Appendix A: VAV Zone Controller Points/Properties
Hysteresis
– The desired difference between the temperature at which the zone color
changes as the zone temperature departs from the acceptable range between the heating
and cooling setpoints (green) into the Cooling 1 (yellow) or Heating 1 (light blue) and the
temperature at which the zone color changes back to the acceptable range between the
heating and cooling setpoints.
For example, the following graph shows the zone color that results as the zone temperature
departs from and returns to the acceptable range in a zone with the following settings:
•
Color Change Hysteresis = .5∆°F (.27∆°C) (applies as the temperature returns to the
acceptable range)
•
Occupied cooling setpoint = 76°F (24.4°C)
•
Occupied heating setpoint = 70°F (21.1°C)
NOTE
The values in the graph below are Fahrenheit.
Time
Temp
Occupied heating setpoint: 70°
75.5°
70.5°
Occupied cooling setpoint: 76°
.5° hysteresis
.5° hysteresis
D:
R:
0.5∆°F (.27∆°)
0.2 to 1.0∆°F
(.1 to .5∆°C)
Learning Adaptive Optimal Start
When the Learning Adaptive Optimal Start algorithm runs, the learned heating capacity or learned cooling capacity values
are adjusted based on the color that is achieved when occupancy begins. The adjustment amounts for each color are
displayed in the thermographic color fields (shown above with English default values).
Point Name/Description
Range
English
Metric
Red
– The amount the zone’s learned heating capacity is adjusted when the Learning
Adaptive Optimal Start algorithm runs, when the zone’s thermographic color at
occupancy is red.
D:
R:
0.1900
0 to 1
.1055
DkBlue
– The amount the zone’s learned heating capacity is adjusted when the Learning
Adaptive Optimal Start algorithm runs, when the zone’s thermographic color at
occupancy is dark blue.
D:
R:
0.1300
0 to 1
.0722
LtBlue
– The amount the zone’s learned heating capacity is adjusted when the Learning
Adaptive Optimal Start algorithm runs, when the zone’s thermographic color at
occupancy is light blue.
D:
R:
0.0600
0 to 1
.0333
VAV Zone Controllers
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