TA-23-C014 – Development and Investigation of Advanced HVAC Demand Control

Demand flexibility control is one of the major measures for decarbonization and energy resilience operation. Due to the lack of appropriate communications among chillers, air handling units (AHUs), and terminal boxes (TBs), existing heating, ventilation, and air-conditioning (HVAC) load management technologies using conventional HVAC control have a technical issue to simultaneously provide accurate demand control and share reduced cooling load evenly among all zones. The purpose of the paper is to develop and preliminarily investigate an innovative HVAC load management approach to resolve this issue by enabling these missed communications. First, two new control loops are set up from chillers to AHUs and then TBs. The water loop pressure differential (WLP) is controlled by evenly adjusting the cooling load setpoint at AHUs instead of the chilled water pump speed and the air duct static pressure (DSP) is controlled by evenly adjusting the zone temperature (ZT) setpoint at TBs instead of adjusting the AHU fan speed. Then a preliminary experiment is conducted on an AHU with seven TBs by implementing the DSP control only. The experiment results show that the AHU cooling load can be accurately controlled at the preset setpoint by evenly adjusting the ZT setpoint at TBs.