Updated on January 30, 2024


Created on June 12, 2014

Thermogenn Cooler (EvaKuula)

Upcoming Update

The EvaKuula is a milk cooler for small dairy farmers with no access to grid electricity, that can cool milk to 4-6 °C for 12 hours.

Tested By
  • Smallholder fortunes and Thermogenn
Content Partners


Product Description

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.

Target SDGs

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

Competitive Landscape

Manufacturing/Building Method

This product is currently in the prototyping phase and not yet manufactured at scale.

Intellectural Property Type

Select 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)

80 L

Time to cool (hr)

3-4 hrs

Cooling retention (hr)

12 hrs

Temperature control


Minimum internal temperature (°C)


Materials of construction

Stainless Steel, charcoal

Protection from insect entry


Refrigeration cycle catalyst

Propane, biogas

Design Specifications

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.

Product Schematics

Technical Support


Replacement Components




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

Other Information

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

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