The right kind of LED lighting, that is also flicker free, has dimming modulation at 500 Hz or higher-well outside any chance of human stroboscopic sensitivity.
Assembly and laboratory spaces, as used by universities and other hightech education and research institutions, require high levels of lighting that can be adjusted to the task at hand, very high light levels for critical assembly work, and lower light levels for chemical analysis where too high light levels might influence indicators used in chemical analysis.
The key objective is to provide the specified light levels for each area while meeting or staying well below the maximum allowable wattage per square foot to pass new commercial building energy codes.
You have to have a lighting strategy for your building and look outside the standard lighting-representatives portfolio to get a comprehensive and coherent lighting system that satisfies those needs and in that quest you will find that not all LED Fixtures are created equal.
Example Educational Facility in Texas: North Texas Enterprise Center
The North Texas Enterprise Center (NTEC) for Technology, located in Frisco Texas, was recently built and designed to assist entrepreneurs with starting and growing medical and clean technology ventures. It also is used by UT Arlington to host their evening MBA program.
This is an excellent example of utilizing performance LED lighting to improve learning environments while significantly reducing energy costs. According to Greg Roach, NTEC Director of Education and Laboratory Services, due to the use of the spaces-such as medical device manufacturing and classrooms involving detailed tasks-the specified maximum light levels required on demand were higher than normal office spaces.
Human Safety and Comfort
When creating or refurbishing a high-tech education facility, plan to use biologically optimized lighting. This is generally in the color temperatures between 2700K and 5200K. Higher color temperatures from 6000 to 10,000K are not suitable for classrooms as they have too high a percentage of polarized near UV blue content that can make some people, those who are sensitive to UV light, feel physically sick.
The blue light in LEDs is not hard UV, but with a wavelength of 635 nm it is still in the upper end of the UV spectrum and can expose UV sensitive film. If you have flown in a new Boeing 737 aircraft and felt sick or uncomfortable when the blue-white light is turned on before landing, that is why. You may get the same feeling looking down and walking on Orchard Street in Singapore where pure blue high intensity LED strips are embedded in the walkway.
Polarized blue light does not affect all of us but surely affects some. An education environment should provide the best quality lighting environment possible at the time to the largest cross-section of students possible.
Class Rooms, Auditoriums, Meeting Rooms and long hallways have always been problematic to dim with conventional dimmer and dimming technology for various technical reasons.
A digital dimming system by which each LED Power Supply, also referred to as a driver, has a built-in digital dimming can control signal repeater, an infinite number of LED fixtures can be dimmed with one digital dimmer coming from a wall mount, a ceiling mount or a networked controller unit.
Another common problem of conventional dimming is flicker. The best LED fixtures have a 500Hz modulation rate which is well outside the widely accepted maximum flicker sensitivity of humans in panic of up to 180Hz and animals of up to 230Hz.
If you already have an investment in a lighting management system- like a Crestron or others-or want to keep the user interface the same with other parts of your facilities, the ability to interface with those systems is important. For example, Active LED systems provide a Building Management System (BMS) Adapter which allows 0 to 10 Volt input from a Crestron, Honeywell or other system to be converted to the digital signal controlling the lighting fixtures.
This BMS system was implemented at NTEC in order to have a single controller drive the lighting and audio visual equipment from the podium. All other high performance LED lighting fixtures can be upgraded at a later time to a more comprehensive LightSpace and Energy Management System.
In some areas, a significant reduction in energy use could be achieved by using motion sensors built into the fixtures or multiple ceiling mount sensors feeding into each other controlling a string of up to 40 fixtures.
Range of Fixtures
For NTEC, ActiveLED provided all the fixture types required for the building from Round Ceiling Down-Lights in 4", 6", 8" and 10.5" diameters, 2' x 4' and 2' x 2' ceiling drop-ins with 72 Watt as well as 75 Watt and 150 Watt round High Bay lighting for the Warehouse and Prototype Manufacturing Area. All were dimmable using LightSpace digital controls in combination with a conventional 0 to 10 Volt dimming system.
Cost of Ownership
For a new build or a total refurbishment, the Cost of Ownership is most important. The top performance LED fixtures can provide warranties of 10 years with guaranteed light levels of 90% of the original light-level.
This translates into a very low-cost of maintenance, whereas in the past re-lamping had to be put into any budgetary planning at least every 3-5 years; with performance LED light fixtures, it may now be budgeted for a 10-12 year replacement or overhaul.
In trials, many of the Fluorescent Tube replacement LEDs do not provide the required light output, or-if they do-they do they do not last very long, sometimes shorter than a fluorescent tube. Screw-in or PAR 38 LED replacements of high wattage do not last very long and cannot produce the same lumens per watt as their FL counterparts.
Replacement lamps and tubes are generally not dimmable, or are only poorly dimmable, with varying results from light bulb to light bulb or tube to tube. Fluorescents, HID Lamps and Induction Lamps contain highly poisonous mercury and have to be treated as hazardous waste requiring training of maintenance personnel for cleaning up broken CFLs, Fluorescent Tubes or HID lamps, while Active LED lighting is fully recyclable and non-hazardous.
The best experience is with high performance LED fixture replacements rather than bulb or tube replacements. For instance, ActiveLED replacements use the whole fixture to dissipate the heat thus eliminating the issue of LEDs and heat which results in both higher efficiency (lumens per watt) and longer life expectancy.
Fixture replacements have demonstrated that it is possible to have no light loss, nor any increase in energy use, after 5 years of constant use as well as tens of turn-on/off cycles per day in covered parking applications the same 5 year period.
With the advent of 48 Volt DC technologies in conjunction with alternative energy generation and storage of electrical energy, high performance LED fixtures can be powered by both Grid and 48 Volts DC making the lighting operation more future proof to allow easy adaptation to 48V DC distribution systems.
Overall budgetary planning will still have to consider 3 to 5 year cycles as furniture and decoration may wear out faster in high use areas. By implementing highly performing and performance guaranteed lighting systems at least during one or two budget cycles, other high-tech advancements can be budgeted for improving the competitiveness of the facility and the productivity of research and students.
is a 30 year veteran in energy conservation, resource saving innovative products for a sustainable environment. If you are interested in ActiveLED high performance lighting and energy saving control products, visit ActiveLED.