $13 million in funding under USAID’s Powering Agriculture: An Energy Grand Challenge for Development. The prize is awarded to projects that integrate clean energy technology into the agricultural sectors of developing countries.

“Powering Agriculture demonstrates how we can harness ingenuity and entrepreneurship to generate and scale real solutions in our fight to end extreme poverty,” said Rajiv Shah, a USAID administrator. “Joining a community of hundreds of innovators…these winning ideas prove that we can change the landscape of what is possible.”

Kisaalita developed a refrigeration unit using the principle of evaporative cooling powered by biogas. The biogas is produced through the collection of cow manure—an abundant resource on dairy farms. The milk cooler design includes a container of milk that is surrounded by water. A vacuum pump depressurizes the container and zeolite, an absorption silicate, captures the evaporating water causing the temperature inside the cooler to drop. The milk is chilled and kept fresh overnight allowing farmers to sell their milk the next day. 

Working with farmers in rural Uganda, Kisaalita will refine the design of his cooler and work with local manufacturers to bring the cooler to these farmers.

“The social, economic and environmentalbenefits to this project are interrelated and will have a rippling effect,” Kisaalita said. “The milk coolers will benefit dairy farmers by decreasing milk spoilage and increasing production and profits. Biogas, also used for lighting and cooking, will save income that otherwise would be spent on kerosene and will replace the use of charcoal and wood for cooking, which is shrinking in availability as Uganda’s forests are depleted. In addition, by extracting biogas from cow manure, greenhouse gas emission from fermenting cow dung is mitigated. Finally, there are health benefits for cooking with biogas—smoke from woody biomass causes respiratory problems for children.”

A native of Uganda, Kisaalita received his doctoral degree in chemical engineering from the University of British Columbia in Vancouver and a bachelor’s degree in mechanical engineering from Makerere University in Kampala, Uganda. Since joining the faculty at UGA in 1991, he has been involved in various research activities and international service-learning projects that have engaged undergraduate students in developing solutions to real-world problems. Along with his teaching and research responsibilities, he has served as the associate director of UGA’s Center for Undergraduate Research Opportunities and is a faculty mentor for students in the Peach State Louis Stokes Alliance for Minority Participation.