HVAC (heating, ventilating/, plus air conditioning) is the technology of indoor and vehicular environmental relieve. Its objective is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the values of thermodynamics, fluid mechanics, and heat transfer. Refrigeration is sometimes added to the field’s contraction as HVAC&R or HVACR, or ventilating is dropped as in HACR (such as the term of HACR-rated circuit breakers).
HVAC is an significant part of residential structures such as single family houses, apartment buildings, hotels and senior living services, medium to large industrial and office buildings like skyscrapers and hospitals, onboard vessels, and in marine backgrounds, where safe and healthy building conditions are regulated by respect to temperature and humidity, using clean air from outdoors.
Ventilating or ventilation (the V in HVAC) is the procedure of exchanging or replacing air in any space to provide high indoor air quality which involves temperature manage, oxygen replenishment, and elimination of moisture, odors, smoke, heat, dust, airborne bacteria, carbon dioxide, and other gases. Ventilation take away unpleasant smells and excessive moisture, introduces outside air, keeps interior house air circulating, and prevents stagnation of the interior air.
Ventilation includes both the exchange of air to the exterior as well as circulation of air within the building. It is one of the most important factors for maintaining acceptable indoor air value in buildings. Methods for ventilating a building may be divided into mechanical/forces and ordinary types.
The three central functions of heating, ventilation, and air conditioning are interrelated, especially with the required to provide thermal comfort and acceptable indoor air quality within reasonable installation, operation, and maintenance cost. HVAC systems may provide ventilation, reduce air infiltration, and maintain pressure relations between spaces. The means of air release and removal from spaces is known as room air distribution.
In modern house the design, installation, and control systems of these functions are integrated into one or more HVAC systems. For very little buildings, contractors normally estimate the capacity, engineer, and select HVAC systems and gear. For bigger buildings, building service designers, mechanical engineers, or building services engineers analyze, design, and specify the HVAC systems. Field mechanical contractors then fabricate and commission the systems. Building allows and code-compliance examinations of the installations are normally required for all sizes of structure.
Although HVAC is executed in person buildings or other enclosed spaces (like NORAD’s underground headquarters), the equipment concerned is in some cases and extension of a larger district heating (DH) or district cooling (DC) network, or a joint DHC network. In such cases, the operating and preservation aspects are simplified and metering becomes essential to bill for the energy that is consumed, and in several cases energy that is returned to the bigger system. For example, at a set time one building may be utilizing chilled water for air conditioning and the warm water it returns might be used in another building for heating, or for the generally heating-portion of the DHC network.