From cooling integrated circuits (ICs) to rooms, fan designs have to address specific application requirements. For getting the heat away from ICs, this specifically requires smaller, quieter designs and, in some cases, alternative cooling technology. Combining the heatsink with the fan provides one technique to cool critical ICs. Thermoelectric cooling using the Peltier Effect provides an alternative to a fan but a supplement to other cooling techniques, such as heat spreaders, heat pipes and heat-sinks. For cooling large spaces, smarter, more intelligent capabilities mean integrating components to provide more of a system approach to cooling. Here are three examples that demonstrate each of these approaches.
Intelligent Airflow
With ebm-papst SK3G centrifugal fan series, constant airflow can be maintained over changing system pressure for large-area cooling. The closed-loop airflow system uses a programmable electronically controlled external rotor motor with an internal proportional integration (P-I) process controller and a differential pressure (?P) sensor to measure the pressure change across the fan inlet nozzle. To maintain constant airflow in spite of changing system pressure, the DP sensor measures the pressure change across the fan inlet nozzle and feeds this data to the process controller. Without installing a variable frequency drive (VFD) and associated filters, the unit provides complete speed control. The direct drive eliminates the need for belts and maintenance-free ball bearings add the unit's useful operating life. Operating at 3-phase, 380 to 480V ac, 50/60 Hz with 12 to 25 inch impeller diameters, the fans use 1 to 3 kW to produce airflow from 2,750 to 9,500 cfm.
http://rbi.ims.ca/5406-557
Open-Fin IC Cooler
JARO Thermal's V6X090 cooler is an open-finned design that combines both natural and forced air convection. For easy installation, the unit uses a pre-applied phase change pad and universal mounts. The 12V integrated fan to heatsink design has a rated power level of 18W. Operation at a rated speed of 5,200 ±7 percent rpm produces an airflow of 7.116 ±10 percent cfm at a sound level of 30.0 ±10 percent dB. The low profile, 70 × 58 × 12 mm fans target limited-space applications such as PCMCIA, PCI express cards, blade servers and all hot chipsets. With a life expectancy of 50,000 hours at 40C, the fans have safety approval of CE, UL, CUL and TUV.
http://rbi.ims.ca/5406-556
Embedded Thermoelectric Cooler
Nextreme's eTEC miniature thin-film embedded thermoelectric cooler addresses thermal management issues for electronic and optoelectronic products. Using the Peltier Effect, an electric current passing through a circuit containing two dissimilar materials produces a cold side where heat is absorbed at one junction and a hot side where heat is released at the other junction. Designed with thin-film compound semiconductor materials, the device pumps a maximum heat flux of 150 W/cm2. Cooling a 4W hot spot may require as little as 2W of input power that can be dynamically controlled to provide active cooling. With a 0.3 × 0.3 × 0.1 mm footprint, the thin-film cooler supplements conventional cooling solutions, such as heat spreaders, heat pipes, heat sinks and thermal interface materials.
http://rbi.ims.ca/5406-558
Tweet This
7 
