Energy Savings Impacts of the Advanced Energy Design Guide: Small Office Buildings

Bing Liu, P.E.Research EngineerPacific Northwest National LaboratoryTel: (509) 375-3710Bing.liu@pnl.gov

February 7, 2005 ASHRAE Winter Meeting, Orlando, Fla. 2

Energy Use Simulation Approach

Scoping Study: Baseline building – Standard 90.1-1999 Advanced building – Off-the-Shelf technology Two Models: 5,000 sf and 20,000 sf office

buildings Use eQuest to test run in four climate locations:

Miami, Phoenix, Seattle and Duluth

Full Study: 15 representative locations in 8 DOE Climate

Zones Use DOE-2.2 directly to make 60 parametric runs

for full study

February 7, 2005 ASHRAE Winter Meeting, Orlando, Fla. 3

5,000 ft² Office Prototype

Square floor plan Single story Frame construction 20% window-to-wall ratio Single tenant

February 7, 2005 ASHRAE Winter Meeting, Orlando, Fla. 4

20,000 ft² Office Prototype

Square floor plan

2-story Masonry

construction 30% window-

to-wall ratio 3 tenants

February 7, 2005 ASHRAE Winter Meeting, Orlando, Fla. 5

What is in the Baseline Building?

Comply with Standard 90.1-1999 Insulation requirements for roofs, walls,

floors and slabs U-Value and SHGC for window glazing U-Value for doors Interior lighting power density Mechanical equipment efficiency Economizer requirement And more…

February 7, 2005 ASHRAE Winter Meeting, Orlando, Fla. 6

What is in the Baseline Building?

When not specified by 90.1-1999… Room Thermostat:

Setpoint: 75°F cooling & 70°F heating Setback/Setup: 80°F cooling & 65°F

heating Office Equipment Plug Load Schedules

Energy Policy Act Standard analysis Recent research study and peer review

comments Fan Static Pressure

Plug Load Schedule - Weekday20,000 sf Office Building

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Hour of Day

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Characteristic Baseline Model Data Source

Architectural Features

Configuration/Shape

Aspect Ratio 1

Zoning 5 zones per floor (one core + four perimeter zones)

Number of Floors 2

Window to Wall Ratio 30% ribbon windows uniformly distributed by orientation

SP 102 Recommendation

Floor-to-Ceiling Height: 9 ft General practice

Floor-to-Floor Height: 12 ft General practice

Infiltration Rate - 0.038 cfm/sf of the gross exterior wall - 0.122 air change per hour for entire building

- ASHRAE 90.1-1989 §13.7.3.2 - 12 feet high Exterior Wall

Infiltration Schedule OFF_M-F_INFIL Off when the HVAC fan is on

Roof

Structure Steel deck with rigid insulation SP 102 Recommendation

Exterior Finish Single-ply roof membrane

Insulation R-15 ci ASHRAE 90.1-1999 Table B-14

Overall U-factor 0.063 ASHRAE 90.1-1999 Table B-14

Emissivity 0.87

Solar Reflectance 0.23 (grey EPDM)

Grey single-ply membranes from PG&E High Albedo (Cool) Roofs CASE Study Report at http://www.newbuildings.org/downloads/codes/CoolRoof.pdf

ASHRAE SP102 Advanced Energy Design Guide Modeling Assumptions & Energy Usage - 20,000 sf Office Building Table 5 Baseline Modeling Assumptions (Round 2) – Seattle, WA

February 7, 2005 ASHRAE Winter Meeting, Orlando, Fla. 9

What is in the Advanced Building?

Envelope Cool roofs Better insulations High performance windows and doors Overhangs for windows except facing north

Interior Lighting Reduced installed lighting power density Daylighting harvest for WWR 25% or higher Daylighting dimming control on south and north

perimeter zones Occupancy Sensor

February 7, 2005 ASHRAE Winter Meeting, Orlando, Fla. 10

What is in the Advanced Building?

Mechanical System Higher efficiency unitary equipment in some

climate zones Motorized outside air damper control Demand Control Ventilation (DCV) Lower duct friction rate: 0.08 in/100 ft vs. 0.10

in/100 ft of standard practice Service Water Heater

Higher thermal efficiency for gas-fired storage water heater or

Gas-fired instantaneous water heater

0%

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5000 sf Bldg 20,000 sf Bldg

30% Goal Over Standard 90.1-1999

Energy Savings of Advanced vs. Base Building(Without Plug Load)

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Energy Savings of Advanced vs. Base Building(Including Plug Load)

Energy Use Index5,000 sf Office Building

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Energy Use Index20,000 sf Office Building

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Miami Baltimore Duluth

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Lighting Cooling Heating Fans SWH

Comparison of Energy Savings 5,000 sf Office Building

35.6% 36.4%

49.1%

Average Savings of All the Climate Zones = 38%

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Miami Baltimore Duluth

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Lighting Cooling Heating Fans SWH

Comparison of Energy Savings 20,000 sf Office Building

35%

38%43%

Average Savings of All the Climate Zones = 38%

February 7, 2005 ASHRAE Winter Meeting, Orlando, Fla. 17

Advanced Simulation Challenges

Real windows vs. DOE-2 window library Window Shading Coefficient Method Window Library Method Window Layers Method

February 7, 2005 ASHRAE Winter Meeting, Orlando, Fla. 18

Advanced Simulation Challenges

Occupancy sensor DOE-2 doesn’t have occupancy sensor

module Modify the lighting schedule to estimate

the potential energy savings from the occupancy sensors

Lighting & Occupancy Sensor Schedule

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Weekday - Hour of Day

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Lighting Lighting with Occupancy Sensor

February 7, 2005 ASHRAE Winter Meeting, Orlando, Fla. 20

Advanced Simulation Challenges

Demand ventilation control No CO2 sensor module in DOE-2 Modify the outside air change rate to

reflect the average reduction of the outside intake using CO2 sensor – 20%

February 7, 2005 ASHRAE Winter Meeting, Orlando, Fla. 21

Advanced Simulation Challenges

Motorized outside air damper control Potentially saving cooling and heating

energy during nights by closing the OA damper when fans cycle on to maintain space setback temperature

Hourly-based simulation may over-estimate the energy savings from the motorized outside air damper in the cold climates

February 7, 2005 ASHRAE Winter Meeting, Orlando, Fla. 22

Questions?

Bing Liu, P.E.Pacific Northwest National LaboratoryTel: (509) 375-3710Bing.liu@pnl.gov