Residential Stakeholder Meeting #2 -...

California Statewide Utility Codes and Standards Program

Residential Stakeholder Meeting #2

Heschong Mahone Group, Inc.

Phone Number: 1-661-705-2010

Access Code: 88026

April 12, 2011

CALIFORNIA STATEWIDE UTILITIES CODES AND STANDARDS PROGRAM

April 12, 2011 CA Utilities 2013 Title 24 Stakeholder Meeting for Proposed Code Changes

2

Meeting Agenda

Number Category Title Time

Allotted Time

CASE Author /

Presenter

Intro 15 9:30 - 9:45 Cathy Chappell

Res 1 Envelope Infiltration and

Testing 55 9:45 - 10:40 Bruce Wilcox

Res 7 HVAC Zone Air Conditioning 55 10:40 - 11:35 Bruce Wilcox

Res 12 HVAC Ducts 55 11:35 - 12:30 Doug Beaman

Lunch 30 12:30 - 1:00

Res

2/3 Envelope

Cool Roofs/

Roof Insulation 110 1:00 - 2:50 John Arent

Break 15 2:50 - 3:05

Res 4 Envelope Windows 55 3:05 - 4:00 Ryan Schmidt /

Ken Nittler

Res 18 DHW Multifamily DHW 55 4:00 - 4:55 Yanda Zhang

Closing Comments 20 4:55 - 5:15 Cathy Chappell

Residential Stakeholder Meeting 2 Phone Number: 1-661-705-2010 Access Code: 88026



3

IOU Support for 2013 Title 24

The California Investor Owned Utilities (IOUs) are actively

supporting the California Energy Commission (CEC) in

developing the state’s building energy code (Title 24)

Base Code (Part 6 of Title 24)

Reach Standard (Part 11 of Title 24)

● The joint intent is to achieve significant energy savings

through the development of reasonable, responsible, and

cost-effective code change proposals for the 2013 code

update and beyond

● As part of the IOU effort, at the request of the CEC, we are

hosting stakeholder meetings to get industry input and

feedback on our code change proposals




4

Schedule: Key Dates

Mar 2010 – Feb 2011

CEC develop foundation /methodology

IOUs:

● Conduct research, and cost effectiveness analysis

● Present results at stakeholder meetings

Mar-May 2011

IOUs finalize code change proposals for submittal to CEC

Apr-July 2011 Pre-Rulemaking activities

CEC workshops/ First Draft Language

September 2011 – CEC rulemaking

CEC opens Rulemaking for Title 24, develop 45-day language

March 1, 2012

Title 24 CEC Adoption date

July 2013

CBSC Publication date

Jan 1, 2014

Title 24 Implementation date




5

Submitting Comments

Informal Comment Process

Comments can be submitted to CASE authors, substantive

comments will receive responses

Questions and responses will not be posted online, but

common or frequent questions will be communicated as

necessary between stakeholders

The team will work with stakeholders to resolve issues as

best we can

The CEC pre-rulemaking process starts this spring and the

formal rulemaking process will start in the fall




6

Meeting Protocols

We want to hear your concerns

Opposing viewpoints are encouraged

We are seeking information, not resolution

Time is limited

Clearly state your name and affiliation prior to speaking –

each time

If you are on the phone, ask questions/comment by “chat”

or by voice

Minutes and presentation material will be

available online – we will distribute link




7

Telephone/Webinar Protocols

To avoid feedback, please make sure you

have a headset if you are using your

computer’s microphone and speakers

rather than your telephone

Please mute your microphone, unless you

want to speak

Please do not place your phone on HOLD



04/12/2011

1

Residential Infiltration and

Testing


Bruce Wilcox

April 12, 2011


04/12/2011

2 2

Residential Infiltration and Testing

● Summary of current code requirements

● Typical practice

● Summary of code change proposals

● Data/findings

● Specifics of code change proposals

● Specific stakeholder requests

CA Utilities 2011 Title 24 Stakeholder Meeting for Proposed Code Changes


04/12/2011

3

Infiltration and Testing

Current Code Requirements

● Prescriptive air sealing

● Caulk and seal

● Certification requirements for windows, ceiling

cans etc

● Performance credit for air barrier

● Performance credit for leakage testing

● Credit for tested air leakage (HERS verified)

● Credit potentially much larger in 2008 Standards

● Effectively no multi-family testing option

● Blower door testing of whole building is

impractical



04/12/2011

4


Typical Practice

● Single family

● Usually default

● No air sealing measures

● No credits

● Some production builders take credit

● Problem of no air sealing contractor

● HERS raters provide testing

● Much bigger credit in 2008 - mechanical ventilation

removes lower limit on air leakage

● Multi-Family no action



04/12/2011

5


Code Change Proposal Summary

● Base code prescriptive maximum air leakage

rate of 4 ACH50 for single family homes in

12 climates

● 3 ACH50 requirement for single family

Reach Standards in 13 climates

● No multi-family requirements

● Use new Resnet Draft Standard 802

● Eliminate current air barrier credit




California New Home Energy Survey

● 40 Single family and 40 Multi-family

● Sample drawn from electric customers of SCE, PG&E and

SDG&E

● New homes 1st connected in 2007, probably 2005 Stds

● Occupied for 2 years

● Geographic distribution of surveys matched to sample at 3

digit zip level

● Mailed invitation letter with prepaid reply letter, web site and

800 number for responses. Recruited by phone from

responders.

● Occupants received $100 for participation

04/12/2011

6




Survey Air Leakage Measurements

● Simple Single Point Blower Door (CFM & ACH50)

● Single point, no baseline

● Air flow at 50 Pa (CFM50 or ACH50) Pressure and

depressure

● ASTM E1827-02 Air Leakage at 50 Pa

● Repeated measurements with baseline

● Air flow at 50 Pa (CFM50 or ACH50) Pressure and

depressure

● Series measurements for leakage to attic and garage]

● E779-03 Air Leakage

● Effective Leakage Area (ELA/SLA) pressure and depressure

● Fireplace Leakage

04/12/2011

7



04/12/2011

8


Envelope Air Leakage SLA (Specific Leakage Area)

0

1

2

3

4

5

6

7

1 19 37

Spec

ific

Lea

kage

Are

a (S

LA)

SF

Apartment

TownHouse

ACM Sealed

ACM Leaky



04/12/2011

9


Envelope Air Leakage ACH50 (Air Changes @ 50 Pa.)

0

2

4

6

8

10

12

1 19 37

Air

Ch

ange

s at

50

Pa

SF

Apartment

TownHouse




Envelope Air Leakage Survey Summary

● Single Family homes are very tight

● Multi–Family homes are much leakier

● Homes with attics and attached garages:

● 47% of the total leakage area is from/to the attic

● 9% of the total leakage area is from/to the

garage

04/12/2011

10



04/12/2011

11


Using New CSE Infiltration Algorithm

leaks &

windows

Sup

Ret

SupLeak

RetLeaK

HVAC

House

Attic

s

Sup

Ret

Tout

Tout

Fan Big Leak



04/12/2011

12


TDV Energy vs Air Tightness

leaks &

windows 0

20

40

60

80

100

120

140

160

180

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Tim

e D

ep

en

de

nt

Val

ue

, kTD

V/f

t2

Climate Zone

ACH 7.6

ACH 5

ACH 4

ACH 3



04/12/2011

13


Air Sealing 2200 ft2 Production Home

5 ACH50 4 ACH50 3 ACH50

Labor 50 75 100

Materials 59 89 118

Sub Overhead and profit 109 164 218

Subcontractor Invoice to builder 218 327 436

HERS verification 130 130 130

Total cost to builder 348 457 566

Builder Markup 30% 104 137 170

Total cost to Home buyer 452 594 736

$/cfa 0.21$ 0.27$ 0.33$




Life Cycle Cost Savings for Air Sealing

● 2700 ft2 CEC Prototype, Base TDV

04/12/2011

14

-2000

-1000

0

1000

2000

3000

4000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

$

Climate Zone

ACH 5

ACH 4

ACH 3




Reach Life Cycle Cost Savings

● 2700 ft2 CEC Prototype, Reach TDV

04/12/2011

15

-2000

-1000

0

1000

2000

3000

4000

5000

6000

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

$

Climate Zone

ACH 5

ACH 4

ACH 3




Code Change Proposals

● Base prescriptive maximum air leakage

● 4 ACH50 criteria with 7.6 default

● All new single family homes in 12 climates

● Post construction blower door test

● HERS verification

● Tighter requirement for reach standards

● 3 ACH50 criteria

● New single family homes in 13 climates

04/12/2011

16




No Action in Multi-family

● Unit by unit tests show big leakage, but

● Some unknown fraction of the leakage is to

other units. Sealing improves IAQ, but energy

savings unknown.

● Testing whole building is not practical, but

whole building compliance is standard.

● More research is needed (PIER?)

● Energy savings from unit by unit air sealing

● Test standard for multi-family ACH50

04/12/2011

17




New Base Code Language in Section 151

04/12/2011

18

2008 Building Energy Efficiency Standards – June 2007 Workshop Draft

(f) Prescriptive Standards/Alternative Component Packages (Component Packages).

….

13. Maximum Envelope Air Leakage.

A. The exterior pressure envelope of the home shall be sealed to achieve a tested air leakage less than or

equal to the criteria in TABLE 151-C COMPONENT PACKAGE D using the criteria in Reference Appendix

YYY.

EXCEPTION to Section 151 (f) 13 A: Multi-family buildings are exempt.

TABLE 151-C COMPONENT PACKAGE D

Climate Zone 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

BUILDING ENVELOPE

Maximum Envelope Air

Leakage

CFM50 4 4 NR 4 4 NR NR NR 4 4 4 4 4 4 4 4



04/12/2011

19


New Reach Code Language

(?) Reach Standards/Alternative Component Packages (Component Packages).

….

13. Maximum Envelope Air Leakage.

A. The exterior pressure envelope of the home shall be sealed to achieve a tested air leakage less than or equal to

the criteria in TABLE ???-C COMPONENT PACKAGE ?? using the criteria in Reference Appendix YYY.

EXCEPTION to Section ??? (?) 13 A: Multi-family buildings are exempt.

TABLE ???-C COMPONENT PACKAGE ??

Climate Zone 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

BUILDING ENVELOPE

Maximum

Envelope Air

Leakage

CFM50 3 3 3 3 3 NR NR NR 3 3 3 3 3 3 3 3



04/12/2011

20


Proposed Standards vs Survey Data

0

1

2

3

4

5

6

7

8

9

1 19 37

Air

Ch

ange

s at

50

Pa

SF Data

Base

Reach

Default




RACM Changes

● Air leakage calculations

● Convert SLA to ACH50 everywhere

● Untested default 7.6 ACH50 (SLA 3.8)

● Eliminate current air barrier credit

● 47% of leakage between house and attic

● New CSE integrated air flow network

● Air leakage testing and verification

● Reference/copy Resnet Draft Standard 802:

● PROCEDURES FOR BUILDING ENCLOSURE AIRTIGHTNESS

TESTING

● http://www.resnet.us/blog/resnet-proposes-amendments-

to-national-home-energy-rating-standards-6/

04/12/2011

21


http://www.resnet.us/blog/resnet-proposes-amendments-to-national-home-energy-rating-standards-6/





















04/12/2011

22


Specific Stakeholder Requests

● Review and comment on

● Proposed Standard

● Cost of air sealing in CA homes

● Cost of CA testing and verification

● Proposed test and verification procedure



04/12/2011

23

Residential Infiltration and Testing

QUESTIONS & COMMENTS


?


04/12/2011

1

Residential Zoned AC


Bruce Wilcox

April 12, 2011


04/12/2011

2 2

Zoned A/C




● Data/findings

● Specific Code change proposals

● Questions



Zoned A/C


● Prescriptive air flow requirement for 350

CFM/ton in every zonal mode, can be traded

away.

● Performance credit (easier heating and

cooling setpoints) for zonal systems capable

of maintaining different set points in “living”

and “sleeping” zones. Common return OK.

● No restrictions on system design, variable

capacity control type, commissioning etc.

04/12/2011

3



04/12/2011

4

Zoned A/C

Typical Practice

● Two types of zonal systems are common:

● Multiple systems, one for each zone

● High performance & high cost

● Single system with dampered supply ducts

● Return ducts are not zoned

● Single speed compressors and fans can’t modulate to

track load

● Supply air flow is low, particularly with one zone

calling.

● Bypass ducts (short circuit from supply into return) are

common

● Results -- low EER



04/12/2011

5

Zoned A/C


● Prohibit bypass ducts

● Eliminate the current zonal AC

performance compliance credit.

● Mandatory air flow and fan Watt

verification in all zonal cooling modes.



Zoned A/C

California New Home Energy Survey

● We have completed the survey of a

sample of 80 new 2007 CA homes and

found:

● AC systems have low capacity and efficiency

● Cooling air flow lower than the standard in

60% of systems

● Cooling duct pressures are very high

● Cooling Fan Watts are high

● MF Duct Leakage is very high, while SF is

pretty good

04/12/2011

6



04/12/2011

7

Zoned A/C

20% Zonal Systems

Single Split System 32

Combined Hydronic Systems 10

Multiple Split Systems 9

Heat Pumps 7

Zoned Split Systems 7

Package System 5

Heat Only Systems 3

Radiant Floor System 3

PTAC systems 2

Resistance Electric System 1

Wall Furnace 1



04/12/2011

8

Zoned A/C

Zonal Systems (red) Have Low EER

0

2

4

6

8

10

12

14

40 50 60 70 80 90 100 110

Se

ns

ible

Ca

pa

cit

y a

t R

eg

iste

r / T

ota

l W

att

s

Outdoor (Condenser Entering) Temperature, F



04/12/2011

9

Zoned A/C

Furnace Fan Power in Cooling

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 30 59

Wa

tt/C

FM

61 Split and 10 Combined Hydronic Units

(Worst 6 are Zoned Systems with all zones calling)

CEC Prrescriptive

SEER Default



04/12/2011

10

Zoned A/C

Zonal Systems = Worst Fan Watts



04/12/2011

11

Zoned A/C

Typical Zonal AC system with Bypass Duct



04/12/2011

12

Zoned A/C

How Zoning with Bypass Works

● In Theory

● With all zones calling damper closes and bypass has no

effect. All zones get the design air flow

● When only one zone calls, whatever isn’t delivered to that

zone is bypassed to the return to maintain coil air flow.

● Actually

● Mixing in bypass air lowers the return air temperature

entering the cooling coil and this ALWAYS significantly

lowers the EER.

● Because of dampers and extra ducts the air flow is

typically very low even when all zones are calling

● Extra dampers and ducts make systems more prone to

construction error and failures are common.



04/12/2011

13

Zoned A/C

Bypass Duct Flex From Supply to Return



04/12/2011

14

Zoned A/C

Bypass Duct 16” Sheet Metal Duct in the Attic



04/12/2011

15

Zoned A/C

Zoned Air Conditioning Model

Impact of Bypass and Reduced CFM



04/12/2011

16

Zoned A/C

Zoned Air Conditioning Data

Impact of Bypass and Reduced CFM



04/12/2011

17

Zoned A/C

Zoned Air Conditioning

Data Compared to Model



04/12/2011

18

Zoned A/C


Results for Survey House 29



04/12/2011

19


Impact of Bypass on Capacity



04/12/2011

20

Zoned A/C

Typical Zonal AC system - No Bypass

● But how to get full CFM?



04/12/2011

21

Zoned A/C

Zonal AC system

No Bypass and No Extra Cost

● Each branch takes ~ 1/3 of the CFM

● Full CFM through the unit at all times

● Obviously cost effective



Zoned A/C

Other Acceptable Zoning Approaches

● Separate system for each zone

● e. g. upstairs and downstairs central

forced air systems

● Mini-split systems for each zone

● Variable capacity equipment

● Variable speed compressor and fan

reduce energy consumption proportional

to load

04/12/2011

22



Zoned A/C


● New Mandatory Requirements for all Zoned

Systems (currently part of prescriptive air

flow)

● No Bypasses

● Minimum CFM/ton and W/CFM in all modes

● Eliminate performance path zoning credit

● Zoning is for comfort, not energy savings

04/12/2011

23



04/12/2011

24

Zoned A/C

New Mandatory Requirements

No Bypass Ducts, Air Flow and Fan W

SUBCHAPTER 7 LOW-RISE RESIDENTIAL BUILDINGS – MANDATORY FEATURES AND DEVICES

SECTION 150 – MANDATORY FEATURES AND DEVICES Any new construction in a low-rise residential building shall meet the requirements of this Section.

….

(m) Air-distribution System Ducts, Plenums, and Fans.

…

11. Cooling System Bypass Duct. Bypass ducts which deliver supply air to the return duct side of the system shall

not be used.

12. Zonally Controlled Central Forced Air Cooling Systems. Central forced air cooling system fans shall

simultaneously demonstrate, in every zonal control mode, an airflow greater than 350 CFM/ton of nominal cooling

capacity and a fan watt draw less than 0.58 W/CFM as specified in Reference Residential Appendix RA3.



04/12/2011

25

Zoned A/C

Change to RACM

Delete Zonal Control Credit

Residential ACM Manual

5.9 Zonal Control

5.9.1 Measure Description

Zonal control is one of the optional capabilities based on the ability of a compliance program to model more than one conditioned thermal zone at the same time. With zonal control, the sleeping and living areas are modeled separately, each with its own separate thermostat schedule and internal gain assumptions. Key features are discussed below. To use this compliance credit the measured air flow in CFM and the fan watt requirements defined in the Reference Residential Appendix RA3.3 must be met. The total non-closable opening area between zones cannot exceed 40 ft2. Other eligibility criteria for this measure are presented in the Reference Residential Appendix RA4.

Algorithms and Modeling Assumptions

The thermostat schedules are in Chapter 3. An alternate set of internal gain schedules is used: one for the living areas of the house and one for the sleeping areas. Both standard schedules and schedules for zonal control are shown in Chapter 3. Internal gains in the living zone shall be 20,000 Btu/day plus 15 Btu/ft². Internal gains in the sleeping zone shall be 15 Btu/ft².

5.9.3 Test Description

For this test, prototype A is divided into living and sleeping zones as shown in Figure R5-2. The boundary between the zones consists of a wall with U-value of 0.29 and net area of 360 ft2. The wall contains a noncloseable opening of 40 ft2, modeled with a U-value of 20.0 Btu/h-ºF-ft². Figure R5-2 – Zoning the Prototype Building Zonal control is added to prototype A as the discrete modification. The heating equipment AFUE is then reduced to find the passing solution and the failing solution as defined in Chapter 4. This test is performed in climate zones 3, 9, 12, 14, and 16. The Energy Commission reference method must pass the passing solution and fail the failing solution. The vendor shall also demonstrate that the compliance program correctly defines the standard design building and calculates the custom budget correctly. The vendor shall create and run a standard design equivalent 5. Optional Capabilities Tests Zonal Control 2008 Residential ACM Manual 5-10 building in climate zone 12. In the standard design equivalent building, the proposed design and standard design TDV energy must equal each other. The standard design equivalent TDV energy must also equal the standard design energy for this test.



04/12/2011

26

Zoned A/C

Change to RACM

Delete Zonal Control Credit

Residential ACM Manual

5.9 Zonal Control

5.9.1 Measure Description

Zonal control is one of the optional capabilities based on the ability of a compliance program to model more than one conditioned thermal zone at the same time. With zonal control, the sleeping and living areas are modeled separately, each with its own separate thermostat schedule and internal gain assumptions. Key features are discussed below. To use this compliance credit the measured air flow in CFM and the fan watt requirements defined in the Reference Residential Appendix RA3.3 must be met. The total non-closable opening area between zones cannot exceed 40 ft2. Other eligibility criteria for this measure are presented in the Reference Residential Appendix RA4.

Algorithms and Modeling Assumptions

The thermostat schedules are in Chapter 3. An alternate set of internal gain schedules is used: one for the living areas of the house and one for the sleeping areas. Both standard schedules and schedules for zonal control are shown in Chapter 3. Internal gains in the living zone shall be 20,000 Btu/day plus 15 Btu/ft². Internal gains in the sleeping zone shall be 15 Btu/ft².

5.9.3 Test Description

For this test, prototype A is divided into living and sleeping zones as shown in Figure R5-2. The boundary between the zones consists of a wall with U-value of 0.29 and net area of 360 ft2. The wall contains a noncloseable opening of 40 ft2, modeled with a U-value of 20.0 Btu/h-ºF-ft². Figure R5-2 – Zoning the Prototype Building Zonal control is added to prototype A as the discrete modification. The heating equipment AFUE is then reduced to find the passing solution and the failing solution as defined in Chapter 4. This test is performed in climate zones 3, 9, 12, 14, and 16. The Energy Commission reference method must pass the passing solution and fail the failing solution. The vendor shall also demonstrate that the compliance program correctly defines the standard design building and calculates the custom budget correctly. The vendor shall create and run a standard design equivalent 5. Optional Capabilities Tests Zonal Control 2008 Residential ACM Manual 5-10 building in climate zone 12. In the standard design equivalent building, the proposed design and standard design TDV energy must equal each other. The standard design equivalent TDV energy must also equal the standard design energy for this test.



04/12/2011

27

Zoned A/C


Bruce Wilcox

[email protected]

(510) 528-4406


?

mailto:[email protected]


04/12/2011

1

Residential Duct Efficiency


Douglas Beaman

Douglas Beaman Associates LLC

Bruce Wilcox

April 12, 2011



● Maximum Duct Pressure Drop

● Cooling Coil Airflow

● Fan Watt Draw

● Duct Sealing and Testing

04/12/2011 CA Utilities 2013 Title 24 Stakeholder Meeting for Proposed Code Changes

2 2



● Survey Results

● Proposed Approach

● Cost Effectiveness

● Specific stakeholder requests


3 3



4


Wilcox/Proctor/Chitwood Survey

050

100150200250300350400450

CFM

/to

n

System

Pre

Post



5


Improvement in Sensible EER

0123456789

10

No

rmal

ize

d S

en

sib

le E

ER

System

Pre

Post



6


25% Average Efficiency Increase

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

4 8 10 17 24 25 27 47 79

Percent

Improvement

Average

Survey

Percentage Improvement System EER – Survey Homes


DUCT PRESSURE DROP / AIRFLOW /

FAN WATT DRAW



7



Maximum Duct Pressure Drop

● Original concept was to establish a

maximum duct pressure drop standard.

● There is no standardized contractor

methodology to measure static pressure

that has been field verified for consistency

and accuracy.

● To establish measured static pressure

requirement would be challenging.


8



Proposed Approach

● Maximum Duct Pressure Drop

● Instead of treating symptom of the problem

(high static pressure) the decision has been

made to address the problem directly by

improving duct design via airflow and fan watt

draw requirements.


9



Airflow and Fan Watt Draw

● Establish mandatory airflow and fan watt

draw requirements.

● If both airflow and fan watt requirements

are met, the improvements to the duct

system are achieved and static pressure

measurement becomes a non-issue.


10



Proposed Approach

● For Ducted Heating & Cooling System, two

options are available to meet mandatory

requirement:

● Use the Return Duct and Return Grill Sizing Table

● Measure Airflow (350 cfm/ton Min) & Fan Watt

Draw (0.58 watts/cfm Max)


11



Single Zone Systems

● The Return Duct and Grill Sizing tables may

only be used for single zone systems.

● Systems with zonal control must meet

specified fan watt draw and airflow

requirements.


12



13


Single Return System

Tons Nominal Airflow (cfm)

Return Duct Size (inches)

Return Grill Gross Area

(square inches)

1.5 600 16 500 sq. in.

2 800 18 600 sq. in.

2.5 1000 20 800 sq. in.

3 1200

Multiple returns required 3.5 1400

4 1600

5 2000



14


Single Return System

Tons Nominal Airflow

Return Duct Size (inches)

Return Grill Gross Area

(square inches)

Example Grill Size (inches)

1.5 600 16 500 " 20 X 25

2 800 18 600 " 20 X 30

2.5 1000

Multiple returns required

3 1200

3.5 1400

4 1600

5 2000



15


Multiple Return System

Tons Nominal Airflow (cfm)

Return # 1 Return # 2 Return Grills Gross Area

(square inches) Duct Size (inches)

Duct Size (inches)

1.5 600 12 10 500 sq. in.

2 800 14 12 600 sq. in.

2.5 1000 14 14 800 sq. in.

3 1200 16 14 900 sq. in.

3.5 1400 16 16 1000 sq. in.

4 1600 18 18 1200 sq. in.

5 2000 20 20 1500 sq. in.



16


Multiple Return System

Tons Nominal Airflow

Return # 1

Return # 2

Return Grills Gross Area

(square inches)

Return # 1 Return # 2

Duct Size (inches)

Duct Size (inches)



1.5 600 12 10 500 " 15 X 20 10 X 20

2 800 14 12 600 " 15 X 20 15 X 20

2.5 1000 14 14 800 " 20 X 20 20 X 20

3 1200 16 14 900 " 30 X 20 15 X 20

3.5 1400 16 16 1000 " 25 X 20 25 X 20

4 1600 18 18 1200 " 30 X 20 30 X 20

5 2000 2-18 14 1500 " 2-30 X 20 15 X 20



17


Percentage Improvement

0.0%

1.0%

2.0%

3.0%

4.0%

5.0%

6.0%

7.0%

8.0%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Percentage Improvement in Total TDV KBtu/sf-yr

Compared to Base Case (300 cfm / .80 W/cfm)

Climate Zones



18



0.0%

1.0%

2.0%

3.0%

4.0%

5.0%

6.0%

7.0%

8.0%

9.0%

10.0%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Airflow 400

Fan Watt

.58

Airflow 375

Fan Watt

.58

Airflow 350

Fan Watt

.58



Climate



19



0.0%

2.0%

4.0%

6.0%

8.0%

10.0%

12.0%

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Airflow 350

Fan Watt .50

Airflow 400

Fan Watt .58

Airflow 375

Fan Watt .58

Airflow 350

Fan Watt .58

Climate Zones





20


Savings – Airflow & Fan Watt Draw

$0.00

$1,000.00

$2,000.00

$3,000.00

$4,000.00

$5,000.00

$6,000.00

$7,000.00

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Post

Adoption

Savings

Current

Savings

Climate

Savings - Airflow and Fan Watt Draw



21


LCC– Airflow & Fan Watt Draw

Measure

Name

Measure

Life

(Years)

Additional Costs1–

Current Measure

Costs (Relative to

Basecase)

Additional Cost2–

Post-Adoption

Measure Costs

(Relative to

Basecase)

PV of Additional3

Maintenance Costs

(Savings) (Relative to

Basecase) PV of4

Energy Cost

Savings –

Per Proto

Building

(PV$)

LCC Per Prototype

Building

Duct

Sealing

and

Testing

($) ($) (PV$) ($)

Per Unit Per Proto

Building Per Unit

Per Proto

Per Unit

Per Proto (c+e)-f (d+e)-f

Building Building

Based on

Current

Costs

Based on

Post-

Adoption

Costs

CLZ 1 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $270.92 -$17.28 -$270.92

CLZ 2 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $780.06 -$526.42 -$780.06

CLZ 3 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $425.06 -$171.42 -$425.06

CLZ 4 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $1,013.61 -$759.97 -$1,013.61

CLZ 5 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $247.56 $6.08 -$247.56

CLZ 6 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $803.41 -$549.77 -$803.41

CLZ 7 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $616.57 -$362.93 -$616.57

CLZ 8 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $1,377.95 -$1,124.31 -$1,377.95

CLZ 9 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $2,148.66 -$1,895.02 -$2,148.66

CLZ 10 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $2,470.96 -$2,217.32 -$2,470.96

CLZ 11 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $3,890.94 -$3,637.30 -$3,890.94

CLZ 12 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $2,307.47 -$2,053.83 -$2,307.47

CLZ 13 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $3,867.59 -$3,613.95 -$3,867.59

CLZ 14 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $3,297.73 -$3,044.09 -$3,297.73

CLZ 15 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $6,389.93 -$6,136.29 -$6,389.93

CLZ 16 30 $253.64 $253.64 $0.00 $0.00 $0.00 $0.00 $1,779.65 -$1,526.01 -$1,779.65



Airflow / Fan Watt Draw

● Allow compliance credit in the Performance

Approach for lower fan watt draw

(algorithms already in ACM).

● Airflow & Fan Watt Draw –

HERS Verification

● Prescriptive Duct Sizing –

Building Department Inspection


22



Airflow / Fan Watt Draw

● Forced Air Heating & Cooling Systems Only

(excludes heating only systems)

● Newly Constructed Homes

● Alterations if New Duct System

● Single Family & Multi-Family


23


DUCT SEALING AND TESTING



24



Duct Sealing and Testing

● Duct testing in previous code cycles has

been shown to be cost effective.

● There had been contractor resistance to

duct testing when they could “trade-off”

other measures.

● Under the 2008 Standards, duct testing

appears to be more widely used.


25



Duct Sealing and Testing

● Survey showed that majority of newly

constructed single family homes had

reasonable duct leakage rates.

● Multi-Family homes significantly worse duct

leakage rates than single family.


26



Proposed Approach

● Mandatory Measure

● Use the same criteria as current Standards

except move duct sealing and testing from

prescriptive to mandatory measure.

● Allow the current exceptions for Alterations such

as ducts constructed with asbestos.


27



28


Cost Savings - Duct Sealing

$0.00

$1,000.00

$2,000.00

$3,000.00

$4,000.00

$5,000.00

$6,000.00

$7,000.00

$8,000.00

$9,000.00

$10,000.00

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Duct Sealing -

Total Savings

Duct Sealing -

Net Savings

Climate Zones

Duct Sealing Cost Savings



29


LCC - Duct Sealing

Measure

Name

Measure

Life

(Years)

Additional Costs1–

Current Measure Costs

(Relative to Basecase)

Additional Cost2–

Post-Adoption

Measure Costs

(Relative to Basecase)

PV of Additional

3

Maintenance Costs

(Savings) (Relative to

Basecase)

PV of4

Energy

Cost

Savings –

Per Proto

Building

(PV$)

LCC Per Prototype

Building

Duct

Sealing

and Testing

($) ($) (PV$) ($)

Per Unit Per Proto

Building

Per Unit Per Proto Per Unit Per Proto (c+e)-f (d+e)-f

Building Building Based on

Current

Costs

Based on

Post-

Adoption

Costs

CLZ 1 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $1,504.06 -$524.06 -$1,504.06

CLZ 2 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $2,036.56 -$1,056.56 -$2,036.56

CLZ 3 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $1,345.25 -$365.25 -$1,345.25

CLZ 4 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $2,162.67 -$1,182.67 -$2,162.67

CLZ 5 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $915.52 $64.48 -$915.52

CLZ 6 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $1,494.72 -$514.72 -$1,494.72

CLZ 7 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $962.23 $17.77 -$962.23

CLZ 8 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $1,919.78 -$939.78 -$1,919.78

CLZ 9 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $3,507.92 -$2,527.92 -$3,507.92

CLZ 10 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $4,068.44 -$3,088.44 -$4,068.44

CLZ 11 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $6,511.37 -$5,531.37 -$6,511.37

CLZ 12 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $4,077.78 -$3,097.78 -$4,077.78

CLZ 13 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $6,343.22 -$5,363.22 -$6,343.22

CLZ 14 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $6,058.29 -$5,078.29 -$6,058.29

CLZ 15 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $8,991.68 -$8,011.68 -$8,991.68

CLZ 16 30 $980.00 $980.00 $0.00 $0.00 $0.00 $0.00 $5,091.39 -$4,111.39 -$5,091.39



Proposed Approach

● Duct Sealing & Testing Mandatory Measure –

Newly Constructed

● All forced air systems –

heating only included.

● Single family homes –

ducts in unconditioned space.

● Multifamily homes -

ducts in conditioned or unconditioned space.


30



Proposed Approach

● Duct Sealing & Testing Mandatory Measure -

Alterations

● Same leakage rates as current standards.

● All Climate Zones.

● All Forced Air Systems.


31



Specific Stakeholder Requests

● Changes required duct system design and

installation.

● Duct testing requirements in cool climate

zones.

● Building department inspection using return

duct sizing table.


32



33



Doug Beaman

[email protected]

(209) 524-1000

?



04/12/2011

1

Residential Cool Roof/

Roof Insulation Measures

Stakeholder Meeting #2

UPDATED – April 13, 2011

John Arent P.E.

Architectural Energy Corporation

April 12, 2011



2 2

Cool Roof/Roof Insulation



● Code change proposals

● Methodology

● High Reflectance Cool Roof Cost effectiveness

● Below Deck Insulation Cost Effectiveness

● Duct Insulation Cost Effectiveness



3



● 2008 Title 24 – Low-Rise Residential

● Prescriptive approach – steep-sloped roofs

weighing more than 5 lbs/sf

● Concrete & clay tile, some metal roofs

● Minimum aged solar reflectance of 0.15, thermal

emittance of 0.75

● All climate zones 1-16

● Steep-sloped roofs weighing <5 lbs/sf

● Asphalt shingle, some metal roofs

● Minimum aged solar reflectance of 0.2, thermal

emittance of 0.75

● Only climate zones 10-15 (inland valleys)



4



● 2008 Title 24 – Low-Rise Residential

● Additions & alterations – Steep-sloped re-roofing

(minimum of 50% of roof area or 1000 sf)

● Must also meet prescriptive requirements, but there are

many exceptions

– Minimum R-30 ceiling insulation

– Insulated & sealed attic ducts OR no ducts in attic

– Radiant barrier is properly installed

– Roof deck insulation of at least R-0.85, or at least R-3 in climate

zones 10, 11, 13 & 14

– 1/150 Attic ventilation with 30% at roof ridge in climate zones 10,

12 & 13



5



● Raised Heel Truss: current code does not require

raised heel trusses and does not give credit for

them

● Roof Deck Insulation: Current code requires 1:150

or 1:300 attic ventilation (CBC 1203.2)

● 50% of ventilating area to be located at least 3 feet above

eave/cornice vents

● Restrictions in wild land interface areas

● 1:300 ventilation allowed if vapor barrier installed on

warm side of insulation

● Unvented attics may be approved on an exceptional basis



6



Measure Type Detail

Roof Deck Insulation Vented Attic Package Insulation varies by

climate; Maintain existing

cool roof requirements

Duct Insulation Increase to R-8 in all

climates; existing cool

roof requirements

Raised Heel Truss Require RHT; existing cool

roof requirements

Increased Attic Insulation Prescriptive

Requirement

R-30 to R-38; R-38 to R-49

existing cool roof req.

Higher Reflectance Cool Roof Compliance Option Level to be equivalent to

vented attic package with

roof deck insulation

Unvented Attic Compliance Option;

Reach Code

To be determined



7


Typical Practice

● New Residential Construction

● Concrete tile roofing seems to be prevalent on

steep-sloped roofs

● Over 5 lbs/sf, minimum aged SR of 0.15

● Aged values of solar reflectance are not available for

many roof materials: equivalent to initial SR = 0.13



8


Typical Practice

● Residential Re-roofing

● Asphalt shingle seems to be the most prevalent

replacement roof

● Less than 5 lbs/sf, minimum aged SR of 0.20

● At minimum aged SR = 0.20, initial SR = 0.20



9


Typical Practice

● Standard practice includes the use of

conventional wood trusses

● Insulation is compressed near the eaves,

reducing thermal performance

● Cold corners can lead to condensation and

moisture problems, ice dams in cold climates



10


Typical Practice

● Typical attic ventilation involves the use of

soffit and ridge vents; attic insulation is

installed above the ceiling

● Duct leakage and conduction are a major source of

energy loss

● Attic ventilation has only minor effect on cooling

loads with a well-insulated ceiling



11



● Hot Climate Vented Attic Prescriptive Package

● Below Deck Insulation

● Duct Insulation Level of R-8 if cost-effective

● Existing requirements for attic insulation

● Keep existing cool roof requirements

● Raised heel truss if cost effective

● Temperate Climate Attic Prescriptive Package

● Similar requirements

● Below deck insulation if cost effective

● Raised heel truss if cost effective

● Higher reflectance cool roof as a compliance option

(alternative to below deck insulation)



12



● Roof deck insulation

● At or below roof deck

● Both cooling and heating benefit

● Investigating spray foam insulation and batt insulation

options

● Higher reflectance cool roof considered as a

compliance option to roof deck insulation

● Many tile products have reflectance to 0.35 to 0.4 with

marginal additional cost

● Asphalt shingle reflectance generally limited to 0.28;

higher reflectance products carry significant additional

cost



13



● Raised Heel Truss: New prescriptive requirement for

raised heel trusses in new construction

● Any change must be shown to be cost-effective

● Change may be climate dependent, based on energy

benefits

● Increased duct insulation requirements

● R-8 if cost-effective



14


Methodology

● “Rolling Base Case” for Vented Attic Package

● Start with current prescriptive standards as base case

● Remove radiant barrier

1. Determine optimal below deck insulation level for each

climate

2. Use results of step 1 as base case; determine cost

effectiveness of increasing duct insulation level to R-8

3. Use results of step 2 as base case to determine cost

effectiveness of raised heel truss for each climate

● Higher Reflectance Cool Roof Compliance Option

● Determine required roof reflectance to achieve energy

equivalence to below deck insulation level above



15


Methodology

● Unvented Attic Compliance Option

● Verify that unvented option uses no more energy than

prescriptive package

● Determine if unvented attic meets requirement for Reach

Code

● Increased Attic Insulation

● Analyzed separately, independent of other measures


HIGHER REFLECTANCE COOL ROOF

Base Code


16



17


Cool Roofs: Initial Findings

● Higher reflectance steep-sloped roof materials do exist



18


Survey Results: Roofing Manufacturers

Do e s yo ur co mp a ny se ll a ny re s id e ntia l, s lo p e d p ro d ucts with

initia l so la r re fle c ta nce o f 0.25 o r hig he r? If so , ho w lo ng ha ve yo u

b e e n se lling the m?More than 10 years

5-10 years

3-5 years

1-3 years

less than 1 year

products still under

development

we don't sell any higher

reflectance products



19


Cool Roof Energy Benefits: North Coast

Light Cool Roof, CZ1-4

30

35

40

45

50

55

60

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

reflectance

kT

DV

/ft2

-y

CZ1 CZ2 CZ3 CZ4

Linear (CZ2) Linear (CZ1) Linear (CZ4) Linear (CZ3)



20


Cool Roof Benefits: Southern Valley and Desert

TDV Energy Use, Asphalt Shingle Roofs

80

90

100

110

120

130

140

150

160

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

Reflectance

TD

V/f

t2-y

r

CZ13 CZ14 CZ15 CZ16

Linear (CZ15) Linear (CZ13) Linear (CZ14) Linear (CZ16)



Cost Effectiveness in Temperate Climates

● Asphalt shingle reflectance limited to 0.25 to 0.28 with current

products on market

● For asphalt shingle, roof reflectance of 0.25 is cost effective in

nearly all climates

● Not cost effective in CZ1 (Arcata), CZ2 (Santa Rosa), CZ3

(Oakland) and CZ5 (Santa Maria)

04/12/2011 CA Utilities 2013 Title 24 Stakeholder Meeting for

Proposed Code Changes

21

CZ1 CZ2 CZ3 CZ4 CZ5 CZ6 CZ7 CZ8

TDV/sfr -1.30 1.81 1.21 2.77 -1.43 3.58 2.92 3.82

PV $/sfr -0.23 0.31 0.21 0.48 -0.25 0.62 0.51 0.66

PV $/sq -22.55 31.25 20.94 48.00 -24.80 61.85 50.58 66.04

Cost $/sq $32.00 $32.00 $32.00 $32.00 $32.00 $32.00 $32.00 $32.00

NPV/sq ($54.55) ($0.75) ($11.06) $16.00 ($56.80) $29.85 $18.58 $34.04

BCR -0.70 0.98 0.65 1.50 -0.78 1.93 1.58 2.06

Costs and present value of savings are shown per square (100 ft2)



22


Cost Effectiveness in Hot and Mountain Climates

For asphalt shingle, roof reflectance of 0.25 is cost effective

in inland valley, desert and mountain climates


TDV/sfr 5.06 5.12 6.05 4.90 6.35 4.79 8.34 4.21

PV $/sfr 0.88 0.89 1.05 0.85 1.10 0.83 1.44 0.73

PV $/sq 87.62 88.59 104.69 84.72 109.85 82.79 144.32 72.80

Cost $/sq $32.00 $32.00 $32.00 $32.00 $32.00 $32.00 $32.00 $32.00

NPV/sq $55.62 $56.59 $72.69 $52.72 $77.85 $50.79 $112.32 $40.80

BCR 2.74 2.77 3.27 2.65 3.43 2.59 4.51 2.28

Costs and present value of savings are shown per square (100 ft2)



23


Cost Effectiveness for Tile Roof

● Concrete tile is 80% to 90% of new construction

market

● Cool roof products with reflectance to 0.35 to 0.40

have zero or marginal markup ($0-6/square)

relative to current requirements in the Standard

● Cool roof tile with reflectance of 0.35 is cost

effective in all climates

● Higher reflectance tile (0.60 or higher) may have

aesthetic issues with color

● Cool roof tile is cost effective alone, but this will be

considered as a compliance option due to

temporary lack of cool roof options for shingles

● Considered for Reach Code


ROOF DECK INSULATION

Base Code


24



25


Roof Deck Insulation Options

● Above deck insulation

● An effective option for tile, but asphalt shingles require a

nailable base, adding cost

● Continuous thermal barrier at roof deck

● Below deck insulation

● Install closed-cell spray foam or fiberglass batts between

trusses

● R-13 insulation below the deck is thermally equivalent to

R-10 to R-11 above the deck

● R-5 below deck insulation is thermally equivalent to

a increase in roof reflectance to 0.40



26


Below Deck Insulation Simulation Results

Below Deck Insulation, Climate Zones 3 and 6

25

27

29

31

33

35

37

39

41

43

45

0 5 10 15 20 25

R-value

kT

DV

/ft2

-yr

CZ3

CZ6

Poly. (CZ6)

Poly. (CZ3)

Biggest benefit for CZ3 (Oakland) and CZ6 (Torrance): insulation to R-10



27


Below Deck Insulation Simulation Results

TDV Energy Use with Below Deck Insulation

100

110

120

130

140

150

160

170

0 5 10 15 20 25

R-value

kT

DV

/ft2

-yr

CZ13

CZ15

Poly. (CZ15)

Poly. (CZ13)

Below deck insulation very effective for inland climates up to R-10;

additional insulation shows diminishing returns from R-10 to R-20



28


Below Deck Insulation Costs

Spray Foam Costs: average of survey data and RS Means

- additional cost of $0.25/ft2 for an ignition barrier

Spray Foam Insulation Installed Costs

y = 0.2465x + 0.0631

R2 = 0.9953

$0.00

$1.00

$2.00

$3.00

$4.00

$5.00

$6.00

$7.00

0 5 10 15 20 25 30

R-value



29


Below Deck Insulation: Simulation Results

Diminishing returns after 2” of spray foam (R-12) is installed

CZ11, TDV Energy Use for Below Deck Insulation

102

104

106

108

110

112

114

116

118

120

0 5 10 15 20 25

R Value

kT

DV

/ft2

-yr



30


Below Deck Insulation: Life-Cycle Cost Analysis

Total Life Cycle Cost for CZ11 (Red Bluff) – equal LCC at R-16.7

CZ11, Below Deck Insulation LCC

y = 0.0038x2 - 0.0634x + 20.478

R2 = 0.9729

20.1

20.2

20.3

20.4

20.5

20.6

20.7

20.8

20.9

0 5 10 15 20 25

R-value

LC

C P

V $

/ft2



31



Total Life Cycle Cost for CZ15 (Palm Springs) – equal LCC at R-23


y = 0.0047x2 - 0.1094x + 26.2

R2 = 0.9705

25.4

25.5

25.6

25.7

25.8

25.9

26.0

26.1

26.2

26.3

0 5 10 15 20 25

R-value

LC

C P

V $

/ft2



32



Total Life Cycle Cost for CZ16 (mountains) – equal LCC at R-11.3


y = 0.0044x2 - 0.0498x + 16.625

R2 = 0.9822

16.2

16.4

16.6

16.8

17.0

17.2

17.4

17.6

0 5 10 15 20 25

R-value

LC

C P

V $

/ft2



33


Below Deck Insulation Cost Effectiveness

8-12% reduction in TDV energy use in CZ11,13,15,16

Effect of Below Deck Insulation, Proposed Requirement

0

20

40

60

80

100

120

140

160

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Climate Zone

kT

DV

/ft2

-yr

Std

Prop



34


Below Deck Insulation Cost Effectiveness

● Below Deck Insulation Levels

● R-9 cost effective in CZ16 (mountains)

● R-15 cost effective in CZ 11 (Red Bluff)

● R-18 cost effective in CZ 13 (Fresno)

● R-21 cost effective in CZ 15 (Palm Springs)

● Below deck insulation would be cost effective in more

climates if fiberglass batts could be used directly below

the deck

● Next Steps

● Determine cost effective levels of duct insulation

● Determine cost effectiveness of raised heel truss

● Analyze cooler roof and unvented attic compliance options


DUCT INSULATION

Base Code


35



36


Duct Insulation Measure

● Proposal: increase duct insulation thickness to R-8

● R-4.2 required in southern CA coast (CZ 6-8)

● R-6 required in climate zones 1-5, 9-13

● R-8 already required in CZ 14-16

● Incremental Costs

● R-4.2 to R-8: $0.24/ft2 to $0.90/ft

2

● R-6 to R-8: $0.13/ft2 to $0.59/ft

2

● Labor Costs under further investigation



37


Duct Insulation Measure

Energy Savings – use ACM assumption on duct surface area -

$0.07/ft2 to $0.21/ft

2 life-cycle cost savings

Duct Insulation Energy Savings

0.00

0.05

0.10

0.15

0.20

0.25

1 2 3 4 5 6 7 8 9 10 11 12 13

Climate Zone

PV

$/s

f



38


Duct Insulation: Conclusions

● Duct Insulation cost effective if little labor markup

for additional insulation

● Additional survey data will verify cost effectiveness

● Results of Roof Deck Insulation and Duct Insulation

measures will be starting point for analyzing raised

heel trusses


RAISED HEEL TRUSS

Base Code


39



40


Initial Findings

● Raised Heel Trusses

● Incorporated into

Building America homes

and other high-

performance homes

● Included in many green

building standards

● Proposed as a

prescriptive requirement

in Energy Star 2011

● Credit provided for

R.H.T. in IECC 2006

● R-30 in place of R-38

● R-38 in place of R-49



41


Methodology

● Determine cost effectiveness of raised heel truss

measure in isolation

● Assess interactive effects by evaluating measures

for vented attic:

● Roof Deck Insulation

● Duct Insulation

● Raised Heel Truss

● Determine required cool roof reflectance as a

compliance option



42


Methodology

● Raised Heel Truss: modified U-factor calculation

procedure for de-rating roofs with compressed

insulation near the eaves

● Calculate roof area where insulation is compressed and

assume average of half-depth insulation

● Apply JA4 framing factors to perimeter

● Use parallel path method to calculate U-factors

● U-factors for raised heel truss similar to published

values in JA4

● De-rating used to assess benefits of raised heel

truss



43


Methodology

● Raised Heel Truss De-Rating Procedure

● Based on parallel path method

● 5:12 roof, framing 24” o.c.

Insulation

Effective

R-Value

R-Value

Compressed U-factor JA4

U-factor

Compressed

R-30 32.3 28.4 0.031 0.0353

R-38 40.0 33.2 0.025 0.0301

R-49 52.6 39.3 0.019 0.0254



44


Raised Heel Truss Cost Effectiveness

Effect of Roof Insulation on TDV Energy Use for CZ3 (Oakland)

y = 114.46x + 36.181

R2 = 0.9989

37.0

37.5

38.0

38.5

39.0

39.5

40.0

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035

U-factor



45


Raised Heel Truss Cost Effectiveness

Effect of Roof Insulation on TDV Energy Use, CZ15 (Palm Springs)

y = 174.17x + 146.91

R2 = 0.9994

150

150.5

151

151.5

152

152.5

153

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035

U-factor

kT

DV

/ft2

-yr

Steeper Slope Roof Insulation has greater impact on energy use



46


Raised Heel Truss: Isolated Measure


PV

Savings $221.32 $242.08 $225.48 $263.62 $104.45 $291.82 $218.86 $215.53

RHT Cost $355.25 $355.25 $355.25 $355.25 $355.25 $355.25 $355.25 $355.25

NPV ($133.93) ($113.17) ($129.77) ($91.63) ($250.80) ($63.43) ($136.39) ($139.72)

BCR 0.62 0.68 0.63 0.74 0.29 0.82 0.62 0.61

Measure Not Cost Effective in Temperate Climates (CZ1-8)



47


Raised Heel Trusses: Isolated Measure


PV

Savings $271.92 $240.40 $387.30 $343.84 $393.23 $411.02 $413.01 $586.90

RHT Cost $355.25 $355.25 $355.25 $355.25 $355.25 $355.25 $355.25 $355.25

NPV ($83.33) ($114.85) $32.05 ($11.41) $37.98 $55.77 $57.76 $231.65

BCR 0.77 0.68 1.09 0.97 1.11 1.16 1.16 1.65

Measure Cost Effective in Inland Valley and Mountains



48


Integrated Analysis

● Incorporate recommendations for below deck

insulation and duct insulation

● Re-run simulations for all climate zones to

determine cost effectiveness



49


Effect of Integrated Analysis

Effect of Roof Insulation on TDV Energy Use, Standalone Measure,

CZ11 (Red Bluff)

y = 163.33x + 114.12

R2 = 0.9991

117

117.5

118

118.5

119

119.5

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035

U-factor

Energy Benefits are proportional to the slope of the curve



50


Effect of Integrated Analysis

Curve is flatter with integrated analysis since R-15 roof deck

insulation is already present energy benefits reduced by 60%

TDV Energy Use vs. Attic Insulation, CZ11 (Red Bluff)

y = 63.955x + 102.93

103

103.5

104

104.5

105

105.5

106

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035

U-factor

kT

DV

/ft2

-yr



51


Raised Heel Truss: Integrated Analysis

Measure Not Cost Effective in Temperate Climates (CZ1-8)

1 2 3 4 5 6 7 8

PV

Savings $227 $250 $228 $272 $110 $293 $219 $228

RHT Cost $355 $355 $355 $355 $355 $355 $355 $355

NPV -$128 -$105 -$128 -$83 -$246 -$62 -$136 -$127

BCR 0.64 0.71 0.64 0.77 0.31 0.82 0.62 0.64



52


Raised Heel Trusses: Integrated Analysis

Measure Cost Effective in Inland Climates that do not

have roof deck insulation requirement

9 10 11 12 13 14 15 16

PV

Savings $286 $250 $152 $360 $117 $421 $194 $232

RHT Cost $355 $355 $355 $355 $355 $355 $355 $355

NPV -$70 -$105 -$204 $5 -$239 $66 -$161 -$123

BCR 0.80 0.70 0.43 1.01 0.33 1.19 0.55 0.65



53


Raised Heel Truss: Conclusions

● With baseline that includes roof deck insulation, not

cost effective

● Verify assemblies (spray foam or batt below deck) meet

moisture analysis tests

● Significant cost for high heel trusses when blocking

is required

● Increased use may reduce costs

● Recommend modifying the JA4 table to include U-

factors for raised heel truss

● Modify existing U-factors for wood-framed roofs to

be more penalizing due to compression near the

eaves



54


Recommended Language: JA4

Rated R-value of Continuous Insulation1

RHT None R-2 R-4 R-6 R-7 R-8 R-10 R-14

Truss Spacing

R-value of Attic Insulation R A B C D E F G H

None 1 0.300 0.187 0.136 0.107 0.097 0.088 0.075 0.058

16 in. OC

R-11 2 0.079 0.068 0.060 0.053 0.051 0.048 0.044 0.037

None 13 0.305 0.305 0.189 0.137 0.108 0.097 0.089 0.075 0.058

R-11 14 0.076 0.076 0.066 0.058 0.052 0.050 0.047 0.043 0.037

R-13 15 0.068 0.068 0.060 0.054 0.048 0.046 0.044 0.041 0.035

R-19 16 0.048 0.048 0.043 0.040 0.037 0.036 0.034 0.032 0.029

R-21 17 0.043 0.0444 0.040 0.037 0.034 0.033 0.032 0.030 0.027

R-22 18 0.041 0.043 0.038 0.036 0.033 0.032 0.031 0.029 0.026

R-25 19 0.037 0.0393 0.034 0.032 0.030 0.029 0.028 0.027 0.024

R-30 20 0.031 0.0353 0.029 0.028 0.026 0.025 0.025 0.024 0.022

R-38 21 0.025 0.0301 0.024 0.023 0.022 0.021 0.021 0.020 0.018

R-44 22 0.021 0.0265 0.020 0.019 0.019 0.018 0.018 0.017 0.016

R-49 23 0.019 0.0254 0.019 0.018 0.017 0.017 0.017 0.016 0.015

24 in. OC

R-60 24 0.016 0.021 0.016 0.015 0.015 0.014 0.014 0.014 0.013

Table 4.2.1 – U-factors of Wood Framed Attic Roofs


ROOF ATTIC INSULATION

Base Code


55



56


Roof Attic Insulation: Isolated Measure

● We also investigated the cost effectiveness of

increasing attic insulation requirements as an

alternative to a raised heel truss

● R-30 to R-38

● R-38 to R-49

● Measure analyzed relative to current Standards

● Energy simulations and updated life-cycle cost

effectiveness showed that increased attic

insulation is not cost effective



57


Higher Reflectance Cool Roof Revisited

● Next step: find equivalent cool roof reflectance that yields

the same energy use as the vented attic package with roof

deck insulation or a raised heel truss

● Very high roof reflectance required for equivalent energy

use

● Possibly include raised heel truss in compliance option with

increased reflectance requirements

Climate Zone CZ11 CZ12

CZ13 CZ14

CZ15 CZ16

Measure

Below

Deck R.H.T.

Below

Deck R.H.T.

Below

Deck

Below

Deck

Reflectance > 0.7 0.32 > 0.7 0.26 > 0.7 0.62


UNVENTED ATTIC

Reach Code


58



59


Unvented Attic Compliance Option

● Control moisture entry at the roof plane

● Fully insulate roof deck to place ducts in

conditioned space

● Use closed-cell foam as air barrier and vapor

retarder

● Duct Sealing becomes less important



60


Unvented Attic Compliance Option

Source: JLC



61


Unvented Attic: Next Steps

● Verify simulation properly accounts for infiltration

with sealed attic

● Determine air leakage rates with sealed attic

● Run simulations to determine required level of

roof deck insulation to have equivalent energy

use to prescriptive Standards

● Verify product options for non-condensing

furnaces and water heaters located in the attic



62


Recommended Language: Table 151-C

Climate Zone

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Ceilings R38 R30 R30 R30 R30 R30 R30 R30 R30 R30 R38 R38 R38 R38 R38 R38

Below Deck Insulation

n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a R-

15

R-6

or

RH

T

R-

18

R-6

or

RH

T

R-

21 R-9

Duct Insulation*

R-8 R-8

R-8

R-8

R-8

R-8

R-8

R-8

R-8

R-8

R-8

R-8

R-8

R-8

R-8

R-8

Component Package D (Vented Attic Package)

● Duct Insulation requirements TBD based on updated costs

● Specify exception to below deck insulation requirements if

roof reflectance is 0.70 or higher (possibly combine with

raised heel truss)



63


Next Steps

● Verify costs for duct insulation and cost

effectiveness

● Will not affect other measures

● Complete Reach Code recommendations

● Unvented attic option

● Complete report and impact analysis

● Demand reduction, environmental impact



64



Thank you for your time!

John Arent

[email protected]

415-970-6513

?



1

Residential Windows


Ryan Schmidt


Ken Nittler

Enercomp, Inc.

April 12, 2011



2 2

Residential Windows

● Context

● Data collection


● Analysis

● Straw proposals

● Impacts

● Next steps

● Questions


Residential Windows

Current Title 24 Requirements

● Standards Table 151-C

Component Package D (prescriptive)

● U-factor, all climate zones

● 0.40

● SHGC

● 0.35 in climate zone 15; 0.40 otherwise

● No requirement (NR) in climate zones 1, 3, 16

● Alternative SHGC compliance options

– Fixed exterior shading devices

– Overhangs on south windows

● Performance method compliance credit for window

overhang or exterior device shading

04/12/2011


3


Residential Windows

Related Codes / Standards

● Federal tax credits for consumer energy

efficiency (nationwide)

● 2010

● U-factor = 0.30

● SHGC = 0.30

● 2011

● Energy Star performance levels

04/12/2011


4


04/12/2011


5

Residential Windows


● Energy Star

Climate Zone

Map

● North Central region: U-factor = 0.32, SHGC = 0.40

● South Central region: U-factor = 0.35, SHGC = 0.30


04/12/2011


6

Residential Windows


International Energy

Conservation Code

(IECC)

Climate Zone

Map


04/12/2011


7

Residential Windows


● International Energy Conservation Code

(IECC) 2012

2 3 4 5, Marine 4 6

U-factor 0.40 0.35 0.35 0.32 0.32

SHGC 0.25 0.25 0.40 NR NR

Climate Zone


04/12/2011


8

Residential Windows

Code Change Proposal Scope

● Update window prescriptive performance

requirements

● U-factor

● SHGC

● Packages C, D, and E

● Include window overhangs (south-facing)

● Prescriptive

● Reach Code


Residential Windows

Data Collection

● Market research process

● Supplier phone / online surveys

● Window manufacturers

● Window dealers / distributors

● Retail site visits

● Window showrooms

● Home improvement stores

● Compliance research calls / survey

● Energy consultants

● Building departments

04/12/2011


9


Residential Windows

Data Collection

● Market research scope

● Performance

● Availability

● Costs


04/12/2011


10


04/12/2011


11

Residential Windows

Typical Window Practice

● Installed type

● Vinyl frame

● Double-pane, air or argon-filled, low-e glass

● Installed performance

● Better than current Title 24 prescriptive

requirements

● U-factor: 0.30 – 0.35

● Solar Heat Gain Coefficient (SHGC): 0.23 – 0.35

● Incremental costs

● Minimal across typical SHGC values


04/12/2011


12

Residential Windows

Typical Window Practice

● Specification and compliance

● Performance values consistent across

orientations

● Building performance-method compliance in

cooling climates includes modeled overhangs

● Prescriptive overhang and exterior shading

device SHGC compliance options are rarely used


04/12/2011


13

Residential Windows

Analysis – Goals/Parameters

● High statewide TDV savings (optimized

energy / demand savings)

● High NPV (optimized cost-effectiveness)

● Minimized impact on heating TDV increases

● Consistency of requirements across climate

zones

● Achievable performance values across

typical window operator types


Residential Windows

Analysis – Scope

● Building simulations

● CALRES 2013, parametric simulation analysis

● Scope

● New construction savings

● Alteration, addition, and retrofit savings (TBD)

● Cost-effectiveness, by climate zone

● Statewide TDV savings impacts (weighted by

construction starts)

● 30-year life cycle costs, $ NPV

04/12/2011


14


● Residential ACM Prototype D

● 2700 sf, 2-story, detached

● Equal glazing distribution on four

orientations

● Per standard design in Title 24

04/12/2011


15

Residential Windows

Analysis – Simulated Prototype Home


04/12/2011


16

Residential Windows

Analysis – Window Simulation Parametrics

Case Description Performance

PKGD 2008 Package D U0.40 / Package D

CLEAR Dual Glazed Clear U=0.49 / S=0.65

HSLE High Solar Low-E U=0.32 / S=0.60

MSLE Mid Solar Low-E U=0.32 / S=0.35

LSLE Low Solar Low-E U=0.32 / S=0.30

ELSLE Extra Low Solar Low-E U=0.32 / S=0.25

TAX Tax Credit U=0.30 / S=0.25

TRIPLE Triple MSLE U=0.25 / S=0.28


Residential Windows

Analysis – Overhang Simulation Parametrics

● South-facing, multiple geometries

04/12/2011


17

Case Description

OHN No overhang

OH1 1ft overhang, 1ft above window







04/12/2011


18

Residential Windows

Analysis – Measure Comparison

Description

Standard

Design

U-factor 0.40

SHGC per Package D*

(No overhang)

Proposed

Design

ELSLE in CZ 2, 4, 6-16 (U-factor 0.32, SHGC

0.25)

HSLE in CZ1,3,5 (U-factor 0.32, SHGC 0.60)*


04/12/2011


19

Residential Windows

Analysis – Life Cycle Cost (LCC)

30-year LCC $ savings = kTDV savings / sf (from building

simulations)

(per prototype home, in 2011 $) x CEC $LCC factor (from Table 2*, below)

x Prototype building area

* per Life-Cycle Cost Methodology, 2013 Building Energy Efficiency Standards (CEC, November 2010)


04/12/2011


20

Residential Windows

Analysis – Results Summary

Climate Heating Cooling Total Heating Cooling Total

LCC

Savings Cost NPV

Zone kTDV/ft2 kTDV/ft2 kTDV/ft2 $ $ $

01 HSLE -2.18 0.00 -2.18 -8% -5% 1019 0 $1,019

02 ELSLE 1.43 -5.88 -4.45 5% -46% -8% 2081 383 $1,697

03 HSLE -1.24 -0.45 -1.69 -8% -6% -4% 790 0 $790

04 ELSLE 1.61 -9.58 -7.97 8% -44% -13% 3727 383 $3,343

05 HSLE -8.61 2.22 -6.39 -41% -17% 2988 0 $2,988

06 ELSLE 1.50 -8.13 -6.63 19% -41% -15% 3100 383 $2,717

07 ELSLE 0.98 -6.59 -5.61 45% -42% -17% 2623 383 $2,240

08 ELSLE 1.08 -9.79 -8.71 18% -29% -16% 4073 383 $3,689

09 ELSLE 1.16 -12.31 -11.15 13% -21% -13% 5214 383 $4,830

10 ELSLE 1.25 -12.21 -10.96 13% -21% -13% 5125 383 $4,742

11 ELSLE 0.99 -14.55 -13.56 5% -17% -11% 6341 383 $5,957

12 ELSLE 0.79 -13.00 -12.21 4% -26% -14% 5709 383 $5,326

13 ELSLE 0.54 -14.04 -13.50 3% -16% -11% 6313 383 $5,929

14 ELSLE 1.85 -13.69 -11.84 9% -18% -10% 5536 383 $5,153

15 ELSLE -0.06 -12.66 -12.72 -3% -8% -8% 5948 383 $5,565

16 ELSLE 10.58 -28.37 -17.79 26% -70% -18% 8319 383 $7,935

Statewide 0.97 -10.24 -9.27 12% n/a -13.0% 4336 350 $3,987Average 0.73 -9.94 -9.21 7% -29% -12% 4307 312 $3,995

Min -8.61 -28.37 -17.79 -41% -70% -18% 790 0 $790

Max 10.58 2.22 -1.69 45% -6% -4% 8319 383 $7,935

Window

Spec

TDV and Net Present Value for a 2700 ft2 Two Story HousePercent Difference Net Present Value

(Proposed - Standard /

Standard

Difference

(Proposed - Standard )

ELSLE ,

Proposed

Design


04/12/2011


21

Residential Windows

Analysis – Results Summary

-$4,500

-$3,000

-$1,500

$0

$1,500

$3,000

$4,500

$6,000

$7,500

$9,000

-15.0

-10.0

-5.0

0.0

5.0

10.0

15.0

20.0

25.0

30.0

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

STATEWIDE: Savings = 9.27 kTDV/ft2 (13%) NPV = $ 3,987

NP

V,

$

kDTV

/ f

t2

Windows Package D Straw Proposal: TDV Savings and NPV(by Climate Zone)

Heating Savings (kTDV/ft2)

Cooling Savings (kTDV/ft2)

TOTAL Savings (kTDV/ft2)

Net Present Value (NPV, $)


Residential Windows

Straw Proposal

● Prescriptive window performance requirements

● Climate Zones 2, 4, 6-16:

U-factor = 0.32, SHGC = 0.25 (Case: ELSLE)

● Climate Zones 1, 3, 5:

U-factor = 0.32, SHGC = NR or 0.60 (Case: HSLE)

● Prescriptive south-facing overhangs

● Viability / details of proposal still being determined

● Code, builder feasibility issues

● Multiple orientations, lot coverage, etc.

04/12/2011


22


Residential Windows

Straw Proposal

● Prescriptive window requirements

● Planned Proposed Changes to Table 151-C

(Package D)

● Note SHGC changes in climate zones 5 and 16

04/12/2011


23

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40

0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32 0.32

NR 0.40 NR 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.35 NR

NR* 0.25 NR* 0.25 NR* 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25

* No Requirement (NR), or 0.60, TBD

Maximum

U-factor

Maximum

SHGC

C L I M A T E Z O N EPrescriptive

Package D:

Fenestration


Residential Windows

Impacts

● Prescriptive window requirements

(Statewide, per prototype home)

● Simulated TDV savings (Package D – Straw

Proposal)

● 73.05 - 63.77 = 9.27 TDV kBtu/sf (13.0%) savings

(weighted by climate zone-specific construction starts)

● 30-year LCC $ savings = $4,336 (in 2011 $)

● Current incremental costs (relative to market

baseline) = $350

● Net Present Value (NPV) of straw proposal =

$3,987 (in 2011 $)

04/12/2011


24


Residential Windows

Impacts

● Prescriptive overhangs

(Statewide, per prototype home)

● Simulated TDV savings

(beyond that for windows performance proposal)

● 0.65 – 2.04 TDV kBtu/sf (1 – 3%), depending on

geometry

● 30-year LCC $ savings and NPV still TBD

04/12/2011


25


04/12/2011


26

Residential Windows

Next Steps

● Integrate stakeholder feedback, as

applicable

● Review and finalize code change proposals

● Complete CEC Codes and Standards (C & S)

proposal document

● Review by IOU’s C & S team

● Submission to CEC

● CEC rule-making workshops


04/12/2011


27

Residential Windows


Ryan Schmidt

[email protected]

(916) 962-7001

Ken Nittler

[email protected]

(530) 885-9891

?








Multi-Family Central DHW


Yanda Zhang


Charlotte Bonneville

Heschong Mahone Group Inc.

April 12, 2011

2/12/2011

1



MF DHW Improvement




● Data/findings

● Specifics of code change proposals

● Coordination with Solar MF DHW CASE

2 2


MF DHW Improvement



● Scope of the CASE Study: Central DHW Systems

● Low-rise and high-rise buildings; hotel and motel buildings

● Three areas of consideration

● Distribution System Controls

● Mandatory - Section 113 (c) 2:

● “be capable of automatically turning off the system”

● Performance - Res ACM Appendix E

● Timer control: assume 10pm – 5am pump off

● “MSC = 0.80, Multiplier - Adjustment factor for installation of monitoring

equipment or demand modulated equipment.” – defined but used

● Distribution System Designs: no requirement

● Water Heating Equipment

● Efficiency: federal standards

● Solar Water Heating: required for electrically heated residential building

3


MF DHW Improvement


Typical Practice – DHW System Controls

● Supply Temperature Control

● Temperature modulation

● Reduce supply temp during low demand

● Recirculation Flow Control

● Three control strategies

● Timer Control: Turn pump off with a fixed schedule

● Return Temp control: Return temp threshold

● Demand Control:

– Turn pump off when there is no demand,

– or return temp is high enough

● Allow pipe temp to cool down

4


MF DHW Improvement


Typical Practice

● Controls

● Timer controls & return temperature controls are

often not set up properly or disabled

● Market share of controls is still relatively low

● Continuous monitoring is used with temp

modulation (EDC system)

● Plumbing Design

● Mostly to create connection w/o considering

efficiency

5


MF DHW Improvement


Summary of Code Change Proposals

● Improve requirements of recirculation

system controls

● Demand Control (with temperature control)

● Temp modulation + continuous monitoring

● Establish standard distribution network

design rule set to encourage good design

practice

● Coordinate with MF Solar Water Heating

CASE to generate unified MF DHW proposal

6


MF DHW Improvement


Data / Findings – Study Methodology

● PIER Multi-family DHW System Research

● In-depth analysis and model development of

central DHW distribution system based on field

performance study of 30+ MF buildings

● Water and Space Heating

● ACM development for recirculation loop and

branch heat loss calculation

● Multi-family Solar Water Heating

● Comprehensive investigation of performance

and cost effectiveness of solar water heating

7

30%


MF DHW Improvement


Data / Findings – PIER Research Findings

● DHW control reduce recirculation loop pipe heat loss

● Measurable from recirculation flow/temp monitoring

● Savings depend on level of pipe temp reduction

● Temp Modulation – reduce whole loop temp

● Pump off – deep temp reduction, but mostly for return sections

● Not always measurable from gas input – need model

● Relative impact of recirculation loop loss

● HW draw variation can overshadow control savings

8

Water Heater

Losses Distribution Losses

End-Use

Energy Branch

Losses Recirculation

Loop Losses


MF DHW Improvement


Data / Findings – DHW System Modeling

● Physical models of two dominant effects

● Pipe flow (average flow, temp)

● Pipe cool down

● Linear transition between control modes

● Detailed distribution network configurations

● Spreadsheet based tool

● Validated with field

monitoring data

9

Model Time Interval

(30 min)

System Response

Time Constant

Qloss,2 Qloss,1


MF DHW Improvement


Data / Findings – Temp Modulation

10


MF DHW Improvement


Data / Findings – Timer Control

11


MF DHW Improvement


Data / Findings – Demand Control

12

4/18/2011


MF DHW Improvement


Data / Findings – Model Validation Results

13

SFDMeasured

(Btu/day)

Modeled

(Btu/day)

Measured

reduction

(%)

Modeled

reduction

(%)

Measured

(Btu/day)

Modeled

(Btu/day)

Measured

reduction

(%)

Modeled

reduction

(%)

Measured

(Btu/day)

Modeled

(Btu/day)

Measured

reduction

(%)

Modeled

reduction

(%)

CONT Pump 608,711 608,711 - - 639,732 643,487 - - 1,875,663 1,879,417 - -

Temp Mod 600,697 582,695 1.3% 4.3% 633,433 616,266 1.0% 4.2% 1,958,764 1,941,597 -4.4% -3.3%

Timer 507,048 461,656 17% 24% 600,803 562,822 6.1% 13% 1,732,428 1,694,446 7.6% 10%

Demand 215,483 191,328 65% 69% 411,903 453,556 36% 30% 1,423,628 1,465,281 24% 22%

Total Hot Water EnergyRecirculation Flow Heat Loss Recirculation Loop Heat Loss

HW Draw

SFD

Hot Water

Energy

(Btu/day)

Modeled

savings

(%)

Measured

(Btu/day)

CONT Pump 1,879,417 - 1,235,931

Temp Mod 1,871,511 0.4% 1,325,331

Timer 1,816,132 3.4% 1,131,625

Demand 1,749,959 6.9% 1,011,725

w/o Flow Variation

Recirculation loop loss represents 34% of total hot water energy

Total hot water energy = Hot water draw + recirculation loop loss


MF DHW Improvement



14


SAMMeasured

(Btu/day)

Modeled

(Btu/day)

Measured

reduction

(%)

Modeled

reduction

(%)

Measured

(Btu/day)

Modeled

(Btu/day)

Measured

reduction

(%)

Modeled

reduction

(%)

Measured

(Btu/day)

Modeled

(Btu/day)

Measured

reduction

(%)

Modeled

reduction

(%)

CONT Pump 368,536 368,536 - - 443,280 456,190 - - 1,030,479 1,043,388 - -

Temp Mod 362,987 355,698 1.5% 3.5% 442,840 435,949 0.1% 4.4% 1,030,039 1,023,148 0.0% 1.9%

Timer 265,214 279,559 28% 24% 421,494 419,521 5% 8% 1,008,693 1,006,720 2.1% 3.5%

Demand


HW Draw

SAM

Hot Water

Energy

(Btu/day)

Modeled

savings

(%)

Measured

(Btu/day)

CONT Pump 1,043,388 - 587,199

Temp Mod 1,025,058 1.8% 587,199

Timer 987,563 5.4% 587,199

Demand 896,508 14.3% 587,199

w/o Flow Variation



MF DHW Improvement



15

SFFMeasured

(Btu/day)

Modeled

(Btu/day)

Measured

reduction

(%)

Modeled

reduction

(%)

Measured

(Btu/day)

Modeled

(Btu/day)

Measured

reduction

(%)

Modeled

reduction

(%)

Measured

(Btu/day)

Modeled

(Btu/day)

Measured

reduction

(%)

Modeled

reduction

(%)

CONT Pump 176,588 176,588 - - 221,165 228,267 - - 3,116,211 3,123,313 - -

Temp Mod 157,692 159,541 11% 10% 204,820 204,057 7% 11% 2,564,910 2,564,146 18% 18%

Timer 151,829 147,709 14% 16% 220,452 228,777 0.3% -0.2% 3,443,807 3,452,131 -11% -11%

Demand 48,168 78,002 73% 56% 178,093 179,729 19% 21% 2,784,551 2,786,187 11% 11%


HW Draw

SFF

Hot Water

Energy

(Btu/day)

Modeled

savings

(%)

Measured

(Btu/day)

CONT Pump 3,123,313 - 2,895,046

Temp Mod 3,108,746 0.5% 2,360,090

Timer 3,108,208 0.5% 3,223,355

Demand 3,092,962 1.0% 2,606,458

w/o Flow Variation




MF DHW Improvement



16

SFHMeasured

(Btu/day)

Modeled

(Btu/day)

Measured

reduction

(%)

Modeled

reduction

(%)

Measured

(Btu/day)

Modeled

(Btu/day)

Measured

reduction

(%)

Modeled

reduction

(%)

Measured

(Btu/day)

Modeled

(Btu/day)

Measured

reduction

(%)

Modeled

reduction

(%)

CONT Pump 177,796 177,796 - - 201,589 207,200 - - 1,094,813 1,100,423 - -

Temp Mod - - - - - - - -

Timer 143,549 145,345 19% 18% 187,240 194,233 7% 6% 942,592 949,586 14% 14%

Demand 90,349 82,244 49% 54% 180,478 173,723 10% 16% 742,710 735,955 32% 33%


HW Draw

SFH

Hot Water

Energy

(Btu/day)

Modeled

savings

(%)

Measured

(Btu/day)

CONT Pump 1,476,183 - 893,223

Temp Mod 1,462,791 0.9% -

Timer 1,449,737 1.8% 755,353

Demand 1,409,352 4.5% 562,232

w/o Flow Variation




MF DHW Improvement


DHW ACM – Recirc. Loop ACM Model

● Loop sections: up to 3 supply sections and up to 3 return sections

● Hourly pipe heat loss calculation based on pipe and ambient temp

17

Hourly ambient temperature

for pipe section, n Hourly average water

temperature for pipe section, n

Average water temperature

during pump-off period

Average water temperature

during pump-on period

● Hourly pipe temp is weighted average of steady flow and cool down

modes

Weighting factor depending

on control schedule

● Hourly control schedule created for controls


MF DHW Improvement


DHW ACM – Control Schedule

18

TEMPERATURE MODULATION

p Pump

off

Time

TS T

S

With cont.

monitoring

0 0 120 115

0 0 120 115

0 0 120 115

0 0 120 115

0 0 125 120

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 135 130

0 0 125 120

DEMAND CONTROL

p Pump

off

Time

TS

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

t 1-t 135

Continuous Pumping

Hour p Pump

off

Time

TS T

S

With cont.

monitoring

1 0 0 135 130

2 0 0 135 130

3 0 0 135 130

4 0 0 135 130

5 0 0 135 130

6 0 0 135 130

7 0 0 135 130

8 0 0 135 130

9 0 0 135 130

10 0 0 135 130

11 0 0 135 130

12 0 0 135 130

13 0 0 135 130

14 0 0 135 130

15 0 0 135 130

16 0 0 135 130

17 0 0 135 130

18 0 0 135 130

19 0 0 135 130

20 0 0 135 130

21 0 0 135 130

22 0 0 135 130

23 0 0 135 130

24 0 0 135 130


MF DHW Improvement


DHW ACM – Default Plumbing Design

● Existing ACM algorithms – only rely on user input

19

• Building Story, floor area

• Number of apartment/guest room

• Boiler room Location

• Number of Loops

• Supply and Return Loop section

locations and length

USER INPUT

• Recirculation loop path

• Branch length and number

• Pipe diameters (Follow UPC)

• Pipe insulation thickness

ACM Generate Standard &

Default Loop Configuration

User

Input

Design

Defaul

t

Design

Compare

Standar

d

Design

Proposed

Design


MF DHW Improvement


DHW ACM – Default Plumbing Design

20

User Inputs

Return Recirculation Pipe

Section #1

30

Section #2 Section #3

10

Supply Recirculation Pipe

Section #1

10

Section #2 Section #3

30

Uncondition

ed Space

2”

Conditione

d Space

2”

4 stories / 2 loops

Conditioned

Space

1”

Uncondition

ed Space

3/4”

Supply Return

Loop 1 80 ft 80 ft

Loop 2 80 ft 80 ft

Total 320 ft

Generate ACM

Default

Total Length <

90% ACM

Default?

Yes No

Keep

user

input

Default Design

Adjust

user

input

Increase total length

to ACM default


MF DHW Improvement


DHW ACM – Standard Recirc. Design

● Dual loop design

● Boiler room near the middle of the building

● Any floor - 1st floor, garage, roof, middle floor

● Smaller pipe diameters less surface area

● Smaller temp drop (not included in savings calc.)

● Verification

● Res: HERS

● NR: follow Appendix NA2

● NR Field Verification & Diagnostic

● Test Procedures

21

Standard Design


MF DHW Improvement


Data / Findings – Prototype Buildings

22

Low

Rise

High

Rise

# of Floor 2 4

# of Unit 40 86

Unit Area (sqft) 870 870

Recirc. Loop Length (ft) 639 880

Recirc. Pump Power (hp) 0.25 0.5

Recirc. Flow Rate (GPM) 6 6

Recirc. Loop Vol. (Gal) 76 175

High Rise


MF DHW Improvement


Data / Findings – Savings Analysis

Low Rise

23

Per Building kWh kW Therm

Temp Mod 0 0 405

Monitoring (-5

F) 0 0 461

Temp Mod + Monitoring 0 0 785

Demand Control 128 0.14 1014

kWh kW Therm

0 0 535

0 0 771

0 0 1199

2035 0.23 1255

High Rise

● Use the PIER MF DHW Recirculation Model

● ACM algorithms proposed by the Water+Space Heating CASE

● Two building prototypes: Low rise and high rise

● Control savings

● Compare recirculation heat loss to continuous pumping

● Savings variations over 16 climate zones are very small


MF DHW Improvement


Data / Findings – Annual Energy Savings

● Demand control as prescriptive requirement

24

Per Building Low-rise High-rise

kWh kW Therm kWh kW Therm

Demand Control 1,228 0.139 1,083 2,035 0.232 1,359

Demand Control +

Plumbing Design 1,429 0.163 1,456 2,651 0.303 2,062


MF DHW Improvement


Data / Findings – Life Cycle Cost (LCC)

● Cost

● Demand control: $1000 each, life = 15 yrs $2000 for 30

yrs;

● Plumbing cost reduction from optimization not included

● 30 Yr TDV values

25


Cost PV

Savings

LCC Cost PV

Savings

LCC

Demand Control $2,000 $ 30,695 ($28,695) $2,000 $42,179 ($40,179)

Demand Control +

Plumbing Design <$2,000 $ 40,530 <($38,530) <$2,000 $62,515 <($60,515)


MF DHW Improvement


Specifics of Code Change Proposals

● Prescriptive Requirements

● Demand control

● Streamlined dual recirculation loop design

● ACM Algorithms – Res ACM Appendix E

● Timer control – no credit

● ACM modeling schedule:

● Demand control, temp modulation, and continuous

monitoring

26


MF DHW Improvement


Data / Findings – Solar Water Heating

● System types

● Flat plate collectors with drainback, active glycol (immersed and

external HX) and forced recirculation freeze protection

● Solar water heating (SWH) used as a pre-heater

● Savings and system cost depend on collector size

27


MF DHW Improvement


Coordination – Solar Water Heating

● System types

● Flat plate collectors with drainback, active glycol (immersed and

external HX) and forced recirculation freeze protection

● Solar water heating (SWH) used as a pre-heater

● Savings and system cost depend on collector size

28


MF DHW Improvement


Coordination – Annual Energy Savings

● Comprehensive central DHW improvement

Consideration – solar water heating

29


kWh kW Therm kWh kW Therm

Demand Control 1,228 0.139 1,083 2,035 0.232 1,359

Demand Control +

Plumbing Design 1,429 0.163 1,456 2,651 0.303 2,062

Demand Control +

Plumbing Design +

SWH (SF = 39%)

864 0.87 2,741 1,634 0.125 4,846

Climate zone 10


MF DHW Improvement


Coordination – Life Cycle Cost (LCC)

● Cost

● Demand control: $1000 each, life = 15 yrs $2000 for 30 yrs;

● Plumbing cost reduction from optimization not included

● Solar WH: ~$130/sf collector, installation & maintenance

● 30 Yr TDV

30


Cost PV

Savings

LCC Cost PV

Savings

LCC

Demand Control $2,000 $ 30,695 ($28,695) $2,000 $42,179 ($40,179)

Demand Control +

Plumbing Design <$2,000 $ 40,530 <($38,530) <$2,000 $62,515 <($60,515)

Demand Control +

Plumbing Design +

SWH (SF = 40%)

<$54,000 $ 68,337 <($14,337) <$116,400 $125,303 <($8,903)


MF DHW Improvement


Coordination –LCC Trend

● High-rise prototype

(less cost effective than low-rise)

31


MF DHW Improvement


Coordination – Unified Approach

● Prescriptive Requirements

● Demand control

● Streamlined dual recirculation loop design

● Solar fraction of 30%

● ACM Algorithms – Res ACM Appendix E

● Timer control – no credit

● ACM modeling schedule:

● Demand control, temp modulation, and continuous

monitoring

32



MF DHW Improvement

33


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