COOLING ARRAYS OF CIRCUIT CARDS USING HEAT PIPES AND FORCED AIR DIFFUSERS.

Typical physical design of electronic equipment consists of electronic circuit cards mounted in racks. As thermal densities increase, natural convection cooling may be insufficient. The next step in augmenting cooling is to use fans locally in the electronic equipment. This may result in problems with extra energy consumption, power distribution, dust filtering, safety, failure alarm and maintenance. Another way to augment cooling is by using heat pipe circuit cards and air velocity kinetic energy from the building air-conditioning system. The air kinetic energy is dissipated over the heat pipe circuit card rack. The heat pipe acts as an efficient heat flux transformer and reduces the electronic circuit heat flux to a level that can be adequately cooled by natural convection or forced convection from the building air-conditioning system. Fifty heat pipe circuit cards are placed in a rack and compared with fifty solid metal circuit cards of the same dimension. In all cases, substantial temperature reductions centering about 8 degree C are achieved when using heat pipe circuit cards. A considerable amount of cooling energy can be conserved using this technique.