Development of a Technology Solution for Cooling of Milk by Biogas in Farms

This article describes the adaptation process from milk cooling machines powered by electricity to cooling machines powered by biogas. Modifications to manufacturer's cooling machines included the combustion engine ignition system, the replacement of electric compressors by mechanical ones, and the electrical and control systems. Once the changes were implemented, a series of laboratory tests were performed. The tests covered the following parameters: speed (°C/h), cooling time (hours), biogas consumption (m3/hour) and cooling system efficiency. Minimum differences were obtained when the manufacturer's parameters were compared to the laboratory tests results. The field validation was done from May to October 2018. Two machines were installed in one farm in Jinotega and the other one in a farm in Matagalpa. Currently, two of them are fully operating. Average values of the final results (combining laboratory and field results) were: Cooling Time 2.59 hours, Cooling Speed of 11.62 °C/h, Biogas Consumption rate of 1.6 m3/h, and an efficiency of 33%. These results allow to conclude that the use of adapted cooling machines fueled with biogas in farms is a feasible technical solution. It is estimated that the investment recovery for this project is two years.