iPower: An Energy Conservation System for Intelligent Buildings International Journal of Sensor Networks Yu-Chee Tseng, You-Chiun Wang, and Lun- Wu Yeh p 電管一 R 吳欣蓉

Outline Introduction Related Works Design of the iPower System Conclusions

Introduction

HVAC Introduction (1/3) Lighting Air Conditioning Ventilating Heating Others Over used Global Problem iPower: Intelligent and personalized energy- conservation system by wireless sensor networks(WSNs)

Introduction (2/3) WSNs are deployed in room of a building to collect information of the environment. Information→ control server→ turn off those unnecessary electric appliances in the building →server sends alarm signal – User don‘t want →triggering some events – No intentional events →turn off

Introduction (3/3) iPower system also provides personalized services. Automatically adjusted to satisfy users’ preferences. Each user can create a profile to describe his/her favorite temperature and brightness.

Related Works

WSNs have been widely used for providing context information in smart space/environment applications. Electric appliances are all controlled by SIP (session initiation protocol) server.

System Architecture Energy Conservations Scenarios System Operations and Message Flows Personalized Services and User Profiles Protocol Stack Design of The iPower System

System Architecture In this architecture, includes: Sensor nodes Control server WSN gateways Power-line control devices User identification devices

System Architecture- Sensor nodes (1/2) To monitor the environment. Form a mutli-hop WSN to collect information in the environment. Three types of sensing data can be collected, including light, sound, and temperature.

System Architecture- Sensor nodes (2/2) Different events can be combined to define a room’s condition. Example: – Low temperature (or a high brightness) + some sound events = the corresponding electrical appliances are turned on to serve users. – Sound events + change of the light degree read by sensors = users are moving around. – Low temperature (or a high brightness) + no sound event = air conditioners (or lights) are unnecessarily turned on = no one in the room.

System Architecture- WSN gateways (1/2) Wireless interface: talk to sensor nodes Wire-line interface: talk to the control server. Four major functionalities: – Issuing commands to nodes of the WSN. – Gathering data from nodes of the WSN. – Reporting the room’s condition to the control server. – Maintaining the WSN.

System Architecture- WSN gateways (2/2) Notify nodes of the WSN→ Start collecting environmental information→ when receives a start command. After gathering sensing reports→ Determine the room’s condition & report to the server.

System Architecture- Control server Collected the system’s status & perform power-saving decisions. Maintains a database of user profiles & checks the states of electric appliances. Can makes decision and adjusts the electric appliances. Provides user interfaces.

System Architecture- Power-line control devices Allow us to turn off or adjust the electric currents of appliances in the iPower system. Use X10 products which contains one X10 transmitter and several X10 receivers. The X10 transmitter can communicate with X10 receivers via power lines.

System Architecture- User identification devices A portable devices. Carry by users so that the system can determine users’ IDs and retrieve their profiles. Use the processor board of our sensor platform for user identification.

Energy Conservation scenarios Room A Electric appliances are turned on but nobody is in the room. Room A Electric appliances are turned on but nobody is in the room. Room B Electric appliances are turned on and somebody is in the room (with user identification device). Room B Electric appliances are turned on and somebody is in the room (with user identification device). Room C Electric appliances are turned on and somebody is in the room (without user identification device). Room C Electric appliances are turned on and somebody is in the room (without user identification device). Room D Electric appliances are turned on in a room with smart furniture. Room D Electric appliances are turned on in a room with smart furniture. Room E electric appliances are turned off. Room E electric appliances are turned off.

System Operations and Message Flows 1. Control Server: begins checking the usage f electric appliances periodically or at predefined time according to the system configuration file. Then send a start message to WSN gateway. 2. WSN gateway receives the message Step 1: Notify its sensor nodes by issuing some event-driven queries to begin collecting information of the environment. Step 2: Then sets a timer and waits for sensing reports from sensor nodes. 3. Sensor node detects any event (ex: low temperature or high brightness), it will report sensing data to the WSN gateway. 4. WSN gateway receives any report and any human behavior report from step 3 before its time expire, it can determine the room’s status according to the following rules: (1). If smart furniture reports that someone is using it, the WSN gateway will report a normal status to the server. If it reported that the user leaves, the WSN gateway will check the room’s status. (2). If sensors report any human behavior (ex: a sound event) the WSN gateway will report a normal status to the server. Also notify the existence of people. (3). The WSN gateway reports an abnormal status = the electric appliances in the room may be turned on unnecessarily. 5.The server receives an abnormal report, it will warn the people by sending an alarm message to the WSN gateway. 6. Receiving the alarm message (1). The WSN gateway will command its sensor nodes to turn their buzzers to generate a beeping sound. (2). The server sends a blink command to the X10 to blink any light on and off for a short period of time. This action are both notify people the server will turn off the electric appliances after ten minutes. 7.Doesn’t receive any human behavior event after ten minutes, then the server knows no one in the room and will turn off the electric appliances by sending turn-off command to the X10 receivers in the room. 8.User in the room hearing the beeping sound or seeing blinked light, he/she can notify the server the room is still in use, by three methods. 8-a. User has a user identification device, the device will directly inform the server (via the WSN gateway) his/her ID, the user does not need to take any action. 8-b. If the user can access the Internet → log in the web page of the iPower system → set up the next checking → so the server will not disturb the user before he/she leaves the room. 8-c. User can make some intentional events by changing the room’s environment, ex: make some voice. Sensor nodes will detect an unusual and thus report these events to the WSN gateway.

Personalized Services and User Profiles Personalized services: automatically adjusted to satisfy users’ preference. The iPower system can adjust the air conditioners and lights when a user enters a room. The user creates his/her profile in the server’s database and carry a user identification device when entering the system. The user’s location is determined by the WSN gateway which collects the user’s ID.

Protocol Stack To implement the iPower system Picture is the protocol stack Defines the rules that a user can access the system through the user interface. Consider two types of users: administrators and end users. Defines the rules by which the system provides and manages its services. OSGi (open service gateway architecture): A service-oriented architecture for networked systems. Following OSGi, service layer is separated into service component and service management. Three service components: (1).Profile setting service (2).Device controller service (3).Sensor handler service Service management: a new service component→ first register Maintain all user profiles and other profiles for sensors, power-line control devices, and rules. Controls the actions of sensor nodes. Include: executing commands from WSN gateway and reporting sensing data to the WSN gateway. Controls the action of power-line control devices. Include: turning off and adjusting the electric currents of appliances.

Conclusions

Conclusion iPower system: energy conservation in an intelligent building and provision of personalized services for environment control. Detect waste → turn off the unnecessary electric appliances via the X10 devices. Provides personalized services. With the iPower system, we can avoid unnecessary electricity consumption of the HVAC system and thus achieve energy conservation.

Thank You