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Zones
Overview
This chapter provides the details for modeling zones and their associated sensors and setpoints. See the Spaces chapter for an introduction to how zones are modeled as a subtype of space.
Occupancy
Determining and controlling occupancy is one of the most critical aspects of building automation. Haystack defines several occupancy related tags and points:
occupied
sp
: setpoint true when occupied, false when unoccupiedoccupied
sensor
: boolean sensor true when occupied, false when unoccupiedoccupancy
sensor
: people counter that measures number of occupantsocc
: marker tag is used on points for occupancy modesunocc
: marker tag is used on points for occupancy modesoccupants
: the people who occupy a space
The primary tag used for the occupied/unoccupied state is the occupied
tag. In most cases, the occupied setpoint is a schedule that determines occupancy based on the time of day and day of the week. We might also use a sensor like a motion sensor to determine occupancy. More sophisticated sensors can actually count the number of people in a space; in which case, we use the occupancy
tag. As a general rule: points with the occupied
tag should have a Bool
kind; points with the occupancy
tag should have a Number
kind.
The occ
and unocc
tags are used in cases when we need to distinguish modes. For example, if we have two different temperature setpoints based on the occupancy mode, then we distinguish them as occ temp sp
and unocc temp sp
.
HVAC
The hvac-zone-space
conjunct models an HVAC zone for the conditioning of space comfort and air quality. The hvacZonePoints
def enumerates the common points used for HVAC control of a space.
The sensor and setpoints associated with temperature control include:
hvacMode
sp
: current mode such as "cooling" or "heating"temp
sensor
: actual sensed temperature of the spacetemp
occ
cooling
sp
: cooling setpoint when occupiedtemp
occ
heating
sp
: heating setpoint when occupiedtemp
unocc
cooling
sp
: cooling setpoint when unoccupiedtemp
unocc
heating
sp
: heating setpoint when unoccupiedtemp
standby
cooling
sp
: cooling setpoint when in standby modetemp
standby
heating
sp
: heating setpoint when in standby modetemp
effective
sp
: current setpoint we are controlling to taking into account cooling/heating mode and occ/unocc/standby mode
Whenever possible, there should be one effective temperature setpoint that takes all the various modes into account. This provides the simplest model to perform analysis of HVAC operations. However in some cases a thermostat will provide two effective setpoints - one for cooling and one for heating. In this case, there must also be a hvacMode
point to determine which one is the true effective setpoint. That setup should look like this:
In addition, we might also find the following points:
pressure
sensor
: measured static pressure of the spacepressure
sp
: static pressure setpoint (commonly used for lab situations)humidity
sensor
: measured relative humidity of the spacehumidity
sp
: setpoint for relative humiditydewPoint
sensor
: measured dew point temperature of the spacedewPoint
sp
: setpoint for dew point temperatureenthalpy
sensor
: measured heat content of the space
All the points above must also be tagged with zone
, air
, and point
.
Air Quality
It is also common in an HVAC zone to also measure and control air quality. We model the typical air quality points using the airQualityZonePoints
def which includes:
ch2o-concentration
sensor
: measured formaldehyde (CH₂O)co-concentration
sensor
: measured carbon monoxide (CO)co2-concentration
sensor
: measured carbon dioxide (CO₂)co2-concentration
sp
: configured max carbon dioxide (CO₂)nh3-concentration
sensor
: measured ammonia (NH₃)no2-concentration
sensor
: measured nitrogen dioxide (NO₂)o3-concentration
sensor
: measured ozone (O₃)pm01-concentration
sensor
: measured particulate matter 0.1pm25-concentration
sensor
: measured particulate matter 2.5pm10-concentration
sensor
: measured particulate matter 10tvoc-concentration
sensor
: measured total volatile organic compounds
All the points above must also be tagged with zone
, air
, and point
.
Lighting
The lighting-zone-space
conjuct models lighting zones. The lightingZonePoints
def enumerates the typical points used for lighting measurement and control including:
light-level
sensor
: brightness level status as percentagelight-level
sp
: brightness level setpoint as percentagelight
illuminance
sensor
: lux, footcandle, or photlight
luminous-flux
sensor
: luminous flux in lumens