In this module, we’ll explore why cooling is crucial in data centers, the limitations of traditional air-cooling systems, and the increasing shift towards liquid cooling in today’s IT infrastructure. Let’s get started.

Cooling is one of the most important topics in the data center industry, and there’s a good reason why. Data centers sit at the core of the digital economy, supporting everything from telecommunications to cloud services to AI. Their operation consumes vast amounts of energy, and a significant portion of that energy is used for cooling.

Every server converts electrical energy into computational processes, and all that energy becomes heat. For example, 1 kilowatt (kW) of electrical power consumed by a server produces 1 kW of heat that must be removed. Multiply this by thousands of servers, and the result is a huge heat load that must be continuously managed.

Without proper cooling, this heat builds up and can lead to serious consequences, such as:

Overheating - If the heat isn’t controlled, it can cause components to fail, leading to downtime or data loss.

Performance issues - High temperatures cause servers to throttle performance to avoid overheating. This reduces the speed and efficiency of central processing units (CPUs), graphics processing units (GPUs), and storage devices.

Reduced lifespan - Excessive heat accelerates wear and tear, increasing maintenance costs and capital expenditure (CAPEX).

Poorly managed cooling systems can increase energy use and environmental impact, leading to reduced Power Usage Effectiveness (PUE) and Water Usage Effectiveness (WUE), as well as higher operating expenditure (OPEX).

Many modern data centers are shifting away from traditional air-cooling methods because they are no longer sufficient for today’s high-performance computing demands. Let’s look at why.

Power density is rising. To maintain low latency, more computational power is being packed into the same space, causing modern CPUs and GPUs to generate more heat. Traditional air systems simply can’t keep up.

Air is less efficient. Compared to liquids, air has a much lower thermal conductivity. Water, for example, is up to 25 times more effective at transferring heat.

Energy use is high. Air-cooling systems rely on powerful fans to move large volumes of air, which can account for up to 20% of the power used by the servers. Air cooling also requires facility water to be kept at much lower temperatures, increasing both energy and water use. Air cooling is simply reaching its practical and economic limits.

That’s where liquid cooling comes in. Liquid cooling uses either propylene-based fluids, water-based fluids, or dielectric liquids to absorb and transport heat away from components. Because liquids conduct heat far more efficiently than air, they offer significantly better thermal performance. There are two main types of liquid cooling systems:

Direct-to-chip cooling, where fluid passes through cold plates mounted directly onto heat-dense components such as CPUs and GPUs.

Immersion cooling, where servers are fully submerged in a dielectric liquid. In both cases, the result is more efficient cooling, lower energy use, and the ability to handle great power densities—all of which are essential for the next generation of data centers.

In the next module, we’ll explore the most commonly used liquid cooling systems and examine how each one meets different cooling requirements in modern data centers.