CalTF TPP3:Case for EnergyPlus as Default Modeling Engine for the Electronic TRM Project

Jan. 28, 2016

2

eTRM

Problem & Position

Electronic TRM (“eTRM”): database of measures & related resources• Supports IOU EE programs, enables sharing, tracking & updates for appropriate actors

DOE-2: building energy modeling (BEM) engine that supports current TRM• Single provider• Poor transparency• CA ratepayers must bear full cost of expensive process• Incongruous with Title-24 compliance process

TPP3: new eTRM should be supported by new BEM engine, EnergyPlus

DEER

3

ECMECMECM

methods

OpenStudioEnergyPlus

Unpacking and Refinement

Current eTRM describes a package of tools• DOE-2.2: BEM engine• eQuest: graphical user interface• MAS (Measure Assessment System): prototype models, measures, methods &

assumptions

TPP3 proposes to replace the entire package using DOE tools• EnergyPlus: BEM engine replaces DOE-2.2• OpenStudio-based applications: graphical user interfaces replace eQuest• OpenStudio content: prototype models, measures, methods & assumptions

ECMECMECM

methods

MASeQUEST

4

TPP3 Executive SummaryTPP3 compares tools using technical, operational & policy criteria• Technical: capabilities, extensibility, development resources, etc.• Operational: licensing, funding & cost-share, development cycle, support models• Policy: use of public funds, competition, intra-state coordination

Part I: DOE-2 EnergyPlus• Expanded coverage of low-energy measures• Reduced need for one-off workarounds in workpapers• Align IOU programs with CEC Title 24 & POU programs• Benefit from DOE and third-party investment

Part II: eQuest/MAS OpenStudio• Increase transparency of engineering assumptions, inputs & methods• Simplify & standardize review of work-papers & custom projects• Engage larger talent pool for development of measures & XA review• Benefit from DOE and third-party investment

Conclusion & Recommendations• Replace DEER with new, more functional eTRM• Use EnergyPlus & OpenStudio as default modeling engine & framework for new eTRM

5

DOE-2 EnergyPlus (energyplus.net)

Policy criteria•Transparency: undocumented extensions to DOE-2.1 fully documented•Transparency: non-useful “compiled source code” available full source code available•Intra-agency coordination: not used by CEC & POUs used by CEC & POUs•Use of public funds: free, but proprietary & single-vendor open-source & multi-vendor

Operational criteria•Ownership: JJH & Assoc. Regents of UC & UI•Licensing: proprietary, derivative works not permitted commercial friendly open-source•Funding: CA ratepayers ($?) federal taxpayers ($3.5/year, stable since 2010)•Updates & bug fixes: few since 2009 biannual major releases/biweekly minor releases

Technical criteria (meta)•Language & platform: FORTRAN C++•Team: JJH & Assoc. (5?) National labs, contractors, vendors (~30 and expanding)•Process: proprietary open source-code, test dashboard, bug tracking & feature request

6

DOE-2 EnergyPlus: Capability LedgerTimestep• Fixed hourly variable sub-hourly• Why it matters: sub-hourly timesteps needed to model equipment startup & cycling as well as control

Solution of space loads & system response, unmet loads calculations• Iterative with simplified unmet loads corrections for space temperatures integrated solution• Why it matters: integrated solution needed to accurately model high-mass buildings

Radiant & convective heat transfer• Combined solution separate solution• Why it matters: separate calculation needed to accurately predict surface temperatures …• ... which itself is needed to calculate thermal comfort, condensation & to model radiant systems

Room air model• Assumes perfect mixing supports both mixed & non-mixed models + user-defined model• Why it matters: non-mixed correctly models advanced air distribution, e.g., UFAD, displacement, etc.

Moisture penetration & condensation• No Yes• Why it matters: moisture modeling needed to identify problematic envelope configurations

7

DOE-2 EnergyPlus: Capability Ledger IILighting• Split-flux split-flux & more sophisticated calcs + Radiance for detailed illuminance & glare• Why it matters: split-flux over-estimates daylighting & does not support visual comfort assessment

Fenestration• Controllable shades controllable shades/blinds, switchable glazing, light redirection, other CFS• Why it matters: advanced, controllable fenestration is an important ECM

HVAC configurations• Pre-configured systems only component-level HVAC, pre-configured systems as templates• Why it matters: component level modeling reduces need for workarounds which may be unrealistic …• … VRF is a prime example here

HVAC, plant, lighting & process control• Limited built-in options expansive built-in options + user-defined control mechanism • Why it matters: EnergyPlus supports modeling of actual control schemes ...• … and other data-driven responsive phenomena, e.g., demand-response, occupant-behavior, etc.

Contaminant analysis & contaminant-based HVAC control• Simplified model direct zone contaminant (e.g., CO2) balance model

• Why it matters: CO2-driven ventilation is an important ECM

8

DOE-2 EnergyPlus: Capability Ledger III

Commercial refrigeration• Available in separate DOE-2.2 build cases & walk-ins, transcritical systems, low-GWP refrigerants• Why it matters: supermarkets, refrigerated warehouses, hospitals, hotels, restaurants

Water use• Domestic hot-water use all water use & collection• Why it matters: water as important as energy in some places, including CA

Utility tarriffs• Single calculation for each energy source multiple tariffs for each energy source• Why it matters: complex tariff structures are common & simplifications lead to errors

Residential modeling• Yes almost there, last pieces (ducts in unconditioned spaces) should be in by Sep. 2016 • Why it matters: homes

9

DOE-2 EnergyPlus: Myth-Busting

“EnergyPlus is slower than DOE-2”• Why yes, I can give you a less accurate answer faster!• EnergyPlus trades execution time for (longer & more expensive) modeler workaround time• Commodity cloud computing makes argument even less relevant

“EnergyPlus has not been validated (against DOE-2)”• DOE-2 is not a ground-truth baseline validation “against DOE-2” is not meaningful• EnergyPlus has been validated against measured data to the same extent (or more) than DOE-2• All simulation tools have been tested against ASHRAE Standard 140• Much easier to validate EnergyPlus than to validate numerous DOE-2 workarounds

EnergyPlus is a research tool• Multiple interfaces: OpenStudio (free, open source), Simergy, DesignBuilder, AECOSim, Sefaira, more• 1000+ AIA 2030 Commitment projects: DOE-2: 28%, EnergyPlus: 13%, TRACE*: 28%, HAP: 2%**

– By this time next year, EnergyPlus will be more widely used than DOE-2• Consultants are successfully using EnergyPlus in Savings By Design programs outside of CA

* TRACE 800 will be EnergyPlus, beta is out (http://trane.com/beta/), product in summer 2016** Carrier also working on EnergyPlus-based HAP replacement

10

eQuest/MAS OpenStudio

Policy criteria•Transparency: prototype models partially described fully described•Transparency: ECMs assumptions & default values not available fully described

Operational criteria•Ownership: JJH & Assoc. DOE•Licensing: proprietary, derivative works not permitted commercial friendly open-source•Funding: CA ratepayers ($?) federal taxpayers ($1.5/year) + cost-share from states & utilities•Updates & bug fixes: few since 2009 biannual major releases/biweekly minor releases•New ECMs: only authored by vendor can be authored by rapidly growing pool of consultants

Technical criteria (meta)•Language & platform: FORTRAN C++ and Ruby•Team: JJH & Assoc. (5?) labs, contractors, vendors (~20), many consultants can author ECMs•Process: proprietary open source-code, test dashboard, bug tracking & feature request•Code baseline updates: slow & expensive code baseline transforms are themselves measures•Parametric analysis: limited leverages cloud for low-cost scalability

11

OpenStudio Example Applications Building

FormConstructions, loads

schedules, etc.HVAC templates

or custom systemsRun, compare, report, QAQC,

and parametric analysis

12

OpenStudio: “Apps” vs the Platform

Platform for creating many apps• Object-oriented abstraction for modeling• Reduces application development effort• Commercial friendly open-source license

Build and deliver the right user interface for the job

Constructions, loadsschedules, etc.

HVAC templatesor custom systems

Run, compare, report, QAQC, and parametric analysis

Detailedbuildingmodel

Example Applicationsare really designed to demonstrate…

BuildingForm

13

Killer Feature: OpenStudio Measures

Help!

Ich bin expert!

Thanks!

Internet

OpenStudio Measures are like Excel Macros for energy models• Transform model e.g., replace constructions, daylighting package, etc.• Perform these actions repeatedly, consistently & quickly on any model• An open way of extending functionality & transferring knowledge

14

Examples of OpenStudio Measures

Add HeatRecovery

Measures: scripts that operate on model• Transform model e.g., replace constructions, daylighting package, etc.• Perform these actions repeatedly, consistently & quickly on any model• An open way of extending functionality & transferring knowledge• Measures can be dragged-and-dropped onto a model or chained together• Can also query model & results reporting, QA/QC, cheat-detection, etc.

Daylighting Package

15

OpenStudio Measures Align with IOU Ex Ante Processes

Energy Conservation Measures• Can be developed by many people (both legally and operationally)• Easy to review, everything is explicitly in there• Large-scale analysis is easy prototype buildings + measures + cloud

– DOE is doing this at the national level• Supports eTRM expansion to ECM packages• Easy to assess uncertainty in savings estimates• Same measures can be used for deemed savings calculations and in custom projects for

lighter touch, less contentious review

Reporting Measures• Create report for both submitter & reviewer• Automate screening and use XA reviewer time efficiently • IOU consultants can self-screen before submission fully transparent – no surprises

16

A Broad View of OpenStudio Measures

Warehouse Large office

Secondary school Strip mall

Large hotel

Restaurant

High-rise

Outpatient clinic

We can use measures to create prototype building models• Inputs are spreadsheet-driven Easy to read + Easy to extend

– Existing spreadsheet entries for ASHRAE 90.1 pre-1980, 1980-2004 & ASHRAE 90.1-2004, 2007, 2010, 2013

– Easily extended for Title 24

Bonus: Applying a variant of this measure to a proposed model yields the baseline model!

17

Prototype

Model

EnergyEfficiencyMeasures

Reporting & Quality

Checking

An Even Broader View of OpenStudio Measures

Cloud-Based

ScalabilityOnline Measure Repository• Rapid distribution• Revision/Access Control• Key to extensibility

18

Measures + OpenStudio Server Cooking with Gas ECM package optimization …

ECMECMECM

Do not apply ERVIf you want this site EUI+

ECM Optimizer(EUI, ROI …)

Measures Outputs

Input parameter distributionsOutput EUIdistributions

EUI

But also uncertainty analysis …

+ Sampler+

WWR Wall U Value

And calibrationMonthly bills Calibrated Monthly kWh

++ Optimizer(Residuals)

Input uncertainties

19

ECMECMECM

methods

OpenStudioEnergyPlus

To Wrap Up

EnergyPlus & OpenStudio should be default engine & platform for new eTRM

There are compelling policy, operational & technical reasons for doing so

ECMECMECM

methods

MASeQUEST