EnergyPlus VRF + DOAS modeling

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Hi Bldg-Sim Group,

I am working on variable refrigerant flow (VRF) system modeling using
EnergyPlus to understand energy savings compared to other conventional
systems.

For VRF modeling, I utilized the example file
"VariableRefrigerantFlow_5Zone.idf". This example uses outdoor air mixer in
each VRF indoor unit for the supply air which goes through cooling and
heating coil to the zone inlet node.

But, a typical VRF system practice uses a separate DOAS system to reduce
cooling and heating load in the VRF side only recirculating return air to
be conditioned.

I am trying to add DOAS in the VRF modeling. The problem is that
HVACTemplate:DOAS (in EnergyPlus 7.2 or 8) does not support this.

Is there anybody who did VRF system modeling with adding DOAS?

Thank you!

Sang Hoon Lee

Lee, Sang Hoon's picture
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Joined: 2013-06-15
Reputation: 0

Sang Hoon,

The point of the HVACTemplate files is to demonstrate how the nodes and
branches are configured.
Using the DOAS and a zonal system template will show you how to configure a
system with a ventilation system and separate zonal cooling / heating
system.

I suggest using the HVACTemplates for DOAS and WaterToAirHeatPump to create
the node connections. Upon running, this will create a file '.expidf' which
is the HVACTemplates expanded out to full .idf.
You can rename this file to be extension .idf and edit it like a normal
.idf

Modify this renamed expanded HVACTemplate file, remove the zonal
WaterToAirHeatPump objects and replace them with the VRF terminals
following the example you are using.

Hope this helps,

Jason

Jason Kirkpatrick's picture
Joined: 2011-10-02
Reputation: 200

Dear Anderson,

The example file (in EnergyPlus 8.0) is indeed what I was looking for.
This has AirLoopHVAC for DOAS and VRF system, which has separate coils
assigned for each system controlling temperature and humidity.
Great!

Thank you!
Sang Hoon

Lee, Sang Hoon's picture
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Joined: 2013-06-15
Reputation: 0