Heating, Ventilation, and Air Conditioning (HVAC) refers to the systems or related equipment responsible for heating, ventilation, and air conditioning in indoor or vehicle interiors. The design of HVAC systems applies thermodynamics, fluid mechanics, and fluid machinery, making it an important branch of mechanical engineering. Its purpose is to create an indoor artificial environment beneficial to human survival.
Sometimes, the abbreviation HVAC is changed by adding "R" for refrigeration, becoming HVAC&R or HVACR. Alternatively, adding "R" and subtracting "V" for ventilation results in HACR.
HVAC systems control air temperature and humidity, improving indoor comfort and are a crucial component of medium to large-sized industrial or office buildings (such as skyscrapers). HVAC plays a vital role in the pharmaceutical, electronics, mission-critical facilities, and oil and gas industries.