Energy Saving Cooling Package for the 5ESS(TM) Digital Switch

We analyze the implications of integrating the cooling system of a building with the cooling system of electronic equipment and study the effects when applied to AT&Ts 5ESS(TM) digital switch. This type of system level packaging option allows customers to optimize their cooling energy or maintenance savings and offers the option of placing the equipment in hitherto hostile environments. 

Realistic estimates of cooling energy savings range from 16% to 65% by increasing the cooling air temperature to the equipment by 10 to 14C higher than required for cooling the room. Alternatively the equipment cooling air temperature may be controlled 10 to 14 C lower than the switch room temperature thereby decreasing circuit pack failure rates and the attendant cost of maintenance. 

The dual possibilities of saving energy or reducing maintenance costs show that when thermal designers consider the environmental control and the computer as a thermal system they can achieve a high degree of leverage in the computer's performance and energy consumption.