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MAXIMIZING ENERGY EFFICIENCY WITH CONCRETE’S THERMAL MASS
Rico Fung, P.Eng., LEED®AP Director, Markets & Technical Affairs CEMENT ASSOCIATION OF CANADA
LEARNING OBJECTIVES
Cement and concrete industry’s advances in
reducing its carbon footprint Concrete’s ability to reduce energy demands
in buildings Concrete’s broader contribution to
sustainability
WHAT WE WILL COVER TODAY Canada’s cement and concrete industry Why focus on energy efficiency Life cycle assessment for a holistic view of
energy use in buildings Concrete’s contribution to energy efficiency Real-world examples Concrete’s broader contribution to
sustainability
A LOOK AT CANADA’S CEMENT AND CONCRETE INDUSTRY
ABOUT CEMENT AND CONCRETE
Cement is A very fine, dry powder Manufactured and shipped
globally Sold in bulk or bags 7% - 11% of a concrete mix The glue that holds concrete
together
Concrete is Created by mixing cement,
aggregate (sand & gravel), water Produced locally, mixed and
hauled over short distances, typically less than 150 km from a project site
The 2nd most used substance on the planet, after water
THE CANADIAN CEMENT INDUSTRY
OUR COMMITMENT TO SUSTAINABILITY
Sustainability is a collective challenge that requires a collective solution.
OUR COMMITMENT TO SUSTAINABILITY
Our industry is committed to: Continuous investment in reducing our operational footprint
Reduced GHGs and Air Emissions Energy Efficiency Alternative and Renewable Fuels Quarry Management and rehabilitation Community Engagement
Being a proactive partner in driving a societal shift to a more sustainable economy Working collaboratively with governments, industry, environmental and civil society groups to identify sustainable solutions
The World Business Council for Sustainable Development Cement Sustainability Initiative
EXAMPLE: REDUCING OUR CARBON FOOTPRINT
We have reduced CO2 emissions per tonne of cement by about 10% in 10 years Improvements in operating energy efficiency Use of alternative and renewable energy sources Use of Supplementary Cementing Materials (SCMs)
Introduced a new cement that will reduce CO2 by a up to 10%
Produces concrete of equivalent strength to that produced with regular Portland cement
TOWARDS GREATER SUSTAINABILITY: FOCUS ON ENERGY EFFICIENCY
WHY FOCUS ON ENERGY EFFICIENCY
Concerns about global warming and climate
change have led to an unprecedented societal call to minimize energy demand and reduce CO2 emissions
WHY FOCUS ON ENERGY EFFICIENCY
From a business perspective, it reduces operating costs, improving the bottom line for building owners
Source: KPMG LLP, Climate Change: Risks & Opportunities in the Canadian Commercial Real Estate Market, 2009
BUILDINGS ARE A MAJOR SOURCE OF ENERGY CONSUMPTION
In 2009, buildings consumed 31% of all secondary energy use in Canada
Source: Natural Resources Canada, Office of Energy Efficiency, Energy Efficiency Trends in Canada 1990-2009
37%
30%
17%
14% 2%
Industrial Transportation Residential Commercial / Institutional Agricultural
BUILDINGS ARE A MAJOR SOURCE OF GHG EMISSIONS
Buildings generated 28% of all GHGs in Canada1 and these emissions are expected to grow by 8% by 20202
1. Natural Resources Canada, Office of Energy Efficiency, Energy Efficiency Trends in Canada 1990-2009 2. Environment Canada, Canada’s Emission Trends 2012
31%
38%
15%
13%
3%
Industrial Transportation Residential Commercial / Institutional Agricultural
THE NEED AND OPPORTUNITY TO MAXIMIZE ENERGY EFFICIENCY ARE GREATER THAN EVER
Nearly 75% of Canada’s buildings will be new or renovated by the year 2035
How expensive will energy be by then? Let’s do it right!
Source: RAIC 2030 Architecture Challenge
THE NEED AND OPPORTUNITY TO MAXIMIZE ENERGY EFFICIENCY ARE GREATER THAN EVER
Both RAIC and CaGBC have embraced the challenge
BUILDINGS LIFE CYCLE ASSESSMENT & EXAMPLES
PHASE 1 INITIAL ENERGY USE
Required to produce the building
PHASE 2 SERVICE LIFE ENERGY USE
Required to operate and maintain the building
PHASE 3 DECOMMISSIONING
ENERGY USE Required to dispose of
the building
Raw material extraction Manufacturing and
processing Transportation Construction
PRE-USE
Plug loads Lighting
HVAC systems Routine maintenance
USE
Demolition Transportation
Recycling/reuse Landfilling
END-OF-LIFE
TYPICAL PHASES AND COMPONENTS OF A BUILDING’S LIFE CYCLE
MIT LIFE CYCLE ASSESSMENT (LCA) STUDY
Single Family Multi-Family Commercial
U.S. Department of Energy benchmarked models of three building types Conventional construction with conventional heating and cooling systems EnergyPlus simulation program to model energy use, GaBi software for LCA
SINGLE FAMILY HOUSE LCA
0
1000
2000
3000
4000
5000
6000
Chicago ICF Chicago Wood Phoenix ICF Phoenix Wood
GW
P (k
g C
O2e
/m2 )
End-of-life Use Pre-use
Global Warming Potential Normalized by Gross Floor Area Over a 60-year Lifespan
MULTI-RESIDENTIAL BUILDING LCA
Global Warming Potential Normalized by Gross Floor Area Over a 60-year Lifespan
0
1000
2000
3000
4000
5000
6000
Chicago ICF Chicago Wood Phoenix ICF Phoenix Wood
GW
P (k
g C
O2e
/m2 )
End-of-life Use Pre-use
COMMERCIAL BUILDING LCA
Global Warming Potential Normalized by Gross Floor Area Over a 60-year Lifespan
0
1000
2000
3000
4000
5000
6000
Chicago Concrete Chicago Steel Phoenix Concrete Phoenix Steel
GW
P (k
g C
O2e
/m2 )
End-of-life Use Pre-use
MIT LCA STUDY - KEY TAKEAWAYS
Operating energy is the predominant component of a building’s total energy use
Initial embodied energy is a small component A concrete structure’s GWP is up to 8% lower
than a corresponding wood-frame structure, over a 60-year period, before considering the impact of energy reducing technologies
UBC LCA STUDY SUPPORTS MIT STUDY RESULTS
Comparative analysis of six-storey concrete and wood buildings in Vancouver with a 60 year service life
Conclusions Buildings’ environmental performance highly
dependant on energy use over their service life Concrete buildings required less energy over
their service life than wood buildings
CONCRETE’S CONTRIBUTION TO ENERGY EFFICIENCY
REDUCED INITIAL EMBODIED ENERGY
Initial Embodied Energy < 10% of Global Warming Potential (GWP)
THERMAL MASS MODERATES INDOOR CLIMATE
Acts as a heat sink, absorbing and storing heat gains during the day, and releasing heat back to interior space during the night
Reduces and delays peak load demands Helps reduce heating and cooling energy demands
Time Lag and Temperature Damping – from ASHRAE Standard 90.1
WHY? CONCRETE’S THERMAL MASS REDUCES OPERATING ENERGY USE
Concrete’s thermal mass
Thermal mass = ability of a material to store heat energy
Permits energy storage and regulation of interior temperature conditions
Maximizes the benefits from integrated energy saving technologies
Temperature moderation in a cave environment
NSW Department of Education and Training, Riverina Environmental Education Center
INNOVATIVE BUILDINGS SHOW EVEN BETTER RESULTS
Buildings where concrete’s thermal mass
was activated with smart energy systems and strategies achieved operating energy reductions of up to 70% when compared to conventional construction
STRATEGIES TO MAXIMIZE ENERGY EFFICIENCY
Designing “smart” buildings that respond to their external environments
Using integrated energy saving technologies and processes Geothermal heating and cooling systems, radiant
floors, hydronic heating, solar panels, etc. Maximizing buildings’ useful service life Build it once. Build it right. Build it to last.
Matching the building’s energy outlook to its design service life
CONCRETE’S THERMAL MASS BENEFITS KNOWN FOR CENTURIES
CLASSIC ADOBE BUILDINGS
http://travel.nationalgeographic.com/travel/world-heritage/pueblo-de-taos/
32
CLASSIC ADOBE BUILDINGS
Used by the indigenous peoples of the American southwest
High thermal mass from thick, rammed earth walls
In hot desert climates moderates the indoor environment from daily high and nightly low temperatures
33
THERMAL MASS MITIGATES THE EFFECTS OF SOLAR RADIATION ON THE BUILDING ENVELOPE
Dark tinted glass wall (Vancouver) Maximum measured surface temperature = 47∘C
Concrete wall (Vancouver) Maximum measured surface temperature = 35∘C
Specific Heat Capacity (Cp) – j/kg °K Heat storage capacity per kilogram of material
Density (ρ) – kg/m3
Mass per unit volume Thermal Conductivity – W/m °K The ease with which heat can travel through a material Moderate value is better for thermal mass effect
Thickness of the material (t)
THERMAL MASS EXPLAINED
0
500
1000
1500
2000
2500
3000
3500
4000
4500
Material
Water
Stone
Brick
Concrete
Clay Brick
Steel
Wood
HEAT CAPACITY OF BUILDING MATERIALS
Spe
cific
Hea
t Cap
acity
(J/k
g . K
)
0
5
10
15
20
25
30
35
40
45
50
Material
Water
Stone
Brick
Concrete
Clay Brick
Steel
Wood
Insulation
THERMAL CONDUCTIVITY
Ther
mal
Con
duct
ivity
(W/m
.K)
Crude Approximation of Thermal Mass (TM) TM = Cp x ρ x t Ignores Thermal Conductivity
Contributing Factors: Climate data, solar radiation, internal loads,
infiltration, ventilation and wind properties
Source: C.A. Balaras. (1996). The Role of Thermal Mass on the Cooling Load of Buildings. An Overview of Computational Methods. Energy and Buildings 24, pp. 1-10.
THERMAL MASS EXPLAINED
THERMAL MASS EXPLAINED (MIT)
For new construction, based on ASHRAE 90.1-2007, on a sliding scale: 12% improvement = 1 point 48% improvement = 19 points
(Measured over the baseline energy performance in accordance with ASHRAE 90.1 – 2007 Standard)
CONTRIBUTION TO LEED® 2009 - ENERGY AND ATMOSPHERE CREDIT POINTS
IN THE SUMMER HIGH THERMAL MASS BUILDINGS
tend take on the average outdoor temperature; cooler during the daytime hours
Less cooling capacity and cooling energy (Saving $$$)
Can push peak cooling needs well into the late afternoon and evening hours (Saving $$$)
more comfortable
41
HOW ABOUT THE WINTER CONDITION?
Thermal mass moderates solar gains, avoids uncomfortable temperature swings during sunny periods
Can result in lower annual heating requirements
42
HOW MUCH CONCRETE IS NEEDED?
Not much! Just enough to hold the building up…
43
THE LESSON?
For the Heating Season: Start with an air-tight building envelope, and do
not over ventilate Thermal mass helps to moderate solar gains to
prevent overheating For the Cooling Season: Take advantage of free cooling when outdoor
conditions permit through natural or forced ventilation Limit solar gains!!!
44
REAL-WORLD EXAMPLES OF MAXIMIZING ENERGY EFFICIENCY Institute for Computing, Information and
Cognitive Systems, University of British Columbia
Earth Rangers Centre Manitoba Hydro Place Del Ridge Homes Greenlife Condominium
Project
INSTITUTE FOR COMPUTING, INFORMATION & COGNITIVE SYSTEMS (ICICS), UBC
Institute for Computing,
Information and Cognitive Systems (ICICS)
Center for Integrated Computer Systems Research (CICSR)
ARCHITECT Hotson Baker (Now Design Dialog) and B+H ENGINEERS Stantec and Bush, Bohlman + Partners
ICICS ENERGY FEATURES Radiant slab heating and cooling Ventilation air distribution Extensive use of natural light Lighting sensors control use of artificial lights Ventilation heat recovery Radiant slab pipe distribution system
differentiated into core and perimeter systems Operable windows provide additional occupant
temperature regulation
0
100
200
300
400
500
600
700
800
Summer Fall Winter Spring Total
Equi
vale
nt k
Wh/
m2
ICICS CICRS
ICICS / CICRS COMPARATIVE ENERGY CONSUMPTION OVER A YEAR
Overall ICICS energy consumption ≈ 60% lower than CICRS 71% in summer and 48% in winter
ICICS ENERGY USE RESULTS
Energy intensity ≈ 60% lower than CICSR’s Energy savings of:
20% over national Model Energy Code for Buildings 60% over the 2005 Commercial and Institutional
Consumption of Energy Survey University results Additional optimization of systems would allow
further energy savings UBC has mandated Silver LEED certification for
subsequent projects
EARTH RANGERS CENTRE
ARCHITECT: Bautech Developments Ltd STRUCTURAL ENGINEER: Internorth Engineering Inc.
EARTH RANGERS CENTRE ENERGY INNOVATIONS
EARTH RANGERS CENTRE – EARTH TUBES
EARTH RANGERS CENTRE - RADIANT FLOORS
EARTH RANGERS CENTRE ENERGY SAVINGS
Improved energy efficiency by 10% per year
Earth Tubes produce savings of $7K per year
Additional concrete paid for itself within the first 5 years of operation
Currently LEED Platinum Existing Buildings: Operations and Maintenance
MANITOBA HYDRO PLACE
Reports energy savings of 70% compared to comparable office towers
Reports estimated energy savings of $500K annually
LEED Platinum Certified
“the concrete and thermal mass it
provides are fundamental to the building’s energy efficient design...”
Energy Use Monitoring Officer, Manitoba Hydro Place, June 2011
1
2
3
4
5
1
1 3 – 6 storey tall atria act as the building’s lungs
24m high waterfall either humidifies or dehumidifies the air depending on the season
Air is distributed via the raised floor distribution plenum
Exposed ceiling mass uses radiant heating and cooling
Geothermal system draws excess heat or cold stored within the soil to condition the building
Air flows to the solar chimney and is exhausted upward in the summer
Air is drawn down in winter and used to warm the parking garage
2
3
4
5
6
7
6
7
Image © Bryan Christie Design. Image courtesy of Kuwabara Payne McKenna Blumberg Architects
MANITOBA HYDRO PLACE AND RADIANT HEATING AND COOLING Exposed radiant
concrete ceiling slabs are primary source of heating and cooling
Reduces demand for forced air systems, which run at higher temperatures
Image courtesy of Kuwabara Payne McKenna Blumberg Architects
MANITOBA HYDRO PLACE AND DISPLACEMENT VENTILATION
Displacement ventilation delivers 100% fresh air
Stale air exits via North Atrium into solar chimney
Conventional ductwork and hung ceiling eliminated Operable
interior window
Computer controlled exterior window
Computer controlled louver blinds
Radiant ceiling slab
Column free space
Perimeter of edge slab
MANITOBA HYDRO PLACE AND CONCRETE’S THERMAL MASS
Image courtesy of Kuwabara Payne McKenna Blumberg Architects
MANITOBA HYDRO PLACE AND GEOTHERMAL HEATING AND COOLING
Includes 280 boreholes, six inches in diameter, 400 feet deep
Provides cooling in the summer and meets 60% of heating demands in winter
Image © Bryan Christie Design. Image courtesy of Kuwabara Payne McKenna Blumberg Architects
DEL RIDGE HOMES GREENLIFE CONDOMINIUM PROJECT, MILTON, ONTARIO
Keith Loffler McAlpine Architects
DEL RIDGE HOMES ENERGY SAVINGS
Operational energy per suite: 4.1 kwh/sf/year − about 20% of the norm
Insulated Concrete Form wall construction Thermal mass moderates hallway and stairwell
temperatures Eliminates the need for 20 - 2.5 kw heaters
Installation of R70 EPS on roof area improves energy efficiency
Enclosed garage ramp saves 70,000 kwh/yr
DEL RIDGE HOMES ENERGY SAVINGS
Solar powered parking lights save about
45,000 kwh/year Motion sensoring in parking stalls and other
common areas reduced demand by about 85% Make up air is tempered by a geo-thermal
“multi-stack” unit
CONCRETE’S THERMAL MASS MAKES IT POSSIBLE TO MINIMIZE ENERGY DEMAND THROUGHOUT A BUILDING’S LIFE CYCLE, REDUCING COST OF OWNERSHIP AND CO2 EMISSIONS
CONCRETE’S BROADER CONTRIBUTION TO SUSTAINABILITY
CONCRETE’S SUSTAINABILITY ATTRIBUTES Durability Resiliency Energy efficiency Versatility 100% Recyclable Produced locally
CONCRETE’S SUSTAINABILITY BENEFITS Maximizes buildings’ service life Allows greater, safer urban density Reduces operating costs and CO2 emissions Offers limitless architectural possibilities Benefits local economies
TODAY’S CONCRETE IS ESSENTIAL TO BUILDING SMART, SAFE, ENERGY-EFFICIENT, SUSTAINABLE COMMMUNITIES
THANK YOU!
