A 20 ton AC unit is a type of air conditioning system that is capable of cooling a large area or building. It is typically used in commercial and industrial applications, such as office buildings, warehouses, and factories. The unit is rated in tons, which is a measure of its cooling capacity. A 20 ton AC unit is capable of cooling up to 48,000 BTUs of heat per hour, which is equivalent to 20 tons of air conditioning. The unit is typically made up of two or more compressors, condensers, evaporators, and other components. It is important to note that the size of the unit should be matched to the size of the area or building it is intended to cool. If the unit is too small, it will not be able to cool the area adequately. On the other hand, if the unit is too large, it will waste energy and cost more to operate.