Thermal zones in building design
In the design of heating ventilation and air conditioning systems (HVAC), a ‘zone’ is an area of a building in which temperature is controlled by one thermostat. This is not the same as a single space or room. For example, a small house, in which thermal demand is relatively constant throughout, might be controlled by a single thermostat and so considered a single zone.
In a more complex, larger building where there may be significant differences in thermal demand, there may be multiple zones.
In simple buildings, a single zone might be supplied by a single boiler, or air handling unit. In more complex buildings with varying demands, multiple zones might be supplied by a single central HVAC system, but each zone might correspond to a single terminal unit that provides local thermostatic control.
Carefully designed zoning can help rationalise different thermal demands and so reduce the number of HVAC subsystems required. This can reduce capital and operational costs. It is important that this is considered as an integral part of the concept design stage and that HVAC is not simply added on at the end of the design process.
HVAC zones can also refer to areas of humidity control, for example office spaces might require humidity control, whilst garages might not.
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