The difference between regular coffee makers and Commercial Coffee Machines is the amount of coffee that a commercial unit can make. About 50 - 100 cups of coffee are there at any time. They work on the same principle. Some commercial coffee makers have the ability to make Espresso too. These machines can get very expensive, try $10,000.00 per machine.
They take hot water pour it through a basket which contains the coffee grinds and it brews coffee. The system is not complicated. Just that it produces more coffee than a home machine. It is built much stronger than a home machine to be able to withstand the pressure of harsh handling by different personnel.
Commercial Coffee Machines produce a lot of coffee and every once in a while need cleaning to protect bacteria growth. The pots and other items have to sanitize after being handled by so many hands.