Lighting industry journalist Craig DiLouie recently interviewed Ethan Biery, Design and Development Leader, Lutron Electronics for an article about controlling LEDs for an article in tED Magazine. The interview follows.
DiLouie: How are LED sources different from traditional sources in terms of their controllability and their behavior?
Biery: As a light source, LEDs are easy to dim by simply regulating the amount of current the driver delivers to the LED modules. Like other light sources, dimming LEDs saves energy, but unlike other light sources LEDs have a very rapid response to any changes in current. The physics of fluorescent and incandescent lamps result in some “filtering” in the light output, which may mask any instability in the input. This filtering does not take place with LEDs, so instability in the power output by the driver is immediately translated to instability in the light output from the LED module, which is perceived as flicker. Proper selection of compatible drivers and controls (and control protocols) is critical to minimize the chance of flicker.
DiLouie: What opportunities (and problems) occur as a result of how controllable LED sources are dimmed, and how they behave while controlled?
Biery: An LED source is a system that consists of the control, driver, and LED module. The intrinsic potential for instability in LED module light output amplifies the importance of using quality controls and drivers, and differentiates products designed to deliver high-performance dimming. This is also what makes compatibility between drivers, lamps and controls such a big deal. Providing performance that is “good enough” for incandescent or fluorescent loads can be disastrous for a project where LED lighting is used and the occupant expects the same quality light output.
DiLouie: What are the top three technology trends impacting control of LED sources?
Biery: Digital control: Large-scale installations of LEDs, especially in commercial spaces, often demonstrate the weakness of existing analog control technologies, such as phase control and 0-10V. These technologies are not only prone to compatibility problems and interference, but they don’t deliver the features and benefits that many building managers are expecting from modern lighting designs.
Wireless technology: Wireless sensors and wireless LED lighting controls (whether fixtures or bulbs) are now widely available. As the cost of LED technology decreases, instances of successful, large-scale wireless control installations increase. Well-designed and reliable wireless fixture and control solutions provide simple design and installation, and a comfortable, efficient environment.
Color tuning: Color tuning is the ability to change the color temperature of white light sources from “warm” (reddish) to “cool” (bluish). This is a feature that many manufacturers are beginning to incorporate into their products. Incandescent bulbs inherently deliver a more orange color when dimmed low, and building occupants have become accustomed to this color shift. In addition, recent studies support claims that different color temperatures can be more beneficial to space occupants depending on the task or time of day. Control systems, luminaires, and user interfaces will become more sophisticated so they can deliver color tuning to give users manual or automatic control over color temperature.
DiLouie: LED luminaires are now frequently installed in new construction, where energy codes mandate a broad palette of lighting controls. How will this impact development of more sophisticated LED products and controls?
Biery: Advanced LED technology and more stringent energy codes are not strictly related, but as technologies improve, the regulatory bodies that develop energy and building codes can create stronger energy mandates. As LEDs become more common in both residential and commercial installations, users will continue to expect better performance. It is also important to keep in mind that lighting is a building system that is critical to the safety of the occupants. Reliable, easy-to-use control systems must be top-of-mind in any new product development, and this balance becomes more challenging to achieve as products and systems become more complex. LEDs are also installed based on their long product life, and building managers will expect manufacturers to be capable of supporting their products for the duration of the product’s life.
DiLouie: What should specifiers be doing to go beyond code and take advantage of the controllability of LEDs?
Biery: Today’s dynamic environments demand flexibility – users expect more from office spaces, classrooms, and other locations where they live, work, and play. While code compliance may necessitate only the most basic control schemes, progressive specifiers will provide their clients with digital control solutions that accommodate greater flexibility and configurability. Legacy analog and 0-10V control schemes will not meet the requirements of today’s sophisticated customer.
DiLouie: LED lamps and to an extent luminaires are being retrofitted into existing buildings. Controls, however, are often left out of conventional lighting retrofits. Has LED penetration into the existing construction market created new opportunities for lighting controls?
Biery: Customers are much more aware of the capabilities and conveniences that controls can provide. Connected home control and “smart controls”, including wireless controls that communicate via smart phones and other smart devices, are now part of the widely promoted Internet of Things. Furthermore, the cost of “controllable” LED lighting continues to be less of a factor, and wireless control makes installation easier than ever. These factors drive adoption of and demand for smart lighting control in both new and existing homes and businesses, and forward thinking manufacturers are working to give consumers what they want and need.
DiLouie: A number of luminaire manufacturers now offer integrated control packages. Is this having an appreciable effect on the lighting controls industry? What will we see in the industry, long term?
Biery: Fixture manufacturers who actively promote integrated control solutions are still a relatively new phenomenon. Traditionally, many have resisted branching out beyond their established fixtures. However, as control systems become more sophisticated, customers are realizing that compatible, well-designed systems can deliver better performance than individually-selected components. It is inevitable that forward-looking fixture manufacturers will offer more integrated solutions. When fixture and control manufacturers actively collaborate to offer the best mix of drivers, fixtures, and controls, the customer benefits, and those manufacturers enhance their market position. As manufacturers, distributors, and contractors, our goal is to add value and provide the best solution to each customer, for each project.
DiLouie: LED lighting presents such a small load that the economic argument for lighting controls is more likely to be challenged. Assuming that LED is the source of the future, what energy-saving control strategies are considered essential and therefore likely to endure?
Biery: From an energy perspective, it is true that LED sources use less energy. But it is also true that, as with incandescent sources, LEDs save proportionally more energy as lights are dimmed. Energy is a very real 21st century concern, and any energy savings that can be achieved are desirable. LED control solutions will continue to deliver the basic, enduring, and essential lighting control strategies such as occupancy sensing, daylight sensing, and timeclock control.
Beyond energy savings, lighting control of any source significantly improves comfort for space occupants. We are learning that the benefits of a comfortable, productive space often outweigh savings from energy reduction strategies alone. The costs associated with a typical office employee on a per-square-foot basis are orders of magnitude higher than the costs associated with lighting. Improving that employee’s comfort and productivity even a little bit, by providing them the right amount of light for the task at hand, will continue to gain attention from architects, lighting designers, and facility managers.
DiLouie: With LEDs, lighting controls can go far beyond energy savings. Lighting controls can respond to individual occupants and completely transform a workspace. What are these capabilities, and how would you characterize demand for them?
Biery: An enormous number of “what if” possibilities and new technologies are being developed. Some, such as the ability for occupancy sensors to count the number of occupants in a space, are not specifically related to LED technology, but are creating buzz in the market as a result of better data-processing capability and the availability of more sophisticated, lower-cost sensors. Other innovations, such as the ability to transmit information through high-frequency light modulation (called VLC, or Visible Light Communication), take advantage of some of the unique characteristics of LED lighting. These sorts of applications are still at the cutting edge of product development, and it will likely be several more years before widespread adoption is realized. However, technologies such as “tunable white,” where the control system has the ability to adjust both the intensity and color temperature of the light, are already generating market demand. Expect to see more fixtures and control systems that offer this capability in the next few years.
DiLouie: What should distributors be doing right now to maximize the value they offer to their customers when lighting controls are included in a project?
Biery: Distributors must realize that LED lighting is not as simple as selling a bunch of separate parts. Good LED designs consist of the control, driver, and fixture. Successful distributors must be able to offer their customers solutions, not just products. That means being knowledgeable about what controls work best for a given LED product (for example, what specific wallbox controls are recommended for use with a particular screw-in LED lamp), and becoming more educated about the products they’re selling. LED loads and controls are more sophisticated than their fluorescent or incandescent predecessors, and there is widespread differentiation in quality and performance across different products. The wrong recommendation or product combination can lead to end-user disappointment, expensive callbacks, or the loss of repeat business.
DiLouie: If you could tell the entire electrical industry just one thing about controlling LED lighting, what would it be?
Biery: The specification of the driver used in a given LED product is perhaps the most underappreciated, yes most critical aspect of any LED system. The design of a driver (whether in the base of a screw-in lamp or as a separate component in a fixture) determines the best possible dimming performance: how low the lights will go, whether they’ll be flicker free, and what control protocol is necessary. When paired with the proper control, the driver can meet its design expectations. However, even the best dimmer cannot overcome the performance shortcomings of a poorly designed driver. Our experience shows that improper driver selection, or last-minute driver substitutions, often result in significant problems in the field due to performance or compatibility issues.
DiLouie: Is there anything else you’d like to add about this topic?
Biery: What customers really want are products that are innovative, simple to specify and use, reliable, and backed with world-class customer service. Manufacturers that can meet these needs will be the manufacturers of choice.