Maintaining Data-Center Environments with Dampers and Louvers

Date: 2024-10-27 03:27:00

By Tim Vogel

(Editor’s note: This article was published in the 2024 edition of AMCA inmotion magazine as "Maintaining Optimal Data-Center Environments with Dampers and Louvers.")

The market for data centers—physical locations housing information-technology (I.T.) infrastructure for building, running, and delivering applications and services and storing and managing the associated data¹—is booming, driven² largely by:

explosive growth in the field of artificial intelligence (AI)
a faster-than-expected rise in cloud adoption
the emergence of new technology hubs (e.g., Latin America, Europe, Asia-Pacific)
a desire for greater sustainability to reduce environmental impact and lower costs
innovation in data-center design and technology

As with other mission-critical facilities, failure is not an option with data centers. Outages can be costly, catastrophic even. One way to ensure continuous operations is by maintaining optimal environmental conditions. Dampers and louvers play a vital role in this process by regulating airflow, preventing water intrusion, and controlling airborne particulates. This article explores the various types of dampers and louvers used in data centers, their specific applications, and their impacts on overall system efficiency and safety.

Data-Center Damper Applications

Simply stated, outside-air dampers control the volume of outdoor air entering a space. Other types of dampers are used to direct air through a space until it is exhausted, in the case of data centers, removing heat from servers along the way. These damper applications are referred to as backdraft, barometric relief, combination fire and smoke, thermally insulated, and thermal-dispersion airflow measurement.

Backdraft. Backdraft dampers mostly are used in conjunction with fan banks. The principal purpose is to prevent short-circuiting of airflow. Short-circuiting limits the ability to properly control air and reduces overall system efficiency. Of course, any fan-inlet airflow obstruction impacts performance, so it is necessary to consider a data center’s efficiency holistically. It is possible that reduced fan performance can be offset by other design benefits and efficiency gains. Recently introduced backdraft-damper designs are claimed to have no fan-performance penalty, so this may be a moot point.

Barometric relief. Barometric relief dampers typically are used in exhaust-air applications. Some designers replace backdraft dampers with actuated control dampers. For sophisticated data-center designs, this is desired because it offers optimum control.

Credit: IR_Stone/iStockphoto

A Closer Look: What’s Driving Data-Center Growth

From 2024 to 2029, the North America data-center market is forecasted¹ to increase at a compound annual growth rate (CAGR) of 10.09 percent, from 15,930 MW to 25,760 MW. Meanwhile, colocation revenue is projected to rise at a CAGR of 18.65 percent, from USD 45,633,800,000 to USD 107,300,100,000. Such growth no doubt can be attributed to advances in technology, such as those related to artificial intelligence, machine learning, the Internet of things, and fifth-generation (5G) cellular networks. But that is not all.

As much as we might want to forget the coronavirus disease 2019 (COVID-19) pandemic, we must acknowledge the influence it has had on cultures globally and the acceleration of digital transformation. Historic growth in remote work, e-commerce, and online services—predominant byproducts of the pandemic—are data-center growth drivers. Increasing demand for high-speed streaming is another. Additional influencers include cryptocurrency mining, hybrid-cloud adoption, edge computing, and high-frequency trading. Sustainability concerns, meanwhile, are forcing consideration of the updating or replacement of older data centers, while better protecting sensitive data and complying with local laws tied to privacy and data sovereignty is necessitating the need for more strategically located data centers.

Reference

Mordor Intelligence. (n.d.). North America data center market size & share analysis - Growth trends & forecasts up to 2029. Retrieved from https://bit.ly/Mordor_DataCenter

Combination fire and smoke. Combination fire and smoke dampers restrict the transfer of fire and smoke to prevent loss of life and mitigate damage to buildings. UL-rated life-safety dampers are a component of smoke-control and evacuation strategies. As such, they are tied to a fire panel and can be controlled by the fire marshal during a life-safety event. Life-safety dampers can be used to control airflow if a modulating actuator is utilized. Use of modulating actuators on life-safety dampers can reduce pressure drop by eliminating a control damper.

Thermally insulated. Some dampers are thermally insulated to prevent condensation from forming on their blades. Condensation can become airborne and pose a danger to I.T. equipment, leading to costly downtime and even failure. Additionally, it is a source of mold and bacteria growth that can lead to sick building syndrome.

Thermal-dispersion airflow measurement. Dampers equipped with thermal-dispersion airflow-measurement instrumentation facilitate tighter control of environments. These products work in concert with building-automation controls to ensure optimum performance and efficiencies. Directing conditioned air to exact locations is essential, especially in high-density data centers where servers are stacked to maximize profit and facility footprint. These dampers can be used to measure any airflow within a complex data-center design. Some data centers are exploring the use of AI for more exacting control of conditioned air.

Data-Center Louver Applications

Though sometimes considered a commodity and given short shrift in facility design, louvers can play a critical role in overall system efficiency and security. A savvy designer considers free area, water penetration, and pressure drop. Though that may appear easy, manufacturer literature can be easily misunderstood. When comparing products, ensure all data are backed by a third-party test agency and that identically sized units were tested. Maximizing free area while eliminating water-penetration risk and improving efficiency should be the goal.

Acoustic louvers are used to mitigate objectionable noise, a concern particularly with edge-computing facilities located near or within high-population centers. Here, a designer may consider outside-air louvers with acoustic properties to reduce or eliminate noise in certain sound bands.

For a data center located in an area prone to severe weather, such as tornadoes or hurricanes, designers should specify products third-party-tested and certified or registered. Pressure-drop, water-penetration, and impact testing should be verified.

Impacts of Dampers and Louvers on Data-Center Design

The previous paragraphs spoke to the general application of dampers and louvers. There are, however, more complex considerations.

In North America, most data centers contain generator rooms and enclosures. With exhaust-air temperatures as high as 500°F (260°C), the conditions can be harsh, with much at stake in the event the primary power were to fail. Supply dampers must open in seconds, while louvers are expected to pull in outside air and prevent excessive water penetration under any weather conditions. If a damper or louver is selected incorrectly, catastrophic failure could result. Insist on partners whose products have undergone extensive third-party testing and verification for a full range of application-specific criteria.

In HVAC systems, control authority and damper authority are intertwined but different. Simply stated:

Control authority refers to the effectiveness of a control system in maintaining mission-critical temperature, airflow, and humidity. Chief considerations are system responsiveness, accuracy, and stability.
Damper authority speaks to the influence a damper has on airflow within a system. Calculated as a percentage, it is the ratio of pressure drop with a damper fully open to pressure drop at design flow. Damper placement within a system and blade action are but two considerations.

Considering dampers can enhance control authority:

Select high-quality, low-leakage dampers, preferably ones designed with specific data-center-friendly features that facilitate precise control, reliable performance, and reduced energy consumption.
Select properly sized actuators providing precise control to facilitate dynamic adjustments.
Use feedback loops to adjust damper position based on system data.
Size dampers based on system requirements.
Position dampers for optimal airflow distribution.
Balance airflow across zones to prevent overloading.
Fine-tune set points and response times in control loops and proportional-integral-derivative (PID) controllers.
Facilitate dynamic adjustments with adaptive-control algorithms.
Control energy-recovery-ventilator (ERV) and heat-exchanger dampers to maximize heat exchange.
Ensure pressure, temperature, and humidity sensors are located properly, accurate, and responsive.

Although dampers are not linear devices, they often are controlled as such. This leads to complications in systems and subsequent reductions in performance and efficiency. Bringing in subject-matter experts during design will ensure the most comprehensive and positive outcome.

Like control authority, system efficiency is a broad subject. However, the influence dampers, associated actuators, and louvers have on efficiency often is understated or overlooked. Most designers consider pressure drop alone, while, as previously noted, damper authority can impact fan performance, increasing energy consumption.

A designer may consider working with a product-design task force to develop a turnkey damper, louver, and actuator assembly with integrated filtration and plug-and-play single-point wiring. Integrated thermal-dispersion-airflow-measuring and other sensors also could be part of the design. Testing in a third-party laboratory would generate critical data necessary for calculating control authority. This could not only improve overall performance but reduce job-site labor.

A comprehensive understanding of damper authority and its relationship to control authority will ensure regulated airflow between hot and cold aisles for optimal efficiency. Precise cooling control based on demand is tied to high damper authority. Other applications where high damper authority can be critical include containment systems for maintaining cooling around server racks, blanking panels for recirculation prevention, free cooling, fire and smoke containment, and overall energy optimization.

Summary

Technological advances, changes in consumer behavior, regulations, and more are driving unprecedented demand for data centers. When selecting dampers and louvers for a mission-critical application, designers must consider new challenges as well as the facility’s mission, application, and geographic location to ensure optimal energy performance and safety.

References

IBM. (n.d.). What is a data center? Retrieved August 18, 2024, from https://bit.ly/IBM_DataCenters
Schaap, A. (2024, January 22). Five trends driving the booming data center economy in 2024 (and why investors are taking notice). Forbes. Retrieved August 18, 2024, from https://bit.ly/Schaap_DataCenters