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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?
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
Doing better with houses: lots of insulation!
Flickr photo courtesy of Smalloy.
CEE 1.964Design for Sustainability
Taking advantage of free heating for “elfhouse”
-10
0
10
20
30
40
50
60
00:1
3.0
45:1
3.0
30:1
3.0
15:1
3.0
00:1
3.0
45:1
3.0
30:1
3.0
15:1
3.0
00:1
3.0
45:1
3.0
30:1
3.0
15:1
3.0
00:1
3.0
45:1
3.0
30:1
3.0
15:1
3.0
00:1
3.0
45:1
3.0
30:1
3.0
15:1
3.0
00:1
3.0
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
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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)
2001 U.S. standard (476 kWh)
1993 U.S. standard (686 kWh)
1600
2000
Figure by MIT OCW.
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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)
CEE 1.964Design for Sustainability
NREL’s rational approach to efficiency and zero-net energy in houses
Source:
Ren Anderson, NREL
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
Canadian Solar Decathlon House
Heat recovery from PV boosts efficiency from ~8% to ~35%
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
Massachusetts State Transportation Building,Boston: a 20-year oldie but goodie
Aerial photograph of the State Transportation Building.
Image removed for copyright reasons.
CEE 1.964Design for Sustainability
Atrium as thermal buffer, source of daylight and central plaza
Photographs of atrium.
Images removed for copyright reasons.
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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%
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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.
Image removed for copyright reasons.
CEE 1.964Design for Sustainability
Open atrium but closed conference rooms
Photographs of atrium.
Images removed for copyright reasons.
CEE 1.964Design for Sustainability
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.
Image removed for copyright reasons.
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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)
CEE 1.964Design for Sustainability
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.
Images removed for copyright reasons.
CEE 1.964Design for Sustainability
Interior Temperatures: July 2003
Luton July 2003
0
5
10
15
20
25
30
35
40
45
7/23
/03
12:0
0 A
M
7/23
/03
4:45
AM
7/23
/03
9:30
AM
7/23
/03
2:15
PM
7/23
/03
7:00
PM
7/23
/03
11:4
5 P
M
7/24
/03
4:30
AM
7/24
/03
9:15
AM
7/24
/03
2:00
PM
7/24
/03
6:45
PM
7/24
/03
11:3
0 P
M
7/25
/03
4:15
AM
7/25
/03
9:00
AM
7/25
/03
1:45
PM
7/25
/03
6:30
PM
7/25
/03
11:1
5 P
M
7/26
/03
4:00
AM
7/26
/03
8:45
AM
7/26
/03
1:30
PM
7/26
/03
6:15
PM
7/26
/03
11:0
0 P
M
7/27
/03
3:45
AM
7/27
/03
8:30
AM
7/27
/03
1:15
PM
7/27
/03
6:00
PM
7/27
/03
10:4
5 P
M
7/28
/03
3:30
AM
7/28
/03
8:15
AM
7/28
/03
1:00
PM
7/28
/03
5:45
PM
7/28
/03
10:3
0 P
M
7/29
/03
3:15
AM
7/29
/03
8:00
AM
7/29
/03
12:4
5 P
M
7/29
/03
5:30
PM
7/29
/03
10:1
5 P
M
Tem
pera
ture
(C)
ground floor averagefirst floor averagesecond floor averageoutside
CEE 1.964Design for Sustainability
Interior Temperatures: August 2003
Luton August 2003
0
5
10
15
20
25
30
35
40
45
8/1/
2003
8/1/
2003
8/2/
2003
8/3/
2003
8/4/
2003
8/5/
2003
8/6/
2003
8/6/
2003
8/7/
2003
8/8/
2003
8/9/
2003
8/10
/200
3
8/11
/200
3
8/11
/200
3
8/12
/200
3
8/13
/200
3
8/14
/200
3
8/14
/200
3
8/15
/200
3
8/16
/200
3
8/17
/200
3
8/18
/200
3
8/19
/200
3
8/19
/200
3
8/20
/200
3
8/21
/200
3
8/22
/200
3
8/23
/200
3
8/24
/200
3
8/24
/200
3
8/25
/200
3
8/26
/200
3
8/27
/200
3
8/28
/200
3
8/29
/200
3
8/30
/200
3
8/30
/200
3
8/31
/200
3
Tem
pera
ture
(C)
outsideFirst floor averageGround floor averageSecond floor average
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
Zion National Park Visitor Center
Image courtesy of the National Park Service.
CEE 1.964Design for Sustainability
California Courthouse candidate for night cooling
Photograph of courthouse windows.
Image removed for copyright reasons.
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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
CEE 1.964Design for Sustainability
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.
CEE 1.964Design for Sustainability
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.