Zone static pressure requests
A sequence for one VAV zone that tells its air handler when the duct static pressure is too low for it. A zone whose airflow stays short of its setpoint asks for more pressure, harder the shorter it is, and a nearly fully open damper asks too. The air handler sums its zones’ requests in the static pressure reset. It runs once per zone: 15 zones, 5 per floor.
Written in our own words. Version 1 followed the Modelica Buildings Library’s VAV terminal system-request sequence; version 2 adapts it to BOPTEST.
Why version 2
Section titled “Why version 2”In version 1, airflow requests counted only once a damper had been above 95 % for a minute. On BOPTEST the zone dampers did not open that far in time: at 50 Pa, airflow fell to 55 % of setpoint within minutes while dampers crept from 0.57 to 0.77 over three hours. No zone ever asked, and the reset trimmed to its floor while zones starved. Version 2 asks from the airflow shortfall itself.
Interface
Section titled “Interface”| Point | Type | Meaning |
|---|---|---|
uDam |
real input | Zone damper position, 0 to 1 |
VDis_flow |
real input, m³/s | Measured zone airflow |
VSet_flow |
real input, m³/s | Zone airflow setpoint |
yPreReq |
integer output | Static pressure reset requests, 0 to 3 |
Behavior in brief
Section titled “Behavior in brief”- With the zone served (setpoint above 0.01 m³/s), a shortfall that has lasted 120 s sends 3 requests below half the setpoint, else 2 below 70 %, else 1 below 90 %. Each shortfall has a 0.01 m³/s release band.
- A damper above 95 % open (held until no longer above 85 %) sends at least 1 request at once.
- Every threshold is strict; a shortfall present at the first frame still waits the full 120 s.
With two requests ignored, a floor’s reset responds once three or more of its five zones fall below 90 % of setpoint.
Validation
Section titled “Validation”- 9 scenarios from the independent reference model: damper band edges, each request level, airflow recovering through the bands, an unserved zone, brief dips, damper and airflow together.
- A 23-block hand-built graph passes all 9; 10 deliberate mistakes each fail at least one.
How it did
Section titled “How it did”- Muse Spark (version 2): first try 0 of 3, after repair 3 of 3. Every first draft missed the same edge (a damper at exactly 85 % must release), each fixed in one repair.
- Version 1 on BOPTEST saved 33.6 % energy by under-ventilating (+51.4 % CO2 discomfort); version 2 settles near 165 to 215 Pa. See Runtime results.
Full spec: specs/zone_pressure_requests/spec.md