The next silent cooling item on our list of worthwhile mentions is the massive Zalman TNN 500A case; basically a thermal exoskeleton for a completely silent computer system. With carefully placed heatpipes, a custom-built 300W power supply, and plenty of extruded aluminum, this large black aluminum 'heatsink' case cools by entirely passive means.

There are no fans in the TNN 500A, and that means cooling becomes a rather interesting design challenge, but not an impossible one. The Totally No Noise Zalman cases come in a variety of sizes, although the TNN-500A series is the most popular.

From left to right; the TNN 800A, 600A, and 500A cases.

Heatpipes are arranged to move heat from the computer components to external heatsink walls.

From the CPU, to the hard drive, heat is moved externally so no fans are required to keep the PC within at correct operating temperatures. Note the vibration mounts for the hard drive.

Even the videocard is equipped with the necessary heatpipes to keep it cool by means of the external case only. In this case, and Pentium 4 CPU forms the heart of this silent PC.

Control panel and EMI gasket for the computer wires to exit the chasis.

The control panel on the initial production TNN 500A cases was nothing more than a couple plates joined at the edges. With the outer doors of the TNN 500A case open, the insides of the PC were essentially exposed. The wave shaped metal at the very bottom is an EMI gasket. It allows power, and connectivity cables to pass through to the computer from outside the TNN 500A case, but restricts EMI emissions.