Ice machines work by passing water through an evaporator and making it into ice. Depending on the principle of the evaporator and the production method, the shape of the ice produced varies and ice machines are generally classified by their shape as pellet ice machines, flake ice machines, plate ice machines, tube ice machines, shell ice machines and so on. The efficiency of ice machines in cold and tropical regions is very different. Tropical areas are much less efficient than colder areas due to the higher ambient temperatures. It is generally not recommended to use ice machines when the ambient temperature exceeds 38 degrees Celsius.