Simulation Based Design and Testing of a Supervisory Controller for Reducing Peak Demand in Buildings

We describe a supervisory control strategy for limiting peak power demand by small and medium commercial buildings while still meeting the business needs of the occupants. The objective of the supervisory control is to operate no more than N loads at all times while satisfying equipment limits on acceptable operation, and to exceed N only when these constraints cannot otherwise be satisfied. This is accomplished with a scheduling algorithm that prioritizes the operation of equipment according to data provided with each request to operate. We demonstrate this algorithm using a simulation model of a gymnasium with four roof top air conditioning units. Notably, this simulation is performing using the control software as it will be installed in the building by having the simulation software expose an interface identical to that used for interacting with the air conditioning equipment. The performance of the proposed algorithm relative to uncoordinated operation based on a typical on/off thermostat is also explored via simulation. These simulations suggest that the scheduling algorithm can reduce peak demand under a modest load and that it degrades gracefully under heavy loads while maintaining the temperature of the gymnasium within the desired range.