Introduction

Custom meters allow users to aggregate and report specific energy data that aren't captured by the standard EnergyPlus output variables or output meters. This article is built on top of previous articles that explain how to add output variables and output meters in DesignBuilder and Creating Energy Meters. This article explains how to create: 

1. custom meters by implementing EnergyPlus Meter:Custom objects
2. concise meter definition by utilising the DesignBuilder's EMS runtime language extension

Definition

We define the Meter:Custom object by following this syntax. 
The Name field is a user-defined name for the custom meter. Names for custom meters cannot duplicate internal meter names. 

A ResourceType should be specified for the meter. All assignments to this meter will be checked to ensure that the same resource type is used.

Custom meters collect data by referencing output variables or output meters. A key name field is only required when the following field specifies an output variable. If the field is left blank, then all the output variables in the following field are assigned to the custom meter. Note that all outputs must reference energy data and not power or temperature data.

Meter:Custom,
  Name,        
  ResourceType,             
  Key Name 1,               
  Output Variable or Meter Name 1,
  Key Name 2,             
  Output Variable or Meter Name 2;

Exemplary custom meter definition using pure EnergyPlys syntax.

Meter:Custom,
  Custom General Lights Meter,     !- Name
  Electricity,                     !- Resource Type
  BLOCK1:ZONEA,                    !- Key Name 1
  Lights Electricity Energy,       !- Output Variable or Meter Name 1
  BLOCK1:ZONEB,                    !- Key Name 2
  Lights Electricity Energy,       !- Output Variable or Meter Name 2
  BLOCK2:ZONEC,                    !- Key Nme 3
  Lights Electricity Energy,       !- Output Variable or Meter Name 3
  BLOCK2:ZONED,                    !- Key Name 4
  Lights Electricity Energy;       !- Output Variable or Meter Name 4

Exemplary custom meter definition using EMS with DesignBuilder language extension.

Meter:Custom,
  Custom General Light Meter,                !- Name
  Electricity,                               !- Resource Type
  <ForAllZone> {ZoneIDFName=BLOCK1//BLOCK2}
  <LoopZoneIDFName>,                         !- Key Name
  Lights Electricity Energy                  !- Output Variable                         
  <LoopNextZone>;

Once defined, your custom meter can be used like any other meter in EnergyPlus. You can reference it in Output:Meter objects, use it in other EMS programs, or include it in your output reports.

Output:Meter,
  Custom General Lights Meter,     !- Key Name
  Hourly;                          !- Reporting Frequency

See also:

Github Output:Meter and Meter:Custom examples
Output:Variable Regex
Energyplus File Extensions
Standard Energy Meters
DB EMS Scripting with DB ERL Extension 
Output:Meter Meter:Custom