Energy saving and heat dissipation of LED lighting will no longer be a problem.
LED lighting is recognized as the next lighting technology due to its power saving, environmental protection, and long life, which will replace the existing lighting technologies. LED is a cold light source and is afraid of heat. As much as 80% of the electric energy is converted into heat, heat dissipation measures must be taken. Although LED lighting technology has developed by leaps and bounds, with reports of up to 200lm per watt, LED heat dissipation is in LED lighting. Very headache, but the problem that has not been effectively solved has become a roadblock on the road to the popularization and development of LED lighting.
The biggest problem hindering the popularization of LED lighting applications is the high price of LED lights. Although upstream LED chip manufacturers share most of their profits and have room for substantial price reductions, they must realize the effective allocation of the entire social resources to the entire LED lighting industry chain to effectively reduce The cost is convenient for ordinary people to purchase and install, and the standardization of LED lighting modules is the only way to go, just like the existing LED lighting (incandescent lamps, fluorescent lamps/energy-saving lamps). The obstacle to standardization of LED lighting modules is the existence of heat dissipation problems.
Heat dissipation is a part of heat transfer. The research on heat transfer by humans has a history of more than one hundred years. The 1960s to 1970s were the peak period of research on heat transfer, and the main driving force was the demand for human development of aerospace. At that time, many outstanding talents gathered in the field of heat transfer technology, and many heat transfer researchers became famous. After that, people's enthusiasm for heat transfer research gradually decreased. At present, there are very few professionals in heat transfer science and technology. Heat transfer and technology are already very mature, like a ripe fruit that falls on the ground and is covered by leaves, and is not seen by people nowadays, so that when the electronic industry, mainly the CPU in the computer, heats up suddenly, People did not pull the leaves on the ground, picked up the ripe fruits, and transplanted the mature knowledge of human heat transfer into the electronics industry. Instead, they started anew and created a lot of new terms: "active heat dissipation", "passive heat dissipation", "heat sink" and so on. It sounds like I don't know what it means. The English "Sink" is also a very rare term in heat transfer and technology.
Regarding the heat dissipation of LED lighting, the current industry lacks clear research results on each heat transfer process in the entire heat transfer process. It is analyzed that: from the LED node to the convective (natural) heat transfer between the air and the surface of the heat sink, each process The proportion of heat transfer temperature difference (ie thermal resistance) in the heat transfer process, which process has the largest temperature difference, that is, the main contradiction, and the factors affecting each heat transfer process, how to reduce the technical direction of its thermal resistance, especially the heat transfer with the largest thermal resistance Thermal process, the technical direction of reducing its thermal resistance is more important. Even with these research results, it must be known to structural engineers, because heat transfer is ultimately achieved through the structure.
In terms of heat transfer and technology, LED heat dissipation is not complicated, it only involves a very small part of heat transfer-heat conduction and convection heat transfer (mainly air natural convection heat transfer), of which heat conduction and heat transfer can be used Ready-made heat transfer computer software can get very accurate solutions, such as analyzing the temperature distribution in the LED package chip (heat transfer process); analyzing the internal temperature distribution from the LED chip to the heat sink. However, special attention should be paid to convective heat transfer, where air flow is involved, and a large number of experimental studies must be carried out. Computer software calculations have only academic significance and no practical engineering significance. Because the error is too large, there are still many Of companies are keen to promote such software.
The reasons for the complexity of the simple problem of LED heat dissipation are: knowledge faults, very few people with mature heat transfer knowledge participate in the research of LED lighting heat dissipation, and the lack of professional LED lighting heat dissipation research institutions to provide clear and correct guidance to the industry There are a lot of thoughts and seminars, but there is little academic atmosphere and a strong commercial flavor. At present, many of the professional heat dissipation technicians working in the industry have transferred from the aspect of computer heat dissipation, and naturally brought the commonly used technology and commercial activities in that area. For example, heat pipe technology is widely used in high-power LED lighting (such as Street lights), creating new business opportunities for heat pipe manufacturers that originally served computer chip radiators. There is even a proposal to use a reflux heat pipe. If the general heat pipe for LED lighting is used for heat dissipation, it is like killing a chicken with a hog knife, then using a reflux heat pipe is like killing a chicken and raising a slaughter knife. An LED lighting company in Taiwan invented the "liquid immersion heat dissipation technology". This invention lacking basic knowledge of convective heat transfer actually won the gold medal at the International Invention Exhibition. There are similar LED lighting companies in China, and they are well-known to develop LED liquid cooling technology and claim that they have applied for more than 30 patents. The creators of these inventions inspired by automobile water tanks do not know the reasons why automobile engines use water (liquid) cooling technology, and the role of water in the heat dissipation process.
This paper proposes a technical solution for standardization of LED lighting modules. The heat sink is classified as a component of LED lighting. The wick composed of LED core and thermally conductive core will be designed and manufactured into LED lighting series standards, using conical cylindrical heat conduction. The core effectively solves the problem of heat conduction between the wick (heat-conducting core) and the heat sink (lamp), and realizes that the wick and the lamp can be easily disassembled and assembled. The structure is very simple and the cost is low. It is a scientific way to realize module standardization. Constant current drive power is more reasonable.
Natural convection heat dissipation, no mechanical movement, high reliability, low cost, naturally preferred by LED lights. This article will explain the principle of natural convection heat dissipation, the maximum heat dissipation and the concept of optimal design; discuss the best application structure of LED lamp heat sink-sun fancy heat sink, and propose the use of convection cover to enhance heat dissipation by using the chimney effect. After a large number of experiments, analysis and research, the results of optimization and enhancement have been obtained, which can achieve less than 4 grams of aluminum per watt for heat dissipation, and the cost of heat dissipation is significantly reduced. In the future, the cost of heat dissipation will no longer be considered. In short, LED lighting heat dissipation It is not difficult and will no longer be a problem.
