J.B. Speed School of Engineering University of Louisville

KEEPS Energy Management ToolkitStep 2: Assess Performance & OpportunitiesToolkit 2J: Building Envelope

Kentucky Energy Efficiency Program for Schools

KEEPS EnergyManagement Toolkit

Step 2

Assess Performance & Opportunities

Toolkit 2J

Building Envelope

2KPPC Kentucky’s Resource Center for Environmental Sustainability

KEEPS Energy Management ToolkitToolkit 2J: Building Envelope

KEEPSEnergyManagementToolkit

Toolkit 2JBuilding Envelope

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7-Step Energy Management Process

1. Make the Commitment

2. Assess Performance and Opportunities

3. Set Performance Goals

4. Create an Action Plan

5. Implement the Action Plan

6. Evaluate Progress

7. Recognize Achievements

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Building Envelope Overview

Definition

Importance

Heat loss/retention

Low-cost/no cost fixes

Fixes requiring capital investment

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What is the Building Envelope?

Separates interior and exterior of a building• Floor• Foundation• Walls• Ceiling• Roof

Components that penetrate the building• Windows• Doors• Vents• Electrical Boxes• Pipes

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Building Envelope Impacts

• Barrier between conditioned inside air and unconditioned outside air

• Significant impact on passive heat lost and gained by the building

• Passive heat transfer increases the load on the HVAC system

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Understanding Heat Transfer

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From Hot to Cold

Heat flows from hotter areas to colder areas.

The bigger the temperature difference the faster it moves.

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Types ofHeat

Movement

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Conductive Heat Transfer

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Heat Loss Illustrated

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A Closer Look at Heat Loss

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Infiltration Through Gaps

• Leaks around windows and doors• Broken window seals, latches and panes• Open doors and windows• Old windows and doors• Vents that do not close properly, if at all • Leaky heating and cooling ducts• Inadequate insulation (thin, sparse, gaps)• Leaks between floor, wall, ceiling, roof

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Quantifying Infiltrative Heat Loss

• Can calculate infiltrative heat loss from single measurable opening

• Cannot calculate total infiltration because of gaps in inaccessible building cavities

• For high-cost projects, heat loss can be quantified through blower door analysis

• Use thermal imaging of heat loss for prioritization

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Solar Radiation

• Orientation of building• Exterior colors• Shade trees or other structures• Landscaping• Window awnings or light shelves• Window films or shades

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Low-cost/No-cost Fixes

• Weather-seal doors, windows, electrical outlets, other openings

• Repair dampers • Keep windows and doors closed• Use kitchen exhaust fan only when

needed• Repair leaks in ductwork

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Easy Fixes

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Look Closer for Best Opportunities

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Fixes Requiring Capital Investments

• Improve insulation in floors, walls, attics• Replace windows and doors• Energy-efficient roof• Change the color of exterior walls• Add awnings or light shelves • Add window films and shades• Improve landscaping

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Evaluating Return on Investment

• Obtain reasonable estimates of heat lost or gained

• Investigate material and labor costs

• Determine time of payback

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Building Envelope Summary

• Building envelope is the barrier between conditioned and unconditioned space

• Heat transfer generally increases the load on the HVAC system

• Materials used and tightness of the structure affect the rate of heat transfer

• Conduct a thorough analysis to quantify energy wasted before implementing large capital projects

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Resources

• Available for download from the KEEPS Toolkit Library• http://www.kppc.org/KEEPS

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J.B. Speed School of Engineering University of Louisville

End of Presentation

(502) 852-0965

www.kppc.org/KEEPS

Kentucky Energy Efficiency Program for Schools

KEEPS is funded by the American Recovery and Reinvestment Act through the combined efforts of the Kentucky Department for Energy Development and Independence, the U.S. Department of Energy and KPPC.