Distributed Energy Feedback Control for Demand Response Operations in Commercial HVAC Systems

Abstract

The goal of this thesis is to identify methods to control a commercial Heating, Ventilation, and Air Conditioning (HVAC) system that results in precise control of the cooling coil load and the ability to prioritize the comfort of certain zones. The state of the art method of zone temperature setpoint adjustments is introduced and the weaknesses are identified. Temporarily resetting the zone temperature setpoints shows the capacity to significantly reduce the cooling coil load, but the load is not controlled precisely. The setpoint reset method is compared through simulation and experimentation to the proposed solutions of Energy Demand Response control (EDR) and Transactive Control and Coordination (TCC) integrated with EDR control. A model of the system that captures the relevant behaviors was developed to test each of the control strategies under different scenarios. Through simulation it was found that EDR control can precisely regulate the cooling coil load but does not provide any way to prioritize the zones. EDR combined with TCC precisely controls the cooling coil load and allows for the comfort of specific zones to be prioritized. The setpoint reset and EDR control strategies were validated experimentally on a multizone variable air volume air handling unit. The cooling coil load during a period of setpoint reset was experimentally found to vary between 1.1±0.4 refrigeration tons. The cooling coil load under EDR control was regulated between 1.1±0.1 refrigeration tons. Future areas of study have been identified, which includes using a virtual flow meter for EDR control and increasing the scale of EDR+TCC implementation.