Full form of HVAC is Heating Ventilation and Air
Conditioning.
HVAC can stand for a climate-control mechanism for providing thermal comfort and acceptable indoor air quality and regulate the humidity and temperature in a living environment.
It is a sub-discipline of mechanical engineering,
based on the principles of thermodynamics, fluid mechanics, heat transfer and
sometimes refrigeration and air conditioning.
This technology is used for indoor and vehicular
environmental comfort. Its goal is to provide thermal comfort and
acceptable indoor air quality.
There are three types of setting done
in HVAC :
Full Heat Setting :
Maximum airflow is directed through the heater core by the
blend door to deliver the most heat possible to the main upper vents.
So in this setting operator has demanded full heat.
Economy
Mode Setting :
Maximum
airflow is directed around the heater core to allow filtered air at ambient
temperature to enter the cabin through the main upper vents.
Max A/C Setting :
In this setting, the HVAC system takes air from the cabin that
has already been cooled once and cools it again instead of trying to cool hot
ambient air.
To get the most cooling power in this setting the operator
has selected max A/C.