As the emerging off-site modular sector continues to expand, we are seeking to embed energy efficiency and grid-interactive building concepts into the factory design, construction and assembly process. We see a big opportunity to meet the challenges of affordability and low energy costs in the multifamily sector through the integration of high performance building strategies into the advanced building manufacturing industry.

1. Integrating Energy Efficiency and Distributed
Energy Resources into Advanced
Manufacturing of Buildings
World Of Modular 3/7/2019
Shanti Pless,
Senior Research Engineer
NREL Commercial Buildings
Stacey Rothgeb,
Senior Research Engineer
NREL Residential Buildings
Photo by Dennis Schroeder, NREL

2. Messaging + Blue
Infographic
Content
NREL | 2
Bioenergy
Vehicle Technologies
Hydrogen
Sustainable Transportation
Buildings
Advanced Manufacturing
Government Energy Management
Energy
Efficiency
Solar
Wind
Water
Geothermal
Renewable
Power
Bioenergy
Vehicle Technologies
Hydrogen
Sustainable
Transportation
Buildings
Advanced Manufacturing
Government Energy
Management
Energy
Efficiency
High-Performance
Computing
Data and
Visualizations
Energy Systems
Integration
National Renewable Energy Laboratory
Science Drives Innovation

3. NREL | 3
1 2
3 4
Why Energy Efficiency and Off-Site Construction?
Energy codes are quickly progressing
• Are you ready for zero energy?
• Now is the time to be figuring out how
benefits of Offsite can be used to meet the
upcoming more stringent energy codes
• Can the Offsite approach be used to more cost
effectively meet upcoming codes to address
affordability and energy trends?
Many Projects are in cities with 100%
renewable commitments
• Can lead to better alignment with city approval
decisions makers

4. NREL | 4
100% Renewables City Commitments
https://www.sierraclub.org/ready-for-100/commitments
• 109 Cities
– 6 achieved
• 11 Counties
• Hawaii and CA
– And DC

5. NREL | 5
Why Energy Efficiency and Off-site?
Save money month over month
• Up to 50% energy cost savings now possible
EE savings can cost effectively be achieved if
well integrated into Offsite manufacturing
processes
• EE savings can easily be achieved with attention to
quality
Non-energy reasons for Offsite
• Can enhance health, indoor air quality, safety,
durability, resiliency, acoustics, climate

6. NREL | 6
Costs for
Renewable
Technologies
are Falling
Advanced energy technologies are providing
real-world solutions
• They drive a domestic energy economy and are
increasingly cost-competitive
• Energy manufacturing and installations provide
major opportunities for American workers
Source: DOE Revolution Now (2016)
How about Building
Construction Costs?

7. NREL | 7
NREL Buildings Research
Commercial and Residential Buildings Research, through
applied research and demonstration, supports speed-and-scale
goals in high performance and zero energy buildings.
https://www.nrel.gov/buildings/
Our Focus areas:
– Whole-building systems integration to reach net
zero
– Comprehensive building energy modeling
– Cutting-edge energy efficiency technologies
– Systematic performance metrics and monitoring
Our team’s key
strength lies in
combining all these
tools to design well-
integrated new
buildings and cost-
effective retrofits.

8. The Need for Lots of New Apartments
• The country will need to
build an average of 324,000
new apartments each year
to keep up with demand
• At least 4.6 million new
apartments by 2030
• 20.4 million existing
apartments today
– As many as 11.7 million
will need to be
renovated by 2030
63% of apartments in 2030
will be new or renovated
weareapartments.org/Vision2030.pdf

9. NREL | 9
How-to Guides for Cost Control of Zero Energy
Buildings
– Strategies in procurement, modular design,
alternative financing, and off-site
construction
– Off-site and design for modular
components key strategies to reach zero
energy on a budget
– How far can we go utilizing this strategy?
https://buildingdata.energy.gov/cbrd/resource/1655

10. Advanced Energy Design Guides Background
AEDGs:
• Design guidance by building type and
climate zone
• Supported by case studies and
energy modeling
• Developed by leading industry experts
• Looked to for beyond code
recommendations
50% Advanced Energy Design Guides
(2009-2013)
Grocery Stores, K-12 Schools, Large Hospitals, Small to
Medium Office Buildings, Medium to Big Box Retail
Buildings
Zero Energy Design Guides
(2018-current)
K-12 Schools
Offices (June 2019)
Mixed Use Multifamily (2020)
www.ashrae.org/freeaedg
K12 Schools
Med-Big Box
RetailOffice
Hospitals
Grocery
Stores

11. NREL | 11
DOE/NREL Buildings Energy Modeling
• OpenStudio/BeOpt and EnergyPlus
– Develop energy modeling tools used in industry
• Core capabilities in modeling of high
performance Multifamily
– Zero Energy Design Guide for Multifamily
• Zero Energy ready multifamily design standards in
Openstudio
– BeOpt Multifamily
– Detailed occupant driven end use characterization
– Sector wide modeling studies to asses MF stock
improvements
• 100% renewables for LA city wide study
• Vision for integration of energy modeling into
off-site design and fabrication process
Model by Eric Studer, PE - TNZ
Energy Consulting, Inc.

12. NREL | 12
Net Zero Multifamily Vision
Could every apartment become net zero with PV solar
resource on south, east, west façade AND maximum
rooftop PV?
Provides a path to net zero high rise apartments
– If efficient enough
• site EUI 15-20 kBtu/ft2/yr is needed
– If cost effective enough for affordable housing
– If it can be integrated into the grid
– If it can be scaled in a repeatable way
– If it works

13. NREL | 13
NREL and iUnit: Leading the Design for Net Zero
Multifamily Construction
NREL is collaborating with
Denver developer iUNIT, using
the Energy Systems Integration
Facility's apartment-in-the-loop
research capabilities and
energy modeling tools to lead
the design, demonstration, and
integration of net zero, grid-
friendly, and technology-
integrated multifamily
construction.
Story at
https://www.nrel.gov/esif/partnershi
ps-iunit.html

14. NREL | 14
iUnit Modular Apartment Development History
www.iunit.co
V1: 2016 - 40 Apartment Eliot Flats
in Denver
– Proof of concept for factory built
module
– Fully metered to baseline end uses
and tenant use type distributions
– Base level of efficiency with small
PV system for common areas
iUnit Denver Delivery
Eliot Flats, Denver
Photo by Dennis Schroeder, NREL

15. NREL | 15
NREL Modular Apartment Development History
Prototype Studio Module: 2017 - 1 Studio
Apartment in-the-loop at DOE/NREL’s ESIF User
Facility (www.nrel.gov/esif)
• Based on V1.0
– Baseline use data feeding apartment-in-the-loop
base loads
• Integration research platform to optimize factory built
module design, technology, and operation
– Scale prototype module to building scale
– Developed solutions to be implemented in V2.0 and to
the multifamily marketplace
Photo by Dennis Schroeder, NREL
Photo by Dennis Schroeder, NREL

16. NREL | 16
NREL’s Modular Test Unit
Photo by Dennis Schroeder, NREL

17. NREL | 17
Modular Apartment Innovations

18. NREL | 18
Current Multifamily Metering Barriers…

19. Factory Built Apartment in the Loop Tenant Engagement
Development
Individual Apartment Utility Metering
• Residential rate with high fixed meter charge
– Blended rate up to $0.16/kWh
• Limits large PV systems on Multifamily
buildings
– Need to tie small PV system into each
apartment meter
• Expensive hardware and install
– Up to $1000/apartment
• Split incentive
– Owner doesn’t pay bill
– Tenant doesn’t control building design
Move to Single Building Utility Meter
• Single commercial building rate
– $0.04/kWh, and $20/ peak kW
– Software metered at $60/apartment
– Allows for large PV install
• Software feedback to tenant to overcome split
incentive
• Develop “effective” real time rate to apply to each
unit in software
– Provide real time feedback
– Provide $ energy budget of solar provided energy
• $25/month of electricity provided in rent
– Pay additional bill if over energy budget, bank if
under
• Investigating application of behavior change of
“Bill Avoidance” and monthly solar budgets
• Investigate “Tenant in the loop” solutions vs
hardware control solutions

20. Demand Management Opportunity

21. NREL | 21
Real Time Electricity Price
for all Apartments
Tenant feedback
loop for live real
time price of
electricity in
prototype unit
168 simulated apartments +
1 apartment-in-the-loop
Solar PV Simulator
Battery
Dispatch
1 minute kW per unit/Total Apartment kW
$/kWh update live
Eliot Flats 40 v1. Apartments
with 1 year of apartment
power data
DHW Power Use and Schedules
Modular Design Strategies for
v2 Units
Total kW
Total kW after
Solar/Storage
v2. Apartment in-the-loop Simulator Approach

22. NREL | 22
New Method of Meter-Based Load Synthesis
Motivation
• Accurate analyses of load-shaping technologies require realistic
building load profiles.
• Especially for all-electric buildings
Example applications
• Design and control of flexible loads and energy storage
Why water heaters?
• Largest tenant-controlled load in the case study building
• Main water heater is electric in 52% of U.S. multifamily bldgs.
with >5 units (EIA 2017)
Why a new method?
• Traditional building modeling strategies lose accuracy at shorter
timescales.
• Existing schedule synthesis tools are difficult to customize for this
application.
Journal Article:
Feitau Kung, Stephen Frank, Shanti Pless, and Ron Judkoff.
“Meter-based synthesis of equipment schedules for
improved models of electrical demand in multifamily
buildings.” Journal of Building Performance Simulation.
December 2018.
https://www.tandfonline.com/doi/full/10.1080/19401493.2018.1539771

23. NREL | 23
Utilizing Eliot Flats meter data to characterize hot water load and
demand profiles
https://www.tandfonline.com/doi/full/10.1080/19401493.2018.1539771

24. NREL | 24
Can you spot the synthetic hot water power use
profile?
Total Water
Heater Electrical
Demand (kW)
for a 40-Unit
Apartment
Building
A
B
C
D
E

25. NREL | 25
iUnit Improvements with Offsite
$/ft2/yr
$/yr
Electricity
Use
kWh/yr Site EUI
Source
EUI
Source
Energy
Savings
EnergyStar
Average Existing All-Electric
Multifamily Apartment Building
(Based on ES 50)
$2.05 $48,027 320,182 47 131 50
Typical New All-Electric Multifamily
Apartment Building (Based on ES
75)
$1.73 $40,402 269,348 39 110 16% 75
Eliot Flats 2017 with 14 kW PV
(2017 Measured) $1.43 $33,423 222,824 33 91 30% 91
Eliot w/ NREL prototype 2017 with
14 kW PV (Measured Prototype) $1.11 $26,039 173,599 25 71 46% 99
Eliot w/ enhanced NREL prototype
2018 with 14 kW PV, demand
management, and commercial rate
(Modeled Goal)
$0.75 $17,560 151,000 22 61 53% 100

26. NREL | 26
NREL Modular Apartment Development History
– Next Steps
– Target zero energy status based on ESIF Prototype
solutions
– Optimize design, technology, control, and tenant
engagement
• Envelope, lighting, hot water, HVAC, appliances, on-site
PV, building scale storage, EV charging, water use,
demand management controls, tenant feedback and
behavior change software
– Create a marketplace to grow US
Manufacturing of zero energy modular urban
apartments

27. NREL | 27
Zero Energy Mixed Use and Multifamily:
2019 Site Built Examples
UC Davis Student Housing at Net Zero
https://www.ucdavis.edu/news/west-village-expansion-start-construction
https://www.ucdavis.edu/news/zero-net-energy
Boulder Commons
http://bouldercommons.com/
https://crej.com/news/boulder-commons-
to-add-more-office-plus-apartments/

28. NREL | 28
• Near Passive House levels of insulation
– Enhanced air tightness
• Triple pane windows
– Electrochromic, automated shades
• Mechanical ventilation with heat recovery
• 100% LEDs
• Electric heating and hot water
– Heat pump hot water heating
– VRF, Air Source, Ground Source Heat Pumps
• High efficiency appliances
• Technology, tenant monitoring, and control integration
– Smart home technology
• Unit level façade and rooftop PV
– Battery storage and grid coordinated controls
Zero Energy Mixed Use and Multifamily:
Site Built Energy Strategies
Revive Properties:
https://revivefc.com/features/#energy-benefits

29. NREL | 29
Barriers in the Building Energy Efficiency World
• High first costs
• Complexity
• Unskilled labor
– And developer and design
• Quality of installation
• New risk? Need to prove it can be done all the time…
• Lack of owner interest
Sound familiar?
Not just building energy efficiency barriers…
Photo by Dennis Schroeder, NREL

30. NREL | 30
https://www.energy.ca.gov/research/notices/2019-01-10_workshop/2019-01-10_presentations.php

31. Permanent Modular
Offsite Construction
• 20%-40% faster to build
• 5%-95% construction offsite in a factory
– Volumetric modular, wall panels, etc
• 3% of new construction in 2017
– Multi family and hotels
• Higher quality
• Can be cheaper to build…
• Any program that can be modularized
• New investment from outside construction
industry

32. NREL | 32
“How can optimal
integration of energy
efficiency strategies and
control systems be achieved
through advanced
manufacturing techniques
and technologies with little
or no additional cost?”
Leverage the emerging factory
construction benefits of higher quality,
faster construction timeline, improved
productivity, increased technology
integration, and labor cost savings to
enable cost effective, energy
efficiency, integrated grid interactive
controls, and renewables
Partner with leading factories and showcase projects to achieve optimal
integration of energy systems within the emerging advanced
manufacturing industry for buildings.
2019-2021 Energy Efficiency in Off-Site Construction Research

33. NREL | 33
Approach – Year 1
Partner with offsite modular factory and pilot projects to:
Baseline existing approaches to
understand opportunities for
energy efficiency and grid
friendly enhancements
Develop factory process
improvement
recommendations based on
advanced manufacturing
approaches to implement cost
effective efficiency
recommendations
Validate costs and savings in
pilot BAU Offsite factory and
projects
Engage innovators in advanced manufacturing advisory group

34. NREL | 34
Year 2 and 3
Develop
Develop Factory
Information Model
(FIM) datasets and
process diagrams of
recommended factory
improvements
Integrate
Integrate FIM with
building models
(energy and
information) to make
the case for advanced
manufacturing
enhancement for
energy efficiency and
grid-integration
Validate
Validate pilot factory
enhancements and
building
improvements in pilot
projects

35. NREL | 35
Offsite Factory Partner Rolele
• Willing to partner to improve prefabrication
process to target high performance and zero
energy ready
o CRADAs, NDAs, etc to formalize
partnership
o Make existing prefabrication process
available for evaluation
• Actively interested and prepared with project
partners within 1 year
• Open to considering improvement
recommendations in prefabrication process
• Willing to partner to make future projects
available for field data collection for
measurement and validation
• Contribute to advancement of high
performance building practices in offsite
construction through participation in Energy
Efficiency in Advanced Manufacturing
Industry Advisory Group
o Quarterly calls to discuss challenges and
opportunities
o 2 in-person meetings
o Commit to approving public participation
in press, website, outreach

36. NREL | 36
What NREL Buildings Can Provide
Zero energy buildings
system integration
expertise in Commercial,
Residential, and
Multifamily
Volumetric modular prototype
apartment in the laboratory at
NREL
https://www.nrel.gov/esif/partnerships-iunit.html
Zero Energy Mixed Use Advanced
Energy Design Guide development
Assessment of existing
approaches to
prefabrication and energy
efficiency/zero energy
strategies
Data collection, prefabrication
recommendations, strategy
improvements based on leading
industry best practices
Recommendations for
prefabrication
improvements to reach
zero energy ready
solutions cost effectively
while addressing industry
quality barriers
Energy and life cycle cost
optimization
OpenStudio Building Energy Model
Platform integration into design
and factory process
Prefabrication innovation
Independent validation
and recognition of
attempted innovations to
utilize prefabrication
benefits to cost effectively
reach zero energy ready
goals
Offer neutral third-party
measurement and verification
•Data acquisition equipment and
installation
•Assessment of performance

37. NREL | 37
Energy Efficiency and DER in Off-Site:
Possible Pathways for EE integration
• Building Energy Modeling integration into the
digital design-factory process and software tools
• Envelope
• EE Controls and Occupant Engagement Platform
• All-electric DHW
• Volumetric modular scale HVAC to maximize
equipment off-site installation
• Appliances
• Renewables

38. NREL | 38
Energy Efficiency and DER in Offsite:
Possible Pathways for EE integration
Building Energy Modeling integration into the digital
design-factory process and software tools
– OpenStudio energy modeling platform integration
– Off-line life cycle cost analysis for standardized designs
– Streamline energy design modeling of individual projects
• Zero energy design
• Code compliance, LEED, etc

39. NREL | 39
Energy Efficiency and DER in Offsite:
Possible Pathways for EE integration
Envelope
–Maximize life cycle cost savings of insulation systems that
include factory installation cost profile
• More insulation at a better quality possible with lower installation costs
• Additional wall/floor/roof cavities available due to structural requirements
of volumetric modular
–Utilize inherent envelope air barrier quality control
opportunities to ensure higher air tightness
• Low infiltration levels can be reached more cost effectively and inherently
• Common interface issues around windows can be detailed and installed with
higher quality
• Manufacturing line air barrier quality control testing
Photo by Dennis Schroeder, NREL

40. NREL | 40
Energy Efficiency and DER in Offsite:
Possible Pathways for EE integration
EE Controls and Occupant Engagement Platform
–Grid integrated HVAC and hot water controls that optimize
to utility price signals and renewables
–Enable single utility meter with software submetering and
tenant feedback with monthly budgets
–Implement sub-metered module hourly real time pricing,
set monthly allocation, and enable real time tracking against
monthly utility bill budgets
• $25/month included in rent, power bill if go over monthly cap
• Rank your use vs others in the building
– Develop factory quality control measures to ensure EE
controls and data platform work as intended from factory
Photo by Dennis Schroeder, NREL

41. NREL | 41
Example of Modular Apartment Prototype
“We have already
uncovered several
manufacturing
efficiencies through
the creation of this
prototype, including
the ability to install
smart apartment tech
at a fraction of the cost
it would normally take
to install in an already-
existing unit”
https://www.skender.com/news-
media-item/skender-celebrates-
unveiling-of-modular-smart-apartment-
prototype/

42. NREL | 42
Energy Efficiency and DER in Offsite:
Possible Pathways for EE integration
All-electric DHW
– Heat recovery options from wastewater, grid responsive
control integration
– Module scale heat pump hot water heater integrated with
HVAC
– Grid controllable water heater
• Delay, setpoint, leak alarms, real time price triggers
Photo by Dennis Schroeder, NREL

43. NREL | 43
Energy Efficiency and DER in Offsite:
Possible Pathways for EE integration
Volumetric modular scale HVAC to maximize
equipment off-site installation
– Integrated exhaust and ventilation heat recovery with
dehumidification/heating/cooling solutions
– Streamline the module to module HVAC system
interconnections
Photo by Dennis Schroeder, NREL

44. NREL | 44
Energy Efficiency and DER in Offsite:
Possible Pathways for EE integration
Appliances
– Ventless dryers to eliminate exhaust vent maintenance and
separate envelope penetration
– Induction cooking
Photo by Dennis Schroeder, NREL

45. NREL | 45
Energy Efficiency and DER in Offsite:
Possible Pathways for EE integration
Renewables
– Single meter to enable large scale PV, with unit submetering
– Modular electrical room(s) with battery UPS and demand management
– Façade rainscreen and roof top PV installed offsite
Photo by Dennis Schroeder, NREL
“Factory installed solar reduces the cost of residential solar by 40%”
www.solarhomefactory.com

46. NREL | 46
March 2019 Status
World of Modular Kickoff
– Industry advisory group engagement
• Ryan Smith/ WSU ModLab
Securing Factory partners
– Factory OS
– Johns Buckley
– Full Stack
– Others as innovation opportunities and
needs arise
– “pop up factories” with Milhender White/iUnit
– Integration of energy modeling tools into prefab
design and process tools

47. 2019 Progress
• 6 Months into a 3 year project
– Held kickoff at World of Modular March 16-18, 2019
– Announced industry advisory panel and recruited leading industry
partners
– Secured partnership agreements with leading commercial off-site
construction factories
• By end of 2019:
– Baseline dataset from factory partners
• Cost, performance, design approach, BAU savings, factory standards
– Industry advisory panel feedback
– Develop initial set of energy solutions for factory partners to
consider
• Design process models
• Smart Apartment technology platform
– An opportunity for factory partners to explore solutions to be able
to meet next round of efficiency codes before they invest in factory
line changes

48. Thanks!
And questions?
• Shanti.pless@nrel.gov
• Stacey.Rothgeb@nrel.gov
• Cedar.blazek@doe.gov
Join our Industry Advisory Group to learn more
Join the discussion tomorrow