Water cooled chests have a refrigeration unit which cools the water in which the bottles rest. Some water cooled chests have a small motor which circulates the cold water to provide more efficient cooling. Still other chests have a refrigeration unit which cools the air inside the chest. Some air cooled chests have fans to circulate the cold air. Instead, the thirsty customer was responsible for paying the clerk at the counter.
All upright machines are air cooled.