美国多行业与电气设备：数据中心冷水机组（1/3）：入门及自然冷却经济性

Data Center Chillers (1/3): Primer and free cooling economics Chillers are a critical part of data center cooling infrastructure both in liquid-cooled andair-cooled environments. They are responsible for creating chilled facility water that thenpumps to CDUs to extract heat from the coolant or to CRAHs to reduce the temperature ofair blowing through the data center.We size this as a ~$8B market in 2026 (fully loadedcost including installation and ancillaries), but the growth outlook can vary significantlybased on how you think chiller penetration changes. Assuming no such changes (our base Varun Govindaraj+1 917 344 8543varun.govindaraj@bernsteinsg.com Steve Song+1 917 344 8401steve.song@bernsteinsg.com We often hear debates of when it makes sense to use air-cooled vs. water cooled units. Asa quick primer, both types of chillers operate using a refrigerant cycle, but air-cooled unitsreject heat from the refrigerant into ambient air, while water-cooled units reject to anotherwater loop (either a cooling tower or a dry cooler). Air-cooled units are lower capex, butmuch less energy efficient. Water-cooled units need more upfront investment and consumelarge quantities of water (if a cooling tower is used), but tend to consume less power for the To illustrate this, we looked at how much it would cost to run an 800 ton chiller (roughly 2.5MW) - assuming it was air-cooled or water-cooled. When the compressor of the chiller ran24X7,annual operating costs were roughly 25% higher for an air-cooled chiller vs.a water-cooled unit, implying a ~3 year payback on the cost differential. So water- It is not that simple.This dynamic can change quite drastically when you take free-cooling into account.Free-cooling is a when the ambient temperature drops enough forthe data center operator to tone down (and in some cases switch off) the compressor in thechiller. It’s a bit of a misnomer, the cooling isn’t entirely free (you still need some power) but Energy consumption drops significantly for both air-cooled and water-cooled units.However, water costs stay relatively constant for water-cooled chillers (assuming a coolingtower is used).So as you spend more time in a free cooling environment, you mayrun into a situation where it is actually cheaper to operate an air-cooled chiller vs. We also spent some time benchmarking chiller offerings by key players available orannounced in the market (like we did with our earlier primer on CDUs).We do not findthe differences to be as stark; while there are some variations between companies, andthey all have their own edge, we think these variations in specs are far outweighed by the This is the first of our three part series on chillers.In part two, we will discuss “chillergate” in more depth and in part three dive into the economics of servicing a chiller unit. BERNSTEIN TICKER TABLE INVESTMENT IMPLICATIONS We rate TTOutperformwith a target price of$550. We rate CARRMarket-performwith a target price of$75. We rate VRTOutperformwith a target price of$416. DETAILS What is a chiller? A chiller is a piece of equipment, which, as the name suggests, reduces the temperature of a stream of matter (usually a liquid).In the context of a data center, chillers are useful not only for liquid cooling (to cool the FWS) but also in air cooled environmentswhere cold water flows to a CRAH to reduce the temperature of air that flows through it. Any chiller runs through a refrigerant Evaporator:The warm liquid that needs to be chilled exchanges heat with cold liquid refrigerant in the chiller. This refrigerantpicks up heat from the warm water and cools it, evaporating in the process. Compressor:The most energy intensive part of a chiller. A compressor (scroll, screw, centrifugal) compresses the gaseousrefrigerant, increasing its temperature. This is done to create a higher temperature gradient which makes heat transfer easier at Condenser:The hot, high-pressure, gaseous refrigerant comes into thermal contact with another stream of heat rejection(usually cool water in the case of a water-cooled chiller or ambient air in the case of an air-cooled chiller). The difference intemperature between the hot refrigerant and the cool heat sink facilitates heat rejection from the former to the latter. The Expansion valve:High pressure, liquid refrigerant passes through an expansion valve. This rapidly reduces pressure, which inturn reduces the temperature of the refrigerant (but keeps it in a liquid state). From here, the liquid refrigerant flows back to the Types of chillers In general, comparisons are made between two types of chillers - air-cooled and water-cooled. The differences due to howthe condenser rejects heat to the environment; if air is used it is air-cooled, if water is used (either through a dry cooler, or morecommonly a cooling tower) it is water-cooled. There are some performance trade-offs from choosing one type of chiller vs.another. Air-cooled units are much less energy efficient