Compiled by Eamonn Ryan based on the SAIRAC Johannesburg Centre Tech Talk on September 19 by Michael Young, mechanical engineer
As the demand for computing power surges, so too does the need for efficient cooling solutions in data centres. This is Part 4 of a ten-part series.
Michael Young, mechanical engineer. © RACA Journal
Let’s delve into two prominent technologies designed to manage heat in high-density environments: rear door heat exchangers (RDHX) and direct-to-chip liquid cooling.
Rear door heat exchangers (RDHX)
At the core of the RDHX system is a heat exchanger coil mounted on the rear of a server rack. This setup is designed to handle the hot air expelled by IT servers. Here’s how it works:
- Hot air exhaust: Servers draw in cold air from the front, process it, and expel hot air out the back. This hot air then flows over the heat exchanger coil.
- Heat exchange process: Cold water, supplied from a chiller, circulates through the coil. As the hot air passes over it, heat is transferred from the air to the water, cooling the air before it recirculates back to the server intake.
- Active module integration: Since introducing the coil adds resistance to airflow, which can limit performance, an active module is often added. This includes fans that assist in pushing air through the coil, ensuring optimal airflow and effective cooling.
This system is a straightforward and effective solution for managing heat in environments where computing demands are high.
Direct-to-chip liquid cooling
Direct-to-chip liquid cooling represents the cutting-edge of thermal management technology. It involves cooling solutions that directly interface with the chips themselves, specifically designed for high-performance applications like artificial intelligence. Here’s a breakdown of how it operates:
- Chip placement: In a typical server, chips such as GPUs, which are responsible for heavy computational tasks, are installed on a plate within the server
- Direct contact cooling: This plate is designed to be in direct contact with the chip. When cold fluid is pumped through pipes attached to the plate, it absorbs heat generated by the chip almost immediately
- Heat transfer efficiency: The efficiency of heat transfer in this setup is significantly higher than traditional cooling methods, as the cooling fluid is applied directly to the source of heat generation. This reduces thermal resistance and ensures that the chips operate within optimal temperature ranges
- Scalability: Direct-to-chip systems can be scaled to accommodate various server configurations, enabling data centres to handle increasing workloads without compromising performance
As we transition into an era characterised by AI and high-density computing, understanding and implementing these advanced cooling technologies is essential. Rear door heat exchangers provide a robust solution for managing heat in traditional rack setups, while direct-to-chip liquid cooling offers unparalleled efficiency for next-gen applications.
Both technologies not only address the immediate need for effective thermal management but also position data centres to meet future demands sustainably and efficiently. Adopting these solutions will be critical for optimising performance and ensuring the reliability of data centres in an increasingly digital world.
