What is air water system?
Also know, what is an all air system?
All-Air Central Systems supply the latent and sensible cooling capacity with cold air ducted to the conditioned space. Heating is accomplished by the same airstream, either in the central system or in each zone controlled by a thermostat. The simplest all-air central system in a single duct, single zone system.
Correspondingly, what is in a HVAC system?
The main parts of the HVAC system are a heating, a ventilation, and an air-conditioning unit. Heating is most often done by a furnace or a boiler in residential buildings. It also includes a pipe system for the fluid delivering the heat, or a duct work for forced air systems.
There are a number of HVAC systems used in buildings. These systems are consolidated units and typically use water as a cooling medium and use extensive ductwork for air distribution.