Immersion cooling is a type of liquid cooling. The server is entirely submerged in a tank with a particular non-conductive solution or oil, based on the cooling type, where heat generated by the immersed server is transferred into the cooling liquid.
There are two types of immersion cooling based on dielectric liquid type – single phase and two-phase. Single-phase immersion cooling method uses hydrocarbon liquids such as mineral, synthetic or bio oils,, and two-phase method uses fluorocarbon liquids, i.e. fully engineered liquids as a cooling solution.
Single-phase liquid does not freeze or boil and does not evaporate, so it requires circulation of liquid using the heat exchanger to facilitate the heat transfer.
In case of two-phase immersion cooling, just like water’s natural circulation, the hot liquid evaporates and re-condenses back into to tank with a non-conductive solution. Circulation happens passively as a natural process of evaporation, so no extra cost is added for this step. This way, no additional cooling systems or components such as fans and heat pipes are required, and server maintenance requirement is also reduced due to removing cooling fans. Due to the passive process of evaporation, the two-phase immersion cooling results in the use of much less energy compared to the traditional air or oil cooling methods.
RSI has partnered with Taisei and Shinohara Electrics to provide a two-phase liquid immersion cooling solution in Japan, enabling customers to significantly reduce data center energy consumption, improve power usage efficiency (PUE) and reduce operating costs and environmental impact.
• Higher Efficiency and Energy Savings. 90% efficiency advantage in the data centers compares to air cooling – including server power consumption and air conditioning costs.
• Improved Reliability. Components are not subject to temperature variations, reducing failure potential & no cooling fans required, eliminating degradation from vibration.
• Higher Computing Density. No need for heat sinks and cooling fans means computing parts can be placed closer, which can increase computing power by 10 times in the same space.
• Lower Maintenance Requirement. Passive cooling system means no unnecessary parts to build or service, useful especially for remote locations such as edge computing stations.
• Deployment Flexibility. No air conditioning and low maintenance requirements, it can be shrunk to expandable modules and deployed in confined spaces and extreme environments.
How does Sola™ two-phase immersion cooling work?
Servers or other IT components are submerged in a thermally conductive dielectric liquid or coolant. Heat is removed from the system by circulating the liquid into direct contact with hot components, whereby the liquid undergoes a low-temperature evaporation process to cool the hot components and transfer the heat out of the liquid. The gas is cooled again by a heat exchanging method such as a condenser coil to allow return flow into the larger liquid volume. Although two-phase immersion cooling has several different variations, Sola™ technology uses an “open bath” system, using a tank which contains a larger body of dielectric liquid where multiple servers are immersed into the bath, sharing the same liquid. The open bath system is fully sealed and can be opened from the top to service IT equipment.