Investigating a relationship among CPU and system temperatures, thermal power, and CPU tasking levels

This paper focuses on experiments investigating the quantity and quality of heat that can be captured from a liquid-cooled CPU on a computer server blade from a data center. This work also evaluates how effectively that waste heat energy dissipated from the CPUs residing on a server blade can be captured with a liquid-cooled thermal-extraction system. The ultimate goal behind this investigation is to determine the feasibility of using the thermal energy from a CPU to drive a cooling process. The unique application of this would be to capture the dissipated heat from many processors on many server blades within a data center and utilize that energy to drive a single-effect lithium bromide (Li-Br) refrigeration system. Another unique aspect of the investigation is the establishment of an interesting and useful relationship among CPU and system temperatures, thermal power, and CPU tasking levels. In response to the incoming system data, we explore the heat, temperature and power effects of adding insulation, varying water flow, tasking the CPU, and varying the cold plate-to-CPU clamping pressure. The aim is to provide an optimal and steady range of temperatures necessary for the chiller to operate. Results shown are for an IBM eServer xSeries 336 1U standalone server blade with dual Intel Xeon 3.6 GHz CPUs. Results are also shown for a simulation setup with an innovative cold plate that provides liquid cooling.