HVAC
Heating, ventilation, and air conditioning is the technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a sub discipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics and heat transfer. “Refrigeration” is sometimes added to the field’s abbreviation, as HVAC & R or HVACR or “ventilation” is dropped, as in HACR (as in the designation of HACR-rated circuit breakers).