2006 AIA Presentation EVA

1
Thermal Mass LEED The effects of thermal mass
on LEED v2.2 New Construction
Energy Atmosphere Credits Presented by Brad
Nesset Composite Technologies Corporation

2
Thermal Mass Sustainable Design

• 36 of ALL energy consumed in the U.S. is
  consumed by buildings
• Natural gas prices are expected to increase from
  30 to 70 compared to one year ago
• Energy efficient building shell is one that
  integrates and optimizes insulation levels,
  glazing, shading, thermal mass, air leakage
  control, and light-colored exterior
  surfaces(Sustainable Building Industry Council
  - High Performance School
  Buildings 2005 Second Edition)

3
Thermal Mass Introduction

• Benefits to Mass

• Energy Efficiency

• Thermal Lag

• Code Impact

• Durability

• Appearance

• Thermal Moisture Protection

• Fire Endurance

• Sound Transmission

4
Thermal Mass Mass Fundamentals

• High Mass Walls
• Concrete
• Brick
• Stone
• Block

• Low Mass Walls
• Lightweight Framing
• Steel Stud
• Metal Building
• Insulated Metal Panels

5
Thermal Mass Mass Fundamentals

• ASHRAE 90.1-1989 Defines
  Lightweight Walls as
• A wall with a Heat Capacity (HC) less than 5
  Btu/ft2.

Metal Buildings
EIFS
Stud Wall
6
Thermal Mass Mass Fundamentals

• ASHRAE 90.1-1989 Defines High Mass
  Walls as
• A concrete or masonry wall with a Heat Capacity
  (HC) greater than 15 Btu/ft2.
• A 6 solid wall has a HC of 15

Brick Cavity wall
Concrete Sandwich Wall
7
Thermal Mass Mass Fundamentals

• As a building material, concrete is
• High Thermal Storage
• Durable (2000 yrs old)
• Flexible
• Easy to Manipulate
• Relatively low cost
• Fire resistant
• Aesthetic
• High Strength
• Green

8
Thermal Mass Mass Fundamentals

• Concrete conducts heat much more efficiently than
  the other materials used in a sandwich wall
  assembly - thus it has poor thermal resistance
  properties.

9
Thermal Mass Mass Fundamentals

• Why is R-value important?
• Payback for client
• In some climates, increasing wall R-Values by as
  little as 5 points can reduce energy use by 30
• Minimum code requirements, ASHRAE 90.1
• Affects HVAC Equipment Sizing
• Moisture Management
• Health of Building
• Sustainable Program LEED

Higher R means more resistance to heat flow More
resistance to heat flow is good!
10
Thermal Mass Mass Fundamentals

• Wall Construction is the key to achieving High
  R-Values
• Key properties are
• Insulation R-Value
• Exterior surface color (solar absortivity).
• Mass heat capacity (density, thickness, and
  specific heat).
• Simulation programs such as BLAST, DOE-2, or
  Energy can be used to determine compliance.
• Position of the insulation relative to the mass
• External, integral, or interior insulation)

11
Thermal Mass Insulating Mass

• Insulation Position is critical
• Interior Insulation on the inside of the bulk
  mass of the wall system.
• Exterior Outside of the bulk mass of the wall
  system.
• Integral Sandwiched between substantial amounts
  of mass.

12
Thermal Mass Thermal Mass Effect
The ability of concrete to store energy and
dampen the effect of temperature change on
heating and cooling systems is know as the
Thermal Mass Effect. Due to the mass effect of
insulated precast walls, the performance R-value
of the high performance wall system can be two to
three times greater than that of the material
R-value, resulting in energy cost savings up to
or exceeding 50.
13
Thermal Mass ASHRAE Standard 90.1 - 2007
14
Thermal Mass ASHRAE Standard 90.1 - 2007
15
Thermal Mass ASHRAE Standard 90.1 - 2007
16
Proposed Exterior Wall Systems
Thermal Mass Wall Comparison

• High Performance Wall

• Veneer / CMU

• Veneer / Steel Stud

17
Thermal Mass Frame Wall

• Building Science is the key to Quality Home
  Construction
• Framed walls
• Energy efficiency
• Moisture control

18
Thermal Mass Frame Wall

• Key problems with wood frame walls today
• Thermal bridging through wood framing.
• Factors limiting the use of cavity insulation.
• Wood framing (more than 16 centers)
• Plumbing
• Heating and cooling ductwork
• Electrical wiring, outlets and junctions
• Wall cavity convection currents.
• Moisture in the wall cavity.

19
Thermal Mass Frame Wall
Where does the cavity insulation go?
20
Thermal Mass Frame Wall
What is Thermal Bridging?
Energy loss through wood framing.
21
Thermal Mass Frame Wall

• 55 of heat loss in typical homes comes from air
  infiltration (38) and wood frame walls (17).

Only insulating the cavities means 25 of the
wall surface is not sufficiently
insulated. Electrical wiring outlets, heating
cooling ducts and plumbing further reduce the
cavity insulation.
25
of the Surface Area is Wood!
22
Thermal Mass Frame Wall
The only consistent thing about batt insulation
23
Thermal Mass Frame Wall

• ASHRAE 90.1 recognizes thermal short circuits and
  applies a correction factor to account for the
  higher heat loss through highly conductive steel
  studs.

• Effective R-value R-value x Correction
  Factor

24
Thermal Mass Frame Wall
Lets look at the assembly of the Steel Stud /
Brick Wall
6 20 GA S.S. _at_ 24 o.c., R-19 Batt ½ Gyp.
R-value 0.68 0.45 0.01 8.60 0.45 0.60 0.80 0.17 11
.76
INTERIOR AIR FILM
GYPSUM BOARD
STEEL STUD R-19 BATT INSULATION
EXTERIOR GYPSUM
AIR SPACE
MASONRY
EXTERIOR AIR FILM
The ASHRAE PARALLEL PATH METHOD was used to
calculate the effective thermal performance for
the metal frame wall construction. The correction
factors from ASHRAE Standard 90.1, 1989 Users
Manual were used to assign reduced thermal
resistance values for the insulated stud cavity.
25
Thermal Mass Frame Wall
26
Thermal Mass Frame Wall
27
Thermal Mass Frame Wall
28
Thermal Mass CMU

• 8 of load-bearing masonry block has
  approximately the same R-Value as a single panel
  of glassR-1.4 !

• Insulation IS Important !

29
Thermal Mass CMU
30
Thermal Mass Brick/Block Wall Comparison

• Brick / Block Wall
• Thermal Inefficiencies short circuits thermal
  bridges
• Construction damage to insulation
• Extensive construction schedule and labor costs
• Insulation saturation during facility life-cycle
• Longer construction schedule
• Shortage of Qualified Construction Labor

31
Thermal Mass Brick/Block Wall Comparison

• Lets Look _at_ the assembly of the Steel Stud /
  Brick Wall

• 6 20 GA S.S. _at_ 24 o.c., R-19 Batt ½ Gyp.

R-value 0.68 1.70 10.00 0.45 0.60 0.80 14.23
AIR FILM
BRICK
AIR GAP
RIGID FOAM
BRICK TIES
MASONRY
INTERIOR AIR FILM
ASSUMED R-VALUE before taking thermal bridges
into account!
32
Thermal Mass Brick/Block Wall Comparison
33
Thermal Mass Brick/Block Wall Comparison
34
Thermal Mass Brick/Block Wall Comparison
35
Thermal Mass Brick/Block Wall Comparison
36
Thermal Mass Green Build Rating Systems

• Energy Star Certification
• Energy Star is a government/industry partnership
  designed to help businesses and consumers protect
  the environment and save money through energy
  efficiency
• Green Globes
• Green Globes is an online, point-based green
  rating system similar to LEED administered by
  Green Building Initiative
• LEED Rating System
• The LEED system is both a standard for
  certification and a design guide for sustainable
  construction and operation. It is performance
  based, and as a design guide, it takes in the
  whole building approach encouraging a
  collaborative, integrated design and construction
  process

37
Thermal Mass LEED

• United Nations Brundtland Commission Report
  (1987) Defined sustainable development and urged
  the world to take note
• Sustainable development is that which meets the
  needs of the present without compromising the
  ability of future generations to meet their own
  needs.
• This Concern Gave Birth to
• The U.S. Green Building Council (USGBC)
• Initiated
• the LEED System
• A nationally accepted standard for developing
  green buildings
• The LEED system currently addresses six (6) areas
  of construction. Projects opting to qualify for
  LEED Certification are graded in those 6
  different categories and must accumulate at least
  26 points.

38
Thermal Mass Sustainable Design NC v2.2

• Credit Category Points Available
• Sustainable Sites 14
• Water Efficiency 5
• Energy and Atmosphere 17
• Materials and Resources 13
• Indoor Environmental Quality 15
• Total Core Points 64
• Innovation and Design Process 5

LEED Certification Levels Certified
26-32
Pts Silver
33-38 Pts Gold

39-51 Pts Platinum
52-69 Pts
39
Thermal Mass Sustainable Design NC v2.2

• Energy Atmosphere 17 Possible
• Prereq 1 Fundamental Commissioning of the
  Building Energy Systems Required
• Prereq 2 Minimum Energy Performance Required
• Prereq 3 Fundamental Refrigerant
  Management Required
• Credit 1 Optimize Energy Performance 1-10
• Credit 2 On-Site Renewable Energy 1-3
• Credit 3 Enhanced Commissioning 1
• Credit 4 Enhanced Refrigerant Management 1
• Credit 5 Measurement Verification 1
• Credit 6 Green Power 1

40
Thermal Mass Mass Fundamentals
Intent Achieve increasing levels of energy
performance above ASHRAE 90.1 to reduce
environmental impact associated with excessive
energy use. Requirement Reduce design energy
cost compared to energy cost budget.
41
Thermal Mass Sustainable Design NC v2.2

Las Vegas, NV

Note AHRAE 90.1-2001 Weighted Average
Note Energy 0.15/kWh, 1.91/therm.
Assumptions Baseline ASHRAE 90.1 Roof R-38
Glass U-0.57 Wall R-7.6ci
Assumptions Roof Area 100,000 sf Wall Area
31,500 sf Glazing Area 5,000 sf
42
University of Charleston Residence Hall
Thermal Mass Exceeding ASHRAE
43
Thermal Mass Summary
44
Thermal Mass Summary
45
Thermal Mass Summary
46
Thermal Mass Summary
47
Thermal Mass Summary

• Benefits to Mass

• Energy Efficiency

• Thermal Lag

• Code Impact

• Durability

• Appearance

• Thermal Moisture Protection

• Fire Endurance

• Sound Transmission

48
Thermal Mass LEED Presented by Composite
Technologies Corporation Manufactures of
THERMOMASS Building Insulation Systems