Post on 17-May-2015
description
IEA Building Envelope Technologies and Policies Workshop, Paris, 17/11/2011
Stephen Selkowitz
Building Technologies Department
Lawrence Berkeley National Laboratory
Overview of U.S. Building Energy Regulations
Additional Content Provided by
Marc LaFrance, USDOE
John Hogan, City of Seattle
Tom Culp, Birchpoint Consulting
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Prior Windows Roadmap: U.S. DOE
Window Performance Goals to 2020
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Envelope Impacts on Building Energy Consumption
Buildings consume 40% of total U.S. energy • 71% of electricity and 54% of natural gas
Envelope Does Not Directly Consume Energy
• Allocating Impact on End Use Energy is a Challenge
42%
57%
Envelope – Building Energy Consumption
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Heating
23%
Cooling
13%
Lighting
18%
Ventilation
3%
Water Heating
10%
Electronics
7%
Appliances
12%
Computers
2%
Other
12%
Impacts 57% of Loads
• 133 Billion $/yr • 13.9% US Energy • 3.5% Global Energy
1/7 US Economy
DOE Building Energy Codes Program
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Codes and Standards: Pathways
• Prescriptive – fixed – Simplest, least costly compliance, most restrictive
• Prescriptive – with tradeoffs – Simple to follow, More flexibility, more complexity
• Performance Based – Design – Design an “equivalent” building that meets code; then show your
building is equal or better
– Very flexible, but costly in terms of design
– Constraints in terms of operational issues
– Requires accurate, useable energy simulation tools
• Performance Based – Measured Outcomes – How to account for actual use, occupancy
– What if performance does not meet goals?
– More pressure on tools to accommodate “reality”
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Design Simulation to Code vs Measured Performance LEED Energy Predictions vs Utility Bills
A few facts: 1. Various building types, ages,
locations 2. Average over all projects not bad 3. Max over-predict by 120% 4. Max under-predict by 65% 5. Almost all under-predicted for low energy designs (red triangle: EUI <= 40) 6. Uncalibrated simulated results
Source: Energy performance of LEED-NC buildings, NBI, 2008
Design EUI (kBtu/ft2)
Mea
sure
d E
UI
(kB
tu/f
t2)
Measured=Design
The Regulatory Ecosystem • National, State, Local
– ASHRAE 90 is primary national Code; 3yr update cycle
– California: Title 20, 24 Building Codes, updated every 3 yrs
• Targets- Net Zero Energy Use by 2025/2030
• Mandatory and Voluntary
– US Green Building Council – LEED ratings- broader than energy
– US EPA/DOE EnergyStar
• Variants: New and Retrofit; Building Type
• Continuous Updates and Revisions – time consuming, costly
• Codes are “Data Hungry” – Where does it come from? Who certifies it? Can it be shared
• Design Operations
– Energy Use Disclosure- private, public
– Audits every 5 years
– Required to Meet Targets?
• Education and Training
– Architects/Engineers
– Code officials
– How to address new technologies, systems etc.
• Overloading the Building Owner? 8
What Not To Do
• Owners swamped by yet another “program” approach to building energy improvements; numerous discrete (overlapping) programs:
– Audit programs
– Rebate programs
– Benchmark programs
– Commissioning programs
– Retrofit programs
– Load Management programs
For New Buildings:
The “determine performance goals, use integrated design approach with state-of-the-art smart systems, construct and commission, operate to meet targets” Program
For Existing Buildings:
The “benchmark your energy use and set goals, actively monitor end use and indoor environmental quality, diagnose and fix problems as they arise -> take operational and/or investment actions to meet goals, and actively monitor feedback, re-evaluate benchmarks in light of costs…” Program
“IT management” problem; Build these programs around a single shared “life-cycle” Building Information Model (BIM)
What’s Needed
DR programs
Renewables programs
LEED programs
EPACT Tax Credit programs
Title 24: Codes and standards
( + Life safety, earthquake, disabled access, ….)
Building Owners Need Integrated Programs for Maximum Market Impact with Lowest Cost and Effort
Framework for Codes • Base Energy Codes
– 2012 IECC
– ASHRAE 90.1
– California Title 24
• Green Codes
– ASHRAE 189.1
– International Green Construction Code (IECC)
• Voluntary – LEED 2012 – Energy Star
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Goals for Standard 189.1
• Establish mandatory criteria in all topic areas: - one “problem” with existing rating systems is that they contain few mandatory provisions - consequently, a designer can achieve “points” & claim that they have a “green building”, but still make no improvements in some areas
• Provide simple compliance options: - another critique of existing rating systems is the need for extensive calculations (e.g. energy)
• Complement green building rating programs: - Std 189.1 is not intended to compete with green building rating programs
Challenges
• Using normative (code) language
• Determining the stringency for a “minimum” standard • Identifying standards or regulations to cite (could not reference guidelines)
• Coordinating with other U.S. National initiatives U.S. Federal agencies Memo of Understanding, American Institute of Architects, National Conference of Mayors
• Creating something that is enforceable by AHJs (authority having jurisdiction)
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Fenestration: What is required if using the prescriptive path? Note: these are very approximate
Current ASHRAE 90.1-2007
2009 IECC ASHRAE 90.1-2010 2012 IECC
Single glazing? Zone 1
(but may need double glazing to meet SHGC)
Zone 1 (but may need double glazing
to meet SHGC) No
Low-e glazing? Everywhere
(unless use dark tint or reflective in zones 1-3)
Everywhere (unless use dark tint or reflective in zones 1-3)
Everywhere
Thermally broken frame?
Zones 4-8 Zones 4-8 Zones 2-8
(Wide TB needed in zones 4-8)
Argon and/or warm edge spacer?
Zones 7-8 Zones 7-8 Zones 4-8
Triple glazing? Not required Not required
Zones 7-8 Zones 6-8 for heavy
products. Maybe zones 4-8 for
very heavy products if cannot use wider TB 15
International Energy Conservation Code (IECC)
• 2012 IECC completed last fall.
• 30% increase in stringency over 2006 IECC – New minimum skylight area requirements in large spaces
– Low-e everywhere
– Increased use of thermal break, argon, warm edge spacers
– Triple glazing in the north
– Removed allowance for monolithic hurricane impact-resistant products in zone 1
– Tighter air leakage requirements
– Recognizes dynamic glazing
– Includes on-site renewable energy (BIPV, rooftop PV)
2012 IECC Prescriptive Requirements
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Zone U
vertical
U skylight
SHGC
8,7,6,5,
and
Marine 4
0.32 0.55 NR
4 except
Marine 0.35 0.55 0.40
3 Marine 0.35 0.55 NR
3 except
Marine 0.35 0.55 0.25
2 0.40 0.65 0.25
1 NR 0.75 0.25
U-factor Changes from 2006 to 2012
Climate
Zone
2006 IECC 2009 IECC 2012 IECC
Vertical Skylight Vertical Skylight Vertical Skylight
1 1.20 0.75 1.20 0.75 NR 0.75
2 0.75
0.75 0.65
(0.75 for
hurricane
products)
0.75 0.40
0.65
3 0.65 0.65
0.50 (0.65 for
hurricane
products)
0.65
0.35 0.55
4 except
Marine
0.40 0.60 0.35 0.60 0.35 0.55
5 and
Marine
4
0.35 0.60 0.35 0.60 0.32 0.55
6 0.35 0.60 0.35 0.60 0.32 0.55
7 and 8 0.35 0.60 0.35 0.60 0.32 0.55
Blue indicates change from previous version.
SHGC Changes from 2006 to 2012
Climate
Zone
2006 IECC 2009 IECC 2012 IECC
Vertical Skylight Vertical Skylight Vertical Skylight
1 0.40 0.40 0.30 0.30 0.25 0.30
2 0.40 0.40 0.30 0.30 0.25 0.30
3 0.40 0.40
0.30 0.30
0.25 0.30
4 except
Marine
NR NR NR NR 0.40 0.40
5 and
Marine 4
NR NR NR NR NR NR
6 NR NR NR NR NR NR
7 and 8 NR NR NR NR NR NR
Blue indicates change from previous version. Note that 2009 IRC has higher 0.35 SHGC, different than 2009 IECC
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