high performance building

8/22/2019 High performance Building

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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

ASHRAE Region VI CRC

Paul A. Torcellini,Ph.D., PE

May 8, 2009

www.highperformancebuildings.gov

Tech Session 2: High PerformanceBuilding Design Strategies

Procurement

Creating the RFP

Example: Office Building

Datacenter

Library

Conference/Meeting Space

Fixed budget $64M (just building) Design Build


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1. Mission Critical

Project Objectives

2. Highly Desirable

3. If Possible

Project Objectives

Safety

LEED Platinum

1. Mission Critical


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Project Objectives

2. Highly Desirable

800 staff Capacity

25kBTU/sf/year

Architectural integrity

Honor future staff needs

Measurable ASHRAE 90.1

Support culture and amenities

Expandable building

Ergonomics

Flexible workspace

Support future technologies

How to manual

Real-time PR campaign

Secure collaboration with outsiders

Building information modeling

Substantial Completion by 2010

3. If PossibleNet 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

Project Objectives


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Energy Consumption Goal

25,000 BTU/sqft

Includes everything, even the datacenter.

Credit for additional space utilization

Credit for additional datacenter capability (beyond thebuilding)

Penalty for using electric resistance

Assumed condensing boilers and good chillers (to avoidcalculation from our central plant)

Methodology document done before RFP issued

Substantiation

Show that building as-built is consistent with energymodels

Will be shown at time of turn-over

No commitment on the operation sidealthough wewill monitor and understand actual performance


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Risk and Reward (from the designer)

RiskDesign competition50% of Phase 1 fee at risk

Energy performance requirementLEED Platinum requirementGuaranteed maximum price

RewardHigh profile projectDesign fees (within GMP)Award Incentive Fee

Risk ManagementDesign-Build partnershipShare risksAbility to control decisions

National Renewable Energy Laboratory Innovation for Our Energy Future

It is Really About the Details

Combinations of lots of little things that causebuildings to use energy

Conceptually, low-energy buildings can bedonefail on the details

Difference between expectations and actualoperation?


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Major Components

Envelope

Windows

Lighting Systems (Including Daylighting)

HVAC Systems

Electrical Systems

Plug Loads

Photovoltaic Systems

Building Form

Set the Energy Goals with the program of thebuilding

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


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Envelope

As building become low energy, the envelopebecomes 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


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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 ofoverhangs and daylighting

Help design teams understand the integration ofpieces

Get the controls right

Toplighting

Daylighting for top floor or single story

North or South facing clerestories


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Sidelighting

Sidelighting with Toplighting


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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 surfacesDimming controlsHigh visible transmittance for daylighting

fenestration Greater than 60%


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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 operablewindows

Frame areas

Glass typeerrors?

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 effectiveOverrides for special functions

NREL PIX 05171


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Lighting Design

Lower levels acceptable in most cases

Effective tasklighting allowedlower ambient levels

Daylightingaugmented spaces;allowed for lowerlevels at night

Circuiting

NREL PIX 09217

Emergency Lighting

Wall packs worked well for egress lightingminimalparasitic load

Integral battery ballasts are a parasitic hog.

24-hour lighting

can be large part oflighting loads

motion sensors

daylighting control

NREL Pix 09229


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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 MHMaximum: 9.0Minimum: 0.9Max : Min: 10.0

Average: 2.8 218W LEDMaximum: 5.2Minimum: 1.2Max : Min: 4.3


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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 dont want to interact with building

(somewhat different than residential)shouldthey?

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


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Energy Recovery Ventilators

Balance air flows

Design exhaust through ERV

Allow for bypass (or no recovery option) Dont sacrifice economizer ability

Oberlin analysis: effective below 60F

Integrated control logic

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

10 20 30 40 50 60 70 80 90

Outdoor Temperature (F)

EnergyRecovered(Btu/hr)

Before filter change

After filter change

Energy Required To

Operate ERV-2


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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


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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 reprogrammedfrom 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 relatedequipment) work to its potential


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Plug Loads (Turn things OFF!)

Night Plug Power Density (W/ft2)

DayPlugPowerDensity(W/ft2)

Annual Plug Load Energy Use Intensity (kBtu/ft2)

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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PV Systems

Work well for UPS systems

Parasitic loads (isolation transformers)

Roughly 1 kWh/watt installed capacity

Inverter trips

Inverter programming

Techniques

Daylightingminimize the lighting loadEfficient lighting (less than 0.7 W/sqft)

Minimize the type of lamps (T-8) CFLs 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 belowgrade, including slab)

Appropriate amounts of glassOperable windows for natural ventilation

Plug loads on timersAppropriate zoning of HVACHot water heatingShould have minimal cooling loadtarget 1000 sqft/ton


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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

Dont delete economizers (especially with heatpumpbased 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 daylightingPlug loads

Design vs. owner loads

Climate specific HVAC designed for the remaining loadsCommissioning (making sure the building works)

Metering and evaluationMake it Simple

Site Specific Renewable generation within footprint,site, off-site

Small amounts of RECs


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Questions?

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