Development of Cooperative Building Controller for Energy Saving and Comfortable Environment

Abstract

The purpose of automatic controllers for building services (air conditioning system, lighting and blinds system) is to save energy in the whole building while keeping occupants’ comfort. Nevertheless, most of automatic controllers don’t optimally operate from the viewpoint of total energy efficiency and occupants’ satisfactions. The main reason is that each controller operates, neglecting states of other controllers and therefore, control point of each controller always doesn’t correspond to best control point in the whole building system. In this study, we propose an innovative controller that communicates with other controllers to control building equipments optimally from the viewpoint of total energy efficiency and occupants’ satisfactions. The developed controller functions as an agent in the control system, which can voluntarily collect available information from other controllers and decide set points to enhance total efficiency in cooperation with one another. Therefore, this controller is called as “cooperative controller”. Several types of cooperative controllers have been developed and experimentally applied to an actual building located in Japan (Sogo et. al. 2002, Honma et. al. 2002, Terano et. al. 2002 ). In this paper, cooperative control using daylight, major example in series of cooperative control system, is reported. Daylight is useful to reduce energy consumption of lighting, however, it has not been widely used. The main reason is that as incoming daylight has complex effects on thermal and visual environment, it is difficult to optimally control amount of daylight. To solve this problem, we propose cooperative control system that can control amount of daylight effectively to optimize total energy efficiency and occupants’ comfort. A series of numerical experiments was conducted to confirm effect of cooperative control system on improvement of total energy efficiency and indoor environment. The results showed that this cooperative control system could save energy use rate of almost 10% compared with no cooperative control system. In addition, in order to use in practice, cooperative controller is designed to apply an actual building easily and keep stability even in the other controllers’ troubles.KeywordsEnergy savingCooperative controlVenetian blind