1. Residential and Prototype Modeling for the eTRM
Larry Brackney
February 23, 2017

2. Bifurcated Title 24 Compliance Modeling
CBECC-Res
CBECC-Com
California
Simulation
Engine (CSE)
Why? ?
eTRM

3. Some of CEC’s Concerns Regarding EnergyPlus
Existing E+ deficiencies impacted residential applications
Foundation heat transfer
Infiltration, duct leakage, etc.
Attics
Others
Historically, little E+ commitment for residential applications
Processing overhead (Simulation runtime)
Switching from CSE would be unnecessarily disruptive

4. Recent Enhancements to EnergyPlus
New foundation heat transfer model
Based on KIVATM model
Validated against IEA Building Energy Simulation Test
Computational time reduced 95% relative to traditional implicit solutions
Can handle full range of residential foundations and insulation configurations
Airflow Network enhancements
NREL + others performed detailed assessment (infiltration, ducts, interzonal mixing)
New features coming in March 2017 release
Using E+ curves for wind pressure coefficients
Refactor to use optimized numerical solver
Features coming in September 2017 release
Allow Multiple Air Primary Loops in the Airflow Network Model
Zone Induced Air by a Constant Volume Fan
Multiple Leakage Components Per Surface
Wind Pressure Coefficients Auto-Calculate
Return air path
Kruis, N Development and Application of a Numerical Framework for Improving Building Foundation Heat Transfer Calculations. Ph.D. Dissertation. Department of Civil, Environmental, and Architectural Engineering. University of Colorado at Boulder.
Kruis, N Kiva: A Numerical Framework for Improving Foundation Heat Transfer Calculations. Journal of Building Performance Simulation. doi: /

5. Recent Enhancements to EnergyPlus
Airflow Network enhancements
NREL and others performed detailed model assessment (infiltration, ducts, interzonal air mixing, usability)
New features coming in March 2017 release
Using E+ curves for wind pressure coefficients
Refactor to use optimized numerical solver
Features coming in September 2017 release
Allow Multiple Air Primary Loops in the Airflow Network Model
Zone Induced Air by a Constant Volume Fan
Multiple Leakage Components Per Surface
Wind Pressure Coefficients Auto-Calculate
Return air path

6. Recent Enhancements to EnergyPlus
New attic model
Based on validated Fraunhofer model
Integrated with Airflow Network
Infiltration
Duct leakage
Radiant exchange – including ducts
Multiple HVAC systems serving single thermal zone
E.g., Baseboard and Mini-Split HP in same house
Partially conditioned thermal zones
Window AC that cools only a portion of the house
Development and verification of the Fraunhofer attic thermal model
Anthony D. Fontanini, Jan Kosny, Nitin Shukla, Ali Fallahi & Baskar Ganapathysubramanian
Journal Of Building Performance Simulation Vol. 10 , Iss. 1,2017

7. Recent Enhancements to EnergyPlus
Enhanced VRF (Mini-Split HP) model
Improved fundamental basis for model
Dynamics of operational parameters
Component-level curves rather than system-level curves (fewer model inputs)
ASHRAE collaboration with VRF manufacturers
Heat Pump Water Heater
Wrapped/coiled condenser configuration predominant in residential HPWH units
Connected to stratified tank model
Ducting configurations
Localized temperature depression
HVAC interaction factor
Lab validated models
Variable-speed HVAC equipment
Lab validated model
High-efficiency equipment
Speed

8. Recent Enhancements to EnergyPlus
Enhanced moisture buffering model
Improved absorption/desorption modeling
Increased accuracy in predicting humidity excursions
Capability needed for low-load homes
Field Validation

9. Recent Enhancements to OpenStudio
Common approach to residential and commercial modeling
OpenStudio measures – common currency for constructing and modifying models

10. Residential Adoption for EnergyPlus/OpenStudio
NRCan/NRC shifting both res/comm compliance to E+/OS
Independent assessment of engine and software platform
Contributing improvements to EnergyPlus for residential
Contributing improvements to OpenStudio
Standards modeling library
eQuest geometry import
Residential Application Use Case: BPA Partnership
Committed to E+/OS for the long-term
Funding E+ model enhancements & validation for technologies of interest
Funding OpenStudio-based analysis for regional power plan
Prioritized technology R&D and incentives
Regional efficiency/demand savings potential
Demand response, load shapes
Co-funding with DOE for simplified OpenStudio Geometry Tool
Single platform to target single-family, multifamily, and commercial

11. Approach for BPA Residential Analysis
OpenStudio/EnergyPlus
Housing Stock Characteristics
– Input Database
Statistical Sampling
– Auto-Generated Models
Building Simulations
– High Performance Computing
Validation/Calibration
– Comparison to RECS consumption data
Output Visualization
– Data-driven analytics
retrofits

12. Preliminary Results – Economic Potential (NPV > 0)
Air Sealing
Attic Insulation (R-49)
Replacing Oil Boilers with Ductless Heat Pumps
Basement Wall Insulation (R-10)

13. Preliminary Results – Economic Potential (NPV > 0)
Supply Curves
Width = total potential savings that is cost-effective
Height = average cost-effectiveness
(more negative is more cost-effective)

14. Top 10 Upgrades for Virginia
Approach:
Model the entire U.S. housing stock with unprecedented granularity (simulated on HPC – Peregrine or cloud)
Results:
Actionable analyses and visualizations of U.S. energy efficiency potential
Leverages: A dozen public and private data sources (e.g. EIA RECS, Census/Housing Survey, Codes, Dept. of Homeland Security data), and DOE’s flagship energy simulation engine (EnergyPlus).
All values are primary/source energy (i.e., raw fuel burned to create heat and electricity).

15. Residential Summation
TPP3 is still valid
E+/OS is a solid platform for the eTRM
Commercial buildings are initial focus
Residential alternatives
Add residential prototypes via E+/OS to eTRM later
Accept bifurcated solution for eTRM and compliance
Develop E+/OS transition plan with CEC
Develop OS/CSE translator
OS already targets multiple engines (Radiance, ESP-r)
CSE would need to be ported to Linux and added to OS Server
DOE has requested budget estimate for this work as a contingency

16. Single Platform – Many Models
More Inputs
Type
Prototype
Models
Increased Fidelity
Vintage
Climate
CBECCS,
CEUS,
CoStar
Model
Populations
Platform makes it easy to create models with:
Consistent methodology
Varying detail
User sophistication in mind
Pick the right level of detail for the job
Technology screening
Customer targeting
Custom incentives
Type
Vintage
Open Source
Zero Touch
Audit
GIS
ft2
# Floors
Owner/
Facility
Mgr
DOE Asset Score
simuwatt™
Auditor
Hand Built
Model
Modeler

17. Prototype/Archetype Models
Vintage
Climate
Model
Populations
Open Source
Zero Touch
Audit
DOE Asset Score
OpenStudio “Standards Gem”
Contains ASHRAE 90.1 data definitions
Library of standardized modeling assumptions
Easily extended to encompass Title 24
Enables Model Automation
Used to infer unspecified data
Code compliant baseline generation
Prototypes are “built” as needed
simuwatt™
Hand Built
Model

18. Inputs for the Standards Gem
Spreadsheet contains data definitions for
Building types
Vintages
Climate zones

19. Inputs + Prototype Measure = Detailed Model
Approach is transparent and extensible
Requisite input data for gem appears to be available on
Inquiry on usage rights in process
Some DOE funding available to begin work once rights are clear

20. Prototype Summation Near-term eTRM work CA Prototypes
eTRM development/testing does not require CA prototypes
Analysis controller development could begin at any time
Integration testing with the eTRM can use 90.1 prototypes
Switching to CA prototypes later is simple
CA Prototypes
DEER data integration
Can begin as soon as CPUC answers legal questions
DOE funding available to start work
Will need CalTF assistance to vet process and outcomes