TOC

1. Intro
2. TagModel
3. Structure
4. TimeZones
5. Units
6. Grids
7. Filters
8. Zinc
9. Json
10. Trio
11. Csv
12. Rest
13. Ops
14. Auth
15. VFDs
16. Networks
17. Energy
    1. Overview
    2. Meters
    3. Meter Loads
    4. Elec Meter
       1. Active, Reactive, Apparent
       2. Import, Export, Net
       3. Elec Meter Points
       4. Elec Meter Diagram
    5. Flow Meters
    6. Thermal Meters
    7. Example Model
18. Zones
19. AHUs
20. VAVs
21. UnitaryEquips
22. Chillers
23. Boilers
24. Tanks
25. ElecPanels
26. Lighting
27. Builds
28. Bacnet
29. ChangeLog
30. License

Energy

Overview

The general problems addressed by the energy tags are:

• modeling meters
• modeling submeters and their relationships
• modeling equip and point loads on meters

Meters

Meters are modeled as equip entities with the meter tag. The following meter types are defined:

• elec meter
• gas meter
• domestic water meter
• chilled water meter
• condenser water meter
• hot water meter
• makeup water meter
• blowdown water meter
• condensate water meter
• steam meter

All meters must additionally define one of these two tags:

• siteMeter: marker applied to the main site level meter
• submeterOf: Ref to parent meter

Meter Loads

Modeling the equip and point loads under specific meters can be used for analysis and visualization. Loads are modeled by applying a tag formatted as "{type}MeterLoad" on an equip or point. The meter load tag should be Ref to its associated meter. If modeling submeters, then the load should reference the closest submeter. Standardized load tags:

• elecMeterLoad
• gasMeterLoad
• waterMeterLoad (no distinction between which type of water meter)
• steamMeterLoad

Meter loads have the same types of points as their associated meters.

Elec Meter

Electricity meters are probably the most common type of meters modeled. They are tagged as elec meter. Haystack supports a model designed to scale from very simple meters (just a power and energy point) up to a comprehensive point list for three-phase power quality meters.

Electricity meter points are described by combining tags from the lists given below. The tags in each set are mutually exclusive. (For example, a power point cannot be both active and reactive.)

The primary measured quantities in an electical system are:

• power: typically measured in "kW"
• energy: typically measured in "kWh"
• volt: typically measured in "V"
• current: typically measured in "A"
• freq: typically measured in "Hz"
• pf: power factor

AC power measurements are further qualified by:

• active: typically measured in "kW" (assumed as default)
• reactive: typically measured in "kVAR"
• apparent: typically measured in "kVA"

Voltage and current measurements are further qualified by:

• mag: magnitude (assumed as default)
• angle: phase angle, typically measured in "deg"
• imbalance: imbalance between phases, measured in "%"
• thd: total harmonic distortion, measured in "%"

Three phase electicrical measurements are qualified by:

• phase: A, B, C, AB, BC, CA, N
• avg: for current, voltage, and power factor (assumed as default)
• total: for power and energy (assumed as default)

Energy exchange with the utility is qualified by:

• import: energy imported from the grid
• export: energy exported to the grid
• net: net exchange (assumed as default)

In addition we define the following general purpose tags:

• ac: alternating current
• dc: direct current

Active, Reactive, Apparent

As the name suggests, the voltage and current in alternating current (AC) electricity networks alternate polarity many times per second. Because instantaneous power is the product of voltage times current, it constantly fluctuates in an AC network. Three quantities describe the time-averaged nature of fluctuating AC power:

• active power, also known as real power, represents real work: a net transfer of energy from source to load. Active power represents the "normal" definition of power: the rate of energy transfer per unit time. The standard unit of active power is the Watt, "W"; the default Haystack unit is "kW".
• reactive power, also known as imaginary power, represents energy that circulates in an AC system without performing any real work. Its standard unit is the volt-ampere reactive, "VAR"; the default Haystack unit is "kVAR".
• apparent power is the combination of active and reactive power and represents the overall magnitude of energy movement. Its standard unit is the volt-ampere, "VA"; the default Haystack unit is "kVA".

If a power point does not have an active, reactive, or apparent tag, active power is assumed as the default.

Import, Export, Net

Some electric meters track and report power and energy imported from the electric grid separately from power and energy exported to the electric grid. The tags import and export differentiate these quantities. More broadly, export indicates power or energy flowing toward the grid (in the direction of the siteMeter) and import indicates power or energy flowing toward the load.

These measurements register power or energy transfer only in their associated direction and always have positive values.

• For instantaneous power measurements, import and export are mutually exclusive. One will report a positive value and the other will report zero.
• For energy measurements tallied over time, it is possible that both import and export may report a positive quantity for that interval, which means that some energy flowed in each direction during that interval.

The net tag indicates the difference between import and export:

net = import - export

Haystack uses the load convention for net electric power and energy.

• Positive net quantities indicate power or energy consumed,
• Negative net quantities indicate power or energy produced.

If a power or energy point does not have an import, export, or net tag, it is assumed by default to be a net quantity.

Elec Meter Points

Common tag combinations for the points of a electric meter:

Power

• power net sensor
• power export sensor
• power import sensor
• active power total sensor
• active power phase sensor
• apparent power total sensor
• apparent power phase sensor
• reactive power total sensor
• reactive power phase sensor

Energy

• energy net sensor
• energy export sensor
• energy import sensor
• energy total sensor
• energy phase sensor

Voltage

• volt mag avg sensor
• volt mag phase sensor
• volt angle avg sensor
• volt angle phase sensor
• volt thd avg sensor
• volt thd phase sensor
• volt imbalance sensor

Current

• current mag avg sensor
• current mag phase sensor
• current angle avg sensor
• current angle phase sensor
• current thd avg sensor
• current thd phase sensor
• current imbalance sensor

Power Factor

• pf avg sensor
• pf phase sensor

Frequency

• freq sensor

Elec Meter Diagram

The follow diagram illustrates these basic relationships with a site level electric meter and its power and energy points. A submeter is associated with a load under the main meter.

Flow Meters

Water and gas meters measure flow rate and total volume consumed. Standardized points are:

• flow: rate of volume flowing through the meter per unit time
• volume: total volume consumption of the meter

Thermal Meters

Thermal meters measure energy as temperature differentials. Energy demand and consumption is modeled using the same tags as electric meters:

• power: energy consumed per unit time such as "BTU/h"
• energy: energy consumption such as "BTU"

Example Model

Let's take a simple example. Let's assume we want to model this "tree" of meters and loads:

Main Elec Meter
 +- LightsGroup (equip load)
     +- Lights-ZoneX (point load)
     +- Lights-ZoneY (point load)
 +- HVAC Elec Submeter
     +- RTU-1 (equip load)
         +- Fan (point load)
         +- DischargeTemp (not a load)
     +- RTU-2 (equip load)
         +- Fan (point load)
         +- DischargeTemp (not a load)

The entities and their tags would look like this:

id:@A, dis: "Main Elec Meter", elec, meter, siteMeter, equip
       dis: "Main Elec Meter Demand", equipRef @A, power, unit:"kW", sensor, point, ...
       dis: "Main Elec Meter Consumption", equipRef:@A, energy, unit:"kWh", sensor, point, ...

id:@B, dis: "Lights", equip, elecMeterLoad:@A, lightsGroup
       dis: "Lights ZoneX", equipRef:@B, elecMeterLoad:@A, lights, cmd, point, ...
       dis: "Lights ZoneY", equipRef:@B, elecMeterLoad:@A, lights, cmd, point, ...

id:@C, dis: "HVAC Elec Submeter", elec, meter, submeterOf:@A, equip
       dis: "HVAC Elec Submeter Demand", equipRef:@C, power, unit:"kW", sensor, point, ...
       dis: "HVAC Elec Submeter Consumption", equipRef:@C, energy, unit:"kWh", sensor, point, ...

id:@D, dis: "RTU-1", equip, elecMeterLoad:@C, ahu
       dis: "RTU-1 Fan", equipRef:@D, elecMeterLoad:@C, fan, cmd, point, ...
       dis: "RTU-1 DA Temp", equipRef:@D, discharge, temp, sensor, point, ...
id:@E, dis: "RTU-2", equip, elecMeterLoad:@C, ahu
       dis: "RTU-2 Fan", equipRef:@E, elecMeterLoad:@C, fan, cmd, point, ...
       dis: "RTU-2 DA Temp", equipRef:@E, discharge, temp, sensor, point, ...

In the example above we have a top-level main electrical meter with the id @A. Note it is tagged as elec meter to model an electric meter. It is also tagged as siteMeter to indicate its the main site-level meter. It has two associated points for power (kW) and energy (kWh).

Then under the main meter, we have a HVAC submeter with the id @C. Note it is tagged as elec meter but not siteMeter, instead it is associated as a submeter of the main meter using the submeterOf tag. You can model submeter trees of arbitrary depth (submeters of submeters). It also has two points for kW and kWh.

Lastly we have three electrical equipment loads defined. The two RTUs are associated with HVAC submeter via elecMeterLoad which references the HVAC submeter via id. Since we don't have a lighting submeter, the lighting load references the main meter directly via its elecMeterLoad tag. We also tag one or more points under the equipment which are meaningful for the load. Actuators would often be tagged as loads since they draw energy, but sensors would typically not be considered loads.