Advancing the Daylighting Discussion

Explore the scientifically proven advantages of automation in daylight management
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Sponsored by MechoSystems
Jeanette Fitzgerald Pitts
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The Impact of Automation

“Even though many of the designers who are interested in daylighting, energy savings, and code understand that automation is a critical aspect of a high-performing daylighting system, clients are often unaware of why a control mechanism other than the traditional pull chain is necessary. The truth of the matter is that people are terrible daylight managers and manual control often relegates shades to a permanent position, often closed, blocking the inclusion of the daylight and views that was intended by the design,” explains Loisos.

Although it was not possible to isolate the energy savings and daylighting contribution made by automated shades on The New York Times project, this subject has been evaluated by other notable members of the industry.

“Measuring the Daylighting Impact of Automated and Manually Operated Shades”, authored by Mudit Saxena, Principal, Vistar Energy, formerly the Director of TRC Energy Services, and funded by Pacific Gas and Electric Company, through the California Emerging Technologies Coordinating Council, compared the effectiveness of manual and automated shading systems as methodologies for daylight control. The test site was a large open office building in San Francisco, California, with windows that had south-eastern exposure. Automated shades were installed next to manual shades, and shade position and levels of daylight illuminance at various depths in the office space were logged throughout the day. Data was collected in 15-minute intervals for four months, from February 20 to June 31 in 2013.

The Manual Shade Control System

In terms of manual shade control, three distinct patterns of manual shade operation were observed: active management, seasonal management, and nonactive management. Active managers were defined as occupants who adjusted the position of their shades regularly, at least once every couple of days and as much as two to three times daily. Seasonal managers refer to an occupant who modifies the position of the shades in response to changes in solar angle. Nonactive managers were identified as occupants who never change the position of their shade or change it rarely.

The Automated Shade Control System

The automated shading system raised and lowered the shade fabric into position based on inputs about the sun position, sky condition (clear or cloudy), and preprogrammed user preferences.

The Results

The study identified unpredictable shade control as the biggest risk in a daylighting investment. For example, when occupants leave the shades or blinds closed in an office, even when diffuse ambient daylight is available, it undermines the original intent of the design and diminishes the positive impact that daylight can have in a space. If occupants leave the shades or blinds up, and the space is exposed to glare and solar heat gain, the costs in productivity, comfort, and energy can be detrimental. Vacant cubicles have no resident occupant assigned to raise and lower the shades appropriately throughout the day. Unfortunately, a degree of unpredictability is inherent in any manual shade system.

The offices of the San Francisco Public Utilities Commission use automated shades to maximize the amount of daylight allowed into the interior, while protecting occupants from glare and solar heat gain.

Photo courtesy of Bruce Damonte

The offices of the San Francisco Public Utilities Commission use automated shades to maximize the amount of daylight allowed into the interior, while protecting occupants from glare and solar heat gain.

Automated shades were found to allow more daylight into the interior than manual shades, which, subsequently, increased the lighting energy savings. In this study, the space using automated shades reduced lighting energy usage by 37 percent when compared to the energy use of the space outfitted with manual shades.

 

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Originally published in Architectural Record
Originally published in May 2016

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