The thin-cavity fluidic heat exchanger from Third Millennium Engineering, Plano Tex., uses highvelocity gas flow to form a thin boundary layer that keeps circuits cool and isolated from possible contaminants or EMI/RFI. According to its developers, this heat exchanger is technically positioned between fans and heatsink methods of cooling, and waterbased cooling subsystems.
The device consists of a heattransfer plate, a cavity spacer, cover plate, and a gas inlet and outlet. Heat produced by circuitry or any other thermal load is conducted to the heat-transfer plate, which can be flat, round, or any other shape. A gas, typically compressed air, is sent into the thin (0.01 to 0.001-in.) gap created by the cavity spacer mounted between the cover plate and heattransfer plate. Tests show that the thinner the gap, the better the cooling. And placing cooling fins and channels in the gap make the cooling device less efficient and less reliable. The air carries the heat away when it exits the cavity through the outlet.
According to the developer, the compressed air can be replaced with nitrogen, oxygen, Freon, or similar gases, and the gas can be hot, cold, or room temperature.
