The EvaKuula milk cooler is a prototype for small dairy farmers with no access to grid electricity. The device uses biogas to cool milk to 4-6 °C for 12 hours.
SDG 2: Zero Hunger
SDG 13: Climate Action
Market Suggested Retail Price
Target Users (Target Impact Group)
Household, Community, Small and Medium-sized Enterprises
Distributors / Implementing Organizations
Thermogenn and The University of Georgia Research Foundation
This product is currently in the prototyping phase and not yet manufactured at scale.
Intellectural Property Type
User Provision Model
Directly from designer. Prototype product
Distributions to Date Status
As of March 2018, 43 units have been deployed in Uganda.
Storage capacity (L)
Time to cool (hr)
Cooling retention (hr)
Minimum internal temperature (°C)
Materials of construction
Stainless Steel, charcoal
Protection from insect entry
Refrigeration cycle catalyst
The EvaKuula kit contains two main components: a thermization unit and an evaporative cooling unit. The evaporative cooling unit is composed of up to four milk canisters placed inside a chamber with water and an external wind-powered mechanical air extraction fan. Each milk canister can hold 20 L of milk. The walls of the chamber are lined with an insulating material such as charcoal. A biogas or propane energy source can be used to speed up cooling time.
Manufacturer Specified Performance Parameters
The designers aim for their product to cool milk to 4-6°C within 3-4 hours and to stay cool for 12 hours.
Vetted Performance Status
Biogas is primarily composed of methane and carbon dioxide, which pose safety concerns if inhaled. Other safety concerns include explosion, asphyxiation, disease, and hydrogen sulfide poisoning.
Complementary Technical Systems
The designer recommends connected the device to a biogas generator to speed up cooling times.
Academic Research and References
Kisaalita, W. S., Franklin, J., Tippie, A., Boyer, B., Faircloth, W., 2006, Comparative Feasibility Analysis of Alternative Renewable Energy Sources for Small Milk Cooling Plants of Southwestern Uganda, Agricultural Mechanization in Asia, Africa and Latin America, 37, pp. 69-75.
Kisaalita, W. S., Katimbo, A., Sempiira, E., Mugisa, D., 2018, EvaKuula Saves Ugandan Smallholder Farmers’ Evening Milk, Sustainable Energy Technologies and Assessments, 29, pp. 155-163.
Compliance with regulations
The EvaKuula met national safety standards and was approved for commercialization by the Uganda Dairy Development Authority. Interview with representative
The EvaKuula kit The EvaKuula received the American Society of Agricultural and Biological Engineers 2019 AE50 Award. This product was designed at the University of Georgia in the ENGR 4920: Engineering design project (international section, with service-learning component) course taught by William Kisaalita. This product is currently in the prototyping phase and not yet manufactured at scale. Anaerobic Digesters and Biogas Safety Biogas generator