> For the complete documentation index, see [llms.txt](https://docs.betterbuilding.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.betterbuilding.io/user-guide/2d-building/building/hvac/plant-hvac/variable-air-volume-system-air-cooled.md).
# Variable Air Volume System (Air Cooled)
A Variable Air Volume (VAV) System (Air Cooled) adjusts the volume of conditioned air based on the cooling demands of different building zones. This system typically uses air-cooled equipment, such as air handlers, to regulate the temperature. The variable air volume allows for precise control, enhancing energy efficiency and maintaining optimal indoor comfort.
### Cooling - Rated CoP
Specify the coefficient of performance of the air-cooled chiller.
### Heating Coil Type
This field is locked to Electric heating coil type only.
### Supply Fan Total Efficiency
Specify the total efficiency of the supply fan. This is the ratio of the power delivered to the air to the electrical input power at maximum flow. This is also the product of the fan motor efficiency and fan (impeller) efficiency. The motor efficiency is the power delivered to the shaft divided by the electrical power input to the motor. The fan efficiency is the power delivered to the air divided by the shaft power. The power delivered to the fluid is the mass flow rate of the air multiplied by the pressure rise divided by the air density.
### Supply Fan Delta Pressure
Specify the pressure rise in pascals at full flow and standard conditions. Standard conditions are considered 20 degrees Celsius at sea level, 101325 Pa.
### Supply Fan Motor Efficiency
Specify the shaft power of the supply fan divided by the electrical power consumed.
{% hint style="info" %}
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{% endhint %}
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