Low-level optimization - Johnson Controls - LIT-12013967 - Software Application - Central Utility Plant - 4.3

OpenBlue Central Utility Plant Control Sequence Math Technical Approach

Johnson Controls
Product name
Central Utility Plant
Document number
Revision date

Low level optimization determines within each group of equipment, what runs and what the optimal setpoints to execute to the allocated load. Plant Optimizer determines this in the mass, momentum, and energy (MME) solver. MME calculates temperature in (Tin), temperature out (Tout), pressure in (Pin), pressure out (Pout), and flow (F) for each device in the system. Any commands from Plant Optimizer are verified to result in conservation of energy, mass, and momentum. Equipment selection is determined using discrete programming, specifically modified branch and bound, to minimize power. Equipment selection and setpoints are determined using a mixed-integer optimization algorithm to minimize the operating cost of the plant while protecting the health of the system and equipment.

OpenBlue Plant Optimizer sends dispatches to BAS to set setpoints for the following systems:
  • Sequencing properties on-off-status per device
  • Chilled water (CHW) flow setpoints
  • Condenser water (CW) flow setpoints
  • Chiller evaporator leaving water temperature setpoints
  • Cooling tower leaving water temperature setpoints or chiller condenser water entering water temperature setpoints
  • Waterside economizer heat exchanger leaving water temperature
  • Hot water flow setpoints
  • Heating water heat exchanger leaving water temperature
  • Hot water generator leaving water temperature
  • Boiler steam pressure
  • Energy storage mode