Abstract:

Building automation systems provide supervisory control of a building’s heating, ventilation and air conditioning (HVAC), electrical, lighting, shading, access control elevators and escalators, security systems, etc., primarily for purposes of automation (reducing manual labor), reducing energy consumption, improving occupant comfort, and recording and communicating information for maintenance and accountability. Control as a subject can drive meaningful innovation in building automation, particularly to reduce the impact that buildings have on climate such as greenhouse gas production. HVAC systems in particular, as the largest consumer of power in buildings, are strongly affected by control, and continued efforts by the industry to improve energy efficiency have made them increasingly multivariable, dynamically interactive, and nonlinear. In this chapter, we focus on both need-based and vision-based control innovation for building automation for HVAC systems. After providing a brief background that describes different HVAC architectures and products, we describe the control challenges and opportunities from a needs-based point of view, at the equipment level, the systems level, and the building level. At the equipment level, increased use of continuously variable actuation such as variable speed compressors and fans, requires application of robust multivariable control that must consider various types of nonlinear behavior across increasingly larger operating envelopes. The objective at this level is to achieve robust and energy efficient operation. At the system level, coupled and interactive dynamics among subsystems are increasingly important to consider, and functional integration of these subsystems, along with set points and operating schedules are designed to minimize energy consumption and improve occupant comfort. At the building level, issues such as integration among other building systems, such as the building envelope and the electric grid, offer opportunities to develop new types of demand response and grid-interactive behaviors and technologies. At the higher levels, system dynamics and robust stability are less of an issue, similar to process control applications, while optimization and integration are more important, although dynamic stability is increasing an issue at the higher levels too. From a vision-driven innovation point of view, we describe three areas that will require sustained re- search efforts and will eventually impact building automation: Digital Twins, Model Predictive Control, and Grid Interactive Buildings. Control as a field can and must play an active role in developing next generation technologies at all levels of building automation, especially because these systems are increasingly dynamically interactive and robust stability is increasingly an important design consideration. These issues, and especially the recognition of the relationship between robustness and performance, are central to control as a field, and arguably differentiate it from related research fields that may emphasize only performance.