Considerations before you order 2.9 Summary The water-cooling option is preferable because it can substantially lower the total power  consumption of z14 servers and the total cost of ownership for the CPC. This savings is  greater for the larger models of z14 servers, as listed in Table 2-17. The water-cooling option cannot be installed in the field. Therefore, you must carefully  consider the present and future computer room and CPC configuration options before you  decide which cooling option to order. For more information, see 10.1.3, “Cooling  requirements” on page 393. Table 2-18 System structure summary All aspects of the z14 structure are listed in Table 2-18. Chapter 2. Central processor complex hardware components  85 Table 2-17 Heat to water based on temperature  Temperature Three CPC drawer  typical configuration Four CPC drawer  typical configuration Four CPC drawer  maximum power  configuration Water-cooled system power in normal room/hot room 12.9 kW/14.1 kW 17.4 kW/19.0 kW 24.7 kW/26.3 kW Inlet air temperature Heat to water and as % of total system heat load 18°C (64°F) 7.3 kW (57%) 9.8 kW (56%) 12.6 kW (51%) 23°C (73°F) 9.5 kW (74%) 12.6 kW (72%) 15.6 kW (63%) 27°C (80.6°F) 11.5 kW (89%) 14.8 kW (85%) 18.0 kW (73%) 32°C (89.6°F)  (hot room) 14.8 kW (105%) 18.2 kW (96%) 21.6 kW (82%) Description Model M01  Model M02 Model M03 Model M04 Model M05 Number of CPC drawers 1 2 3 4 4 Number of SCMs 6 12 18 24 28 Total number of PUs 41 82 123 164 196 Maximum number of  characterized PUs 33 69 105 141 170 Number of CPs 0 - 33 0 - 69 0 - 105 0 - 141 0 - 170 Number of IFLs 0 - 33 0 - 69 0 - 105 0 - 141 0 - 170 Number of ICFs 0 - 33 0 - 69 0 - 105 0 - 141 0 - 170 Number of zIIPs 0 - 22 0 - 46 0 - 70 0 - 94 0 - 112 Standard SAPs 5 10 15 20 23 Additional SAPs 0 - 4 0 - 8 0 - 12 0 - 16 0 - 16 Number of IFP 1 1 1 1 1 Standard spare PUs 2 2 2 2 2