difference between air conditioner and central air conditioner

How does an air conditioner work?

An air conditioner transfers heat from the inside of a building, where it is not wanted, to the outside. Refrigerant in the system absorbs the excess heat and is pumped through a closed system of piping to an outside coil. A fan blows outside air over the hot coil, transferring heat from the refrigerant to the outdoor air.  Because the heat is removed from the indoor air, the indoor area is cooled.

 How does an central air conditioner work?

Central air conditioners have two separate components: the condenser and the evaporator. The condenser unit is usually located outside the house on a concrete slab. The evaporator coil is mounted in the plenum or main duct junction above the furnace.

Most central air conditioners are connected to a home's forced-air distribution system. Thus, the same motor, blower, and ductwork used for heating are used to distribute cool air from the air conditioning system. When a central air conditioner is operating, hot air inside the house flows to the furnace through the return-air duct. The hot air is moved by the blower across the cooled evaporator coil in the plenum and is then delivered through ducts to cool the house. When the air conditioner works but the house doesn't cool, the problem is probably in the distribution system.