IBM z13: Energy efficiency, increased environmental range, and flexible data center characteristics

A maximum configuration IBM z13™ provides 45% more compute capacity per watt than its predecessor mainframe, the IBM zEnterprise® EC12 (zEC12). The z13 adds support of the American Society of Heating Refrigeration and Air Conditioning Engineers (ASHRAE) class A2 environment, with a maximum air-inlet temperature of 35
$^{\circ}\hbox{C}$
, versus 32
$^{\circ}\hbox{C} $
for the class A1, zEC12. It accomplishes this while maintaining a wide range of AC and higher voltage DC power capability, overhead and/or under-floor I/O cabling, raised or non-raised floor installation, and external air or direct water cooling, also with increased temperature. The z13 is discussed, in the context of the history of IBM z Systems™ energy efficiency and data center flexibility, with significant attention paid to the system's redesigned airflow and its customizable exhaust air direction capability. Using computational fluid dynamics modeling, this paper discusses the integration of the system into several data center environments. Also reviewed are the potential advantages of intermittently operating the data center at higher temperatures, including discussion of the cooling energy and hardware costs, economizers, and robustness improvements when faced with cooling infrastructure failures. Lastly, we describe the cooling innovations, designs, and protections that enable its wider temperature range capability.