Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
If you want to model a Multispeed or Variable Speed ASHP, you can configure AirLoopHVAC:UnitarySystem with Coil:Cooling:DX:MultiSpeed/VariableSpeed and Coil:Heating:DX:MultiSpeed/VariableSpeed.
https://bigladdersoftware.com/epx/docs/9-5/input-output-reference/group-unitary-equipment.html#airloophvacunitarysystem
"This system is unique in that it can accommodate all fan and coil types whereas other system types are specific to the type of fan and coil available for simulation."
"Links to the fan, cooling coil, heating coil and reheat coil specifications are provided in the unitary system input data syntax."
Select the heating coil object type here: https://bigladdersoftware.com/epx/docs/9-5/input-output-reference/group-unitary-equipment.html#field-heating-coil-object-type-002
select from: - Coil:Heating:DX:MultiSpeed or - Coil:Heating:DX:VariableSpeed depending on your application.
Similarly, select the cooling coil object type here: https://bigladdersoftware.com/epx/docs/9-5/input-output-reference/group-unitary-equipment.html#field-cooling-coil-object-type-002
In the Unitary System Outputs, you can see that thermal load variables like Unitary System Total Heating Rate, Unitary System Total Cooling Rate, and Unitary System Electricity Rate are available.
https://bigladdersoftware.com/epx/docs/9-5/input-output-reference/group-unitary-equipment.html#outputs-038
If you use multispeed coils, you need to add this object.
https://bigladdersoftware.com/epx/docs/9-5/input-output-reference/group-unitary-equipment.html#field-design-specification-multispeed-object-type
"correct specification of the heat/cool unitary system requires specification of the following objects in addition to the unitary system object":
Fan (Fan:OnOff or Fan:ConstantVolume)
Cooling coil
Heating coil
Reheat coil
Direct air unit (AirTerminal:SingleDuct:ConstantVolume:NoReheat) for each zone served by the unitary system when used in an air loop.
