Tech Session 2 from the 2009 ASHRAE Region VI CRC in Des Moines, Iowa. Presented by Paul Torcellini of NREL May 8, 2009

1. Tech Session 2: High Performance
Building Design Strategies
ASHRAE Region VI CRC
Paul A. Torcellini,
Ph.D., PE
May 8, 2009
www.highperformancebuildings.gov
NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy operated by the Alliance for Sustainable Energy, LLC
Procurement
Creating the RFP
Example:
– Office Building
– Datacenter
– Library
– Conference/Meeting Space
– Fixed budget $64M (just building)
– Design Build

2. Project Objectives
1. Mission Critical
2. Highly Desirable
3. If Possible
Project Objectives
1. Mission Critical
Safety
LEED Platinum

3. Project Objectives
2. Highly Desirable
800 staff Capacity Flexible workspace
25kBTU/sf/year Support future technologies
Architectural integrity “How to” manual
Honor future staff needs Real-time PR” campaign
Measurable ASHRAE 90.1 Secure collaboration with outsiders
Support culture and amenities Building information modeling
Expandable building Substantial Completion by 2010
Ergonomics
Project Objectives
3. If Possible
Net zero design approach
Most energy efficient building in the world
LEED Platinum Plus
ASHRAE 90.1 + 50%
Visual displays of current energy efficiency
Support public tours
National and global recognition and awards
Support personnel turnover

4. Energy Consumption Goal
25,000 BTU/sqft
– Includes everything, even the datacenter.
Credit for additional space utilization
Credit for additional datacenter capability (beyond the
building)
Penalty for using electric resistance
Assumed condensing boilers and good chillers (to avoid
calculation from our central plant)
Methodology document done before RFP issued
Substantiation
Show that building as-built is consistent with energy
models
Will be shown at time of turn-over
No commitment on the operation side—although we
will monitor and understand actual performance

5. Risk and Reward (from the designer)
Risk
Design competition
50% of Phase 1 fee at risk Reward
Energy performance requirement High profile project
LEED Platinum requirement Design fees (within GMP)
Guaranteed maximum price Award Incentive Fee
Risk Management
Design-Build partnership
Share risks
Ability to control decisions
It is Really About the Details
Combinations of lots of little things that cause
buildings to use energy
Conceptually, low-energy buildings can be
done—fail on the details
Difference between expectations and actual
operation?
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6. Major Components
Envelope
Windows
Lighting Systems (Including Daylighting)
HVAC Systems
Electrical Systems
Plug Loads
Photovoltaic Systems
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Building Form
Set the Energy Goals with the program of the
building
– Form will follow the function and the goals
– Many times the form is really historical in context
Typically want no more than 60 foot width
Long East-West Access
East and West windows a problem

7. Envelope
• As building become low energy, the envelope
becomes more important (percentage-wise)
• Reduce the glass
– Cannot engineer around it
– Design for views and daylighting (more on that later)
– Is low-e the answer (or high-performance glass)
• Reduce Thermal Bridging
– Detail books
– Insulated panels
– Spray foams
– Ground losses
Lighting Energy
One of largest end uses
– Up to 40% of total end uses
One the top of the list for meeting energy savings
– Inexpensive and offer rapid payback
– Helps to reduce cooling loads

8. Lighting Systems
• Separate daylighting fenestration from view glass
• Design the daylighting system to provide enough,
but not too much daylighting
• Daylighting must be “superior” to electrical lighting
– Provide lighting needs or 50% to 75% of occupied hours
• Allow for reductions in A/C load because of
overhangs and daylighting
• Help design teams understand the integration of
pieces
• Get the controls right
Toplighting
Daylighting for top floor or single story
North or South facing clerestories

9. Sidelighting
Sidelighting with Toplighting

10. Tubular Daylighting Devices
Daylighting Hints
High ceiling heights
– Greater than 10’
Eliminate direct beam penetration
– Exterior shading
– Light shelves
– Diffusing films
– Baffles
High reflectance on ceiling surfaces
Dimming controls
High visible transmittance for daylighting
fenestration
– Greater than 60%

11. Daylighting Design
Slight over design needed
– Never as bright as predicted
– Darker colors common issue
– Occupant perception
– Do not over glaze
(especially lower windows)
Screens on operable
windows
Frame areas
Glass type—errors?
Glare control
NREL Pix 09226
Daylighting control
Enable daylighting where ever possible
– Default on some sensors is no daylighting
Central controls easier to calibrate
– Retrofit on some projects
Minimize photocells
Minimize occupancy sensors
Manual control is not effective
NREL PIX 05171
Overrides for special functions

12. Lighting Design
Lower levels acceptable in most cases
– Effective task
lighting allowed
lower ambient levels
– Daylighting
augmented spaces;
allowed for lower
levels at night
– Circuiting
NREL PIX 09217
Emergency Lighting
Wall packs worked well for egress lighting—minimal
parasitic load
Integral battery ballasts are a parasitic “hog.”
24-hour lighting
– can be large part of
lighting loads
– motion sensors
– daylighting control
NREL Pix 09229

13. LED Outdoor Area (Parking Lot) Lighting
Why LEDs make sense for commercial parking lots
– Save energy
• Enhanced luminaire optical efficiency
• Better total system efficacy (lumens per watt)
• Control capability, e.g., dimming
– Reduced maintenance costs
– Improved uniformity
Timing for common specifications
– Retailer Energy Alliance working group established in April
2008
– Specifications completed in 2009
Metal Halide Parking Lot LED Parking Lot
Average: 3.5 455W MH Average: 2.8 218W LED
Maximum: 9.0 Maximum: 5.2
Minimum: 0.9 Minimum: 1.2
Max : Min: 10.0 Max : Min: 4.3

14. Lighting Design
Put Lighting Power Densities on space plans by zone
Set goals for LPDs
0.6 W/sqft for offices
0.8 W/sqft of retail
Also look at kWh/sqft annually (or BTU/sqft)
Watch lamp efficacy
Spend the resources to do it correctly.
HVAC Systems-Natural Ventilation
Natural ventilation
– Occupants don’t want to interact with building
(somewhat different than residential)—should
they?
– Automatic windows worked well
• Set-up issues
• Interface with EMS
• Open area (screens, window distance)
• Hardware failures
• May be better to use relief dampers
Control strategies
More limited than economizer

15. Energy Recovery Ventilators
Balance air flows
Design exhaust through ERV
Allow for bypass (or no recovery option)
– Don’t sacrifice economizer ability
Oberlin analysis: effective below 60°F
Integrated control logic
140,000
120,000
100,000
Energy Recovered (Btu/hr)
Before filter change
80,000 After filter change
60,000
40,000
Energy Required To
Operate ERV-2
20,000
0
10 20 30 40 50 60 70 80 90
Outdoor Temperature (ºF)

16. Ground Source Heat Pumps
Watch backup mechanism
– Electric boiler backup
– Controls
Well capacity
Watch temperatures
– verify loop capacity
HVAC
Look at system efficiency and not just components
useful stuff divided by what you pay for
More water, less air
Separate ventilation air from heating and cooling
Good zoning

17. Control Systems
Mixed feelings: Only as smart as the operator
Flexibility important to tune building
Probably the biggest success factor
Well thought out algorithms
Demand management
– Set points, setback, control
to goals and comfort
Staff to program
– All systems from case studies
were reprogrammed
from original sequencing
Controls
Simple programmable T-stats
Push button overrides
Include plug loads on same system
Keep it simple
On-off control of lights or good diming control
Manual on – Manual off – Auto off
Controls can only make the design (and the related
equipment) work to its potential

18. Plug Loads (Turn things OFF!)
Night Plug Power Density (W/ft2)
Day Plug Power Density (W/ft2)
Annual Plug Load Energy Use Intensity (kBtu/ft2)
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Minimize Plug Loads
• Timers for all plug loads
• Minimize water coolers
• Energy Star equipment
(computers/copiers, etc.)
• Consolidated printing via network
– Document processing equipment
– Minimize (no?) fax machines
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19. PV Systems
Work well for UPS systems
Parasitic loads (isolation transformers)
Roughly 1 kWh/watt installed capacity
Inverter trips
Inverter programming
Techniques
Daylighting—minimize the lighting load
Efficient lighting (less than 0.7 W/sqft)
– Minimize the type of lamps (T-8)
– CFL’s are not a substitute for area lighting
– Minimize decorative lighting
– Wall pack egress lighting, no emergency ballasted fixtures
More insulation (R-25 walls, R-40 ceilings, R-10 below
grade, including slab)
Appropriate amounts of glass
Operable windows for natural ventilation
Plug loads on timers
Appropriate zoning of HVAC
Hot water heating
Should have minimal cooling load—target 1000 sqft/ton

20. Techniques
Set specific/measurable goals early
Use simulation to engineer the building
Envelope to provide HVAC&L
Use daylighting within (15-ish feet) of exterior surfaces
Use standardized metrics for reporting
Don’t delete economizers (especially with heatpump
based systems)
How to Achieve ZEB… Summary
Envelope and Orientation to Reduce Loads
• Well Insulated roofs, walls, floors, windows (with shading)
Envelope and Orientation to Meet Loads
• Daylighting
• Passive Solar Heating, Trombe walls
• Natural Ventilation
Lighting design to match daylighting
Plug loads
• Design vs. owner loads
Climate specific HVAC designed for the remaining loads
Commissioning (making sure the building works)
Metering and evaluation
Make it Simple
Site Specific Renewable generation within footprint,
site, off-site
Small amounts of RECs
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21. Questions?
www.highperformancebuildings.gov
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