Andrea Love, AIA, LEED A.P. Libby Hsu, MEng

Andrea Love, AIA, LEED A.P.Libby Hsu, MEng

Life Cycle Assessment of Life Cycle Assessment of Commercial BuildingsCommercial Buildings

Life Cycle Assessment of Life Cycle Assessment of Commercial BuildingsCommercial Buildings

Industry Day – August 31, 2010

Presentation Outline

Motivation Approach & Methodology Results Going Forward



Office Building in Amsterdam, Claus en Kaan Architecten

MOTIVATION

Why Commercial Buildings?

1/3 of current construction private, non-residential 10% are office buildings Over $500 billion annually spent on office building construction in 2009 & 2010

Buildings are #1 CO2 Emission Sector:

40% Primary Energy Usage

72% Electricity Consumption

39% CO2 Emissions


Sources: U.S. Census Bureau News, June 2010 Construction at $836.0 Billion Annual Rate, 2010& Environmental Information Agency, EIA Annual Energy Outlook, 2008

Why Commercial Buildings?

Financial Benefits 9% decrease in operating costs 8% building value increase 7% improvement on ROI 4% increase in occupancy ratio 3% increase in rental rates

Source: McGraw-Hill Construction, Key Trends in the European and U.S. Construction Market Place SmartMarket Report, 2008 & 2007


http://blog.lessonpathways.com

Goals


What reductions can be made in the carbon emissions of a concrete structure commercial building office building over the life cycle of the building?

What role does thermal mass play for commercial buildings?

Yellow Building in London, Allford Hall Monaghan Morris

Goals


More specifically first looking at . . .

A concrete structure versus a steel structureIdentical exterior envelope and other building features

dfgs


APPROACH

& METHODOLOGY

Previous Studies


Operational energy savings from: 5% energy increase to 30% energy savings1

Don’t look at embodied energy

LCA Studies Inaccurate or excluded operational energy Not U.S. data

1. “Modeling Energy Performance of Concrete Buildings for LEED-NC Version 2.2: Energy and Atmosphere Credit 1” by M. Marceau & M. VanGeem;

“Thermal Mass” by The Concrete Centre

“Concrete for energy-efficient buildings: The benefits of thermal mass” by European Concrete Platform

“Framing Systems and Thermal Mass” by M. Gorgolewski

2. “Comparison of Environmental Effects of Steel- and Concrete-Framed Buildings” by A. Guggemos and A. Horvath

“A comparative LCA of Steel and Concrete Framed Office Buildings” by K. Eaton and A. Amato

Life Cycle Assessment


LCA

http://www.isover.com



We consider: Embodied energy of material Operational energy of building Material maintenance Building demolition

Phoenix, AZ & Chicago, IL

75 year life



Included: All operational energy All core and shell building materials

Excluded: HVAC & building equipment Tenant space materials & furniture

Software: GaBi

Models are created in terms of mass and energy units

Results are shown in terms of energy usage and Global Warming Potential (lb CO2e)


Software: DesignBuilder


Energy Modeling Scope

ENERGY USE

Hot Water Production

Plug Loads & Lighting

System Type System Sizing Fuel Type CoP or Efficiency Temperature Setpoints Schedule

Air InfiltrationAir Infiltration

HVACHVAC

Internal GainsInternal Gains

Solar GainsSolar Gains

HVAC

FuelSchedule

Glazing RatioGlazing PropertiesEnvelope Properties and Dimentipns

Fuel TypeEfficiencySchedule

Lights, People, Equipment Schedule

Software: DesignBuilder


Approach & Methodology


Large Commercial Office Building

500,000 ft2

12 Stories + Basement 40% Glazing 60% Aluminum Panel

Rain Screen VAV System



Department of Energy, Commercial Building Benchmark Models Based on quadrennial survey of approximately 5,500 buildings 16 building types 16 locations

ASHRAE 90.1-2007 R-values Lighting Power Density Equipment Efficiency



5 Zones per Floor 65% Core Zone



Steel Exposed ConcreteSlab 2” decking w/5” slab 2-way, 12” thickColumns W14 shapes, 37’x40’ o.c. 12”x12” & 16”x16”, 27’ o.c.Beams W24x131 22”x10”Girders W27x217, W27x258 22”x10”Joists 24K10 NoneCeiling Acoustical tile ExposedFloor 90% carpet, 10% tile Exposed



Steel

Floors• 5” concrete

Concrete

Floors• 12” concrete



Steel

Roof• No Concrete

Concrete

Roof• 12” concrete



Concrete Structure Internal Mass



MaterialSteel Structure Concrete Structure

lb/ft2 lb/ft2

Concrete* 68 191Structural Steel 26 14Insulation 0.3 0.3Glazing 0.6 0.6Other 12 7

TOTAL 107 psf 213 psf

*Concrete Mix: 564 pounds of cement per cubic yard of concrete

Thank YouThank YouThank YouThank You

Questions?Questions?Questions?Questions?


MAXXI in Rome, Zaha Hadid

RESULTS

Results


Results


+11%

CO2e

Results


Heating:

- 6% Chicago

- 27% Phoenix

CHICAGO PHOENIX

Results


Cooling:

- 4% Chicago

- 4% Phoenix

CHICAGO PHOENIX

Results


Pumps & Fans:

- 6% Chicago

- 3% Phoenix

CHICAGO PHOENIX

Results


Total HVAC:

- 5% Chicago

- 6% Phoenix

CHICAGO PHOENIX

Results


Chicago

- 2.5%

Phoenix

- 2.7%

Results


Results


Thermal mass does show energy savings

Difference in embodied CO2e of concrete structure materials can be over come in life time of building

Optimized designs are need to increase savings potential from thermal mass


Embodied CO2e: 75.5 lbs/sf

Annual Operational CO2e: 1,610 lbs/sf

End of Life CO2e: 117 lbs/sf

Embodied CO2e: 76.0 lbs/sf

Annual Operational CO2e: 1,600 lbs/sf

End of Life CO2e: 21.3 lbs/sf

The Cor Tower in Miami, Chad Oppenhein architecture + dessign

YEAR TWO WORK

Year Two Work


1. LCA Sensitivity Study

Year Two Work


LCA Sensitivity Study: Strategies to reduction CO2e of concrete

More efficient material usage

xenophilius.wordpress.com

Year Two Work


Year Two Work



2. Envelope Assemblies

Year Two Work


Envelope Assemblies Thermal mass Percent glazing Albedo Thermal bridging

http://www.nrc-cnrc.gc.ca/eng/ibp/irc/cbd/building-digest-97.html

Year Two Work



2. Envelope Assemblies

3. Advanced HVAC Strategies

Year Two Work


Passive strategies Night cooling Passive solar heating

Active strategies Radiant systems Low-lift cooling

“Predictive Pre-Cooling Control for Low Lift Radiant Cooling using Building Thermal Mass” by N. Gayeski, 2010

Year Two Work


Year Two Work


Next Generation

Concrete Buildings

Thank YouThank YouThank YouThank You


Andrea Love, AIA, LEED A.P. Libby Hsu, MEng

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Transcript of Andrea Love, AIA, LEED A.P. Libby Hsu, MEng