Thermally Advantaged Tested Chassis Guide

Section 2
E34579 / TAC 2.0 Design Guide 7
2 Section 2
2.1 Thermally Advantaged Chassis Description
The following design is intended to provide a desirable internal thermal environment
for standard ATX and µATX tower style chassis. One key goal is to achieve a
temperature rise from external ambient to the processor fan heatsink (T
rise
) of 5 °C or
less (or 40°C inlet to the fan heatsink at the typical maximum external ambient
temperature of 35°C). Details on thermocouple placement for CPU fan heatsink inlet
temperature measurement can be found in applicable Thermal Design Guide (TDG)
documents. This design does not require any special ducting or other components
typically not found in PC enclosure designs and relies entirely on vent size/placement
and proper air flow.
Figure 1 represents a generic µATX tower chassis similar to that used in many
platforms currently available. The single side vent shown has been optimized in size,
location, and effective open area to provide desirable internal temperature conditions
at external operating temperatures of 35 °C or less. The vent relies entirely on typical
internal system fans (one rear chassis exhaust fan, one power supply exhaust fan, and
one active CPU heatsink fan) to distribute air throughout the system components.
There is no requirement for a side panel intake fan with this design approach. Detailed
size and location dimensions for the side vent are shown in Section 5.
Figure 1. Typical Tower Platform With Optimized Side Vent