Data Center Thermal Zone Mapping

Thermal Zone Mapping (TZM) is a visualization tool developed to present in graphical format high-level thermal metrics developed by HP and targeted for use as part of the HP Data Center Thermal Assessment service. This tool uses data generated from computer models of the data center and generates metrics, which are then post-processed and visualized in the three-dimensional data center space. Output from the tool can be used to optimize the placement of equipment in a data center, investigate failure scenarios, and make sure that a proper cooling solution has been achieved.
HP currently provides a Data Center Thermal Assessment service to customers through TSG. This service uses off-the-shelf computer tools to evaluate the thermal performance of data centers. Features available within these tools allow the visualization of parameters such as temperature, air velocity, and pressure, which are then used to evaluate the thermal conditions in the data center. Although HP was the first to offer such a service in 2003, and validate its use1, similar services are now being offered by data center consultants as well as other computer manufacturers. However, in recent years HP has developed several unique, higher-level metrics that utilize temperature data to quantify various phenomena within the data center2 environment. Two such high-level metrics are the supply heat index (SHI) and the thermal correlation index (TCI). Both enable analysts to better understand results and optimize data center layouts. Detailed information about each can be found in references 2 and 3 at the end of this white paper.
In particular, TCI quantifies and identifies the regions of influence of air conditioning units within the data center environment. Previous publications disclose the process by which TCI can be determined either from experimental data, for use in Dynamic Smart Cooling3, or from numerical data. However, there is currently no tool available for taking temperature data generated from computer models and manipulating it to evaluate and visualize TCI in three-dimensional space throughout the data center. This tool enhances the HP Data Center Thermal Assessment service and provides differentiation from other data center service companies’ current thermal analysis services.
The thermal metrics developed by HP are effective in highlighting key physical attributes of fluid flow and heat transfer in a data center, but they can be cumbersome to generate with off-the-shelf tools. Our solution automates the transfer, calculation, and visualization of higher-level metrics from native software tools. The method uses the data generated from a computer model simulation, and presents the thermal metrics in a user-friendly graphical form. Refer to Figure 1 for a high-level overview of this process.
Current TZM capabilities include the visualization of each computer room air conditioning (CRAC) region of influence, which is obtained via a procedure called “numerical commissioning.” Each region defines the space within the data center where a particular CRAC unit has an effect over environmental conditions. Refer to Figure 2 for a pictorial representation of these regions in a data center space. By performing numerical commissioning, the customer will gain a better understanding of how their cooling resources are distributed and managed in their data center space.
Once a computer model has been developed for a data center, TZM can be used to visualize the region of influence for each CRAC. We applied the TZM method to a typical data center design. This data center has a total of six air handlers. Each unit has a sensible load capacity of 100 kilowatts. A total of 145 computer racks are in the room, arranged in five rows of 29 racks each. The total heat load from the racks is 507 kilowatts. It has an underfloor supply plenum and a ceiling return plenum. The data center layout and a temperature plot generated from the computer model are shown in Figure 3.