1. 2006/12/05ICS-20061 iPower: An Energy Conservation System for Intelligent Buildings by Wireless Sensor Networks Yu-Chee Tseng, You-Chiun Wang, and Lun-Wu Yeh Department of Computer Science National Chiao-Tung University {yctseng, wangyc, lwyeh}@cs.nctu.edu.tw

2. 2006/12/05 ICS-2006 2 Outline Introduction iPower System System Architecture Energy Conservation Scenario Message Flows in the iPower System Personalized Services and User Profiles Protocol Stack Implementation of iPower System Conclusions

3. 2006/12/05 ICS-2006 3 Introduction According to statistics  more than 1/3 of energy consumption is spent on HVAC systems, which include heating, ventilating, air conditioning, and other related equipments. Energy saving  exploit the context information of an environment to automatically control the usage of electric appliances

4. 2006/12/05 ICS-2006 4 iPower System iPower (intelligent and personalized energy- conservation system by wireless sensor networks) system  reduce energy consumption of HVAC systems by exploiting the context-aware capability of sensors  provide personalized services in which electric appliances can be automatically adjusted to satisfy users’ preferences.

5. 2006/12/05 ICS-2006 5 System Architecture (1/2) System architecture  Sensor nodes Form a multi-hop WSN to collect information in the environment  WSN gateways Four major functionalities  gathering data from nodes of the WSN  reporting the room’s condition to the control server  issuing commands to nodes of the WSN  maintaining the WSN  periodically broadcast heart- beat messages to the WSN  sensor node will reply an alive message to the WSN gateway

6. 2006/12/05 ICS-2006 6 System Architecture (2/2) System architecture  Control server collect the system’s status make a smart decision to control electric appliance devices perform power-saving decisions  Power-line control devices turn on/off or adjust the electric appliances  User identification devices portable devices that can be carried by users so that the system can determine users’ IDs and retrieve their profiles

7. 2006/12/05 ICS-2006 7 Energy Conservation Scenarios p pressure sensor abnormal Energy Saving normal state smart desk Room A: Electric appliances are turned on but nobody is in the room.  abnormal state AC is on but nobody in the room  Electricity is wasted no user identification device is detected  server will send a alarm message to room A alarm message  trigger the beeper on sensor nodes  beeps imply that the system will turn off electric appliances after k minutes, system will turn off electric appliances Room D: Electric appliances and smart furniture  when to turn on a lamp pressure sensor detects a person the sensor on the chair is nearby the sensor on the lamp (in communication distance)  when to turn off a lamp pressure sensor detects no person lamp is on Room E: Electric appliances are turned off.  normal state AC is off no one in the room Room B: Electric appliances are turned on and somebody is in the room  normal state AC is on and somebody is in the room the person carries on a user identification device  system detects someone in the room no action will be taken Room C: Electric appliances are turned on and somebody is in the room  normal state AC is on and somebody is in the room the person doesn’t carry on a user identification device  server will send a alarm message to room A 1) alarm message 2) user intentional behavior  making some noise by clapping  covering any sensor with a light sensor to change its light reading 3) system will cancel turning off electric appliances 4) after 2k minutes, go back to step1

8. 2006/12/05 ICS-2006 8 Message Flows in the iPower System

9. 2006/12/05 ICS-2006 9 Personalized Services and User Profiles Personalized Services  Electric appliances can be automatically adjusted to satisfy users’ preference  Create a profile in the server’s database to record users’ preference  User should carry a identification device An example of user profile.

10. 2006/12/05 ICS-2006 10 Protocol Stack User layer Service layer Profile layer Sensor layer Actuator layer

11. 2006/12/05 ICS-2006 11 Implementation of iPower System Hardware devices  MICAz mote  X10 devices User Interface  Monitor area  Configure area  Attribute area monitor area configure area attribute area

12. 2006/12/05 ICS-2006 12 Conclusion iPower System  energy conservation in an intelligent building  provide personalized services automatically adjust electric appliances to users’ preference  avoid unnecessary electricity consumption of the HVAC system turn off the unnecessary electric appliances  achieve energy conservation