A Hot-Button Issue: Keeping Data Center Operations Cool And Sustainable

Businesses increasingly rely on data centers to store and process reams of complex information. A typical organization has more than a dozen data centers, which can range from a server room in the office to large, remote sites.

Keeping all that processing power at the optimal temperature — below 80 degrees Fahrenheit — requires a lot of resources. Data centers account for more than 1% of world energy usage, which is more than the energy needs of some nations. These facilities can also consume a considerable amount of water, with about 1.8 liters used for every 1 kilowatt-hour the center uses. 

Bisnow spoke with Eric Jensen, vice president and general manager of cooling solutions company Data Aire, about how data center operators can reduce both their operating costs and environmental footprints. A solution for many facilities is a hybrid approach to cooling that combines refrigerant-based direct expansion air cooling with water-based cooling.

Bisnow: What is precision cooling and why is it important in data centers?

Jensen: Precision cooling is air conditioning that is designed specifically for a process environment such as IT equipment in data centers and computer rooms. With precision cooling, you're using only the energy that you need.

In the case of colocation providers, which are increasingly prevalent, precision cooling is even more critical because they're very much trying to manage their allocation of power, especially in a multitenant type of operation.

Bisnow: Server rack density continues to grow to keep up with demand. What impact does that have?

Jensen: As the densities grow, you end up with higher airflow requirements per kilowatt of cooling. Those higher airflows require more control of various fans, which are typically configured in an array.  

Now, you've got airflow requirements across an array of fans as opposed to one or two fans. Efficient control of that equipment becomes a critical piece of designing and operating your data center.

Bisnow: What should be a data center’s priorities in selecting an environmental control system? 

Jensen: Capacity and reliability are givens, but beyond that, it's efficient power utilization and scalability. 

Scalability refers to a couple of different things. One aspect of scalability is very tactical, and it is the ability to ramp up and down as the load demand changes, either daily or seasonally, or potentially even from one point in a data center to another.

A bit more of a strategic consideration is scalability over time. Depending on the type of data center that's being built or operated, the time horizon might range from as low as five years and up to 20 or 30 years. Scalability over a long period of time requires the ability to add additional equipment to keep pace with growth.

Bisnow: What impact does all of this have on a data center’s carbon footprint and water usage?

Jensen: A higher-efficiency cooling process naturally means less power consumption. Depending on the kinds of technologies that are employed, an efficient process could also lead to reduced refrigerant management, which is highly important for the planet. 

The industry is migrating to lower global warming-potential types of refrigerants, but that comes with a tradeoff in the form of high operating pressures and potentially higher flammability. Like with everything, it's always a balancing act, but refrigerant management is key.

Whether you're talking about an air-cooled chiller or a DX CRAC [direct expansion computer room air conditioning] unit-cooled facility, refrigerant management becomes important because the more total refrigerant that you have on-site, the higher your carbon footprint is going to be. 

Reducing your total refrigerant usage on-site is one piece of operating more sustainably. The other piece of it is to reduce some of your risk associated with any leakage of refrigerant through pipes. Leakage is always a risk just through routine maintenance.

Data center environmental management also concerns water consumption. The strategies you choose for your cooling infrastructure come into play quite a bit in how you will achieve that because energy economization is a way to reduce your carbon footprint or your water utilization.

There are lots of different economization technologies out there, but essentially there's air-side and water-side technologies. On the air side, you can introduce outside air on a cold, dry day, mix it with your recirculated indoor air and reduce your carbon footprint through reduced energy consumption. 

Another method is water-side economization. This introduces more infrastructure but water-side economization can end up being highly efficient.

Bisnow: Why do you think a hybrid solution that combines air and water cooling is the best solution?

Jensen: It can provide the best of both worlds in terms of reliability, scalability and efficiency. Air-side economization is not necessarily easy to achieve because it's hard to predict the outside environment and how many hours of the year you might be able to have suitable air quality. However, water-side economization is more predictable and easier to achieve.

Bisnow: Can you give an example of a successful application of hybrid cooling?

Jensen: A good example is One Wilshire, a 50-year-old office building in Los Angeles that was converted for use as a data center. The client did the research to understand its water and energy consumption needs.

A hybrid solution such as the one at One Wilshire strikes the balance between the efficiency of evaporative water-cooled and water consumption of an open-loop system. When combined with variable speed DX technology in the CRAC units, the efficiency benefits outweigh the scarce water consumed in the generation of power serving the site. 

One Wilshire also is a prime example of adaptive reuse of commercial real estate, and it was made possible in part by the use of a hybrid cooling system.

This article was produced in collaboration between Studio B and Data Aire. Bisnow news staff was not involved in the production of this content.

Studio B is Bisnow’s in-house content and design studio. To learn more about how Studio B can help your team, reach out to studio@bisnow.com.