Cooperative Distributed Demand Control by Environmental Sensor Network - Estimating the Number of People by CO 2 Concentration - Tomokazu Tachikawa † , Akihiro Oda † , Toshihiko Handa † (Keio University), Junichi Ichimura †† , Yuji Watanabe †† (Tokyo Gas), Hiroaki Nishi ††† Member, IEEE (Keio University) Department of System Design Engineering, Faculty of Science and Technology, Keio University, 3-14-1, Hiyoshi, Kouhoku-ku, Yokohama-shi, Kanagawa-ken, Japan Product Development Dept., IT Service Sect, Tokyo Gas Ltd., 3-13-1, MinamiSenju, Arakawa-ku, Tokyo, Japan Abstract — KNIVES is a system for providing balanced power supply and effective demand control. This system controls the power of electric devices over the Internet, due to reduce total power consumption. For the control, KNIVES also considers indoor environmental affinity by using environmental sensors. In this paper, CO 2 sensor is implemented on KNIVES terminal and it enables to measure CO 2 concentration for assessing indoor vitiation. This paper verifies the effectiveness of this sensor by estimating the number of people. Also, the number of people is one of the parameter for effective control. Existing estimating method for counting the number of people, however, is difficult to install in a existing building. This paper describes the new estimating method for the number of people by CO 2 concentration. As a result, this method can accomplish accurate measurement, and it can be applied to various applications for a future demand control. I. INTRODUCTION Currently, the possibility of global heating is severely clamed in world. To prevent this undesirable trend, various efforts toward energy saving are being undertaken by establishing energy saving systems. Demand supply control system receives international attention as an effective and feasible energy saving system. Demand control system turn off electric devices and reduces power consumption when power consumption exceeds demand value Demand supply control system also controls power generation according to total power consumption. This system eliminates redundant power generation, and conserves natural resources. Deregulation of electric utilities is outspreading in Japan. Electric power market is inaugurated, and client can freely select power selling agency. Not only major electric power suppliers but small electric power plants attempt to join this market. Thus, this electric power market becomes more complex. Client will attempt to purchases electric power from electric power market at low cost as possible. In the future, the price of electric power will be depended on a category of energy resource used for a power generation or the amount of CO {tachikawa, oda, handa}@west.sd.keio.ac.jp, {ichimura, y_wata}@tokyo-gas.co.jp, west@sd.keio.ac.jp 2 emission due to the power generation. These approaches will make the market more complex. Information Technology (IT) based energy saving system solves these problems by connecting consumer and generator as a network client and server by sharing various information including environmental sensing data. The system enables to control for effective usage of energy resources or considering environmental load. Thus, IT becomes a key of this future market. To control both consumers’ demand and electric power effectively, sensing is an important factor of prediction or decision of control. For example, in summer, as temperature goes up, it is expected to increase power consumption. As the indoor temperature goes down, the use of air-conditioner is decreased. If the system can seize the number of people in a room, this can be affected to the control sequence; the crowded room can consume more electric power than a nearly empty room. CO 2 emission from human body is also affected by the amount of exercise. This can be applicable to effective control of air conditioner according to the scene of human activity. Moreover, the timing of power shifting should be controlled by the indoor air quality. A worth room in air quality recycles the air while the air conditioner is off. It cannot be concluded that the room of higher CO 2 concentration has the larger number of people in a room. This is affected by the amount of air ventilation of the room and the air ventilation rate should be estimated precisely first. In this point, demand control based on simple CO 2 concentration is different from the demand control based on the number of people. Integration of IT based demand control system with environment sensor, including CO 2 sensing and counting the number of people, is necessary to inquire the controlling algorithm without losing environmental amenity. KNIVES aims a cooperative