Data centers are the backbone of our digitized world. They process and archive a vast amount of data, and with the rapid growth of AI, the volume of information continues to increase at an unprecedented rate.

This surge puts a spotlight on the environmental impact of data centers. A critical aspect here is high water consumption used for cooling. Given this context, is it possible to operate data centers efficiently and sustainably?

When processors and hard drives run at full capacity, data centers generate a considerable amount of heat, which must be dissipated to ensure reliable operation, and reduce the risk of overheating and failures. Traditionally, this has been managed using water-intensive cooling methods. To improve sustainability, operators must explore water-saving alternatives.

Principle and challenges of evaporative cooling

Data centers typically use two main cooling approaches: sensitive heat dissipation, which reduces temperature without altering the humidity, and latent heat dissipation, which leverages water evaporation to remove heat.

The latter, also known as evaporative (or adiabatic) cooling, is widely used in the industry. Warm water is circulated through cooling towers where it is sprayed and evaporates, lowering the temperature of the remaining water, which is then recirculated to cool the systems. 

While this method consumes relatively little energy, it comes at a significant cost – continuous water loss. Depending on the data center’s size and climate zone, water consumption can reach millions of liters per year. 

In water-scarce areas, this high demand creates competition with other water users and strains the local water supply. Climate change further exacerbates this issue, leading to prolonged droughts and declining groundwater levels worldwide. These developments raise an important question: is such a water-intensive approach still viable, and what are the alternatives? 

Alternative cooling methods and strategic location planning

There are several solutions for saving water in the operation of data centers. One approach is the use of air-cooling systems, where waste heat is released directly into the ambient air. This method requires no water, but its efficiency decreases with high outdoor temperatures.

Another alternative is direct water cooling, such as ‘water-to-chip’, or immersion cooling, where individual IT components are in direct contact with water or a coolant. This enables efficient heat dissipation, often eliminating the need for evaporative cooling altogether. Hybrid cooling systems also represent a sustainable compromise, combining multiple methods and using evaporative cooling only when absolutely necessary.  

Regional differences also play a crucial role in water-saving data center operations. When selecting a location, operators should consider regional water availability. In water-scarce areas like southern Europe, for example, evaporative cooling should be avoided, while in colder climates like Scandinavia, it may be a viable option.

Additionally, the proximity to renewable energy sources is key. Because alternative cooling methods are often more energy-intensive, it is essential to source this additional energy in a CO2-neutral manner, whenever possible.

Beyond environmental concerns, the choice of cooling method and location also impacts operational reliability. In water-scarce regions, over-reliance on water-intensive cooling methods can create vulnerabilities.

It is therefore vital to develop cooling concepts that ensure reliable data center operations, even during crises. This could be achieved through redundant cooling systems or the ability to temporarily switch to less water-intensive methods. 

Future prospects for sustainable data centers

The need to operate data centers more sustainably and water-efficiently will only grow in importance in the coming years. As the digital sector expands and data-intensive technologies, such as AI, increase computing demands, the need for computing power rises, all while climate change worsens water scarcity in many regions.

Developing water-saving and sustainable data centers is no longer a choice but a necessity. It represents a critical step in addressing climate change and ensuring a sustainable digital future. The knowledge and technologies to develop innovative data centers are available now, and it is up to the IT industry policymakers and city planners to set the right course. 

A promising approach is the intelligent use of waste heat, by incorporating it into local energy cycles. Solutions such as this must be integrated into data center planning at an early stage. The future lies in a holistic approach that equally prioritizes water efficiency, energy efficiency, and waste heat recovery. This is the only way data centers can effectively support the digital world without placing undue strain on natural resources.