Is a modular data center the right option?

Modular data centers can meet the needs of building owners that need a flexible data center quickly and with less upfront cost.

By Bill Kosik, PE, CEM, LEED AP BD+C, BEMP, Hewlett-Packard Co., Chicago December 22, 2015

Learning objectives:

  • Compare advantages and disadvantages of modular data centers.
  • Inspect the energy costs and other efficiencies that can be found in flexible data centers.

The data center market has expanded dramatically in the past few years, and it doesn’t show signs of slowing down. Many clients and building owners are requesting modular data centers, which can be placed anywhere data capacity is needed. Modular data centers can help cash-strapped building owners add a new data center (or more capacity) to their site, and can assist facilities with unplanned outages, such as disruptions due to storms. Owners look to modular data centers to accelerate the "floor ready" date as compared with a traditional brick-and-mortar facility. Modular data centers are not for everyone; however, this Q&A will explore whether it’s appropriate for your next project.

Question: What are some of the primary advantages of modular data centers?

Kosik: The use of standardized designs and techniques, industrialized precast assemblies for construction, and prefabricated power and cooling components are important advantages in keeping quality, cost, and operating expenses to a minimum. In addition, with the benefits of lower expenses and reduced time to commissioning, modular design makes it easier to offer mixed levels of capacity within the same facility and allows expansion in phases as requirements change over time. Modular design is also a perfect complement to the modern trend toward infrastructure convergence and cloud computing.

What is the range of modular data center design approaches?

At one extreme you’ll find the typical monolithic "brick-and-mortar" data center. This type of data center is usually custom-built on-site. It can be costly and not very scalable. It often requires a long deployment time. Its design has one goal in mind: build it now for all future eventualities.

At the other end of the spectrum are containerized data centers that can vary greatly in information technology (IT) capacity and type of power/cooling systems. This solution takes a minimalist approach, with racks of servers preinstalled in an industrial-type container. An excellent choice when the speed of deployment is important, the containerized data center works best for small-scale data center environments or emergency situations. The container solution enables very rapid deployment of IT assets when the capabilities of a more permanent facility aren’t required.

Is there a modular data center approach that is somewhere in the middle of these two extremes?

There is another option: an industrialized, comprehensive, turnkey solution with a modular architecture, and built using tilt-up, precast, or prefabricated construction techniques. Typical characteristics of this data center type include a menu-driven selection of mechanical and electrical components, and cooling systems that take advantage of local climate to significantly reduce energy costs. These data centers offer scalability to meet changing demands for critical IT power. It also can be constructed in much less time and at a lower cost than would be possible using traditional, onsite brick-and-mortar construction methods—but without compromising quality. In other words, this solution offers the best of both worlds: the large capacity and creature comforts of the traditional data center along with some of the flexibility and efficiency found in a container. Because it’s modular, flexibility is achieved without the initial cost of trying to design and provision for an uncertain future.

What are some of the features and characteristics of the industrialized data center approach?

Modular design: Including a choice of options that allow meeting today’s requirements, then building out in phases as IT needs grow.

Future scalability: With the capability of adding capacity as necessary.

Efficient tilt-up, precast, or prefabricated construction: Based on standardized materials and processes that minimize bidding time and complexity and reduce field-labor requirements; you can even include traditional brick-and-mortar construction, if desired.

Menu-driven selection: Using a standardized set of construction materials and prefabricated components for easier, more straightforward planning and reduced onsite installation time.

Variable density: Allowing future flexibility and growth within an IT space that’s configured to load variable-density requirements.

Broad turnkey options: Full IT infrastructure (hardware, storage, networking, and software) can be integrated into the data center solution.

How does the cost of an industrialized data center compare to traditional, brick-and-mortar solutions?

The modular design and construction of this type of data center can significantly improve time-to-commissioning. In fact, from concept and commissioning, you can occupy the data center within a year. Cost is another advantage. Because of a number of factors, generating meaningful comparisons of actual construction costs for data centers is difficult. However, based on a midlevel estimate of capital costs for a traditional data center at about $15 million per megawatt, building a 6-MW data center appropriate for enterprise use would require an outlay of $90 million with a median estimate of around $9 million/MW for a modular design (see Figure 1).

What about ongoing energy costs?

It’s clear that on an annual basis the flexible data center will use less power than the conventional data center. Moreover, power-usage effectiveness (PUE) for the modular data center is also lower (1.19 versus 1.34), indicating its superior efficiency as compared with the monolithic structure (see Figure 2).

Much of the savings is the result of the use of indirect evaporation, air-to-air heat-exchanger cooling systems. When you figure in both the significantly lower first cost of a flexible data center, plus its lower ongoing energy and maintenance costs, the evaporatively cooled flexible data center can have 5-yr costs that are $24 million less than a traditional data center relying on water-cooled chillers with water economizers.

How does the "industrialization" part fit into the big picture?

Underpinning a flexible data center concept is a foundation of innovative supply-chain management techniques that cut time-to-commissioning and reduce capital expenditures. The reduced speed to deployment and lower construction costs stem from many factors, including standardization of components, the menu-driven selection process for choosing those components, and using a turnkey methodology with one point of contact for all aspects of the project.

The supply chain approach has other advantages, too. For instance, using standardized assemblies augmented by leveraged purchasing agreements and volume purchasing is a very effective method in keeping the project duration and costs to a minimum.

Bill Kosik is a distinguished technologist, data center facilities consulting, at Hewlett-Packard Co. He is a member of the Consulting-Specifying Engineer editorial advisory board.