Designing The Green Data Center
The green data center is certainly an evolving solution. As architects focused on data center design, the following are design aspects that we are seeing and implementing in our data centers today.
The proliferation of technology, data generation, digital consumption, and connected devices will continue to expand the data center market. This growth will only continue to place additional pressures on data center designers and operators to pursue more efficient solutions that reduce energy consumption and lower operational costs. As data centers rise in public and governmental exposure, corporate responsibility and environmental expectations are solidifying as drivers of the end solution. While reducing energy consumption may be the primary focus, reduction of the overall environmental impact is what makes it green.
The data center building has traditionally been a secure and robust envelope shell that minimizes environmental risks to reliable operations. The green data center is all that, and one that efficiently integrates high performance infrastructure systems in the building solution.
Cooling is the current driver in the data hall configuration and the building envelope. Implementation of 100% outside air cooling, direct and indirect economization, or even direct evaporative cooling solutions have a substantial impact on the envelope design. As infrastructure systems and building architecture become more integrated, the building form is becoming directly responsive to the functional airflow and technical system requirements.
While not necessarily a visible aspect of an efficient data center, the planning and configuration can affect the initial and operational costs of a facility. An efficient plan supports reliable operations, as well as optimizes feeders and piping, which minimize losses.
Integration of Efficient Infrastructure
The green data center comes out of a core focus on efficiency. The expanded ASHRAE operational parameters opened up the operational window and created the opportunity for significant gains in efficiency. This and the general industry push for efficiency brought a wider range of mechanical and electrical systems solutions to the table.
Data hall hot/cold containment is a system that bridges IT systems, infrastructure, and architecture. Proper integration and implementation can provide efficiency gains for both IT and infrastructure systems. While the raised access floor plenum is the dominant air delivery approach, the use of overhead cooling, thru-the-wall cooling, and close coupled in-row cooling systems are on the rise and focused on efficiency gains.
The water consumption of evaporative cooling in traditional chiller and cooling tower designs has become a significant problem in some areas. The issues can range from lack of available capacity, to unreliable source availability, to poor water quality, to potential curtailments in drought prone areas. In facilities where mechanical cooling is required, yet the elimination of water as a critical system is a requirement, DX is still the system of choice. While today’s DX systems are more efficient than ever, it is when DX is coupled with indirect or indirect evaporative air systems that the efficiencies move into the green range. These types of systems are being utilized in a wide range of environments and in a wide range of data center types, and depending on the system they can have a significant impact on the building design.
In solutions where the heat from the IT equipment can be effectively transferred via direct or indirect systems to the occupied office mechanical systems, waste heat can be reclaimed as free energy.
Waste water reclamation and reuse can be implemented on facilities with cooling towers or evaporative systems to capture blow down. Depending on the on-site treatment, the water can be stored and used as a graywater source for toilet flushing or irrigation, reducing the demand on potable water.
Reduced Environmental Footprint
While reducing energy consumption through infrastructure systems selection and IT operations may be a primary focus of a high efficiency data center, reduction of the facilities’ overall environmental impact is part of being a green data center.
Site selection and site development of greenfield projects have typically been focused on security and operations, but the green data center is one that also incorporates site environmental factors into the design. Implementing storm water management solutions that curtail run-off and provide water quality control are critical to preserve local watersheds and environmental quality. Establish extended site buffers that provide natural environmental zones and act as natural security screening buffers. Reestablishing or preserving the variety of regionally native planting zones is the basis of maintaining healthy and diverse natural ecosystems.
Building reuse or urban facilities can also be green data centers. Use of existing building stock can yield environmental savings by avoiding significant manufacturing energy, raw material resource avoidance, and landfill diversion. Large data center conversions can also make use of old industrial and manufacturing facilities, which can languish on the real estate market as they are difficult to convert into other office or warehouse uses.
An efficient data center takes advantage of opportunities in the surrounding environment.
Green or renewable utility power use is becoming more common in the data center market due to the availability and corporate responsibility drivers. Unfortunately, efficient renewable power generation is rarely in the same location as data center operations, so power purchase agreements or renewable energy credits are used to support renewable power generation on the grid.
The implementation of on-site photovoltaic arrays has been a growing trend in data center facilities where corporate environmental goals have been targeted. Most of these arrays have been sized to generate enough power to offset the office load of the facility. Others have expanded that capacity to take full advantage of the large roof or open land areas that are often available at data center facilities. While most entities choose to take the utility green power approach when looking to go green for the entire facility load, one client implemented a private photovoltaic array sized to offset the entire 20 mega watt (MW) data center load. On-site implementation of photovoltaic arrays can introduce potential risks to roofing systems, which can be mitigated, but they should be addressed as part of an effective envelope solution.
Water use is a trending environmental concern in most areas and rainwater capture is an effective water reduction approach in green data center design. Rainwater captured and stored from the large roof areas can be used for site irrigation, gray water plumbing systems, and cooling tower makeup water. Captured water stored in large tanks or cisterns allows use with minimal treatment. Site detention systems can also be an effective way of capturing site run-off for use by irrigation systems or potentially emergency water use. While open ponds are the most common approach for site detention, structured water detention systems below paved areas and pervious paving offer good solutions in constrained sites.
Taking advantage of the earth through geothermal systems is another green systems approach. These systems are implemented in closed-loop piping arrays sized to offset the office load up to entire facility loads. Siting for these systems is critical to their ability to effectively reject heat. On the extreme end of geothermal, locations like Iceland can also take advantage of geothermal for power generation.
IT Equipment and Operations
The focus of this article is on the numerator end of the PUE equation, but it would be lacking to not mention the progress on the IT side of the equation and the design impacts on the green data center.
One trend is the halting of the rise in power density. While there are lots of drivers for this change, the use of more efficient IT equipment and more efficient utilization of that equipment are significant factors. This has brought the design and programmatic conversation back around to establishing the balance between data hall space and power/cooling infrastructure. In a perfect world these two would be optimized, but the ability to provide accurate long term projections is very difficult. Recently we are seeing more decisions favor the approach of not stranding power or cooling capacity, which is a shift from the past concern of having unused “white space” or even underutilized cabinets.
Monitoring and optimizing performance has long been an operational goal for data centers, but one implemented at a wide range of granularity and utilization. Information is the key to better operations, but only when appropriately analyzed and acted upon. The green data center must provide seamless and reliable adjustments to operations as loads and conditions change. Facility and IT operations staff are critical to the process and can enhance the efficiency of the data center through operations, and system’s optimizing. The need for long-term optimizing has also brought a renewed focus to the flexibility of facility and systems design.
The concept of close coupled operations between the IT equipment and the building infrastructure equipment promises efficiencies on both sides of the PUE equation. DCIM is a growing discussion in the design and operations of data centers. As a relatively new technology approach, and one that crosses the facility operations and IT operations divide, it has yet to mature across the industry. Once realized, its impact on the data center facility would allow an optimized facility infrastructure capacity.
The green data center is one that has energy savings, waste reduction, and environmentally responsible solutions as top priority goals. The shift across the last decade from almost a pure reliability focus to a balanced focus where IT solutions, infrastructure systems, and the building envelop are evaluated on both efficiency and reliability has brought a green approach to data center solutions.
This green shift has not happened all on its own, the economic downturn and tight monetary policies have created a market where the efficient data center is aligned with economic value. Additionally, data centers are no longer flying under the public or oversight radar. Prominent companies have external pressures to reduce power consumption and lower their carbon foot print. To this end many companies have responded with programs to green their data centers and improve operations, with impressive improvements in efficiency.
These are but a few attributes that make up a green data center and effective implementation of these depends on how they apply within the greater context of a balanced facility solution.
What is a green data center?
- Green is efficiency. There is no doubt that energy efficiency is the primary focus of a green data center.
- Green is integration. The data center of today and the future integrates the IT systems with the building infrastructure systems with the building architecture.
- Green is a commitment. It has been remarkable to see the intensity of effort the data center market has brought to focus on reducing the impact of data center consumption. This is evident in the number of science-based metrics that have been developed and the rapid adoption of these tools which provide knowledge, benchmarking, and opportunities for improvement.
- Green is advancement. The leaders in high performance data center development are still looking for the savings and efficiencies that are yet to be gained.