Towards Aware Building Ecosystem

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Towards Aware Building Ecosystem

• David E. Culler
• EE290N
• Feb 2, 2009

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Demand
Supply
Figure Courtesy Professor Arun Majumdar, UCB, LBNL
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BUILDINGS CONSUME SIGNIFICANT ENERGY

• The Numbers Tell the Story
• 370 Billion
• Total U.S. Annual Energy Costs
• 200
• Increase in U.S. Electricity Consumption Since
  1990
• 40
• Total U.S. Energy Consumption for Buildings
• 72
• Total U.S. Electricity Consumption for Buildings
• 55
• Total U.S. Natural Gas Consumption for Buildings

Source U.S. Department of Energy 2007 Building
Energy Data Book. Sept 2007
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Buildings Matter!
Buildings construction/renovation contributed
9.5 to US GDP and employs approximately 8
million people. Buildings utility bills totaled
370 Billion in 2005. Buildings use 72 of the
electricity and 55 of the nations natural gas.
Source Buildings Energy Data Book 2007
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EPA Nat Action Plan for Energy Efficiency

• 30 of energy consumed in buildings is wasted
• 66 electrical, 34 gas and other
• 15.5 kWh per square foot

2003 EIA Commercial Building Consumption Survey
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Conventional Metering

• What can you tell from the monthly bill?

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Whats a kilowatt?

• 1000/year
• 8,766 hours per year 0.11 /kwh 964
• A unit of the capability to do work
• 1000w / 746 w-per-hp 1.34 horsepower
• 3414 BTU/hr
• Sunlight falling on 52 sq ft _at_ 5 hours per day
• Average power consumption of average house
• residence consumes 25 kwh per day on average
• Average power consumption is 1 kw
• Electrical service is 100A _at_ 220v 22kVA

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So how green are our buildings?

• 511 kw average power consumption
• 4.5 M kwh per year
• 41.2 kwh/sq ft annually
• 3 times national average

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Larger Picture of Campus
kWh/sqft yr Building kWh Approx cost_at_ 0.1/kWh
63.33 Stanley Hall 4,210,004 421,000.40
62.86 Koshland Hall 9,661,247 966,124.69
47.37 Calvin Lab 1,703,022 170,302.20
46.51 McCone Hall 5,811,878 581,187.79
46.27 Giannini Hall 3,187,903 318,790.30
44.59 Life Science Addition 9,086,784 908,678.41
43.42 Hildebrand Hall 5,633,679 563,367.90
41.94 Cory Hall 8,645,079 864,507.89
41.85 Silver Lab Addition 1,810,020 181,002.00
40.34 Soda Hall 4,480,668 448,066.80
39.69 Barker Hall 3,461,192 346,119.20
38.62 Tan Hall 4,571,520 457,152.00
Totals for 2006 129,005,552 12,900,555.15
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What does it take

• To figure out where the power goes?
• To figure out how what to do to reduce it?

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A Simple Energy Model of Everything

• Energy Power Time
• Power Fidle Pidle Factive Pactive Fsw
  Psw
• where Fidle Factive Fsw 1

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The Improvement Loop
Analyze
Observe
Act
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State of the Art Building Energy Monitoring
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Intense Facilities Monitoring
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With a little programming
Do nothing well
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Where does it all go?

• Lighting?
• Heating, Ventilation and Cooling (HVAC)?
• Plug Loads desktops, laptops, kitchenettes?
• Servers?
• Microfab?

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Utility Focus on Peak Demand Response

• Everything sized to peak average
• Sources must match loads
• Baseline (nuclear, hydro)
• Intermittent
• Peaker
• Arbitrage
• A little correlated usage drives peak average
  towards sum of peak !!!
• But better to reduce ALL load

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Auto-DR Study
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Further evidence that behavior matters

• 3x difference in consumption for same setting

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Peaks or Baseline?
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Open Challenge bldg-Spice
Heat
People
Supply Air
Return Air
Water
Waste Water
Electricity

• Components and their model
• Interconnection of all the components
• External drivers
• Observe behavior over time, validate, what-if,

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Long Term, Environmental / Electrical Modeling
and Simulation
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Structural Soda Electrical
Lighting Pumps Fans
Machine Rooms
Offices
Classrooms
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Structural Soda HVAC
Cooling Towers

• Blow cold air throughout building
• Maintain circulation
• Adjust cooling with vents and VFDs
• Heat it where needed
• AC determined by needs of the worst heat load
• Comm closet

Fans
530
420
340
287
288
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Machine Room ACCs
Pumps
2x chillers
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Open Challenge Instrumentation Coverage

• Large Scale Structure
• 48 x 48 potential circuits x
• Many different sub systems
• Functions share section
• HVAC and Lighting on HP
• Servers and Plugs on LP
• Each function uses multiple sub systems
• Servers fed by PDU and ACC
• What points at what fidelity is required to
  disambiguate the important contributors?

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Some initial steps

• When you dont (cant) have the sensors you want,
  get as much as you can with the ones you have.
• Take inventory
• Build models
• Point measurements
• Sample in time, space, population

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Blueprint Analysis of Lighting
Total Provisioning 193 kVA How much is Active?
Idle?
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SCADA portion

• 1300 sense / ctrl points in Soda Hall
• Vast database of action / effect
• No science to turning all the knobs

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HVAC components

• Chillers 2 x 130 kw
• Colling Towers 2 x 33.2 kw
• Computer Room units 12 x 45 kVA
• AHU SF 3.2 kw
• AHU RF 2.3 kw
• Economizers 4 x 2.6 kw 2.1 1.4
• Supply fans 4 x 2.3 kw 1.4
• Pumps 2 x 9.3 kw 2 x 14 kw
• Compressors 2 x 5 kw
• - Its all duty cycle

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Estimating the Server Load

• Forsake temporal dimension
• Inventory the servers
• Measure their idle and active power
• Estimate total load

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Research Server Rooms - 443 Machines
Ganglia
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Server Power Consumption

• Do nothing well

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Putting it Together

• x 1/PDU efficiency ACC
• If Pidle 0 wed save 125 kw x 24 hours x 365

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Breaking Soda down
HVAC Plug Loads
Lighting
HVAC / CRU / PDU support
Servers / Clusters
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Plug Loads

• 1178 Hosts (desktops, laptops, switches) in
  network database
• Power profile, duty cycle?
• Kitchens
• Projectors

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Subset (plugs) of a region (RAD lab)
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Working up from the leaves
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Sample of the RAD Lab population
Appliance Actual Measured
Desktop 4 2
Laptop 25 6
LCD 25 4
Refrigerator 1 1
Coffee maker 1 1
Projector 6 2
Xbox 1 1
Conf. phone 5 1
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Wireless IPv6 Power Meter Architecture
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Measuring Power Sense Resistor

• P IV, I V/R
• Put a tiny resistor in line and measure the
  voltage drop across it with an microcontroller
  ADC
• Simple, but introduces a voltage drop
• And you need to be very careful about what is
  coupled to ground,
• Its 120v but its AC
• Put a huge resistor in parallel with the load and
  measure instantaneous power P(t)I(t)V(t)

Supply
Load
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Kinds of Power

• Real Power (watts)
• capacity to perform real work
• Apparent Power (VA)
• what the utility provides
• What you use to size things
• Power Factor RP/AP
• Determined by phase angle ? of Voltage and
  Current
• PF cos ?
• Resistive load (heaters, filaments), ? 0, PF
  1
• Reactive Loads store or return energy so PF lt 1
• Capacitor (power lines, buried cables, caps) I
  leads V
• Inductors (motors, transformers) I lags V
• Distortion (rectifiers, )
• AC
• 1-phase balanced I amps, E volts, and PF f True
  power EIf watts
• Three-phase True Power v3 EIf watts

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Current Transformer

• Electromagnetic induction, works only for AC
• I2(N1/N2)I1
• Works on High currents
• Galvanic isolation
• Split-Core Clamps make easy measurements
• Need to tap into line for phase

Neutral
Load
Hot
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Hall Effect Sensor

• Applying a magnetic field creates a potential
  difference in a current carrying conductor
• Hall effect sensor is a transducer that varies it
  output voltage in response to changes in a
  magnetic field.
• Used for contact-free tachometer,
• Current in a conduct creates a magnetic field
  that can be sensed.
• Works for both AC and DC

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Acme sense resistor
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Using Hall-effect
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Using current-transformer
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Rad Lab Power Usage (72 hours)
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Guess this load
Active Power
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Guess this Load
Half the idle power!
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Guess this Load

• Active power actually depends on what it is doing
• Actually sleeps!
• Midnight madness

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Guess this Load
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Guess this Load
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Guess this Load
Not so big and beautiful, But a whole lot
greener! Busy person
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Guess this Load
Desktop monitor
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Guess this Load
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Guess this Load
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Guess this Load
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Guess this Load
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Guess this Load
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Guess this Load
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Guess this Load
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Guess this Load
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Guess this Load
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Composite Power Picture
inauguration
Projector left On
Desktop Idle
Clean Shutdown
Monitor On, Unplugged
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The Rad Lab Power Pie
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Relationship to the Bigger Picture
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Open Challenge Bldg Operating System
Courtesy of Arun Majumdar
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Resources

• http//www.demandless.org/building/
• http//www.epa.gov/cleanenergy/documents/sector-me
  eting/4bi_officebuilding.pdf