# System No. 3 PSZ-AC (Packaged Rooftop Air Conditioner)

A Packaged Rooftop Air Conditioner (PSZ-AC), as defined in EnergyPlus HVACTemplate, is a climate control system commonly used in commercial and light industrial buildings. It consists of a self-contained packaged unit, typically installed on the roof, that integrates all cooling, heating, and air handling components in a single assembly. 

The system uses a direct expansion (DX) cooling coil for air conditioning and may include gas furnace heating, electric resistance heating, or hot water coils for space heating. The PSZ-AC draws outdoor air for ventilation and supplies conditioned air through ductwork to serve a single zone. Fans within the unit distribute the conditioned air throughout the space, ensuring effective temperature control and ventilation. This configuration is particularly suitable for applications where a simple, packaged single-zone solution is preferred.

<figure><img src="/files/e8Za3Z0Pyc3n71IfGzsI" alt=""><figcaption></figcaption></figure>

A PSZ-AC comprises:

* Plant HVAC component - Air Handling Unit
* Space HVAC component - Air Terminal

The 'Select HVAC Template' form allows for multiple Spaces to be served. Clicking into the 'Spaces' field shows a list of available Spaces. Each selected Space will have one Packaged Rooftop Air Conditioner Space HVAC component, providing dedicated single-zone climate control for that space.


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