energy performance: requirements and verification · energy discussion agenda ¨ discuss viewpoints...
TRANSCRIPT
Green Globes 2017 Summit
David S. Eldridge, Jr., P.E. May 3rd presentation:
Energy Efficiency Consultants Sustainable Design Engineers
ENERGY PERFORMANCE: REQUIREMENTS AND VERIFICATION
An example of “high energy”
Why I work for sustainability
Energy discussion agenda
¨ Discuss viewpoints for GGAs and GGPs/owners
¨ Review four NC energy paths ¨ What is need from the client ¨ What should the assessor
review ¨ Challenges and how to
handle them ¨ Multi-family ¨ What can be done ¨ Hotel/multi-family ¨ Fidelity example ¨ MGM example – multiple use
facility
Energy models central to four NC paths
¨ All four cases will use energy models based on the proposed design
¨ Recommended documentation is provided in ASHRAE 90.1-2010, but most energy modelers will provide a narrative report describing the model
Energy models central to four paths
¨ Geometry, wall constructions, windows ¨ HVAC system types, setpoints, efficiencies ¨ Schedules and occupancy ¨ Zoning ¨ Weather files ¨ Utility prices ¨ PNNL Appendix G Reference Manual is a great
resource
Energy modeling report parameters
PNNL Reporting Excerpt
Energy modeling check figures
Energy modeling results
Actual modeling results from 2008 NBI Study
Energy models central to four paths
¨ DSE recommends: narrative to include a list of EEMs, and best case may show parametric improvements for each major EEM
¨ Assessor with energy modeling experience may be needed for complex facilities
LEEDBase
Roof_Ins
Ext-Wall_Ins Glazing
DIEvap-CHW-Bak
fanefficienc
yLDP Daylight DCV Basebo
ardsProposed_30pct
Ext. Equipment $529 $529 $529 $534 $532 $532 $534 $534 $534 $531 $533DHW $900 $900 $900 $900 $896 $896 $897 $897 $896 $895 $894Fans $5,078 $4,877 $4,866 $4,488 $5,507 $5,396 $5,269 $5,154 $5,083 $4,438 $4,540Pumps - Natural Gas $2,763 $2,720 $2,711 $2,616 $2,598 $2,598 $2,605 $2,605 $2,605 $55 $54Pumps - Electricity $1,279 $1,270 $1,269 $1,244 $1,356 $1,353 $1,321 $1,319 $1,315 $1,233 $1,088Cooling $13,042 $12,344 $12,316 $10,993 $4,307 $4,298 $4,175 $4,151 $4,140 $3,793 $2,587Heating - Electricity $0 $5 $5 $5 $15 $15 $15 $18 $18 $21 $19Heating - Natural Gas $9,484 $8,582 $8,418 $8,235 $9,462 $9,471 $9,443 $9,458 $8,994 $3,576 $3,812Process Loads $14,299 $14,296 $14,292 $14,260 $14,218 $14,219 $14,224 $14,225 $14,226 $14,137 $14,251Area Lighting $13,285 $13,283 $13,277 $13,540 $13,636 $13,633 $11,759 $11,624 $11,627 $11,585 $11,641
$0
$10,000
$20,000
$30,000
$40,000
$50,000
$60,000
$70,000
Ann
ual E
nerg
y C
ost,
$
Energy models central to four paths
Relative comparison of Green Globes criteria
50% 55% 60% 65% 70% 75% 80% 85% 90% 95%
100% Hyatt Regency Chicago
Palmer House Hilton Chicago Hilton
Sheraton Chicago Hotel & Towers
Chicago Marriott
Hyatt Regency O'Hare
Hilton Chicago O'Hare
Congress Plaza Hotel
InterContinental Chicago
Hyatt Regency McCormick Place
Westin Michigan Avenue
Fairmont Chicago Chicago Marriott O'Hare
Swissotel Chicago Renaissance Chicago Hotel
Drake Hotel
Hampton Inn
Courtyard by Marriiott
Aloft
Embassy Suites
Homewood Suites
Holiday Inn
Hyatt Place
Crowne Plaza
Bed and Breakfast Mont Rest Inn
Green Globes Performance by Category Energy Water Resources Emissions IEQ EMS
Energy model discussion
¨ ASHRAE 90.1 documentation or other output reports
¨ Summary narrative is highly desirable
¨ May have knowledge of some programs, but not all – not expected to open modeling files and review
¨ Additional expense for modeling is often a hurdle
¨ Producing a narrative report describing the modeling is out of scope
¨ Hand over the model files to assessor and let them decide
GGA GGP/Owner
Energy model discussion
What doesn’t work here?
¨ COMCheck – could be awarded for partial credit, but isn’t a substitute for whole-building modeling
¨ Advanced Energy Design Guide (AEDG) – provides a pre-modeled prescriptive approach and could earn nearly full credit equivalent to modeling
¨ Spreadsheet calculation – doesn’t capture the dynamic and interactive effects in most cases
Different viewpoints
¨ GGA ¤ Reviewable ¤ Verifiable ¤ Relies on a summary from
the modeler in most cases ¨ GGP/owner
¤ How to document many features and summarize?
¤ Additional cost of modeling ¤ How to leverage modeling
expense throughout project lifecycle
9% 6% 5% 5% 5% 3% 3% 2%
0
100,000
200,000
300,000
Annu
al En
ergy
Use
(kBt
u)
Annual Energy Savings by Measure
Energy Paths - NC
¨ Target Finder ¨ Appendix G ¨ Carbon equivalent ¨ Building Energy Quotient
¨ What about HERS? ¤ Limited applicability for buildings with common area, central
utilities, high-rise setting – includes a “model” ¤ How to establish equivalency to existing pathways
Target Finder
¨ Proposed energy model is compared against ENERGY STAR Target Finder model ¤ Target Finder based on actual building operating data
(yay!) normalized based on many factors (uh-oh!) ¤ Process and plug loads are difficult to quantify in the model
¨ Assessors: ¤ Need to review assumptions about process loads to be
reasonable in comparison to peer group. ¨ GGPs:
¤ Document assumptions, particularly about process/plug loads
Path A point scale for Target Finder
Earning 100 points in NC scale requires a 94 or higher equivalent to ENERGY STAR
74 and below earns zero
Verification documents
Appendix G
¨ Proposed energy model is compared against a baseline model constructed per 90.1 Appendix G ¤ Plug and process loads modeled identically in both – bias error is
reduced since result is based on difference between two models that have the same errors built in
¤ Accuracy measured as a comparison to actual data must also be a focus ¨ Assessors:
¤ Verify baseline assumptions and cross-check savings to be substantiated by equipment in the project
¨ GGPs: ¤ The best way to compare against code ¤ Model may be useful for tax deductions, modeling of EEM alternatives,
living resource into the future
Path B point scale for Appendix G
Earning 100 points in NC scale requires 50% savings vs a baseline
Has to reduce by at least 5% to earn credit
Carbon equivalent
¨ Proposed energy model is compared against ENERGY STAR Target Finder
¨ Assessors: ¤ Verify plug and process assumptions
¨ GGPs: ¤ The best way to compare against code ¤ Model may be useful for tax deductions, modeling of
EEM alternatives, living resource into the future
ASHRAE Building Energy Quotient
¨ Similar to Appendix G modeling ¤ Provides a rating scale with more resolution at the high-
performance end ¤ Allows extra credit for net zero energy ¤ ASHRAE’s workbook will provide a lot of detail on the
modeling – could be a resource for non-bEQ projects
Multifamily challenges - NC
¨ Reasonable assumptions, wide variance in density and amenity make it difficult to normalize
¨ HERS applicability to low-rise and less complex buildings
¨ Plug and process loads when modeling – highly dependent on occupancy assumptions
¨ Hardwired lighting vs tenant fixtures using receptacles
Multifamily challenges - EB
¨ Access to spaces – often can’t review rented units
¨ Retail tenants ¨ Owner upgrades result in
lower utilities for tenants…not incentivized financially from common EEMs
Energy Paths - EB
¨ ENERGY STAR Portfolio Manager
¨ What if the property isn’t an eligible type? ¤ Modeling ¤ Peer group benchmarking ¤ CBECS modeling ¤ HERS rating for multifamily
¨ Appendix G ¨ Carbon emissions ¨ Building Energy
Quotient
Multifamily challenges - EB
¨ Tenant data – many buildings give up here
¨ Some utilities provide an aggregation of anonymous data for tenants ¤ (ComEd, Con Ed, others) ¤ This is needed for ENERGY STAR
Portfolio Manager entries ¨ Normalization for unit size,
occupant density, level of amenity – pools, workout rooms, kitchen exhaust, laundry
Multifamily challenges - EB
¨ North Water Apartments is 2/3 of a building with a Loews hotel in Chicago
¨ Relatively new building with advanced features
¨ Two owners for separate building segments
¨ Could de-rate by 1/3 if hotel didn’t submit data?
Multifamily challenges - EB
¨ ENERGY STAR can be provided for the whole facility as an apartment building with a hotel
¨ Benchmark the apartments only, but take 2/3 of applicable points.
¨ Benchmark the apartment x 2/3 and hotel x 1/3
¨ Might take a zero if not reaching minimum threshold
Fidelity examples
¨ Green Globes will generally apply to a whole building, but what if energy data is available for a portion?
¨ Tenant may use ENERGY STAR Portfolio Manager for whole building in some cases
¨ Standalone portions of a strip mall – how to rate, eligibility as a standalone facility?
MGM examples
¨ Hospitality campuses were split up into multiple assessments
¨ Segments use common energy (and water) infrastructure – must be rated together as a lowest common denominator
¨ NC project on a campus – problem solved, energy modeling to the rescue…
MGM examples for EB
¨ Hotel ESPM normalization another area of concern ¤ Luxury properties have different level of amenity and
expectations for construction ¤ CBECS is for all hotels ¤ Client and assessor jointly came up with a third-party
peer group other than CBECS to track similar properties (Same thing for Labs – use I2SL benchmarking tool)
