# Modelling four-pipe heat pumps

A four-pipe heat pump is a device capable of providing cooling and/or heating, separately or simultaneously. It is also referred to as a multi-function chiller.

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Advanced HVAC enables you to model four-pipe heat pump systems using the [EnergyPlus HeatPump:PlantLoop:EIR:Cooling (and Heating) objects](https://bigladdersoftware.com/epx/docs/22-2/input-output-reference/group-plant-equipment.html#plhp_eir). Please note that this does not account for heat recovery - this object assumes that only one side (either heating or cooling) will be active at any given simulation timestep.
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To model a central air handling unit system with a four-pipe heat pump system providing the cooling device on a chilled water loop and the heating device on a hot water loop, follow these steps. 

This will create a four-pipe heat pump system central plant component, along with two related (children) objects: 1) Four-pipe heat pump (Heating) on the hot water loop and 2) Four-pipe heat pump (Cooling) on the chilled water loop.

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On the HVAC Schematic, select 'Select Template'. Next, choose 'Four-pipe Heat Pump System' from the list and complete the other form options as desired. 
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<figure><img src="https://content.gitbook.com/content/fKJnzF2TwHA3APPbiCpF/blobs/tQ3VnMbH4XbLVvQ6Fsw7/four-pipe%20heat%20pumps.gif" alt=""><figcaption></figcaption></figure>