Self-Sufficient Photovoltaic Powered Chiller for Dairy Applications

Milk spoilage is a common issue in remote dairy farms due to the unavailability of power grid. Many farmers rely on diesel engines to power their milk chillers. A sustainable approach is to replace the environmentally harmful diesel generators with solar powered chillers. Solar energy is attractive in such application because the peak cooling demand occurs at the peak solar irradiance. Solar energy can be converted to cooling through PV powered chiller or through thermally driven chillers. This concept was applied to a Modular Solar Bulk Milk Chiller (MilkPod™) which uses the solar energy to generate electricity in 6 kWp PV panels. The system cools 600 liters of milk per day as well as produces hot water for cleaning the milk tank. A detailed model was used in the design process and the system equipment were selected such that the system uses about 98% of its energy from the sun throughout the year. The effect of the solar energy utilization ratio, equipment supplied current as well as milk loading were investigated on the system performance.