Milk cooling tanks primarily utilize compressor-based refrigeration: the refrigerant (typically Freon or an eco-friendly alternative) is compressed into a high-temperature, high-pressure gas and then releases heat through the condenser to become a high-pressure liquid; after passing through a throttling device to reduce pressure, it enters the evaporator, where it absorbs heat from the milk, thereby lowering the milk's temperature.

Finally, the low-temperature, low-pressure refrigerant gas is drawn back into the compressor to repeat the cycle.