Server Rack Cooling Solutions

Cooling is a crucial part of data center functioning. No network setup can function without proper ventilation and heat removal. In addition as the size, density, and processing power of data centers increase, the need for well-organized cooling grows.

Proper cooling is essential for system reliability, smooth and durable performance, and hardware long service life. Inadequate cooling will lead to equipment overheating and damage, which will result in the downtime of the entire system and data loss. Thus, in the article, we’re going to discuss this issue and list the most effective data center cooling methods.

Why Do Server Racks Require Cooling?

When in operation, each component of a network system (servers, computers, routers, and other active hardware) emits heat. It’s like a side product of equipment functioning. Accumulated together, this heat can do a lot of harm to the DC setup. Moreover, imagine that most systems are accommodated in solid enclosures, where there is no way out for heat. Although cabinets are equipped with holes and slots for air circulation, it’s not enough. Trapped inside without the opportunity to leave the enclosure, heat can lead to overheating, performance issues, and hardware failure.

Thus, equipping a network system with a proper cooling system is a mandatory step to prolong its lifetime and reduce the risk of hardware failure and malfunction. System administrators should pay attention to this issue at the stage of planning a layout because installed hardware can form airflow aisles or, vice versa, impede air circulation.

Common Cooling Methods for Server Racks

When organizing cooling in a data center, technicians can choose different strategies. Each option has its specifics, both pros and cons.

1. Passive cooling

It is a method of removing excess heat without the use of active mechanical systems, for example, fans or air conditioners. Instead, passive systems rely on natural physical processes such as convection, radiation, and conduction to maintain optimal temperatures inside cabinets.

The main characteristics of passive cooling are:

• natural convection (using airflows created by temperature differences. Hot air rises and cold air sinks, creating a natural flow);
• materials with good thermal conductivity (using materials that can conduct heat efficiently, like aluminum or copper, to improve heat dissipation);
• design and ventilation (optimal installation of equipment in the cabinet and the use of vents and openings to provide positive ventilation);
• minimizing heat sources (designing equipment and using technologies that generate less heat.

Passive cooling can be an effective solution for small server rooms or cabinets, but larger or denser infrastructures may require active cooling to maintain reliable temperatures.

2. Built-in fans or air conditioning units.

Specialized equipment, such as air conditioners or fans, is attached to ensure sufficient airflow and direct the air. Holes in cabinet enclosures are provided for fans by most data center cooling manufacturers. They are fastened to enclosures to guarantee stability.

Such solutions guarantee smooth and durable functioning. But, note that fans may work loudly (if outdated or their physical capacity is exceeded) and consume extra energy. 

3. In-row cooling systems.

These are systems that use dedicated channels or pipes located within rows (for instance, rows of racks or cabinets) to transfer coolant or air to lower the temperature of equipment or the room. These systems are widely used in industrial and commercial cooling installations. Their pros include:

• cooling efficiency;
• space savings;
• installation flexibility;
• noise reduction.

However, such systems require careful planning and design; installation can be more complex than traditional systems. Difficulty with accessing piping and ducts for maintenance can complicate the process. Furthermore, such systems are rather expensive; initial installation and equipment costs can be significant.

4. Liquid cooling (cold plates, rear-door heat exchangers).

It’s a cooling system that uses a liquid (usually water or specialized coolants) to transfer heat away from components that generate a lot of heat, including processors, graphics cards, and other computer components. Cold plates and heat exchangers are commonly used. The main pros of such systems include:

• efficiency (liquid cooling is often more efficient than air cooling due to the high heat capacity of the liquid);
• noise (liquid cooling systems tend to be quieter because they can use slower fans);
• improved thermal performance (they maintain low temperatures even under heavy loads, which can improve performance and extend the life of components);
• compactness (they take up less space than bulky air coolers).

However, there is a risk of leaks, which can damage system components. Furthermore, installing a liquid system can be more difficult and requires specialized knowledge. Typically, such systems are more expensive than traditional cooling systems.

5. Immersion cooling.

It is a method of cooling electronic components by placing hardware in a special liquid that is characterized by good heat transfer properties. This technology is widely used in big data centers and high-performance computing, where efficient heat removal is required. Immersion cooling benefits include:

• high efficiency (the liquid is able to absorb heat quickly and efficiently, reducing the risk of equipment overheating);
• compactness (the ability to place denser servers and equipment due to better heat dissipation);
• resistance to dust and contamination (the equipment is protected from external contaminants, as it is completely immersed in the liquid);
• environmental friendliness (the liquids used can sometimes be more environmentally friendly compared to traditional cooling methods.

As for drawbacks, such systems cost more. Additionally, special equipment, hardware, and setup knowledge are required.

6. Rear-door heat exchangers.

These are systems used to improve thermal insulation and a comfortable climate in enclosures. They are attached to the rear side of server cabinets. They absorb extra heat, cooling down the indoor environment.

How to Choose the Right Cooling Solution?

Above, we listed the most effective data center cooling solutions. But how do you decide what technology is the best for your very case? What are the criteria for choosing suitable and unsuitable methods? Make sure to follow this guide and assess the listed points when picking a suitable option:

1. Rack density and heat output. Evaluate your server furniture to find how dense the equipment is placed and what channels are available for heat output.
2. Available space. Assess the space in and around enclosures to think about what solutions a room can accommodate.
3. Noise levels. Evaluate the neighborhood of a server room and the level of existing noise. Think about how critical the noise level is for your case.
4. Upfront cost VS energy efficiency. Evaluate how much money you need to invest to integrate the system into your DC infrastructure. Compare it with expected energy savings.
5. Scalability. Finally, think about the future prospects of your network system. How will you be able to scale a cooling system if your DC setup grows, and new components are added, which will require more cooling capacity?
6. Ease of maintenance. Study what maintenance effort each type of data center cooling technologies requires. Assess them. Calculate your expenses if you need to hire staff. 

If you go through all these steps, you’re guaranteed to find the best solution for your data center facility and ensure its effective cooling.

Best Practices for Efficient Rack Cooling

When arranging a data center and planning its ventilation system, keep in mind these practices to ensure high effectiveness of hardware cooling:

1. Maintain front-to-back airflow. Make sure that the air passes from the front side to the back side, which will contribute to quick and effective heat removal without mixing cold and hot airflows.
2. Use blanking panels for empty slots. Server enclosures are designed with extra holes for cable routing or fan installation. But they are not always used. Outside air can penetrate the enclosure, disturbing the indoor climate, which is vital for the smooth operation of system components.
3. Monitor temperatures with sensors. Install sensors and innovative control equipment to monitor the climate and react promptly if some indicators go beyond the norm.
4. Clean filters and fans regularly. Make sure to maintain devices and keep them clean to ensure their proper functioning and prevent pollution.
5. Implement hot aisle/cold aisle layouts. Hot and cold aisle maps are created to ensure the correct direction of air circulation, which contributes to effective heat removal.

To draw the line, note that the arrangement of a proper, well-functioning cooling system is vital for any data center infrastructure. Thus, specialists should approach the issue of choosing a suitable technology seriously. Nowadays, diverse data center cooling systems are offered on the market. Make sure to use the provided guide to make the right choice and organize an effective cooling system at your facility.