Submittal

WW-CPWP-09, Rev.0, 09/2009

Deploying a Vertical Exhaust System

to Achieve Energy Efficiency and Support Sustainability Goals

Introduction

Business management applications and rich collaboration software for both employees and customers require

increasingly complex and large-scale database processing capabilities. Data center managers are under

constant pressure to manage growth while reducing capital and operational expenses. With per-cabinet

equipment densities increasing to meet these processing demands, network stakeholders need new and

effective cooling conservation strategies for managing growth and the resulting high heat densities over the life

of the data center.

Organizations are looking to Unified Physical Infrastructure

(UPI) solutions that take a holistic approach to the

data center, turning to passive exhaust containment solutions to optimize energy efficiency and mitigate risk

throughout the physical infrastructure. One such solution, the Vertical Exhaust System (VES), is a passive

exhaust containment system that eliminates hot exhaust air recirculation to active equipment inlets throughout

the data center. These systems channel heated server exhaust air directly into the hot air return plenum,

separating hot exhaust air from cool supply air. This allows data center managers to operate the data center at

higher supply air set point temperatures to achieve operational savings.

This white paper discusses thermal management considerations associated with deploying a Vertical Exhaust

System in the data center, and its impact on the data center physical infrastructure. An example scenario is

presented to demonstrate the cost savings that may be achieved by deploying a VES in a typical data center

environment. Best practices include minimizing airflow impedance in the back of the cabinet and up through the

vertical duct, and keeping the server exhaust area clear of airflow obstructions. When deployed in conjunction

with infrastructure best practices, VES containment strategies achieve cooling efficiencies, support

sustainability goals, and lower cooling system operating costs by 25% or more.

Reaching the Limits of Traditional Cooling Systems

Typically, airflow management in a data center is achieved by strategic placement of Computer Room Air

Handling (CRAH) units and physical layer infrastructure elements, with equipment rows positioned in a Hot

Aisle / Cold Aisle arrangement (see Figure 1) as defined in TIA-942 and in ASHRAE’s “Thermal Guidelines for

Data Processing Environments.”

Figure 1. Traditional Raised Floor Hot Aisle / Cold Aisle Data Center with Ceiling Returns