Why LED Lighting Is Not In Your Home Yet
These benefits, coupled with society's growing environmental concerns and subsequent demand for green, energy-efficient products, have continued to drive the development of LEDs for challenging new industries and markets, such as general illumination for commercial and residential buildings.
With the escalating demand for solid-state lighting, LED manufacturers are motivated to develop high-lumen LEDs while LED lighting companies will work hard to integrate the most recent technology into retrofit packages and luminaries. However, new perspectives might be required for individuals to adopt LED technology as an illumination source in new installations, or incorporate LED technology in existing light fixtures.
Are LEDs ideal for commercial and residential lighting applications?
LEDs are arguably the absolute most energy-efficient source of light available. Case in point, LEDs have created upwards of 80 percent energy savings in the traffic signal industry. However, in this application, the LEDs had two natural advantages:
1. LEDs are monochromatic, so almost all of the light generated is used.
In comparison, the white light generated by an incandescent bulb must transmit through a colored filter. Light not in the frequency of the colored lens is wasted.
2. LEDs are directional, so almost all of the light generated was emitted towards the lens. In comparison, light from an incandescent bulb must be reflected toward the lens, leading to loss of efficiency.
Commercial and residential lighting applications stand to get similar, if not more, energy-savings by converting to LEDs. However, most applications are not as straight-forward as stuffing a PC board with a number of directional red, amber or green LEDs. LED light fixtures and retrofit packages need to be built to distribute the directional light generated by the LED over wide areas.
Moreover, white LED technology, while continuously improving, does not even have the optical color and brightness that consumers have become used to with incandescent lights. However, the energy savings could be significant, for example, in California the power commission has adopted efficiency standards for residential and commercial buildings. These standards, Title 24, have accelerated development of LED illumination technology.
Why LEDs are not in your house?
Unlike incandescent bulbs, high-power LEDs can not be simply attached to a wall socket. Several companies will work to overcome the technological and economic challenges by developing LED strip light fixtures and retrofit LED lighting products using high-power LEDs. Thermal management, complex drive circuitry, optics, and packaging are challenging hurdles for developers to contend with.
There's also educational barriers to overcome in the development of commercial LED illumination products. Getting users to adopt new kinds of fixtures, understand the illumination characteristics of LEDs, choose the correct viewing angle for confirmed application, select the correct intensity for confirmed application, and understand the limitations of LED color temperatures are pivotal to developing industry for LED technology in commercial and residential lighting.
Thermal Challenges
For days gone by couple of centuries, traditional luminaries have consisted of a light bulb and lamp socket that permits consumers to continually replace bulbs that have burned out. Whether it's an incandescent, compact fluorescent or fluorescent light bulb, it will just screw or drop into an industry-standard socket and the luminary will remain operational.
Several LED lighting companies are suffering from high-flux LED bulbs that retrofit into existing sockets; but this method is significantly less than ideal. For example, a conventional light bulb socket provides a inadequate thermal path for cooling an LED light source.
Incandescent light bulbs are basically heaters that produces visible light, and the socket it is screwed into is made to protect the lamp base and wiring from that heat. With high-power LEDs, a lot of the wattage consumed is changed into heat and, if it can't be dissipated through the lamp socket, will dramatically shorten the LED life.
Complex Drive Circuitry
To protect the LED from degradation factors, such as heat and voltage spikes, the drive circuitry design is critical. Ideally, LED circuit designs must be tailored to the specifics of the application because mechanical and economic constraints make it difficult to create a "catch-all" circuit.
Most LED indication or lighting designs operate from a top voltage AC power source. Since LEDs are DC-driven, utilizing a particular AC to DC power to reach a DC source voltage is often the most cost-efficient and reliable LED lighting solution.
To make certain efficient LED operation, DC-to-DC LED driver circuitry are often required in conjunction with the principal power supply. Along with providing the mandatory power and protection from current fluctuations, LED drive circuitry also generates heat - increasing the thermal management challenge. And, generally, the greater the amount of light that is required, the more LEDs are expected, leading to more complicated the circuitry, packaging challenges, higher heat flux, etc.
Optics: Illumination Angle
LEDs are incredibly energy-efficient from an illumination efficacy standpoint, i.e., lumens per watt. Upwards of 95 percent of the light could be directed at the mark part of illumination whereas a typical incandescent bulb might be only 60 percent effective.
Quite simply, plenty of the light made by an incandescent bulb doesn't visit the intended target. Incandescent bulbs require reflectors, louvers, and/or diffusers to compensate for unnecessary light. Fluorescent bulbs are more energy-efficient than incandescents, but the ballast may consume up to 20 percent of the electrical energy going into the fixture.
Retrofitting LED technology in traditional luminaries is tricky because most fixtures are created to overcome the limitations of traditional spherical light output. Reflectors, cones, masks, shades and diffusers help bend, redirect, or shield the light emitted from incandescent, fluorescent and halogen sources, but it makes unnecessary physical barriers for implementing LED technology.
Designing specific forward-fit LED-based luminaries can produce many times foot-candles on confirmed area per watt than other traditional incandescent bulb technologies. Because of the directional illumination pattern that LEDs provide the light could be directed to the particular area that really needs to be illuminated.
Optics: Light Color
Over the years, fluorescent bulb manufacturers had some challenges getting users to accept the white color made by fluorescent technology. Because of the limitations of phosphor technology, the fluorescent industry introduced subjective terms such as "cool white" or "warm white" to draw comparisons to incandescent white.
Not coincidentally, white LED manufacturers face the exact same challenges since white LED technology is dependant on phosphor energy. To place things in quantitative perspective, LED manufactures have described Color Rendering Index (CRI) which is a measurement of a mild source's ability to render colors accurately. The larger the CRI, the more natural the colors appear, with natural sunlight having a CRI of 100.
However, this might not be the very best metric for comparing light sources. Originally developed in 1964, this index is dependant on color models with broad spectral distributions. White LEDs are narrow-band sources. Color Temperature can be a more desirable tool for comparison because it is just a less subjective measure, predicated on degrees Kelvin. Presently there are many white emitters to choose from in the 3,200 degree-Kelvin and 5,500 degree-Kelving range.
Regardless of how along with is measured, LED manufactures have made great strides to complement the warm white glow of an incandescent bulb with high-quality LEDs due to the tremendous demand for incandescent white tones.
Education
Users attended to know the brightness of incandescent and fluorescent light bulbs when it comes to watts; however a watt is technically the machine of electrical power employed by the lamp during its operation. Consumers know from experience just how much light a 40, 60, or 100 watt light bulb will produce.
The same can not be said for LED assemblies, as LED lamps are generally designed to meet up the particular targeted illumination requirements of confirmed application. For example, it is possible to compare an LED comparable to a 50 watt MR16 bulb as this sort of lamp is employed as a directional light source.
However, a typical 60 watt incandescent bulb produces a spherical light pattern. An LED lamp that may provide equivalent light in most directions would be tricky to create in the exact same mechanical envelope. With present technology, multiple LED emitters and/or secondary optics would be required to reach a 360-degree illumination pattern.
