DIRECT LIQUID COOLING

Cold isle racks and rear door cooling (RDHX) can help traditional data centres provide 10kW in a 42u rack, but these are inefficient cooling methods and come with some potential risks. Traditional data centres typically achieve mPUE ranging from 1.2 to 1.7 but thanks to the advancements of Immersion cooling from GRC, we are able to reduce this to 1.03 which is a huge improvement and helps drive Carbon Neutrality targets. Data centres have most of the infrastructure already in place such as chilled water loops so it is an easier transition to start building immersion ready data halls.

The principle of the DLC is to establish a cooling loop. Cold liquid is sent to cold plates, mounted directly on the hottest components, this absorbs the heat which is sent to a coolant distribution unit (CDU) to a heat exchanger whose function is to dissipate the heat. They are usually located in the rack or shared by rows. When the liquid has been cooled, it is returned to the cold plates, thus closing the cooling loop.

This method of cooling for servers can deliver circa 100kW per rack and capture 60-70% of the heat, improving the Data Centre efficiency and reducing energy costs. The rest of the heat needs to be dissipated with another method, usually from a fan wall at the rear of the rack. Whilst Immersion cooling can deliver circa 190kW per 42u rack (with a chilled water loop) and capture up to 100% of the heat, some customers may want to look at Direct Liquid Cooling as a middle ground.