.Buildings.Controls.OBC.ASHRAE.G36.ThermalZones.Alarms

Information

This block outputs zone alarms. The implementation is according to the ASHRAE Guideline 36, Section 5.3.6.

Zone temperature alarm

1. High-temperature alarm
   • If the zone temperature TZon is 2 °C (3 °F) above the cooling setpoint TCooSet for 10 minutes (timChe), generate Level 3 alarm.
   • If the zone temperature TZon is 3 °C (5 °F) above the cooling setpoint TCooSet for 10 minutes (timChe), generate Level 2 alarm.
2. Low-temperature alarm
   • If the zone temperature TZon is 2 °C (3 °F) below the heating setpoint THeaSet for 10 minutes (timChe), generate Level 3 alarm.
   • If the zone temperature TZon is 3 °C (5 °F) below the heating setpoint THeaSet for 10 minutes (timChe), generate Level 2 alarm.
3. Suppress zone temperature alarms as follows:
   • After zone setpoint is changed per Section 5.1.20 of Guideline 36, uResSet=true.
   • While zone group is in warm-up or cooldown modes.

For zones with CO2 sensors:

• If the CO2 concentration ppmCO2 is less than 300 ppm, or the zone is in unoccupied mode for more than 2 hours (modChe) and zone CO2 concentration exceeds 600 ppm, generate a Level 3 alarm. The alarm text shall identify the sensor and indicate that it may be out of calibration.
• If the CO2 concentration exceeds setpoint (CO2Set) plus 10% for more than 10 minutes (timChe), generate a Level 2 alarm.

Revisions

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