Ugandan Dairy Farmers Get Help from RE

Ugandan dairy farmers will receive help from a renewable energy technology that will allow them to cool their stocks of milk. Without this new technology, the farmers would otherwise see their profits depreciate when the dairy product spoils from insufficient refrigeration needed to keep the temperature stable, ultimately caused by a lack of steady electricity supply in many developing countries in Africa and globally. The country’s government estimates that there are 2.5 million small dairy farmers in Uganda, which supply 75% of the the local market with milk.

Ugandan engineer William Kisaalita, a professor of biological and agricultural engineering at the University of Georgia in the US, has expanded on the CoolSystem beer cooler to meet the needs of dairy farmers in the East African country.

Kisaalita told VOA news that his remodeled cooler uses a mineral called zeolite – a natural, volcanic, rock-like substance with a "micro-porous structure" that’s mined in various parts of the world, including the United States. Zeolite has a remarkable capacity to absorb water.

Kisaalita explains, "The idea is that you…expose water adjacent to the container containing milk to (a) low vacuum, through a valve, and because of that, the water vaporizes. When the water vaporizes it (removes) the heat from the milk. Then you have the zeolite absorbing the water vapor, so that the vacuum and the vaporization continue. The principle is what is very well known as evaporative cooling. But this…has been configured so that we can achieve very high temperature drops, or temperature cooling."

He explains that the system has to be regenerated to enable it to cool the milk repeatedly.

"The way this product is configured is that if you go through a cooling cycle, you can’t cool again, because the zeolite I talked about would be full of water," Kisaalita comments. "So the system has to be regenerated, and the way it’s regenerated is by heating the zeolite, so that the zeolite can lose the water."

Kisaalita continues, saying that this essential regeneration will happen by means of renewable energy, namely biogas as the waste from cattle.

"There are a number of other countries outside sub-Saharan Africa that have similar (milk cooling) problems. So there is this sense that if we succeed in sub-Saharan Africa, there will be others – like Vietnam or Colombia – that would be interested in the product," Kisaalita said.