Adaptive and distributed operation of HVAC systems: Energy and comfort implications of active diffusers as new adaptation capacities

Human-aware HAVC operations have been shown to be effective in improving energy efficiency, which is constrained by the HVAC system configuration and operational logic. These constraints can result in a lack of operational flexibility, which in turn reduces the adaptation capacity for energy efficiency. Therefore, in this study, we investigated the energy efficiency implications of novel adaptive capacities for HVAC including the use of proposed active diffusers, which add to the dynamics of the HAVC systems by adjusting the behavior of diffusers using two modalities of (1) binary actuation of air flow (turning flow on and off), and (2) adjusting the flow direction to target individual needs in an environment. Computational fluid dynamics was used to model and simulate the behavior of a “real-world” thermal zone to evaluate five scenarios of adaptive operations using distributed feedback from the environment, as well as active diffusers. Three scenarios used binary actuation at the thermal zone (collection of rooms) level, and two examined the adaptive operations at the diffusers level. Moreover, we examined the integration of distributed feedback at occupant locations into the control loop using averaged temperatures (in the first three scenarios) and individual-level feedback (in scenarios with diffuser level actuation). The coupling of distributed feedback and independent directional flow at the diffuser level considerably improved thermal comfort while reducing energy demands by ~25%—reflecting a considerable impact on improved energy efficiency. These findings demonstrate the potentials that artificial intelligence frameworks could bring about by enabling autonomous adaptive operations.