Cool It

With electronic circuits operating at higher speeds and handling increasing amounts of data and power, cooling has become an even more important system design issue. When a heatsink and convection cooling are insufficient, one of the traditional ways to cool electronic products is to add a fan. More innovative techniques are emerging especially for special applications. In contrast to a refrigeration system’s evaporator, condenser and compressor, the three main working elements in thermoelectric cooling — also known as Peltier Effect — are a cold junction, a heat sink and a dc power source. Two thermoelectric products that offer non-electromechanical solutions and one heat pump example show advanced approaches to cooling.

HIGH-PERFORMANCE COOLING SYSTEM

Taking advantage of its expertise in fans, ebm-papst developed a compact liquid cooling technology for high- performance computers and servers. The maintenance-free AquaCube heat pump system consists of a liquid cooling cube and heat absorber modules. The cooling cube contains the heat exchanger, a new patented pump and fan. Advanced 92-mm winglet fan technology produces quiet operation at high air performance eliminating the need for another fan within the housing in most applications. Using a highly conductive copper heat pickup and optimized fluid mechanics provide maximum heat transfer from the heat absorber. This design methodology can be extended to integrate more heat absorbers, cool multiple CPUs, or to cool multiple components in one chassis. Maintenance-free capability comes from using ball bearings for the fan, a ceramic bearing for the pump, and corrosion inhibitors in the coolant. Get more information on ebm-papst’s AquaCube.

PELTIER COOLING MODULES

Using thin-film thermoelectric elements that consist of n and p-type semiconductor materials from separately manufactured wafers, MicroPelt produces a 1470 × 720 × 428 µm³ (hot side L × W × H) micro peltier cooler module. The cooling power of more than 80 W/cm2 (in a vacuum at 85C) and a response time of less than 50 ms. Maximum temperature difference, ?T, is 31.9K, with a hot side temperature of 85C, and cooling power (?T=20K) of 0.313W. The package’s gold metallization connections simplify assembly for cooling silicon-based products such as integrated circuits. Target applications include electronics and chip cooling, chip spot cooling, industrial and telecom lasers, micro fluidics, sensors and more. Get more information on MicroPelt’s MPC-D301-M11 Peltier cooler.

THERMOELECTRIC COOLING SYSTEMS

TECA Corp. thermoelectric products use solid-state materials to transfer heat through dissimilar semiconductor materials. A basic thermoelectric module’s cold junction temperature decreases through absorption of energy by the electrons as they pass from one semiconductor to another. A dc power source pumps the electrons from one semiconductor to another and a heat sink discharges the accumulated heat energy from the system. A 0.38 × 0.38-inch TECA 930-7 module operates from 3.7A and 0.8V dc maximum to produce a maximum ?T at Qc=0 of 78.1 and a maximum Qc at ?T=0 of 2.0W with TH=50C. The 1.57 × 1.57-inch 980-127 module operates at 8.5A and 15.4 Vdc maximum and produces a maximum ?T at Qc=0 of 77.2 and a maximum Qc at ?T=0 of 84.9W with TH=50C. To simplify the technology’s use, TEAC offers the solid-state cooling in cold plates, air conditioner and liquid chillers. Get more information on TECA Corp.’s thermoelectric products.