Variable Key Value - External Interface - EnergyPlus-co-simulation-toolbox [closed]

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Hello everyone!

I am using EnergyPlus to model a cold room, and I am using the EnergyPlus-co-simulation-toolbox to connect it with MATLAB.

I have trouble understanding when it comes to the "Key Value".

To configure the data mapping between EnergyPlus and the external interface, we have to create an XML file (called variables.cfg) in which we declare the variables that the external interface sends or reads. For reading data, the "variable source" is set “EnergyPlus", because they are computed by EnergyPlus, "EnergyPlus name" should be set to the zone name "ZoneName" which is the "Key Value" in the Output:Variable object, while "type" should be the variable name "Zone Outdoor Air Drybulb Temperature", as shown below.

<variable source = "EnergyPlus">
<EnergyPlus name = "ZoneName" type= "Zone Outdoor Air Drybulb Temperature"/>
</variable >

Output:Variable,
    ZN,                                       !- Key Value 
    Zone Outdoor Air Drybulb Temperature,     !- Variable Name
    Timestep;                                 !- Reporting Frequency

I have learned that the "Key Value" is not always the zone name. I found an example in "ExternalInterfacesApplicationGuide" in which they defined the ExternalInterface:Schedule as an Output variable and the key value was the ExternalInterface:Schedule name, as shown below

ExternalInterface:Schedule ,
     TSetCoo ,         !- Name 
     Temperature ,     !- ScheduleType 
     24;               !- Initial value , used during warm-up

Output:Variable ,
     TSetCoo ,              !- Key Value
     Schedule Value ,       !- Variable Name
     TimeStep;              !- Reporting Frequency

My question is, what is the appropriate "Key value" to use if I want to read the Output variable "Refrigeration Air Chiller System Total Compressor Electric Power" ?

I hope I explained the problem clearly.