Air handling unit (AHU): Air handling unit (AHU) is a centralized air handling system, which comes from a forced hot air heating and ventilation system with centralized equipment and distribution of heated air through air ducts. The basic centralized system is a single-zone all-air system, typically including fan, heater, cooler and filter components. The AHU here refers to a primary air return system. Its basic working process is as follows: After the fresh air from outside is mixed with part of the indoor return air, harmful substances such as dust, smoke, black smoke and particles Organic substances present in the air are filtered through a filter.
