Control with building mass-Part II: Simulation

Reductions in building peak electrical demand can be achieved by incorporating building-specific models of thermal dynamics into controllers that will implement short-term peak-period curtailment of HVAC capacity or pre-cool the building prior to peak-period cutbacks to increase the magnitude and duration of the load reduction. The same building-specific model can be used to effect energy savings by providing optimal-start control or optimal-pre-cooling control during unoccupied hours. Control logic was developed for pre-cooling with a central HVAC plant equipped with an air-side economizer. Measurement-based estimates were made of chiller performance and internal-gains schedules. The general transient-thermal-response model of the companion paper (Armstrong et al. 2006) was then used to determine building-specific thermal response and estimate the seasonal benefits of several peak-shifting and night-cooling strategies in the office building. Simulations showed a 30% to 60% reduction in seasonal mechanical cooling loads in the office building due to night cooling.