Introduction to Fluid Submersion

Fluid submersion cooling is made possible by GreenDEF™ coolant, a specific but not proprietary formulation of dielectric (nonconductive) white mineral oil that has 1,200x more heat capacity by volume than air. OEM servers are placed vertically in coolant-filled tanks and the coolant dissipates server heat as it circulates through the system.

This is what Green Revolution Cooling’s CarnotJet™ system looks like:

Multiple-rack installation, featuring six 42U server racks and two pump modules. In this case, each pump module is responsible for circulating coolant through three racks.

Although fluid submersion for electronics seems counterintuitive, it has been the standard for many high-density industrial cooling needs since the 1920s. Many high-voltage electrical transformers, circuit breakers, capacitors, and power substations depend on liquid cooling for electrical insulation and heat dissipation. So while GRC did not invent fluid submersion cooling, we did find a way to bring it to the data center to offer tremendous performance gains and energy savings at the lowest possible cost.

This is what servers look like when immersed in our dielectric coolant. Aside from being clear, the coolant also has a light viscosity and a high heat-retention ability. And it’s safe; the coolant is essentially baby oil without the fragrance.

OEM servers installed in a 42U rack.

The key advantages of GRC’s fluid submersion cooling are as follows:

Energy Savings: One reason fluid submersion cooling costs much less than air cooling is the lower differential temperature required of the coolant relative to the servers. In other words, GreenDEF™ coolant can cool servers very efficiently at 40°C (104°F) while air generally needs to be around 24°C (75°F). It requires significantly less energy to maintain a coolant temperature of 40°C than it does to cool air to ~24°C (75°F), which typically requires cooling water to 7°C as the first link in the cooling chain.

We also save energy by removing server and power supply fans from servers, as they become unnecessary when servers are submerged. Fan removal results in additional power savings of 10-25%, depending on the server.

 

Perfomance:

While energy savings are a direct result of 1) Lower required temperature differential of GreenDEF™ coolant and 2) Removal of server fans, the system’s superior cooling efficiency means that more compute can be cooled using less energy. In fact, our system is so powerful that we can install 100kW or more of compute in each 42U rack.

Here is an example of a 42U server fully-loaded with servers:

42U rack, filled with clear GreenDEF™ coolant and OEM servers. The lid is raised allowing for quick access to servers. Coolant will not evaporate.

 

Because our system can dissipate more heat than air cooling, more compute may be installed in a smaller space. Many of our early adopters have had interest in high density applications, including overclocking CPUs, GPU-accelerated computing, and blade computing.

 

Cost Savings:

There are many types of liquid cooling and most of them require large capital expenditures, complex maintenance, and proprietary servers. GRC was founded on the premise that total cost of ownership, ease of use, and compatibility are the most important components of a server cooling solution.

Our system offers top efficiency at the lowest cost per Watt, is simple to maintain and to operate, and supports any OEM server on the market.

Please explore the rest of our site, including the Product section, the Installation guide, and the Gallery. We also have Case Studies and other Downloads available.

If you have any questions or comments, please email us at info[at]grcooling[dot]com.