2013 residential compliance software project program advisory committee (pac) meeting july 17, 2012...

2013 RESIDENTIAL COMPLIANCE SOFTWARE PROJECT

Program Advisory Committee (PAC) Meeting

July 17, 2012

Bruce Wilcox, P. E.Berkeley [email protected]

mailto:[email protected]

7/17/2012 Wilcox - 2013 Residential Compliance Software Project 2

2013 RESIDENTIAL SOFTWARE COMPLIANCE PROJECT GOALS

Provide public software for 2013 Standards compliance

Improve accuracy, particularly in cooling, to support zero net energy goals

Foster collaborative software environment for the future

Project Technical Team Bruce Wilcox Prime Contractor, Project Manager, Technical Lead

Chip Barnaby CSE Lead Programmer

Scott Criswell Compliance Manager Lead Programmer

Dave Krinkel Development Plan

Phil Niles CSE chief scientist

Robert Scott Compliance Form Generator

Ken Nittler Compliance Ruleset

Marc Hoeschele DHW Simulation

Doug Herr DHW Programmer

John Proctor HVAC modeling


3rd Party Tool 3rd Party Tool

Building Energy Code Compliance (CBECC)

Compliance Manager Software HERS Ruleset2013 Title-24 Compliance

Ruleset& TDV

Compliance Report Generator

CSE Simulation Engine

Transfer of building model (multiple arrows imply transfer of multiple building models)

Transfer of compliance reports

Diagram key:

Inter-process communication of data and/or API calls

Pale Blocks Possible future modules

DHW Engine

Compliance Data Registry

2013 Title-24weather data

Compliance User

Compliance Data Repository


Current Project ScheduleMonth of

Activities Sep

-11

Oct

-11

Nov

-11

Dec

-11

Jan-

12

Feb

-12

Mar

-12

Apr

-12

May

-12

Jun-

12

Jul-

12

Aug

-12

Sep

-12

Oct

-12

Nov

-12

Dec

-12

Jan-

13

Feb

-13

Mar

-13

Apr

-13

May

-13

Jun-

13

Jul-

13

Aug

-13

Sep

-13

Oct

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Nov

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Dec

-13

Compliance Manager Software

CSE upgrades

New Construction Rules

New Construction Software Beta Test

3rd Party Compliance Manager Pilots

Additions and Alterations Rules

Additions and Alterations Software BetaNew Construction Compliance Software

Additions and Alterations Software

Draft ACM Manual

Final Draft ACM Reference Manual

CEC Compliance Software Certification

Deadline for CEC Software Certification

Support

PAC Meeting x x x

Workshop x x


CSE SIMULATION ENGINE STATUS Energy calculation for “typical” buildings done and testing:

Integrated & improved 2008 attic and duct models

Multiple conditioned and unconditioned zones

Pressure flow inter zone air flow network for infiltration, natural ventilation, mechanical ventilation and duct leakage

State of the art ASHWAT window model

Variable convective films and mass for all surfaces

Sky temperature and radiant heat transfer for all surfaces

Improved air conditioning model with latent load calculation


CSE SIMULATION ENGINE STATUS Not done yet:

HVAC sizing for the simulation

Central fan cooling ventilation (Nightbreeze etc.)

Other HVAC systems:

Heat pumps

Hydronic and other unducted heating

Evaporative condensers

Multi-segment duct model


ENERGY CALCULATION RULES Will be documented in the 2013 Residential ACM Reference

Manual following the Compliance Manager data model organization

Prescribe the user inputs for compliance calculations

Explain how those inputs are used to set up the CSE and DHW calculations for the Proposed and Standard Design

Specify the Reporting and Verification required

For this presentation, focus is on new rules and rules that have changed

To accommodate new and improved algorithms

To respond to changes in the 2013 Standard


RULES CATAGORIES

The Building/Project

Conditioned Zones

Attics

Other unconditioned zones


THE BUILDING/PROJECT RULES Standards Version

Dwelling Units

Solar

Construction Assemblies

Cooling and Heating Subsystems

Fan Subsystems

Distribution Subsystems

HVAC Systems

Ventilation Systems

Zoning

Air Leakage and Infiltration


STANDARDS VERSION New Input: Standards Version

Compliance 2014: through December 2014 (with current Federal Air Conditioning efficiency requirements

Compliance 2015: any time (with 2015 Federal Air Conditioning Requirements)

Standard Design: AC efficiency at specified Federal level

Reporting:

Standards Version

SEER & EER if Compliance 2015


DWELLING UNITS Inputs

For each dwelling unit type in the building input

Conditioned Floor Area (CFA)

Number of bedrooms

For Multi-Family input the number of each dwelling unit type

Calculate the Indoor Air Quality (IAQ) Ventilation CFM for each unit type

Standard Design: Same Unit Types as Proposed Design

Reporting: Unit Types and minimum IAQ ventilation CFM’s for verification.


SOLAR For single family and town houses if

standards version is “Compliance 2015”

and Zone is 9-15

Then input the kWdc of the proposed Photovoltaic system (minimum 2 kWdc)

Calculate the PV compliance credit as the smaller of:

PV Generation Rate (kTDV/kWdc) * kWdc

Max PV Cooling Credit * Standard Design Cooling Energy (kTDV)


SOLAR PV Credit:

Max PV Cooling Credit Maximum ImpactClimate PV Generation Rate (% of Standard Design on Prototype

Zone (kTDV/kWdc) Cooling kTDV/ft2) % of total TDV09 30269 13% 7%10 30342 15% 8%11 29791 18% 10%12 29556 17% 6%13 29676 17% 10%14 31969 16% 9%15 29536 19% 17%


CONSTRUCTION ASSEMBLIES Replaces 2008 Joint Appendix 4 U-factor Tables

U-factor calculated in Compliance Manager for Prescriptive compliance and user feedback

U-factor is not an input to the CSE Simulation

Creates Layered constructions for CSE input

Material layers selected from CEC approved library

Flexible R values for insulation layers

Separate frame and cavity surfaces for frame constructions

Reporting: to be determined


COOLING SUBSYSTEMS Improved Cooling Algorithm

Adds calculation of indoor humidity and latent load

Evaporator air flow and conditions affect sensible heat ratio

New relationship based on R410 refrigerant

New input for fan motor type: PSC or BPM

Drop cooling size credit

Little used

No consensus on calculation or energy savings

New input, algorithm and report for bypass duct (TBD)


HEATING SUBSYSTEMS Standard Gas Furnace algorithm unchanged from 2008

RACM (but the Federal minimum efficiency changes)

New air source heat pump algorithm, inputs and reporting to be developed


Fan Subsystems Component of

Cooling and Heating systems

Ventilation Cooling systems

IAQ Ventilation systems

Inputs

CFM

W/CFM

Type (PSC, BPM)

Model

Fan operates at specified CFM in Airnet

Fan heat added to air stream


Distribution Subsystems Ducts in unconditioned spaces are an important component:

Cooling and Heating systems

Cooling, Heating and Ventilation systems

Same model as 2008 with added features:

Multiple duct systems located in any zone (attic and crawl for example)

Improved treatment of insulation thickness and conductivity

Duct segments for accuracy and to support input of reduced area, buried ducts etc

Operates in ventilation mode to accurately model CFI IAQ ventilation systems


HVAC Systems An HVAC system is a collection of one or more of the

following components: cooling subsystem

heating subsystem

fan subsystem

Distribution subsystem

Examples

Split system cooling subsystem, gas furnace, PSC furnace fan, ducts in attic

Whole house fan

Bathroom exhaust for IAQ ventilation

All components of a system use the distribution subsystem


Cooling Ventilation Systems

Natural ventilation through openable windows

Mechanical Cooling Ventilation

Whole House Fan

Integrated Central Fan (Nightbreeze, Smartvent etc)


Window Ventilation Cooling Same inputs, defaults and reporting as 2008

Effectiveness reduced by 50% to reflect behavior and experience

Available from dawn to 11 PM

Modeled as envelope holes in airnet


Whole House Fan Ventilation Cooling New measure for 2008

Input is total CFM of fans and W/CFM

Effectiveness reduced by 75% to reflect average behavior

Available from dawn to 11 PM (requires windows to be opened)

Modeled as exhaust fan from conditioned zone to attic in airnet

CFM and W/CFM from CEC fan listing

Standard Design and default:

2 CFM/CFA at 0.1 W/CFM in single family in Zones 8-14

Reporting: Proposed CFM and W/CFM


Integrated Central Fan Ventilation Cooling New measure for 2013

Available any hour of the day

Modeled as supply fan from outdoors to zones with relief to attic in airnet

Controlled on current vent setpoints and indoor-to-outdoor delta T

Fixed speed systems (Smartvent etc) input fixed CFM and fan W

Variable speed systems (Nightbreeze, etc) use manufacturer certified max CFM, W/CFM and off max functions

Reporting: Type, CFM, W/CFM

Verification:

Type, CFM & W/CFM at max flow

Duct leakage in air conditioning mode with damper normally closed (but not specially sealed)


Indoor Air Quality Ventilation Systems Same functional requirements as 2008

New 2013 requirement to verify whole house outdoor ventilation CFM for each dwelling unit.

Reporting:

Type, CFM for each dwelling unit, W/CFM

Verification:

Type, CFM of outdoor air, and W/CFM if not default.


Zoning the Building Zoning the spaces in the building is optional (recommended

for added accuracy even for single zone systems)

A 40 ft2 opening will be assumed between adjacent zones

Building components such as ceilings, floors, walls, windows and point source internal gains (such as the kitchen) must be assigned to the correct zone

Heating and cooling, up to the CSE sized capacity of the system assigned to the zone, are assumed to be delivered to each zone as required to meet the scheduled set points.

The location of duct system return grills must be input

The Standard Design building has the same zoning as the proposed design.


Zonal Systems The cooling system zonal thermostats are deleted and all

spaces operate in cooling at the conditioned zone set points

The heating system zonal thermostats and schedule are maintained for systems that meet the current requirements for that credit

An algorithm will be developed to model the impact of bypass ducts on cooling system performance


Air Leakage and Infiltration Envelope air leakage is a building level characteristic

Input is Air Changes at 50 Pascals (ACH50) measured according to the CEC approved method (copied from Resnet).

Default and Standard Design is

5 ACH50 for single family and multi-family homes

7 ACH50 for Townhouse leakage measured as a single unit

A lower value may be used for single family and townhouses if verified

Reporting: ACH50 if other than default

Envelope Air Leakage (ACH50)

0

1

2

3

4

5

6

7

8

9

10

11

1 19 37

Air C

hang

es a

t 50

Pa

SF

Apartment

TownHouse


Air Leakage Distribution Envelope air leakage is located at the building surfaces

% of Total House Leakage by Surface

Configuration Ceilings FloorsExterior Walls

House to Garage Surfaces

Slab on grade 50 0Raised Floor 40 10No Garage 50 0Attached Garage 40 10

Leakage Location Single Family

0

1

2

3

4

5

6

7

8

9

10

ACH

50

Other

Garage

Attic


Airnet Holes

The leakage in a surface is represented by 2 holes spaced vertically at 25% and 75% of the height of the surface

If the air in the space is warmer than air outside, air density (stack effect) causes air to flow in the bottom hole and out the top hole.

If the air in the space is colder the flow goes the other way


Wind and Mechanical Effects

Holes are needed on each side because wind pressure is different on each side of the building (upwind, downwind and parallel sides assumed, wind is not orientation specific).

Fans and duct leaks change the pressure uniformly on the whole space

The combined pressure on each hole is the sum of the wind, stack and fan pressure (which may add or cancel each other)


Multi-Zone Gets pretty complicated…

There is also a hole between each pair of zones (door or stair)

Then we add Windows..

The Compliance Manager calculates the size and location of each hole

The Airnet calculation finds the air pressure in each zone that makes the air flows in the entire network balance


CONDITIONED ZONES Dimensions and Location

Internal Gains

Exterior Surfaces

Ceilings below Attics

Exterior Walls

Surfaces between Zones

Interior walls, ceilings and floors

Slab on grade floors

Raised Floors


Zone Location and dimensions Location and dimensions added for Airnet

Floor to floor height

Elevation of the bottom of the Zone

Window head height of the top windows

Zone types and thermostats are unchanged except

The zonal cooling thermostats are deleted


Surfaces Surface inputs unchanged except for Construction instead of U-factor

Airnet holes automatically created in each wall, floor and ceiling. Hole size proportional to area as fraction of total area of surface type in building

Ceilings below Attics

Defined in the conditioned space zone below

Air net hole to attic automatically created in each surface

Floors, roofs and ceilings between zones

Dimensions and constructions must be entered in one zone

Openings defaulted to 40 square feet between conditioned zones in the same dwelling unit

Air net holes to unconditioned zone automatically created in each surface


Windows Window and skylight inputs and reporting unchanged

Shade operation for windows

Interior shades half open during day, 80% closed at night

Automatically operated exterior shades closed when air conditioning. Rules to be developed.


Thermal Mass Inside the zone light mass and surfaces are fixed:

Light mass (Cair) is 2 BTU/CFA

Interior wall with one side area equal to CFA

Interior floor if multi-story zone

Furniture made of 2.5” wood with one side are equal to 2 times the CFA

No change to slab floors (default 80% carpet, 20% bare)


HERS II Internal Gain Internal gains according to HERS II formulas and schedule

Appliance efficiency and fuel types default in both Proposed and Standard Design

If multi-zone, specify the zone where point sources (such as kitchen) are located

Added latent fraction to HERS II gains:

Sensible LatentLights 1 0People 0.573 0.427Misc 0.97 0.03

Refr 1 0Dishwash 0.75 0.25cook 0.33 0.67Washer 1 0Dryer 0.5 0.5


Sensible Internal Gain Comparison

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

-

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

Fig. 3. 2700 ft2 4 BR Prototype Average Internal Gain

LightsEquipPeopleRefrig

Time of Day

Inte

rna

l G

ain

(B

tu/h

)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

-

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

HERS II

2008 RACM

Time of Day

Inte

rna

l G

ain

(B

tu/h

)


UNCONDITIONED ZONES Attic

Floor Area

Ventilation

Attic Edge

Other zones (optional) Crawl Spaces

Basements

Garages


Attic Attic floor area defined by ceiling areas of zones below

Attic ventilation is no longer a compliance variable

1/300 soffit ventilation assumed

Vent area increased if needed to provide a minimum of CFM/375 ft2 free area for cooling ventilation fan relief

Insulation in the attic

Input is R value

Insulation type (cellulose, fiberglass, foam, etc) is not a variable

Assume R = 2.6/inch (light blown fiberglass)


Attic Edge - Not Part of the Attic


Attic Edge

Solution is to treat the attic edge area as a cathedral ceiling

No heat flow to the attic from this area

Attic floor area (and volume) reduced by the edge area

Tapered insulation cross section (and truss path) on left above can be approximated by 2 rectangular sections on the right that provide nearly the same steady state heat flow and can be simulated as a 1 dimensional surfaces in CSE


Attic Edge Inputs

Roof Pitch

Distance from top plate to roof deck, default 3.5”

Ceiling Insulation and Below deck insulation R

Length of attic edge For simplicity not an input

Assume 3 times the square root of Attic Floor Area

Compliance Manager generates the cathedral surfaces

Standard Design: default geometry with Prescriptive R

Reporting: Heel height for verification if not defaulted


Other Unconditioned Spaces Modeling (optional) for improved accuracy and flexibility

Crawl Spaces

Basements

Garages

Rules to be developed

Default: Current rules (not modeled as zones)

Standard Design: Same modeling as proposed

Reporting: to be developed


Other RACM Topics To Be Developed

Domestic Hot Water

Additions/Alterations

Testing

2013 residential compliance software project program advisory committee (pac) meeting july 17, 2012...

Documents

standards compliance

compliance calculationsexplain

residential building

project manager

duct leakagestate

natural ventilation

mechanical ventilation

new rules