buildings and energy - mit opencourseware · building america usdoe-sponsored partnerships between...

Buildings and Energy

Les NorfordBuilding Technology ProgramDepartment of ArchitectureMassachusetts Institute of Technology

CEE 1.964Design for SustainabilityNovember 1, 2006

CEE 1.964Design for Sustainability

Outline

1. Buildings and energy – some data2. Residential buildings3. Commercial buildings4. Buildings in other (mainly developing) countries5. Is current progress good enough?


Global energy consumption

0.000

50.000

100.000

150.000

200.000

250.000

300.000

350.000

400.000

450.000

500.000

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

Year

EJ

World Total

North America

Central/South America

Western Europe

Eastern Europe Former USSR

Middle East

Africa

Asia and Oceania

450 EJ = 14.3 TW

CEE 1.964 Source: Goldemberg et al.

00.500

20

40

60

80

1000 40 80

Energy Consumption per Capita (MJ/Day)

120 160 200

1.00

Kilowatts per Capita

Phys

ical

Qua

lity

of L

ife In

dex

1.50 2.00 2.50

Agric Exporter

Primary ExporterOil ExporterIndustrialized CountriesBalanced Economics

Other Agric

Design for Sustainability

Does energy use correlate with quality of life?

Figure by MIT OCW.


U.S. energy end-use

Source:EIA

Electricity –buildings 71%

Total energy–buildings 39%

21%27%

Residential buildings

Commercialbuildings

Transport

34%18%

Industry

Residential buildings

Commercial buildings

Transport

Industry

29%

35%

0%

36%

Figure by MIT OCW.

Figure by MIT OCW.


U.S. residential and commercial building energy use intensities

0.0

0.5

1.0

1.5

2.0

2.5

1975 1980 1985 1990 1995 2000 2005

year

Ene

rgy

use

inte

nsity

, GJ/

m2

residential primaryresidential site

0

0.5

1

1.5

2

2.5

1975 1980 1985 1990 1995 2000 2005

year

Ener

gy u

se in

tens

ity, G

J/m

2

commercialprimarycommercial site

1 GJ/m2 = 277 kWh/m2

Apparently not a lot of progress in 25 years


Residential buildings end-use energy 2003


Commercial buildings end-use energy 2003


2. Residential buildings: savings potential in new construction

30%: little or no increase in first cost50%: about the same life-cycle costNet-zero energy or carbon neutral: much harderHow? INTEGRATED, SYSTEMS DESIGN

Better wallsBetter windowsSmaller HVAC equipmentBetter appliances

Savings relative to early 1990s benchmark


Doing better with houses: lots of insulation!

Flickr photo courtesy of Smalloy.


Taking advantage of free heating for “elfhouse”

-10

0

10

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30

40

50

60

00:1

3.0

45:1

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30:1

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15:1

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00:1

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45:1

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30:1

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15:1

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00:1

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45:1

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15:1

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00:1

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45:1

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30:1

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15:1

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00:1

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45:1

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15:1

3.0

00:1

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45:1

3.0

30:1

3.0

15:1

3.0

00:1

3.0

Time (hours)

Tem

pera

ture

(deg

rees

C)

Average Temperature First Week = 16.9 deg CAverage Temperature Second Week = 17.3 deg C


Insulation, glass and mass for a full-size house

Walden made of 15 cm extruded polystyrene (no openings, no airflow):~1,000 W of heat needed at 0 oF.Henry David needs fresh air, which requires another 500 W to heat.

image: Montgomery Co. Public Schools, VA www.mcps.org


Walden with south-facing, double-pane glazing and water for thermal storage

Indoor and outdoor temperatures

-30

-20

-10

0

10

20

30

40

1 10 19 28 37 46 55 64 73 82 91 100 109 118 127 136 145 154 163

time (hour)

tem

pera

ture

(oC)

ToutTin,n

5 m2 glazing, 1000 kg water


Building AmericaUSDOE-sponsored partnerships between consulting engineers and building industry, leading to prototypes and large-scale production~33,000 houses constructedGoals

Design and construct more energy efficient homesReduce construction costs to provide more affordable housingImprove comfortImprove health and safety and indoor air qualityIncrease resource use efficiency Increase building durability

Energy target: 35-45% reduction in heating, cooling and hot-water energy use


Glazing

http://www.efficientwindows.org/BuilderToolkit.pdf

visible

Full spectrum

~1/2 visible, 1/2 infrared

Window Visible transmittance

Solar heat gain coefficient

Single clear 0.90 0.86 Double clear 0.81 0.76 Double low e 0.76 0.65 Double low e tint 0.45 0.35 Double low e, Ar fill, spectrally selective

0.72 0.40

$0

Single clearAluminum frame

6% Savings#

16% Savings#

32% Savings#

Single tintAluminum frame

Double clearWood/Vinyl frame

Double clearLow-solar-gain low-E

Wood/Vinyl frame

Window Type$200 $400 $600 $800

$0

Single clearAluminum frame

27% Savings#

#Compared to the same 2000 sf house with clear, single glazing in an aluminum frame.

32% Savings#

39% Savings#

Double clearWood/Vinyl frame

Double clearHigh-solar-gain low-E

Wood/Vinyl frame

Triple clearMod.-solar-gain low-E

Insulated frame

Window Type$400 $800 $1200 $1600

Annual Cooling Energy Cost for a Typical House in Phoenix, AZ

Annual Heating Energy Cost for a Typical House in Boston, MA

Figure by MIT OCW.


The builders’ perspective: pros and cons

Durability is keyBetter moisture managementFewer warranty problemsHappier customers and buildersMore referrals, sales

Less construction wasteFewer dumpstersReduced tipping fees

New construction system to learnNew concepts may require changes to local building codes


The systems approachFeature Minneapolis Grayslake,

ILAtlanta Tucson Banning,

CAAdvanced framing -250 -250 +250 Insulating sheathing 0 +400 Insulate basement +600 Slab-edge insulation +200 Unvented, conditioned attic +750 +750 Eliminate roof vents -500 Eliminate housewrap -400 High-performance windows +250 +1,000 +250 +300 +750 Reduce infiltration +100 Controlled ventilation system +150 +125 +150 +150 +250 Locate ducts in conditioned space

0

Simplify or downsize duct distribution

-250 -300

Downsize air conditioner -350 -750 -750 -1,000 High-efficiency, direct-vent furnace

+750 +400 +400

Power-vented gas water heater

+300 +150

Dehumidifier +175 Set-back thermostat +100 Total premium -150 +1,525 -25 +100 +2,150 Annual homeowner savings 225 480 400 390 370


Refrigerators

Source: Collaborative Labeling and Appliance Standards Program

01960 1970 1980

Time (years)

1990 2000

400

Ann

ual e

nerg

y co

nsum

ptio

n (k

iloW

att-

hour

s)

800

1200

1974, California law authorizes energy-efficiency standards (1,825 kWh)

1977, first California standards take effect (1.546 kWh)

Average before U.S. standards (1,074 kWh)

1990 U.S. standard (976 kWh)



1600

2000

Figure by MIT OCW.


Lighting efficacies

Source: IESNA

0 20

Standard IncandescentTungsten Halogen

Halogen Infrared ReflectingMercury Vapor

Metal Halide

White Sodium

Compact Metal HalideHigh Pressure Sodium

Fluorescent (Full size and U-tube)

Compact Fluorescent (5-26 watts)Compact Fluorescent (27-40 watts)

40 60Lumens/watt

lamp plus ballast

80 100

Figure by MIT OCW.


Potential gain from solid-state lighting

Source: Sandia National Lab

19700

100

200

1980 1990Year

Eff

icie

ncy

(lm/W

)

2000

Fluorescent

Halogen

Semi-conductorwithoutaccelerated effort

with accelerated effort

Projected

Incandescent

2010 2020

Figure by MIT OCW.


Residential clothes washers and central A/C

Washing machine energy

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Federal2004

Energy Star2004

Aailable2006

Federal2007

Energy Star2007

kWh/

cycl

e

Residential A/C peak power

0

1

2

3

4

5

6

1978average

Federal1992

Federal2006

EnergyStar 2006

Available2006

GSHP2006

peak

-load

kW

Manufacturers identify Energy Star products. A/C and furnace/boiler producers list efficiencies but clothes washer manufacturers do not tout energy consumption for their equipment, which only costs ~$20/year in electricity


Lakeland, Florida, PV houseAnnual energy use, kWh

2500

4700

18400

net PV efficiency

Better choice of envelope construction would drop payback period from 23 to 9 years without PV and 40 to 28 years with PV.

Photograph of a photovoltaic house.

Image removed for copyright reasons.


Habitat for Humanity houses, Tennessee –Oak Ridge National Lab

Five low-energy houses with very advanced technologies: wall panels, mechanical ventilation, waste-heat scavenging for hot water, PVHeating, cooling and hot water costs about $0.70/ day (!!)“Other” costs $1.00-1.38/day – Christmas lights (!!)Research houses: not cost effective locally ($20K efficiency investment to save $400/year)


NREL’s rational approach to efficiency and zero-net energy in houses

Source:

Ren Anderson, NREL


Automated search for best combination of improvements


Tuning efficiency investments for a given location


PV is expensive, at least for now

Location

Atlanta

Chicago

Houston

Phoenix

San Francisco

32

28

38

39

27

1,749

3,899

2,585

2,585

1,337

49

46

51

52

43

10,351

15,168

8,762

9,553

8,432

42,000

57,000

46,500

40,500

36,000

PV cost

Present value of efficiency investment,

NZE, $

Savings at minimum

cost, %

Savings at NZE, %

Present valueof efficiency investment,

minimum cost, $

Figure by MIT OCW.


Solar Decathlon National Mall 2005


Canadian Solar Decathlon House

Heat recovery from PV boosts efficiency from ~8% to ~35%


3. Commercial buildings

Systems approach is lackingNo Building America equivalentOptimization tools are not as well developedStandards do not take systems approachFew buildings go beyond basic code compliance

Notable successesIndividual buildings, 1/3 -1/2 below averageExpanding data base of high-performance buildingsPrivate-sector labeling program (LEED) a helpGuideline for small commercial buildings


Massachusetts State Transportation Building,Boston: a 20-year oldie but goodie

Aerial photograph of the State Transportation Building.



Atrium as thermal buffer, source of daylight and central plaza

Photographs of atrium.

Images removed for copyright reasons.


What’s missing in this schematic?

Hint: not what you would expect in New England winters

Storage Tank 3

AC-2cooling coil

AC-3cooling coil

HE-3

HWR

CHWR

AC-4cooling coil

Storage Tank 3HE-2

Storage Tank 1

KEY

HWSCHWS

CWR

Hot waterpumps

Perimeter

Condenserwater pumps

CWS

CT-1 CT-2

Chilled water pumps

Zones

RU-2 RU-3

HE-1

HWS = Hot water supply HWR = Hot water return CWS = Condensed water supply CWR = Condensed water returnCHWS = Chilled water supply CHWR = Chilled water return

AC-1cooling coil

RU-1

Figure by MIT OCW.


Potential for wasted energy: simultaneous (same instant, same day) heating and cooling

Mild weather: perimeter may need heat in early morning, cooling in afternoon (like houses)

Year-round: core needs cooling constantly, even when perimeter must be heated

Perimeter zone

Core


Energy consumption

173 kWh/m2 year (277 – US average)End use energy:

Lights 41.6% (13.7 W/m2 peak)Variable mechanical 26.1%Steam 11.2%Appliances 5.4%Elevators 6.2%Computer rooms 5.4%Base mechanical 4.0%


Is this a low-energy building?

173 kWh/m2 yr transp bldg653 state office bldg717 state office bldg270 comm office bldg196 comm office bldg186 comm office bldg

The lower-energy buildings all recover heat from the building core


UK Office #1

Three-story office building5,100 m2 (54,900 ft2) net floor areaSealed windows100% mechanical conditioning1+ year of monitoring and modeling

Photograph of office building.



Open atrium but closed conference rooms

Photographs of atrium.



Airflow MeasurementsVery important!! Air must be heated or cooled, seasonally

40 L/s-person

About four times code requirements

One-half expected occupancy

Conference rooms controlled design

Heat-recovery system broken

Photograph of people taking airflow measurements.



CO2 in conference rooms

CO2 levels were typically well below the 1000 ppm limit

0

CO

2 Le

vels

(ppm

)

Sun12am

Mon12am

Mon12pm

Tue12am

Tue12pm

Wed12am

Wed12pm

Thur12am

Thur12pm

Fri12am

Fri12pm

Sat12am

Sat12pm

Outside CO2 Levels = 415 ppm

Sun12pm

400

600

200

800

1000

1200

Figure by MIT OCW.


Savings due to heat recovery and lower airflowCO2 emissions, kg/m2

Energy consumption, kWh/m2

Natural gas Electricity Total

Current 30.8 162

71.7156

102.5318

Current airflow and heat recovery

19.8104

71.7156

91.5260

Reduced airflow and heat recovery

24.7130

45.098

69.7228


Savings potential due to better operation of buildings

California: energy crisis9% electrical demand reduction in 2001 relative to 2000, due to increased prices

Texas: continuous commissioning20+% energy savings in 100+ large buildings, less than 3 year paybackFor 20 buildings

28% savings in chilled water54% savings in hot water2-20% savings in electricity (fans, pumps)


UK Office #2: nearby, naturally ventilated building

The following pages contained photographs of the office building,

atrium views, interior views including windows and blinds,

exposed structural mass, and open doors for airflow.



Interior Temperatures: July 2003

Luton July 2003

0

5

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7/23

/03

12:0

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M

7/23

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PM

7/29

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10:1

5 P

M

Tem

pera

ture

(C)

ground floor averagefirst floor averagesecond floor averageoutside


Interior Temperatures: August 2003

Luton August 2003

0

5

10

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45

8/1/

2003

8/1/

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/200

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3

Tem

pera

ture

(C)

outsideFirst floor averageGround floor averageSecond floor average


Results from occupant survey – views on temperature

0Neutral

Temperature

20 Slightly warm

Warm1) Warm inside building

this summer but...2) Not overly hot for

most occupants

Hot

Too Hot

Occ

upan

t Res

pons

e (%

)

40

60

80

100

Figure by MIT OCW.


Comparison of UK #1 and UK #1, kWh/m2 year

MV std MV GP NV std NV GP Sunbury A

Luton

Total NG

178 97 151 79 162 140

Total elec

226 128 85 54 156 76

L +OE 85 50 65 42 55 51

Refrig 31 14 0 0 29 0

Fans + cntls

60 30 8 4 50 5

UK #1 UK #2


Dealing with conference rooms: San Francisco Federal Building


Façade details coordinated• Trickle vent and heater

at floor• Manual operable window

at desk height• Motorized window above

2400

2800

(Top

of c

abin

)30

50 (c

onc.

low

pt.) 32

50 (c

onc.

hig

h pt

.)

8001350

740870

2250 @ 14th Floor (width Varies)

PERFSUNSCREEN

WINDOW WALL CONDITIONTYP BOTH SIDES MAX

ALLOW CLEAR OPENING TO BE 90MM TYP

Figure by MIT OCW.


Testing the configuration: predicted degree-hours above base temperature

Base temperature (oF)

Wind only

Internal stack

Int & ext stack

Int stack + wind

Int & ext stack + wind

72 288 507 432 279 285

75 80 118 103 76 76

78 13 25 19 11 12


DOE’s high performance buildings data base

4 Times Square 201 kWh/m2

simulated; daylight, fuel cells, a little PV

EPA office, NC, 89 kWh/m2

simulated; shading, daylight, outside air when suitable


Chesapeake Bay Foundation, Annapolis 131 kWh/m2 measured consumption, 117 kWh/m2 purchased, 10% of consumed energy generated from solar thermal and PV on site; shading, daylight, natural ventilation, ground-source heat pumps

Chesapeake Bay Foundation

0%Fans/pumps

Lights Plug loads

Cooling Other

Heating

26%

20%

26%

20%8%

Figure by MIT OCW.


Zion National Park Visitor Center

Image courtesy of the National Park Service.


California Courthouse candidate for night cooling

Photograph of courthouse windows.



Annual Building-Total Electricity Costs

0

Case #1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

40Ann

ual E

lect

ricity

Cos

t (k$

/yea

r)

80

120

160

200

RatchetOn-Peak kWMid-Peak kWOn-Peak kWhMid-Peak kWhOff-Peak kWh

Figure by MIT OCW.


Energy Design Guide for Small (< 20,000 ft2) Commercial Buildings

30% savings relative to 1999 standardStrategies

Reduce loadsUse properly sized, efficient equipmentRefine systems integration

Climate-specific prescriptive recommendations:

roof, walls, floors, slabs, doors windows, skylights, lighting HVAC, ventilation, and hot water


4. Good enough?

Lifestyle vs. efficiencyMarket acceptance and technology gains for lights, appliances and HVACGrowing but still modest evidence of cost-driven efficiency gainsOpportunity to contribute to carbon stabilizationIntegrated design needs to be pushed


Floor area counters efficiency gains

Source: LBNL report

01950 1960

Year

1970 1980 1990 2000

500

1000

1500

2000

2500

Single-family (mean)

Single-family (median)

US New Housing Floor Area: Single-Family

(1950-2000)

Floor area/cap

Figure by MIT OCW.


Major potential gains from market acceptance

CFL sales up 10x in Northwest, 2001 –2004, but only 11% of market during energy crisis (source: J. DiPeso)

High-efficiency appliances and HVAC are on the market now

Clothes washers 2x code efficiencyResidential A/C 1.5x code efficiency

Near-maximum efficiency gains have been realized in some cases: fridges, furnaces


Atmospheric CO2 stabilization wedges –Pacala and Socolow

Efficiency option: cut building and appliance emissions by 25% relative to business as usual

Renewable electricity and fuels

CO2 capture and storage

Forests and soils

Nuclear Fission

2004

Stabilization Triangle

2054

14 GtC/y

7 GtC/y

Fuel switch

Energy efficiency and conservation

Figure by MIT OCW.


To-do listPromote market acceptance

InformationCarbon taxEmissions trading at micro-level

Work to doCheaper, more efficient technologies

LightsPV, using waste heatVentilation: demand-controlled, heat recovery, night cooling

Ubiquitous integration tools for new construction and retrofits

Individual buildingsCommunities (heat capture, local power generation)Component-level optimization is NOT enough!! Think at systems level.

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