iPower: An Energy Conservation System for Intelligent Buildings by Wireless Sensor Networks

1
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_at_cs.nctu.edu.tw

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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
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

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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.

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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 rooms 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

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System Architecture (2/2)

• System architecture
• Control server
• collect the systems 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

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Energy Conservation Scenarios
normal state

• 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 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 doesnt 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

normal state
abnormal
Energy Saving

• 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

smart desk
normal state

• 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

p
pressure sensor
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Message Flows in the iPower System
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Personalized Services and User Profiles

• Personalized Services
• Electric appliances can be automatically adjusted
  to satisfy users preference
• Create a profile in the servers database to
  record users preference
• User should carry a identification device

An example of user profile.
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Protocol Stack

• User layer
• Service layer
• Profile layer
• Sensor layer
• Actuator layer

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Implementation of iPower System
configure area
monitor area

• Hardware devices
• MICAz mote
• X10 devices
• User Interface
• Monitor area
• Configure area
• Attribute area

attribute area
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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