When paired with a lighting control system, as it almost always will be, tools like astronomic timeclocks can change the color temperature throughout the day, allowing for warm lighting in the mornings and evenings and cool light in the afternoons. This pattern mimics the cycle of the sun, to which human bodies respond.

Full-Color Control

Color mixing allows for complete color control to create any color, not just different hues of white, usually accomplished by mixing red, green, and blue light (commonly referred to as RGB). This technology gives users a color-changing fixture to adjust for their specific application. RGB was initially used primarily for theatrical lighting, giving flexibility for usage as stage lighting. In more recent years, as LED technology improved and more control systems started supporting it, color mixing has made its way into more mainstream lighting. They can now be found in many commercial and residential applications as accent pieces, decorative pieces, or other specific applications.

Some of the concerns with color mixing are the requirements for a mixing algorithm to create different colors. This is almost always achieved by adding some kind of show controller that houses the mixing logic and provides the user with the interface to make their adjustments. These controllers, depending on their capability, can be expensive. Another common concern is the source’s color rendering ability. While most color-changing fixtures use three colors—red, green, and blue—more colors are needed for better color rendering, increasing the light source’s capability and price and making the mixing algorithm and controllers more complicated.

Natural Light Control Technologies

Although the least expensive option is manual control (which does not require motors), this control method limits the amount of daylight and views as users infrequently operate manual shades. Research indicates, on average, that less than 10 percent of manual shades are moved more than once per day.1 As a result, the potential benefits of daylighting, views, and energy savings are unrealized.

Motorized shades make it easier to move the shades and can improve building aesthetics by maintaining alignment. However, if they remain undeployed, motorized shades provide little value in optimizing for views, daylight autonomy, and energy efficiency.

To get the full value out of a fenestration system, automated shades maximize comfort and energy efficiency by keeping the shades as open as they can be without causing glare. In addition, the incremental cost of going from a motorized to an automated system is relatively small. The most significant cost is motorizing the system. Based on this, an automated system is the best choice for improving building performance and aesthetics.

Automation Leads to Improved Energy Performance

Manual shades in commercial spaces are generally not moved, primarily due to a lack of ownership of controlling these shades. People will usually move shades when they are uncomfortable, such as when there is glare. However, they don’t think to move them when the glare is gone, leaving the shades too closed to maximize the amount of glare-free daylight and views.

The images on this chart highlight the limited daylight received when using manual shades. The yellow indicates a valuable amount of daylight (between 20 and 200FC) for more than 50 percent of work hours. The purple zone shows where there is too little daylight, requiring significant electric light supplement.

As illustrated on the left, where the shades were mostly closed all year, much less beneficial daylight is coming into the building. The automated shades on the right show a significant increase in beneficial daylight, which will also result in energy savings via daylight harvesting.

The current version of IECC requires two daylight zones, and the next version of IECC requires daylighting in smaller areas. Automated shading solutions can help maximize the investment in what is required in the building per code. Providing equipment for daylighting is required, so automating the shades allows full utilization of available natural light and saving more energy.

SEQUENCE OF OPERATIONS FOR HUMAN-CENTRIC LIGHTING DESIGN

These are the requirements to implement a human-centric lighting design:

1. Verify the sequence of operations for optimal lighting scenarios.
2. Work with the fixture manufacturer.
3. Match controls and fixtures for the desired outcome.
4. Work with the client to explain the differences between warm/cool and intensity/CCT.
5. Work with the client to explain the importance of tunable white and human-centric lighting.

The first part of implementing human-centric lighting is understanding how people want to use the space. The designer should discuss various scenarios for the activities that people often do in the space and determine how the lights need to respond.

For example, in a conference room, an occupant may present over a video call, use the markerboard, or show a video clip. Each of these may require different distributions and intensity for the lights.

Once the goals for the lights are established, the designer should work with the fixture manufacturer to ensure the desired fixtures can perform in the way necessary to match the sequence of operations. Ensure that the controls and the fixtures can work together from a protocol perspective. Answer questions that come up as to why a particular functionality is needed (such as intensity and CCT control tunable-white fixtures as opposed to warm-cool-controlled tunable white). Ensure that the human-centric lighting benefits you would like to achieve are essential to the client and explain how the sequence of operations, fixture selection, and control system supports that goal.

Five Questions to Consider for a Tunable White Job

1. What are the control inputs to the fixture (warm intensity/cool intensity or CCT/intensity)?
2. Are the control inputs digital (Digital=DALI, DMX. Analog=0-10V)?
3. What are the maximum and minimum CCTs for all fixtures?
4. Is the fixture a two-color white or a multi-color LED fixture?
5. What is the sequence of operations?

Considerations

The feeling the designer wants to create varies between space types, with different sequences required to feel natural. A residential-feeling office differs from that of a traditional office space. The lighting controls company needs to know how the clients want the system to behave. For its new headquarters, as seen in the case study, BlackRock assembled a skilled team that understood the vital role of lighting and shading in creating a unified, comfortable, and adaptable atmosphere. Features included tunable white lighting, daylighting, automated shading, and a sequence of operations designed to mimic the sun’s natural progression.

CONCLUSION/SUMMARY

Lighting control for electric and natural light continues to evolve and improve the occupant experience. It also helps to meet building and energy-saving goals. There are many ways to implement human-centric lighting on projects. Understanding the nature and science of lighting leads to better specifications to meet human needs. Automated shading helps ensure the best daylighting environment for occupant wellness and business success.

END NOTES

¹Source: Estia SA. 2014. OFEN Project: EPFL Innovation Park.

Kathy Price-Robinson writes about building and design. Her remodeling series “Pardon Our Dust” ran for 12 years in the Los Angeles Times. She specializes in writing about buildings that are durable and resilient to climate disruptions, as well as products and designs that provide shade in hot climates. www.kathyprice.com