As the world trends toward a more sustainable future, data center operators need to find ways to make their facilities more environmentally friendly while still meeting the growing demand for data. This is no easy task — data demands require new IT equipment, which runs hotter than legacy technology, leading to increased cooling demands.  

Research estimates that today’s data centers account for approximately 1% of electricity use worldwide. With the demand for new data centers only rising, many data center managers are looking for ways to implement sustainability initiatives into their growth strategies. 

As the data center industry develops and managers implement innovative new approaches that drive energy efficiency, taking action to reduce environmental impact often also leads to cost savings. Regulatory and customer pressures also make it imperative for data center managers to consider overall environmental impact. Here are several areas where data center managers can focus on operating in a more environmentally sustainable way.   

1. Power usage effectiveness (PUE) — It’s not news to anyone in the industry that better PUE leads to more cost-efficient operations. To put as much energy as possible toward powering next-generation IT equipment, data center managers need to minimize energy spent on facility operations and, most importantly, cooling. With the heat loads generated by next-gen IT equipment, traditional air-cooling methods often cannot get the job done, let alone get it done efficiently. We’ve crossed a line for applications where cooling the room with air is simply not feasible anymore — it takes too much energy and may no longer be the most efficient cooling methodology.
So, what is the answer to driving an ideal PUE while running advanced IT equipment? Many facilities are turning to liquid cooling. Liquid is better at capturing heat than air and can get closer to chips where heat is generated to efficiently cool equipment. Even facilities that are not ready to take on the project of running liquid lines to racks can benefit from liquid cooling technologies. Solutions like in-row coolers, rear door coolers, and aisle containment systems can help manage rising heat constraints in a more environmentally conscious way.

2. Water usage effectiveness (WUE) — Liquid cooling systems might be great for PUE, but water use is also an important environmental consideration. Data center managers need to maintain a steady supply of clean, treated water for water-cooled liquid lines. Alternatively, closed loop water cooling systems are configured to cool the same treated water through a chiller or heat exchanger before recirculating back to the liquid cooling loop.
Surprisingly, some air-cooled data centers can consume more water than liquid-cooled facilities. In some cases, evaporative cooling may be a potential water waster in data center operations. Evaporative cooling systems require cold water running into facility air conditioners and warm water carrying heat running out to exterior evaporative coolers. When facilities rely on air-cooling operations, this cold water running to air conditioning needs to be extremely cold. The evaporation that results from warm water hitting freezing cold chilling coils results in a large amount of water loss. This methodology may be expensive for data center operators and potentially problematic for municipalities because of the added water usage from public water systems. Therefore, warm water cooling or immersion cooling can help limit water loss in water-stressed areas or where regulations limit water use. Minimizing the fluid used on immersion and direct-to-chip cooling is also important to prevent unnecessarily heavy cabinets and racks.

3. Coolant fluid considerations — Immersion cooling may be one of the most effective methods of cooling IT equipment. However, when data center managers decide to implement immersion cooling, they need to be conscious of which fluids they choose to use. There are two primary types of immersion cooling fluids: hydrocarbon base fluids and fluorocarbon base fluids.
Hydrocarbon base fluids evaporate very slowly, which means they hardly ever need to be replaced or refilled. They also have a relatively low-global warming potential (GWP). This means that hydrocarbons that do evaporate into gaseous states do not remain in the atmosphere for very long. These coolants can also be fully recycled when they are used in a sealed chassis that prevents them from being contaminated. However, hydrocarbon base fluids are oily, making them more difficult for data center managers to work with, and their refinement process is not the most environmentally friendly.
 Conversely, fluorocarbon liquids are more similar to alcohol than oil. They are quicker to evaporate and need to be refilled more frequently. However, they are easier to work with and less messy. Both fluid types have benefits and drawbacks, and when considering total environmental impact, data center managers need to look at immersion coolant choices within the context of their operations to determine the most appropriate path forward.  

4. Physical space — The day-to-day operations of data centers can be managed in an environmentally friendly way, but data center managers can think beyond their own walls when driving sustainable operations in the industry. Rising demand for data, cloud storage, and streaming applications requires an increased volume of IT equipment, but data centers need to be conscious about expanding physical footprint due to both cost and environmental considerations. Cooling demands often prevent data centers from getting the most out of their existing physical footprints.  Upgrading to more efficient cooling systems can contribute to improving PUE while providing an option for data center operators to increase density of equipment mounted in server racks. This limits the need to develop more land to build new data centers. Avoiding new construction also saves time and reduces environmental impact from pouring concrete and running large machinery in the construction process. 

5. Alternative energy sources — Driving efficiencies within data centers is critically important, but even the most efficient data centers require a lot of energy to operate. Large data centers can offset their carbon footprints by installing on-site renewable energy, such as rooftop or vertical solar arrays. These investments can also contribute to lower energy costs and total cost savings over the life of operations. Sustainable choices in data center facility management can often compound one another — for instance, the removal of large evaporative coolers as centers switch to liquid cooling could free up space for solar array installations. If on-site renewable energy is not feasible due to space or facility considerations, data centers can also invest in off-site renewables to produce energy or work with local utilities to execute green energy contracts. In some cases, data centers can also use the heat generated from their operations to contribute to municipal energy systems by using heat pumps in combination with liquid cooling to transfer heat from data centers to hospitals, district heating, and even under-road heating in colder environments.