2006/12/05 ICS-2006 1

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

Yu-Chee Tseng, You-Chiun Wang, and Lun-Wu YehDepartment of Computer Science National Chiao-Tung University{yctseng, wangyc, lwyeh}@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

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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 ap

pliances 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 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

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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

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Energy Conservation Scenarios

Internet

Room A

Cellphone

PC

PDA

Control Sever

X10receiver

X10receiver

X10receiver

X10receiver

X10receiver

X10transmitter

WSN gatewayWSN gateway

WSN gateway

WSN gateway

User identificationdevice

Room E

Room CRoom B

Room D

wire line

WSN gateway

power line

p

pressure sensor

ONOFF ON ON

OFF

abnormalEnergy Saving normal state normal state

normal statesmart 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 ide

ntification device server will send a alarm message to r

oom 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 electri

c appliances 4) after 2k minutes, go back to step1

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Message Flows in the iPower System

Internet

PC

WSN gateway sensor node

electric applianceuser identification

device

1. start command 2. event-driven query

4. normal/abnormal

5. alarm signal

3. report event

6. beeps command

6. b

lin

k c

omm

and

8. t

urn

-off

com

man

d

7(a) user ID

7(b) manual configuration notify

7(c)

hum

an e

vent

s

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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 server’s 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

User Layer Administrator End usersUser Layer Administrator End users

SensorLayer

Environment

sensorsSensorLayer

Environment

sensors

configuration status

event commandcontrol

Control Server

ActuatorLayer X10 devices

Electric Appliances

Profile LayerService Layer

Service Component

Service Management

Rule Profiles

TCP HTTP

Profile Handler

Device Handler Service

Sensor Handler Service

Profile Setting Service

Discovery Registry

Devices Profiles

Sensor Profiles

User Profiles

Profile LayerService Layer

Service Component

Service Management

Rule Profiles

TCP HTTP

Profile Handler

Device Handler Service

Sensor Handler Service

Profile Setting Service

Discovery Registry

Devices Profiles

Sensor Profiles

User Profiles

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Implementation of iPower System Hardware devices

MICAz mote X10 devices

User Interface Monitor area Configure area Attribute area

monitor area configure area

attributearea

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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