HVAC

Heating, ventilation, and air conditioning systems regulate temperature, humidity, and indoor air quality in residential, commercial, and industrial buildings, and in enclosed vehicles. They are used to provide thermal comfort and to control airborne contaminants through heating, cooling, ventilation, filtration, and humidity control. HVAC system design is a subdiscipline of mechanical engineering based on the principles of thermodynamics, fluid mechanics, and heat transfer. Design considerations include energy efficiency, indoor air quality, maintenance, and environmental impact, particularly in green building projects. In building design, mechanical, electrical, and plumbing engineers may integrate HVAC systems with other building systems and use energy modeling to evaluate performance and operating costs. Refrigeration is sometimes added to the field's abbreviation as HVAC&R or HVACR, while ventilation is sometimes omitted, as in HACR.