5 building sensors healy

7/31/2019 5 Building Sensors Healy

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William HealyNational Institute of Standards and Technology

Gaithersburg, MD USA

Building America Meeting on Diagnostic Measurement and Performance Feedback for Residential Space

Conditioning Equipment

April 26, 2010


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Sensors for Building ApplicationsCurrent StatusKey Challenges

Energy Monitoring Systems in Homes


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TYPICAL NEW CARS 40-50 sensors per car Wide range of types

Temperatures Pressure sensorsAccelerometers Oxygen Fluid level Proximity

TYPICAL BUILDINGS

Residential Thermostat Electric meter Gas meter

Water meter

Smoke sensors CO sensors Others embedded in equipment

Commercial (in addition tothose seen in residential apps)

RH Occupancy Light CO2


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Buildings do contain a large number of sensorsMany sensors in buildings are contained withinequipment and inaccessible outside that

equipmentPace of change much slower in types and

number of sensors included in buildingscompared to automobiles 30 years ago, typical automobile had 5 sensors Were the amount and types of sensors used 30 years ago

in buildings drastically different?

Bottom Line There are still many places where

improved sensing could be valuable in buildings


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From Wikipedia:Smart Systems typically consist of diversecomponents, such as:1. sensors for signal acquisition

2. elements transmitting the information to thecommand and control unit3. command and control units that makedecisions and give instructions based on theavailable information

4. components transmitting decisions and instructions 5. actuators that perform or trigger the required actions


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A prerequisite to a smart buildingUbiquitous sensing could enhance smart

building operations by:

Sensing newphysical quantities

to improve

occupant comfort

and reduce energy

consumption

Providing finer

spatial resolution of

measurements

Enabling

monitoring of more

building equipment


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Examples of types of sensors either neededor in need of improvements for buildingapplicationsLow-cost electric power meters

Low-cost and easy-to-install gas flow meters

Low-cost and easy-to-install water flow metersVentilation sensors (e.g., air flow rates)Indoor Air Quality sensors (e.g.,VOCs, particulates)Reliable occupancy sensorsLight sensors (e.g., intensity & color)Thermal comfort


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Sensors must be easily installed in abuilding and must easily integrate into a

building monitoring and/or control

system

Easy, low-cost, and fast physical installationLittle expert knowledge required to activate

sensor

Little expert knowledge required to include andmake use of data in monitoring system


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WirelessEliminates wiring costsEliminates intrusion of wiringIncreases initial cost of equipment

On-board radio, antennaSoftware to manage wireless data transmissions on

board sensor node

Many commercial products have emerged overthe last 5 years.


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MESH NETWORKS

Internet Model Multiple paths from sensor to

data collector

ExpandableAd-hoc networks can be self-

healing Disadvantages:

More complex software More data transmissions by

intermediate nodes leads toshorter battery life

STAR NETWORKS

Point-to-point communications Simpler system More predictable power

requirements Disadvantages:

Prone to disruption fromsingle points of failure

Limited range


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Application Key Design Issues Protocols

Telephones Quality of Service, Latency CDMA2000

Internet Bandwidth IEEE 802.11 (WiFi)

IEEE 802.16 (WiMAX)

Peripherals Bandwidth IEEE 802.15.1 (Bluetooth)

Wireless USB

Sensors Power IEEE 802.15.4 (ZigBee)

EnOcean


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Still need cost reductionsReliability concerns

Buildings present challenging environmentInterferenceMost hardware uses same open spectrum used by wireless

internet, cordless phones, and other consumer products

Power management

InteroperabilityEase-of-use and maintenanceSecurity


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IEEE 802.15.4 uses 2.4 GHz Industrial,Scientific, and Medical Band same as manyother protocols.

Other non-communication sources ofradiation in this band, e.g., microwaves

0.00%

2.00%

4.00%

6.00%

8.00%

10.00%

12.00%

14.00%

16.00%

0 2 4 6 8 10 12

Pa

cketErrorRate

Transmitter to Receiver Distance(m)

Control

WiFi

BlueTooth

Microwave

0.0%

1.0%

2.0%3.0%

4.0%

5.0%

6.0%

7.0%

8.0%

9.0%

10.0%

0 2 4 6 8 10 12

Pa

cketErrorRate

Transmitter to Receiver Distance (m)

Control

WiFi

BlueTooth

Microwave

Interference Source to Receiver Distance = 0.5 m Interference Source to Receiver Distance = 4 m


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Most networking schemes in place enable self-forming networksPlug-and-Play ? IEEE 1451 Standard for smart sensorsEach sensor maintains on-board identification informationStandard provides for multiple physical connections to

network, both wired and wirelessAutomatically announce its existence when connected to

network

Requires more hardware and softwareLingering Needs

Standard data models Holy Grailself-locating sensorsIt is feasible outdoors, but indoor installations present a wide

range of challenges


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Self-Diagnosing

Self-Healing

Self-Calibrating

Self-Correcting

Low Battery AlertsGross Damage Alerts

Ad-hoc networks can

self-heal

Research phase

Research phase

Redundancy

provided bysensor

networks can

be utilized


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Battery power

Typical energy consumption of wireless sensors:

Typical shelf life of batteries ~ 5 yearsEnergy Harvesting

Photoelectric ThermoelectricVibrations

Radio mode Power consumption (mW)

Transmit 15

Receive 13

Idle 12Sleep 0.016

Lesson: Transmit

and Receive

messages as little as

possible


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World Business Council for

Sustainable Development:Technical devices to measure energy

consumption and provide immediate

feedback help to cut energy consumption

by as much as 20 %

U.N. Intergovernmental Panel on

Climate Change:Infrequent meter readings provide

insufficient feedback to consumers on their

energy use and on the potential impact of

their efficiency investments


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Parker et al. (2006) two year study of 22 homes in Florida Average change in energy usage of-7.4 %; significant variation (from -27.9 %

to +9.5 %)

Ontario Hydro One Study (2006) of over 400 homes

Average change in energy usage of-6.4 %


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Whole-house electricity monitoring

17 products identified in 2009

Most provide instantaneous power Some provide logging capabilities Range of installation procedures

Information Technology products for feedback 6 products identified in 2009 (probably undercounted) most were in development

Rely on other sources to provide dataPoint-of-use monitors

Five identified in 2009 Device inserted between outlet and end-use


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Sensor-richMany low-cost sensors monitoring end-usesData collection, analysis, and display at a central

point

Analysis-richFewer sensors (e.g., single sensor at main meter)Signal analysis to dissect end-usesNon-invasive load monitoringMIT work from the 1980s and 1990s


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From Hart (1992)

Reactive power may be needed

to differentiate end-uses


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Proliferation of new electronic devices has added more signatures to track

Variable speed motors do not havedistinct signature

CostCurrent commercial implementation costs ~$8k

But.it may have application for FDD


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Decreasing cost

Creating easy-to-install systemsWill not require professional plumber, electrician, orHVAC technician

Cannot require cutting into pipes

Should not require major electrical workSoftware setup should be straightforward

Improving methods to determine fossil fuelconsumption

Key Questions:How accurate must the measurements be?How can we minimize the number of sensing points

yet still provide adequate information for fault

detection?


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Key challenges related to sensor use inbuildingsDevelopment of new sensorsIntegration of sensors in a more straightforward

manner

Preservation of sensor performance with little humaninvolvement

Home Energy Monitoring SystemsMany systems have recently emerged

Many improvements are still neededEase of installation and useCostPresentation of data to user

5 building sensors healy

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