Morning cool-down - Johnson Controls - LIT-12011950 - Building automation software - Smart Equipment Controller - 5.0

Smart Equipment Controls Sequence of Operation Technical Bulletin

Product name
Smart Equipment Controller
Document type
Technical Bulletin
Document number
LIT-12011950
Version
5.0
Revision date
2024-06-06
Product status
Active

Setpoints and related data

The setpoints and related data include the following items:

  • Morning cool-down enable ON (MornC-En)
  • Morning cool-down/return air temperature setpoint (MornCRAT-Sp)
  • Early start period (EarlyStrtPeriod)
  • Optionally, occupancy BI enabled, optimal start enabled, schedule
  • Optionally, operational VAV cooling setpoint (for optimal start)

Inputs

The inputs include the following items:

  • Operational space temperature
  • Operational occupancy

Outputs

No outputs are required for morning cool-down.

Operation

The following sections outline the operation details.

BI input

With a BI occupied command, the supply fan turns on for a 5-minute stabilization period, and then the operating space temperature is compared to morning cool-down return air temperature setpoint.

If the value is equal to or above the morning cool-down return air temperature setpoint, all compressors operate for at least 5 minutes. If the value is below the morning cool-down return air temperature setpoint, the control goes into occupied mode.

The compressors energize until 5 minutes pass and the operating space temperature is below the morning cool-down setpoint or the early start period expires. Then the control goes into occupied mode.

Optimal start

Historical data determines when the optimal start begins. The optimal start time is always within the same calendar day. All compressors run until the demand is satisfied. The control uses the operational VAV cooling setpoint to determine when the demand is satisfied. Then the control goes into occupied mode.

Schedule

At the early start period before the scheduled occupancy, the supply fan turns on for a 5 minute stabilization period and then the operating space temperature is compared to the morning cool-down return air temperature setpoint.

If the value is equal to or above the morning cool-down return air temperature setpoint, all compressors operate for at least 5 minutes. If the value is below the morning cool-down return air temperature setpoint, the control goes into occupied mode.

The compressors energize until 5 minutes pass and the operating space temperature is below the morning cool-down setpoint or the early start period expires. Then the control goes into occupied mode.