> 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/workflows/energy-efficiency/advanced-hvac/modelling-four-pipe-heat-pumps.md).

# 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.

{% hint style="warning" %}
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.
{% endhint %}

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.

{% hint style="success" %}
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. 
{% endhint %}

<figure><img src="/files/lAxsO93WbNpP8IQRCKwa" alt=""><figcaption></figcaption></figure>


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