数据中心液冷：单相DTC之后是什么？CoolIT的15kW冷板，还需要其他吗？

Liquid Cooling in Data Centers: What comes after single phaseDTC? With CoolIT's 15kW cold plate, does anything even need to? When you hear the term “liquid cooling” today, most people are referring to single phasedirect to chip (DTC). It’s called single phase because the coolant stays in a liquid state (anddoesn’t undergo a phase change to vapor). The broader market seems to believe we arecoming up on a theoretical limit on future generations of GPUs being cooled with singlephase (especially as you start to reach TDPs around Rubin Ultra which are above ~2.5kW).Two technologies are seen as successors to single-phase DTC; (i) two-phase DTC and (ii)direct to die. These have been explained in more detail below. Varun Govindaraj+1 917 344 8543varun.govindaraj@bernsteinsg.com Chad Dillard+1 917 344 8469chad.dillard@bernsteinsg.com Alasdair Leslie+44 20 7762 4952alasdair.leslie@bernsteinsg.com Two-phase DTC:The more likely to see commercial viability in the next ~12- 18 monthsaround the same time as Rubin Ultra. Undergoes a phase change (evaporation) of thecoolant in a cold plate enabling it to capture more heat vs. single phase DTC operating atsimilar conditions. Most major players are likely investing in the space, either directly (e.g.,VRT, CoolIT) or through partnerships (e.g., JCI with Accelsius, Carrier with ZutaCore, etc.).Still has real engineering challenges to solve for (backward flow, refrigerant choice, etc.) soit is by no means a done deal. Miguel Marques, CFA+1 917 344 8432miguel.marques@bernsteinsg.com Om Kela+44 20 7550 2192om.kela@bernsteinsg.com Direct-to-die:Eliminates the need for cold plates entirely by cooling through the silicondie itself. Far more technically complex and R&D is extremely early stage but couldtheorectically offer materially better heat flux vs. DTC. We do not expect to see anythinghappen at scale before 2030. Microsoft and TSMC are both making investments and havesignalled activity (potentially manufacturing in 2026) but we’re yet to hear anything aboutwidespread adoption because of more practical challenges (e.g., deionized water causingcorrosion to silicon). Specialist Sales Steve Song+1 917 344 8401steve.song@bernsteinsg.com The wildcard, CoolIT’s 15kW single phase cold plate:About a month ago, CoolIt alsoannounced that they’re proven single-phase DTC could work with a cold plate rated at15kW under relatively standard operating conditions (1.2 lpm, 450C inlet temperatures,thermal paste, PG25 coolant, etc.). This is counter to the narrative that single phase won’twork at GPU TDPs >2.5kW (CoolIT’s number is 6x that). While the technology was testedin a lab scale setup as per their white paper, we do think this is a credible product. If itcan be commercialized at scale, it essentially pushes out the need for two-phase DTCwell beyond 2030. Most technological evolution on power and cooling in a data center isdriven by necessity, and if we don’t NEED two-phase or direct-to-die anymore, it’s easierfor data center operators to continue using single-phase cooling setups. If the 15kWcold plate can be commercialized, we think it has mixed implications on white spacecooling equipment (CDUs and cold plates). On one side, there’s less of a structural shiftto new technologies that could create pricing pressure on these components (becausethe innovation premium starts to dry up) and commoditization may be accelerated. To beclear, it is unlikely to materially impact revenues or margins in the next couple of yearssince demand far outstrips supply, but it is a risk beyond that. It depends on how quicklycompetitors can replicate CoolIT’s approach (which may not be immediate since theydo have a patent on the underlying technology). On the positive side (for cold plates inparticular), it does eliminate the obsolescense risk (since there’s no real need for direct-to-die) for the forseeable future. BERNSTEIN TICKER TABLE INVESTMENT IMPLICATIONS We rate VRTOutperformwith a TP of$416We rate NVTOutperformwith a TP of$220We rate TTOutperformwith a TP of$555We rate JCIOutperformwith a TP of$173We rate CARRMarket-Performwith a TP of$75We rate ETNOutperformwith a TP of$534 DETAILS RECAP: OVERVIEW OF SINGLE-PHASE DTC COOLING The predominant format of liquid cooling today is single-phase DTC. DTC stands for Direct-To-Chip. It involves cold plates(which are aptly named slabs of metal that have reduced temperature due to refrigerant that circulates inside them) coming intocontact with GPUs to extract heat. Inside the cold plates, liquid flows through arrays and flow loops with the intent of maximizingthe amount of heat they are able to extract from the GPU. Coolant Distribution Units (CDUs) pump low temperature coolant(usually a water - propylene glycol mix in single-phase setups) through the cold plates and recollect the spent liquid once theyhave extracted heat from the server. The heat is then extracted from the coolant (making it cold again) and the process repeats. It is called singl