HIGH PERFORMANCE DESIGNKristine Chalifoux, SEDAC

Trade Ally Rally │Illinois │December 2014

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What will it take to achieve high performance?

A. Goal Setting: design & performance energy goals

Know where you are and where you want to go.

B. Pick the right team: identify an energy champion

C. Focus on energy: in design & construction

Know the most effective strategies

D. Verify energy goals: model & measure

E. Plan to maintain: training & ongoing verification

WHAT IS HIGH PERFORMANCE DESIGN?

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BENCHMARKING

Obtain at least one year’s worth of energy data on the building (two years or more is better).

Plot the energy consumption for each month versus heating degree days and cooling degree days.

Review the graphs for anomalies.

Here is a bank…

ENERGY USAGE ANALYSIS

www.degreedays.net/

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Envelope Dominated: energy usage pattern tied to the climate, generally with some base load electrical and natural gas usage.

Internal Gain Dominated: energy usage pattern only slightly or not linked to the climate. Cooling load year-round.

Typically, small buildings are envelope dominated and large buildings are internal gain dominated – although this is not cast in concrete.

TWO TYPES OF BUILDINGS

ENERGY STAR® Target Finder was consulted for a comparison with similar buildings. Target Finder uses a large collection of building energy data to provide an estimate of an average building’s energy consumption, taking into account its location, size and use.

Energy Star Target Finder Score 1-100 www.Energystar.gov

UTILITY BILL ANALYSIS/BENCHMARKING

Annual Consumption Annual Costs Average Unit Cost

Electricity 504,000 kWh $ 50,249 87% $ 0.10 $/kWh Natural Gas 8,551 therms $ 7,236 13% $ 0.85 $/therm Total Facilities Area

Total: $ 57,485 15,753 ft2

Electricity Use Intensity

32 kWh/ft2/yr Gas Use Intensity

0.54 Therms/ft2/yr

Energy Use Intensity

163 kBtu/ft2/yr Energy Cost

Intensity $ 3.65 $/ft2/yr

Target Finder Results Bank Average ENERGY STAR Certified Energy Performance 31 Percentile 50 Percentile 70 Percentile Energy Use Intensity 163 kBtu/ft2/yr 104 kBtu/ft2/yr 82 kBtu/ft2/yr

050100150200250300350400450500

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kWh (3,753,262) CDD (1,237)

We know…

A school

No summer school

Heated

Cooled

Comfortable

TYPICAL DATA ANALYSIS – A SCHOOL…

REMEMBERWhen you shift a secondary axis you

are changing the story you tell.

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kWh (3,753,262) CDD (1,237)REMEMBERThe graph tells only part of the story! A school with minimal summer occupancy…

OR is the baseline electric use closer to~275,000 kWh?

April is a reasonable “guess” for baseline

monthly usage

High electric use in air conditioned schools - late spring/ early fall is not unusual as students return to classes and cooling demand can be high.

Base Load is typically lights, fans, pumps, plug loads, etc.

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kWh (3,753,262) HDDREMEMBERRemember to look for the unexpected!

Correlation with heating degree days likely means electric resistance heating somewhere in the building (i.e. teachers bringing in small space heaters)

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Nat'l Gas Usage (Therms) HDD

REMEMBERWhen you shift a secondary axis you are changing the story you tell.

Consider whether or not it is likely the baseline (base utility) natural gas use is ~2,500 Therms/month?

Base Load is typically DHW, pilot lights, etc.

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Nat'l Gas Usage (Therms) HDD

Or is it more likely that high natural gas use in summer indicates excessive use of ventilation system reheat – and the baseline (base utility) use is closer to 300 Therms/month.

REMEMBERWhen you shift a secondary axis you are changing the story you tell.

Don’t forget the power of interval data analysis when available!

Figure 1: 1/2-Hour Interval Metered Electric Energy Demand – November 2010

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1/2-Hour Interval Metered Electric Energy Demand (kW) November 2010

Monday November 1, 2010

Tuesday November 2, 2010

Election Day, school is closed. But some portions are open for polling.

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TOP 10 STRATEGIESNEW AND EXISTING BUILDINGS

TOP TEN ENERGY STRATEGIESForm & Environment

1. Orientation & Form

2. Insulation

3. Air Sealing

Loads

4. Lighting

5. Loads

Heating, Ventilating, & Air Conditioning

6. Heating

7. Cooling

8. Motors & Pumps

9. Building Automation

10. Commissioning

EXTRA CREDIT: After implementing all of

these, consider renewables such as solar and wind.

CASE STUDY

Science & Technology magnet school Replaces existing building

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Baseline Annual kWh Proposed Annual kWh

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 Base Case Annual

kWhProposed Annual

kWhSavings Annual

kWh% Saved % Total

Heating 437,167 25,197 411,970 94% 45%

Cooling 74,963 31,606 43,357 58% 5%

Pumps/Fans 72,140 166,560 -94,420 -131% -10%

Interior Lighting 123,298 104,357 18,941 15% 2%

Exterior Lighting 18,505 18,505 0 0% 0%

Plug Loads 200,509 200,509 0 0% 0%

Total 926,582 546,734 379,848 41% 41%

Orient buildings on the east-west axis (+/- 10°)

Reduce west facing glass

Shade south glazing

Take advantage of, or block, prevailing winds

Orientation makes a difference in energy use!

ORIENTATION & ENVIRONMENT

East West Axis South overhangs Northern and southern windows

CASE STUDY ORIENTATION

0° 90° 180° 270°$70,000

$72,000

$74,000

$76,000

$78,000

$80,000

$82,000

Curtain wall…

ORIENTATION “DON’TS”

Curtain wall…

ORIENTATION “DON’TS”

JUST SAY NO!

…faces west

Beware of value engineering!

Shading devices compensate for the heat gain from large banks of windows, only to be eliminated later in order to cut up-front costs. If the windows themselves are not re-designed, the result is visual discomfort from glare and higher energy costs.

ORIENTATION “DON’TS”

Exceed codeWall and roof insulation levels

Continuous insulation

Windows Percent of wall area Low-e coating

Reduced infiltration Air sealing Air barrier Vestibules

Envelope commissioning

ENVELOPE

Air infiltration is unwanted air flow into and out of the building caused by leakage paths and pressure differences between inside and outside of the building.

Openings at the top and bottom of the building are the most important to seal.

plumbing chases wiring recessed lights chimney enclosures sill plate look above a recessed ceiling ducts in unconditioned areas surprises that you will find

AIR SEALING

SEALING THE ENVELOPE

Pre-Retrofit Post Air Sealing

From SEDAC report

Current condition

Wall to Roof Junction Air Sealing

STACK EFFECT

Positive pressure (with reference to outside)

Neutral pressure plane

Negative pressure (with reference to outside)

Photo Credit: David Keefe, Vermont Energy Investment Corporation

Don’t let this happen to your building!

R-18 to R-24 walls3” continuous insulation (polyiso)

R-37 roof insulation6” continuous insulation (polyiso)3” minimum at drains

Windows U-0.27, SHGC-0.31

Vestibules

Designed with heat exchanger to make up for reduced air infiltration

CASE STUDY ENVELOPE

Building in southern Illinois

Built in 2005

Designed to code

ENVELOPE “DON’TS”

Occupants were cold

No continuous insulation

Don’t underestimate the impact of thermal bridging

ENVELOPE “DON’TS”

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Avoid these common pitfalls

• Assemblies with significant thermal bridging

MORE ENVELOPE “DON’TS”

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Avoid these common pitfalls

• Assemblies with significant thermal bridging

MORE ENVELOPE “DON’TS”