IACS CO., LIMITED (Yiwu Fuwei e-commerce firm)

The LED chips in the LED lamp are electronic components with high heat flux density. During operation, due to their static and dynamic losses, a large amount of excess heat is generated, which is radiated to the outside through the heat dissipation system to maintain the stability of its working temperature. At present, the luminous efficiency of LEDs is still relatively low, resulting in an increase in junction temperature and a decrease in lifetime. In order to reduce the junction temperature to improve the life, it is necessary to pay great attention to the problem of heat dissipation. The heat dissipation design of the LED must be from the beginning of the chip to the entire heat sink, and every step must be given full attention. Improper design of any link can cause serious heat dissipation problems. Therefore, the design of heat dissipation must be given full attention.

High-performance micro-slot group composite phase-change heat transfer technology meets the heat dissipation requirements of high-power LED lighting. The technology is named “micro-slot group composite phase change integrated cooling technology”. The technology has been successfully applied to the LED lamp, and the heat of the LED chip can be instantaneously distributed in the entire heat dissipation space, which prolongs the life of the LED lamp and improves the luminous efficiency.

First, micro-slot group composite phase change integrated cooling technology:

The heat generated by the LED chip is always dissipated into the air through the outer casing of the luminaire. The general heat dissipation is: the heat generated by the LED chip comes out of its metal heat sink, first through the solder to the PCB of the aluminum substrate, and then through the thermal adhesive to the aluminum heat sink. The heat dissipation of LED lamps actually includes two parts: heat conduction and heat dissipation. One concept to be clear first is the difference between heat conduction and heat dissipation. Heat conduction is to transfer heat from the heat source to the surface of the heat sink as quickly as possible, while heat dissipation is to dissipate heat from the surface of the heat sink to the air. The first thing to do is to export the hottest ones, and then to get the most out of the air. The heat sink of the traditional radiator is aluminum fins, and our heat sink is: micro-groove group phase change technology.

The micro-slot group phase change cooling technology relies on technical means (such as equipment structure: micro-groove, etc.) to change the closed circulating cooling medium (if the medium is water) into a nano-order water film. The thinner the water film, the thermal evaporation capacity. The stronger the stronger the latent heat exchange capability, the higher the heat of the high-power electronics is carried away by the vapor.

Cooler system composition and working principle:

1. The composition of the cooler:

The system is mainly composed of four parts, namely, heat extractor, condenser, conveying pipeline, and heat taking medium (such as water, ethanol, etc.).

The heat extractor is generally made of imported aluminum alloy. The inner cavity of the plate has many channels of micron order. Its function is to change the heat taking medium (such as water) into the required liquid film according to the design requirements. The heating power device and the aluminum alloy The surface is in close contact, and the heat energy is transferred to the liquid film through the heat of the aluminum, and the liquid film is instantaneously vaporized, and the heat energy is sent to the condenser through the pipeline for cooling. Because the heat extraction capacity of the heat extractor is very strong, its thermal conductivity is greater than 106 W/(m*°C), so the volume of the heat extractor can be made small.

The condenser is generally made of imported aluminum alloy. The inner cavity of the plate has many channels of the order of millimeters. The outer part of the aluminum alloy plate has fins. The heat medium is sent through the pipeline to transfer heat energy. It is responsible for convective heat exchange with the outdoor air. Radiation heat transfer, the heat energy of the heat medium is released through the condenser, and the liquid state changes from liquid state to liquid state. The liquid heat taking medium returns to the heat extractor by its own gravity to prepare for the next heat energy exchange cycle.

2, working principle:

A plurality of microchannels are processed on the inner surface of the composite phase change heat extractor of the capillary microgroove to form a microgroove group structure, and the heat transfer mechanism is enhanced by the micro-scale composite phase transformation to realize a high heat flux density in a small space and a small volume. High-power devices take heat efficiently. The heat extracted by the capillary phase change group composite phase change heat extractor is transported by steam through the steam circuit to a remote high-efficiency microstructure condenser, and high-intensity micro-scale steam is carried out on the surface of the fine-scale condensation groove group structure in the microstructure condenser. Condensation is exothermic. The heat released by condensation of the condenser can be quickly diffused to the surface of the fine-scale condensation groove group structure and transmitted to the surface of the rib of the outer wall of the microstructure condenser through the wall surface, and the heat is released by convection heat exchange with the external environment. Go in the environment. The condensate flows through the condensing liquid circuit and flows back to the microchannel group composite phase change heat extractor under a pressure gradient. Therefore, the system achieves high efficiency and no power consumption closed loop of heat and heat release, and achieves the purpose of device cooling. The heating surface of the micro-slot group composite phase change heat extractor is in close contact with the power electronic device, and the inner surface is engraved with a plurality of composite phase change microchannels, which are integrated into a composite phase change micro-groove group. There is a small amount of liquid working medium with a certain latent heat of vaporization in the micro-slot group composite phase change heat extractor. The liquid working fluid flows along the micro-groove under the action of the capillary pressuregradient formed by the structure of the micro-groove, and forms a high-intensity micro-scale composite of the thin meniscus evaporation and the thick liquid film nucleate boiling in the microgroove. The phase change strengthens the heat exchange process, turns the liquid working medium into steam, and utilizes the huge heat generated by the power electronic device during the vaporization of the submerged zone, thereby reducing the operating temperature of the device and controlling it within an ideal range. The micro-slot group composite phase change cooling system is composed of a small-sized heat-receiving element (micro-groove group composite phase change heat extractor), a heat and fluid transport pipeline, and a remote heat radiating element (remote microstructure condenser). Wherein, the heat and fluid transport pipeline comprises a steam loop for transporting heat and a condensate loop for transporting the condensate, respectively connecting the microchannel group composite phase change heat extractor and the remote microstructure condenser to form a A micro-negative pressure circulation system that is closed to the outside. The huge heat extracted by the micro-slot group composite phase change heat extractor is transported by steam to the remote microstructure condenser under the action of evaporation and condensation pressure difference of the system, and fine-scale condensation in the inner cavity of the microstructure condenser High-intensity micro-scale steam condensation heat release on the surface of the trough group structure. The heat released by the steam condensation is transmitted from the surface of the fine-scale condensation groove group structure to the cooling water channel group on the rib surface or the outer wall of the outer wall of the microstructure condenser through the wall surface facing outward (Note: the microstructure condenser wall faces the external environment and The cooling water is separated from the interior of the microstructure condenser, the externalenvironment and the cooling water are not in contact with the condensate in the microstructure condenser, and the air (natural or forced) convection heat exchange with the external environment or the cooling water channel group The cooling water in the process undergoes single-phase forced convection heat transfer and eventually is lost to the external environment. The condensate flows through the condensate circuit and returns to the micro-slot group composite phase change heat extractor by means of the pressure gradient generated by gravity and the system fine-scale groove group structure. Therefore, the whole system forms a unidirectional flow with working medium according to the sequence of the micro-slot group composite phase change heat extractor, steam circuit, remote microstructure condenser, condensate circuit and back to the micro-slot group composite phase change heat extractor. The liquid-vapor-liquid phase heat-removing and heat-releasing mode of the power-free cycle (passive cycle) achieves the purpose of cooling the high-power power electronics that generate heat.

3, the difference with the heat pipe

Formally similar to heat pipes, but in terms of heat transfer mechanism, structure and performance are fundamentally different:

1. Using a powerful micro-scale composite phase transformation to enhance the heat transfer mechanism; the heat pipe is only ordinary liquid film evaporation;

2. There is no heat transfer limit such as boiling, sling, capillary force inherent in the heat pipe;

3. The high contact thermal resistance and thermal resistance of the heat pipe without heat pipe and the complicated and complicated operation of the device;

4. No problems with heat pipe startup and work stability;

5. The heat capacity per unit area at the same temperature is about 100 times higher than that of the heat pipe, and the system is simple, light and compact.

Second, the characteristics of the micro-slot group composite phase change LED high-power light source cooler:

1, super thermal conductivity:

The micro-slot group composite phase-change cooling technology has super-thermal conductivity, and its thermal conductivity is 10,000 times that of the aluminum substrate. This technology can timely transfer the heat of the LED chip to the heat-dissipating surface of the infinite aluminum substrate.

The thermal conductivity is greater than 106 W/(m*°C). Copper is an excellent conductor and an excellent thermal conductor. The thermal conductivity of copper is about 400 W/(m*°C). The thermal conductivity of MGCP is comparable to that of copper. It has superconducting properties. Using a solid copper rod 60 cm long and 1.3 cm in diameter to deliver 200 W of thermal energy at a working temperature of 100 ° C, the temperature difference between the two ends of the copper rod is as high as 70 ° C; the MGCP heat extractor is made of half the weight of the above copper rod. The heat energy of 200W is transported at a working temperature of 100 °C, the heat transfer distance is also 60 cm away, and the temperature is only reduced by 0.5 ° C. Experiments show that the MGCP technology has super thermal conductivity.

2, the cooling capacity is super strong:

The heat flux density has reached 400W/, its capacity is 1000 times higher than water cooling, and about 100 times higher than heat pipe. The heat extraction capacity is 100 times higher than forced water cooling and 1000 times higher than forced air cooling.

At a standard atmospheric pressure, the boiling point of water is 100 ° C, 1 Kg of water is raised from 99 ° C to 100 ° C, the required thermal energy is 4200 Jol; 1 Kg of 100 ° C water endothermic to 100 ° C vapor, the temperature does not change, but The amount of heat extracted is 2260000 joules. Water cooling is sensible heat exchange, heat exchange heat is low, MGCP technology is latent heat exchange, and heat exchange capacity is super strong. 1Kg of water is heated at 1 °C and only needs 4200 joules of heat. 1Kg of 100 °C water absorbs heat to 100 °C of steam, the temperature does not change, but the absorbed heat is 2.26 million joules, the difference between the two absorbed heat is more than 500 times, therefore, There is a huge difference in the heat exchange capacity between the two.

3, no power cooling:

Passive cooling, no need for fans or pumps, no cooling energy consumption, no power running, energy saving. MGCP technology is the ingenious use of the energy generated by high-power power electronic devices to evaporate the heat-receiving medium to generate kinetic energy and potential energy. The vapor flows to the condenser to dissipate heat into a liquid, and is returned to the liquid by the capillary force of the micro-slot group of the heat extractor. The high-power power electronic device is closely attached to the heat extractor, thereby achieving a closed heat dissipation cycle without external power.

4, light weight, small size:

It weighs less than 25% of the existing heatsink and can be as small as 20%.

5, high reliability:

The device is compact and compact, stable in operation, has no startup problems, and is much more reliable than fans, water cooling and heat pipe radiators.

6, low cost, environmental protection:

The product cost is less than the radiator of the fan, water cooling and heat pipe; the phase change working environment is friendly, the quantity is small and no consumption.

7. Waste heat utilization:

The heat (waste heat) generated by high-power power electronic devices can be changed to 50 ° C ~ 60 ° C hot water for daily use, replacing electric water heaters to achieve energy savings.

LED lighting technology is still advancing rapidly. With the advancement of technology, the micro-slot group composite phase change technology has matured. Many LED lighting companies in China are gradually in use. I believe that in the near future, this technology will be Into the high-power LED lighting manufacturers who are more troubled by the heat dissipation problem, truly solve the heat dissipation problem.

Yiwu Fuwei e-commerce firm (IACS Co., Limited) is a very professional Led manufacturer who produces high quality outdoor led light. Our popular products are solar led lights, UFO lights, underwater lights and so on. If you have any question about the led product, please feel free to contact us.