Heating, ventilation, and air conditioning (HVAC) is a technology of indoor and vehicular environmental comfort. Its goal is to provide thermal comfort and adequate indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics and heat transfer.
In buildings, HVAC systems are used to control temperature and humidity, usually in combination with fresh outside air ventilation. The most common type of residential HVACHVAC system is the forced-air furnace, which circulating cooled and heated air through ductwork. However, many homes use other types of heating systems as well, such as radiant heating or hydronic heating. In larger commercial buildings and high-rise office towers, central plants are often used to distribute chilled water or steam for cooling and warmth.
The three main functions of an HVAC system are to:
1) Control temperature
2) Control humidity
3) Provide acceptable indoor air quality
