.Buildings.Controls.OBC.ASHRAE.G36.TerminalUnits.CoolingOnly.Subsequences.SystemRequests

Information

This sequence outputs the system reset requests for cooling only terminal unit. The implementation is according to the Section 5.5.8 of ASHRAE Guideline 36, May 2020.

Cooling SAT reset requests yZonTemResReq

1. If the zone temperature TZon exceeds the zone cooling setpoint TZonCooSet by 3 °C (5 °F)) for 2 minutes and after suppression period (uAftSup=true) due to setpoint change per G36 Part 5.1.20, send 3 requests (yZonTemResReq=3).
2. Else if the zone temperature TZon exceeds the zone cooling setpoint TZonCooSet by 2 °C (3 °F) for 2 minutes and after suppression period (uAftSup=true) due to setpoint change per G36 Part 5.1.20, send 2 requests (yZonTemResReq=2).
3. Else if the cooling loop uCoo is greater than 95%, send 1 request (yZonTemResReq=1) until uCoo is less than 85%.
4. Else if uCoo is less than 95%, send 0 request (yZonTemResReq=0).

Static pressure reset requests yZonPreResReq

1. If the measured airflow VDis_flow is less than 50% of setpoint VSet_flow while the setpoint is greater than zero and the damper position uDam is greater than 95% for 1 minute, send 3 requests (yZonPreResReq=3).
2. Else if the measured airflow VDis_flow is less than 70% of setpoint VSet_flow while the setpoint is greater than zero and the damper position uDam is greater than 95% for 1 minute, send 2 requests (yZonPreResReq=2).
3. Else if the damper position uDam is greater than 95%, send 1 request (yZonPreResReq=1) until uDam is less than 85%.
4. Else if the damper position uDam is less than 95%, send 0 request (yZonPreResReq=0).

Revisions

• August 1, 2020, by Jianjun Hu:
  First implementation.