Page 31 - RC14-EDGE-Spring Issue-1Z

Spotlight: ENERGY EFFICIENT TECHNOLOGIES

Innovative Lighting Design Relies on the
Original Light Source

Brian Dauskurdas

Lutron Electronics

In building design, daylighting refers to the archi-
tectural practice of utilizing daylight as the primary
source of ambient light in substantial portions of a
building. Effective daylighting makes use of windows,

skylights, solar tubes and other methods of bringing

daylight–which consists of direct sunlight and reflected

skylight–into the building, to reduce dependence on

electric light and save energy.

In mathematical terms, daylight autonomy is measured

as a percentage of annual work hours during which all,

or part of, the lighting requirement can be met through

daylighting alone. While this is not a new concept–out

of necessity, the earliest buildings relied on daylight–

architects and lighting designers are now adapting the

way daylight is used in today’s intelligent buildings to

simultaneously exploit and tame the sun’s energy.

Especially in today’s massive glass super towers,

daylighting and dynamic facades are essential tools for

maximizing energy efficiency, enhancing views, and creating

high performance buildings. Strategies such as automated

shade control alloww the building to use daylight more

effectively and minimize the use of electric light.

In the last decade, much of the focus on daylighting

design has addressed energy efficiency improvements in

new buildings. A 2012 paper by researchers from Lawrence

Berkeley National Laboratory looked at savings from 32 Figure 2: Automated shades can extend the useful daylight zone to significantly increase lighting
installations, and concluded that the average savings from energy savings.

daylighting was 28%, with a maximum reported energy Automated, solar-adaptive shading solutions bring daylight back
savings of 60%1. into the mainstream of modern design

These are substantial numbers and represent huge potential As related to energy use, automated shading control works to maintain

for improving building energy efficiency1. Implemented correctly, a consistent light level in all environments, minimize the need for

daylighting controls can also contribute positive health effects on people supplemental electric light, and increase the opportunity for daylight

in the space–benefits that are recognized and acknowledged by such autonomy. The ideal solution combines automated shades, solar-

high-performance building standards as LEED for new buildings, ASHRAE adaptive software, and localized cloudy-day/brightness sensors that

Standard 189.1, and IgCC. communicate with the shading software to evaluate and respond to

real-time, dynamic daylight conditions.

Manual shades can theoretically provide the same

benefits, but virtually never work in practice. Occupants

are only likely to adjust manual shades when they are

uncomfortable, for example lowering a shade to block

Figure 1: Solar-adaptive shading, like Lutron Hyperion systems with Radio Window sensors, direct sunlight, and are unlikely to reopen the shade
adjusts shades throughout the day based on the position of the sun as well as real-time when the glare event is over, thereby eliminating the
environmental conditions. positive benefits of daylight in the space.

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