HVAC:
Heating, ventilation, and air conditioning
Heating, Ventilating, and Air Conditioning (HVAC) equipment perform heating and/or cooling for residential, commercial or industrial buildings. The HVAC system may also be responsible for providing fresh outdoor air to dilute interior airborne contaminants such as odors from occupants, volatile organic compounds (VOC’s) emitted from interior furnishings, chemicals used for cleaning, etc. A properly designed system will provide a comfortable indoor environment year round when properly maintained.
RAC
Refrigeration And Air Conditioning
An RAC air conditioner is a rectangular or square unit which is attached through a wall or in a window and only cools and/or heats a single room. The air is distributed through a vent on the front of the unit
Wrong statement about RAC, Refrigeration is the process where temperature can be removed In wide range from 30deg C to -18 deg C, it needs a bigger units and the same units are utilise to maintain the 18 deg c temp for other room is called Air conditioning.
The unit which you said is Split or window type aur conditioner. Alwys read about the things before posting