ACTIVE LED THERMAL MANAGEMENT

The use of light-emitting diodes (LEDs) as a lighting source is gaining interest due to the demand for low-powered lighting sources. LED is a form of solid state lighting (SSL). Hence, LED devices have inherently better power consumption and reliability compared to traditional energy-saving lights, such as, compact fluorescent lamp (CFL) lights. However, due to the use of physical electronics to generate light in a LED device, heat dissipation becomes an issue. Heat sinks have been traditionally used to dissipate excess heat from the device and to avoid overheating.
With this view in mind, Nuventix, a company based in Austin, Texas, has a novel approach of using active cooling to reduce the heat build up on LED devices. The company has developed its patented SynJet technology, which utilizes an active cooling approach that forces air over the heat sinks for better heat dissipation. According to sources from Nuventix, the SynJet technology is expected to match or exceed current LED device reliability performance, which could make it attractive for LED manufacturers.
The SynJet approach begins by integrating together both a heat sink with the SynJet blower module to provide the active cooling component. The blower module contains a vibrating diaphragm, which moves up and down to provide air movement. This air movement is funneled through a nozzle system, which accelerates the air into a high-velocity pulse. This pulse of air is then channeled across the heat sink to draw away heat. Due to the design of the nozzle, the air pulse that is ejected from the nozzle is at high velocity and draws additional air flow behind the jet stream. This is due to the momentum generated by the initial air pulse and the subsequent low pressure zone behind the high velocity air pulse. Nuventix believes that this additional stream could provide up to ten times the original air volume from the initial pulse, which increases the overall air streaming across the heat sink. Furthermore, the airflow is twisted to provide a turbulent air flow, which is claimed to provide better heat transfer coefficient as the air travels along the heat sink fins.
The company believes that utilizing its technology could allow SSL manufacturers to design LED devices, which can provide greater light output with the same amount of space. The SynJet design can be customized to meet specific customer shapes to optimize the cooling capacity. Since there is no bearing involved in the oscillating diaphragm, Nuventix believes the system could last up to 100000 hours of operation. Further to this, the device consumes less than 1 W of power, making it a feasible cooling solution for LED designers wanting to increase their output power and yet maintain a low-foot print design. Existing designs could even reduce their heat sink footprint size as a result of using this active air flow cooling method.
Nuventix sources believe that with the use of their SynJet technology, higher lumen LED designs could be introduced, making the adoption of SSL devices as a means of primary lighting more attractive. According to them, there exists a trend for the usage of LED devices in accent lighting and also in general illumination purposes. By allowing a brighter device at reasonable cost and size, SSL could be a valid option for mass scale adoption worldwide as a device for lighting. With a recent $10 million venture funding, Nuventix hopes to be able to ramp up its technology research to support the proliferation of SSL devices.