COLUMN DATA CENTERS FIGURE 2 Typical liquid cooling infrastructure schematic diagram for liquid cooling Classes W1, W2 and W3. Cooling Tower or Drycooler IT Equipment Heat Exchanger Condenser Water Loop Chiller Water Loop Water Chiller Supply Temperature To IT Equipment 36°F to 63°F W1 36°F to 81°F W2 36°F to 90°F W3 FIGURE 3 Typical liquid cooling infrastructure schematic diagram for liquid cooling Class W4. Cooling Tower or Drycooler Heat Exchanger IT Equipment Supply Temperature To IT Equipment 36°F to113°F W4 FIGURE 4 Typical liquid cooling infrastructure schematic diagram for liquid cooling would often be referred to as the chilled water cooling system in non-data center applications. It is the loop between the chiller(s) and the cooling equipment that contains the liquid-to-air (e.g., chilled water cooling coils) or liquid-to-liquid heat exchangers. * The technology cooling systems (TCS) in Figure 1 assumes that the cooling distribution unit (CDU) is effectively a liquid-to-liquid heat exchanger that uses the chilled water provided by the FWS. The TCS loop then runs between the CDU and the actual IT equipment racks. * There are some IT equipment racks that contain a fan and coil arrangement within its enclosure and then circu- www.info.hotims.com/49809-46 84 ASHRAE JOURNAL ashrae.org O CT O B E R 2 0 1 4 Class W5. Cooling Tower Heat Exchanger IT Equipment Supply Temperature To IT Equipment >113°F W5 Building Heating System late air within the confines of its own volume in a closed circuit. In Figure 1, however, we are showing the potential for another liquid-to-liquid heat exchanger in the rack with the final liquid loop from the rack heat exchanger to the actual load source (IT equipment) being defined as the datacom equipment cooling system (DECS). www.info.hotims.com/49809-41