Unlike previously used incandescent lamp and fluorescent lamp, though energy loss is big, yet most of the energy is directly dissipated by infrared radiation while light source produce less heat. But for LED, all energy is transformed into heat except partial energy being consumed as visible light . Besides, in recent years, electronic products gradually are developed to higher density and higher integration ones, in which LED products is not exceptional. Therefore, solving LED heat dissipation has currently become the key issue to improve LED performance and develop LED industry.
LED’s causes to dissipate heat:
The reason of LED dissipating heat is the electrical power can’t 100% be changed to light energy, whose part is converted to heat energy. LED’s luminous efficacy currently is only 100 lm/w, among which electro-optic conversion efficiency is only about 20 ~ 30%.That is to say, about 70% of electrical power has been converted to heat energy.
Specifically, the generation of LED junction heat come from two factors:
Internal quantum efficiency is not high, which means, electrons cannot 100% produce photon when compound with holes, usually as a result of “current leakage” lowering compounding ratio on PN area. Leakage current multiplied by the voltage, its calculated value is the power that has been converted into heat, but it does not occupy a main component part, because now the internal efficiency of photon is close to 90%.
Photons produced interiorly cann’t all emit out the chips and thus finally be converted to heat, which part is the main; because efficiency of these named external quantum is only about 30%, most of which is converted into heat.
As previously mentioned, although luminance efficiency of incandescent lamp is very low, only 15 lm/W, but it can mostly convert electrical power into light energy to radiate out. Most radiant energy is infrared, so the luminance efficiency is very low, but can be exempt from the heat dissipation problem.
Solutions to LED heat dissipation:
Solutions to LED heat dissipation mainly come from two aspects: before encapsulation and after encapsulation, which can be understood as LED chip heat dissipation and LED lamps heat dissipation. The former is mainly related to board ,and selection and technology of the circuit, which temporarily won’t be discussed here. This article mainly introduces Led lamp heat dissipation, because LED chip made into Led lamp thus heat generated by Led chip will finally emit out to air through the shell of lamps. LED chip thermal capacity is small, thereby a little heat accumulation will make chip junction temperature increase rapidly; so, if heat dissipation is not good, its lifespan will be quickly shortened when working in the condition of high temperature for long time. However, this heat need go through many procedures to be emitted out chip to the outside air. In particular, the heat produced in the LED chip, emits out from metal heat block, first through solder to the aluminum substrate PCB, then through the heat conduction glue to the aluminum heat sink. So actually, LED lamp heat dissipation include heat conduction and heat dissipation in two parts.
However, LED lamp shell heat dissipation will choose different method according to the power size and operation place. Now basically has the following several kinds of heat dissipation methods:
Aluminum heat dissipation fin: the most common way of heat dissipation, use aluminum heat dissipation fin as a part of the shell to increase the heat dissipation area.
Thermal conductive plastic case: thermal conductive material is added when injecting molding into the plastic shell, to improve plastic shell’s ability of heat conduction and heat dissipation.
Air fluid mechanics using the lamp shell shape to create convection air, this is the lowest cost of improving the ability of heat dissipation.
Fan lamp shell internal reinforced with long life and high efficiency fan, this method has advantages of low cost and good effect. Merely, replacing fan will be troublesome, and it is not suited to be used outdoor. This design is relatively rare.
Heat pipe makes use of heat pipe technology to transform heat from LED chip to shell heat dissipation fin. In the large-scale lamps such as streetlight , this is a common design.
Overall current LED luminous efficiency is lower, leading to high junction temperature arising thus reducing lifespan. As we see, heat dissipation is a key issue for reducing junction temperature and lengthening lifespan.
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E-12 candelabra base: This type of base typically is found in chandeliers, wall sconces and some bath bars. It is typically topped by a blunt tip, flame tip, or globe shaped bulb. There are also E-11 mini candelabra bases and E-14 European bases. Although all are referred to as 'candelabra' they are not interchangeable.
The E17 intermediate base is in between a candelabra base and a medium base. These are frequently found in commercial Exit signs. The intermediate base is sometimes used in ceiling fans and appliances. Although a lamp base adapter may be used, it's best to make sure an appliances is suited for a LED bulb replacement. LED bulbs are not advised for use with some appliances such as microwaves and range hoods, although they are just fine in refrigerators.
E-39 E-40 Mogul base. Except for commercial lighting applications, this base size is somewhat of a dinosaur. Sometimes made of ceramic, the mogul base incandescent bulb was used in torchiere lamps and had to be larger and sturdier to take the heat a 300W incandescent bulb produced. You may want to think of a lamp base adapter to size this down so you can use a medium base LED bulb.
There are several other types of fluorescent bases; only the two most common are shown here. Typically, a fluorescent tube has two pins, or one larger single pin in the center. Check with your electrician as he or she may be able to replace the 'tombstones' in your fluorescent fixtures more economically than waiting for supply on one type or the other. A 'tombstone' is the receptacle the bulb sits into. Our LED Fluorescent Replacements shine!
The GU-10 base is typically found in bath bars, ceiling fans and track lighting. GU-10 halogens typically operate at 120VAC. Our
The GU-5.3 is an MR-16 type lamp base. It has two pins. MR-16's are found in track lighting heads, bath bars, some ceiling fans. Our LED replacement MR16 lamps operate at low voltage and work particularly well with magnetic transformers. If you have an electronic transformer, you will want to purchase just one LED MR16 to try in your fixture to make sure it will work properly.
A-shape. Not so sure why this is called A. It doesn't look like an A unless you turn it upside down. Perhaps it's because it's the first type of light bulb produced. It's more of a pear shape. It won't be long before the next generation has no clue what we mean when we say "like a 60 watt incandescent bulb". Soon enough, people won't know what that is. The most common A shaped bulbs are A19's and A15's. The A15 is smaller and is often found in refrigerators and bath bars and can easily be used in some chandeliers. Our
B stands for Blunt as opposed to 'flame tip' bulbs of this type. These can be had with candelabra or medium bases. You would typically choose a blunt shape in more contemporary chandeliers if the bulb itself will be seen. Its counterpart is the flame tip bulb. It has a more traditional appearance and goes well with more traditional crystal and brass chandeliers, or in the type of candle lights you would place on window sills at Christmas time.
G is an easy one. G stands for Globe shape. The G 16 1/2 is much smaller in diameter than the G-25. It is available in candelabra or medium base. The G-25 is larger. It's the size of the globe shape bulbs you may have in a bare light bar above your vanity. The G-25 is medium base only. You have your choice of color temperatures in both variations. in stock here at TheLEDLight.com in both types.
R stands for reflector. The numerical designation indicates how wide the bulb is. LED lamps are available in sizes from R20 up to R40. You'll find these in gimbal track rings, recessed cans, indoor and outdoor spot and flood fixtures. The R type bulb is usually not waterproof, but can be used in a fixture protected from the weather as long as it is not sealed. LEDs need room to breathe. Cooping them up inside a closed container will shorted the life of your LED bulbs. Find our LED R lamps here.
BR stands for 'bulged reflector'. The 'bulge' allows the light to be distributed in a subtly different manner. It is very pleasing to the eye. You will see by comparison to the R-20 shown above, that the glass part is more curved. It's optical, but not an optical illusion! Take a look at this 250W LED replacement BR40.
MR stands for 'mirrored reflector'. We still call it that in the LED industry, but a LED MR-16 doesn't require those tiny mirrored squares to put the light where you want it to be. MR16's are found in track lighting and in all kinds of display case lighting. We now have a 50W equivalent (to a halogen) at a fraction of the wattage consumption and without all that heat.
And next, the PAR lamps. PAR stands for Parabolic Reflector. The guts are U shaped. Once again, the LED PAR bulbs don't require that to produce the same kind of light output and performance as the traditional PAR. You'll see either an "S" or an "L" in this bulb shape description. That stands for either short neck or long neck. What you want to consider is how deep is your fixture. Measurements arealways on our site for each type, so you can easily decide which length you need.
And last but not least, you have the T shaped bulb. T stands for 'tube'. T type bulbs are found in things likebankers lamps and podium lights. The T designation also fits fluorescent tube replacements. The number associated with it determines the bulb diameter.
