AIA/CES Provider Number: 50111167

EE201: Daylight Harvesting, Part 1: Introduction to Daylight Harvesting

Course Number: 000000002011

Educator: Craig DiLouie, LC

EDUCATION CREDIT

At the end of this course, participants will be able to complete an online exam, with a passing grade of 70+% to qualify for CALCTP (CALCTP),

NLCAA (NLCAA) and LEU (NCQLP) credit and 80+% for LU/HSW hours (AIA/CES). Upon a passing grade, you will be able to download a Certificate

of Completion for each type of credits. For CALCTP, NLCAA and LC certification maintenance (LEUs), credits are self-reported. For AIA /CES,

Lighting Controls Association will report credit earned for this course to AIA CES.

NO ENDORSEMENT BY ACCREDITING ORGANIZATIONS

This course is registered with CALCTP, NCQLP and AIA CES for continuing professional education. As such, it does not include content that may be

deemed or construed to be an approval or endorsement by these organizations of any material of construction or any method or manner of handling,

using, distributing, or dealing in any material or product.

COPYRIGHT

This presentation is protected by US and International copyright laws. Reproduction, distribution, display and use of the presentation without written

permission of the Lighting Controls Association is prohibited.

DISCLAIMER

The information contained in this course has been obtained from sources believed to be reliable. Damages arising from errors, omissions or damages

as a result of the use or misuse of the data or information contained in this course are not the responsibility of the Lighting Controls Association,

National Electrical Manufacturers Association, ZING Communications, Inc. or their employees or members. All information contained in this course is

published for professionals seeking information about the subjects contained therein. It is not the intent of this course provide professional services

such as design, engineering or consulting. If these services are sought, they should be rendered by properly trained, registered, regulated and

insured professionals.

COURSE DESCRIPTION

Welcome to Part 1 of EE201: Daylight harvesting course, Introduction to Daylight Harvesting. Part 1

introduces participants to daylight harvesting, including typical energy savings, typical equipment, ideal applications and how daylight harvesting

relates to LEED and energy codes.

Daylighting, the use of daylight as a primary source of general illumination in a space, has become a more important feature of mainstream

construction due to the sustainable design movement.Numerous studies over the last 50 years attest to the importance of daylight in design.

Research indicates that daylight can improve user satisfaction/performance and retail sales. These characteristics can make daylighted buildings

more valuable and marketable.

Daylighting also enables daylight harvesting, a control strategy that has been demonstrated to generate up to 70 percent lighting energy savings. A

daylight harvesting system decreases electric light contribution as daylight contribution increases.

EE201: Daylight Harvesting describes a simple process for design and application of lighting controls used to enact energy-saving daylight harvesting

control strategies.

LEARNING OBJECTIVES

At the end of the course, participants will be able to:

define the purpose and benefits of daylight harvesting, a lighting control strategy that reduces electric lighting in response to high daylight levels,

saving energy. At the end of the course, participants will be able to conceptualize a daylight harvesting strategy.

recognize the elements of a basic daylight harvesting control system, and match daylight harvesting strategies to ideal applications.

utilize daylight harvesting conceptually as part of LEED-based design and energy code compliance.

articulate the importance of transparency of automatic control effects, resulting in proper selection of switching or dimming as the system output.

DAYLIGHT

Daylight may enter a building via toplighting (e.g., skylight) or sidelighting (e.g., window) apertures. Good daylight design enables diffuse daylight to

serve as a primary source of general illumination, while avoiding glare and heat gain.

Image courtesy of Southern California Edison

DAYLIGHT VERSUS SUNLIGHT

While daylight is highly desirable in a building as a source of illumination, direct sunlight

generally should not be allowed anywhere in the building except circulation areas (e.g., corridors, atria, etc.). This means daylight itself should be

controlled.

Various types of glass, daylighting features such as light shelves, and/or shading can be used to diffuse the light as broadly and uniformly as possible

throughout the space.

Top image courtesy of David Weigand

DAYLIGHT CONTROL

Automatic window shades, blinds or other devices can dynamically reduce direct glare and heat gain. Using the

same control station, users can override automatic control functions and set both daylight and electric light levels to preference.

Image courtesy of Lutron Electronics

DESIGNING FOR DAYLIGHTING

Daylight should be provided where people need it most. Since daylight often does not enter the space uniformly,

however, visualize it as gradients in a pattern, with each gradient representing an area of consistent daylight availability.

Each of these areas in turn presents an opportunity to separately zone the general lighting for daylight harvesting.

This may require designing lighting circuits to support separate control of general lighting, such as separately circuiting the first one or two rows of

light fixtures parallel to daylighting windows.

Image courtesy of the New Buildings Institute

DESIGNING FOR DAYLIGHTING

Daylight should be provided where people need it most. Since daylight often

does not enter the space uniformly, however, visualize it as gradients in a pattern, with each gradient representing an area of consistent daylight

availability.

Each of these areas in turn presents an opportunity to separately zone the general lighting for daylight harvesting.

This may require designing lighting circuits to support separate control of general lighting, such as separately circuiting the first one or two rows of

light fixtures parallel to daylighting windows.

Image courtesy of Leviton

DAYLIGHT HARVESTING

Energy savings occur by automatically switching the lights OFF or proportionally reducing electric light levels continuously (dimming) in response to

variable daylight levels.

Image courtesy of the Lighting Design Lab

DAYLIGHT AVAILABILITY

The energy savings potential for daylight harvesting in a given application will depend largely on

daylight availability, including:

1) daylight penetration into the space--in other words, how much of the task area receives daylight;

2) quantity of daylight in the space--in other words, what is the density of illumination on the task area in footcandles; and

3) duration of daylight availability during the day--that is, for how long each day the task area receives high, consistent enough daylight levels to

warrant daylight harvesting control.

TYPICAL SYSTEM

Automatic daylight harvesting control systems are comprised of a photosensor that

measures light levels and shares this information with a controller, which decides, using its algorithm, whether the lighting load should be switched or

dimmed. In some cases, the ballast and the controller may be the same unit.

Image courtesy of David Weigand

TRANSPARENCY IS ESSENTIAL

Effective daylight harvesting should be transparent to occupants in the controlled space. It should offer energy savings with no adverse effects to

visual comfort. Lights should change levels without distracting occupants. Dimming is typically preferred by occupants, particularly in spaces where

users perform stationary, critical tasks and/or where lamps are visible in the normal field of view, because it is not as noticeable as switching. In

addition, dimming may occur gradually over a period of several minutes to virtually make the change in light level unnoticeable.

Image courtesy of David Weigand

IDEAL APPLICATIONS

Daylight harvesting controls can be effective in virtually any type of facility where

the lights operate much of the time and where ample daylight is present.

Spaces with skylights and corridors, private offices and open cubicles near windows—particularly those with task lighting—are good candidates for

daylight harvesting.

Image courtesy of the California Lighting Technology Center

IDEAL APPLICATIONS

If the entire space is uniformly skylighted (as in the skylighted space shown here, with properly spaced skylights covering about 3-5 percent of the

floor area), energy savings can accrue on the entire lighting load. More commonly, daylight harvesting applies only to the perimeter zone of a

windowed installation, where typically general lighting within two window heights (distance from floor to top of window) deep into the space is suitable

for daylight harvesting.

Image courtesy of LC&D

ENERGY SAVINGS

The amount of energy cost savings a daylight harvesting control system can yield is variable, dependent on a

number of factors such as daylight availability, but research suggests significant savings in common commercial applications.

Space Type

Lighting Energy Savings Demonstrated in Research or Estimated as Potential

Study Reference

Private Office (manual blinds) 50% National Research Council Canada, 2002

Private Office (manual blinds used optimally, or automatic shading)

70%

Open Office 40%

Classroom 50% Heschong Mahone Group, 2003

Image courtesy of Lutron Electronics

DAYLIGHT HARVESTING AND LEED

The Leadership in Energy and Environmental Design (LEED) 2009 green building rating system encourages daylight and daylight harvesting. IEQ,

Credit 8.1 awards 1 LEED point for introducing at least 25 footcandles of daylight into at least 75% of regularly occupied building areas, while IEQ,

Credit 8.2 awards 1 point for providing a direct line of sight to perimeter glazing in at least 90% of regularly occupied spaces.

Daylight harvesting controls can then be used to earn energy points and/or, if registering under LEED for Commercial Interiors, 2 LEED points by

introducing daylight harvesting controls in all regularly occupied daylighted areas (for 1 point) and/or on 50% of the lighting load (for an additional 1

point). All daylight harvesting controls must be commissioned (prerequisite), with enhanced commissioning worth 2 LEED points.

Image courtesy of U.S. Green Buildings Council

DAYLIGHT HARVESTING AND ENERGY CODES

Because of the strong energy savings potential offered by daylight harvesting, coupled with advancing technology, codes and standards are now

beginning to require daylight harvesting—specifically, International Energy Conservation Code (IECC) 2009, ASHRAE/IES 90.1-2010, ASHRAE

189.1 and Title 24-2008.

DAYLIGHT HARVESTING AND ENERGY CODES

All of these codes and standards are different in the particulars, and yet have similar major themes. First, they define daylight availability as zones

around daylight apertures. Second, they require separate control for general lighting in these zones.

DAYLIGHT HARVESTING AND ENERGY CODES

The standard may also specify whether the control must be manual or automatic, switching or dimming, stepped switching or simple ON/OFF. And

the standard may reward aggressive daylight harvesting with power adjustment credits that can be used to increase the lighting power density

(expressed in watts/square foot) for the controlled load above what is normally allowed by code, offering greater design flexibility.

YOU'RE FINISHED

This concludes The American Institute of Architects Continuing Education Systems Course Daylight Harvesting, Part 1: Introduction to Daylight

Harvesting.

Please take a moment to provide feedback about your experience with this course.

You may also take the Comprehension Test to test your learning and to qualify for CALCTP (CALCTP), LEU (NCQLP LC) and LU/HSW (AIA CES)

credit. A 70+% passing grade is required for LEU and CALCTP credit and 80+% for AIA CES credit. Upon passing the test, you may download a

Certificate of Completion on the Courses page. If you are an AIA member, please email your course completion certificate to LCA with your AIA

number.

EE201: Daylight Harvesting - Introduction to Daylight Harvesting

mailto:cdilouie@zinginc.com?subject=AIA Credit for Education Express&body=My name and AIA number are: mailto:cdilouie@zinginc.com?subject=AIA Credit for Education Express&body=My name and AIA number are: mailto:cdilouie@zinginc.com?subject=AIA Credit for Education Express&body=My name and AIA number are: http://aboutlightingcontrols.org/EducationExpress/quizzes/ee201-daylight-harvesting-introduction-daylight-harvestinghttp://aboutlightingcontrols.org/EducationExpress/quizzes/ee201-daylight-harvesting-introduction-daylight-harvestinghttp://aboutlightingcontrols.org/EducationExpress/quizzes/ee201-daylight-harvesting-introduction-daylight-harvesting