Development of event-driven optimal control for central air-conditioning systems

Abstract

Event-driven optimal control was recently developed for central air-conditioning systems to speed up the response of optimal control to irregular changes in the system optioning conditions. In a time-driven paradigm usually the optimization is carried out with a constant frequency, however the event-driven optimal control triggers optimization actions by events, which will be essentially defined to catch up with the irregular changes. Considering that the occurrence of events should imply the necessity to execute optimization, this paper investigates the necessity of optimization actions, based on which a new method to develop event-driven optimal control law is proposed. This can naturally lead to the establishment of an event-action map. This map indicates that not all the decision variables should be optimized when an event occurs, different from other methods that require optimizing all decision variables. The merits of the new method were also demonstrated using several case studies.

Generic load regulation strategy for enhancing energy efficiency of chiller plants

“…A central chiller plant mainly consisting of chillers, cooling towers, and their associated pumps and fans, and their connections are shown in Figure 1(a). The power consumption of the chiller plant Psys is contributed from the pumps in the primary chilled water P chp and the secondary loop P chs , the compressors of the chillers P ch , the pumps in the condenser water loop P ctp , and the fans in the cooling tower P ctf , which can be formulated as (Hou et al 2020…”

“…Referring to Hou et al (2020), the power consumptions of the chiller plant are the functions of the chilled water supply temperature T chws , the condenser water return temperature T cws , the building cooling load Q bld , and the outdoor air wet bulb temperature T wb . Thus Equation (1) can be rewritten as…”

A review of optimization approaches for controlling water-cooled central cooling systems

“…For example, the computation time of an EDOC was found to be 59.6-83.5% shorter than that of TDOC with a 15 min interval, and the energy-saving rate was slightly higher than that of TDOC [88]. Hou et al [122] further improved the EDOC method by establishing an event map between event-actions and influential decision variables. When an event occurs, only the corresponding decision variable is optimized, rather than all the decision variables, to further reduce the computational cost.…”

Task-based paradigm for the design of office occupant-building interactions

“…The design of the control system, or occupant-building interaction paradigm, dictates how a building will operate and what type of indoor environment is produced (Brackley et al, 2021;Hou et al, 2020;Luo et al, 2016). Since the indoor environment is a multivariate system, there is no single solution (Andersen et al, 2016;O'Brien et al, 2020;Pita, 2002).…”

“…In any design problem there lies a consistent, underlying logic and reasoning that guides decision-making, i.e., a design concept. Regarding building control system design, the design concept provides a consistent basis to establish a control strategy driver, outline evaluation criteria, and define occupant-building interaction factors (Hou et al, 2020).…”