1. CMS TK II cooling Brainstorming P. Tropea (update after meeting on June 13 th with Duccio, Antti, Hans, Jerome, Paolo, Bart) 20 June 2016

2. Outline Summary of known requirements General concept for CO2 redundancy during operation The “keep it cold” function One possible scenario & its implications The testing needs 13/06/16P. Tropea

3. TK II layout The TB2S is made of three layers, with 2 ladders along z, each housing 12 modules. It is envisaged to put 2 adjacent ladders in series in a single cooling loop. Forward section There is a different number of rings in each layer. The multiplicity in phi is the same as for the panels in the central section. One cooling loop per ring is assumed. The power is slightly different in the different loops, but differences are very small (<1%). Average values are given. The TBPS is made of three layers, each with a central section made of panels and a forward section made of rings Central section The panels have an odd number of modules along z, different in the three layers. Note that there is only one panel along z. TB2S TBPS TEDD 13/06/16P. Tropea

4. Summary of requirements TEMPERATURES Evaporating T @ detector outlet = -30 0 C T @ detector inlet? = from simulations, design to have 2 0 C DT at the inlet (i.e. 28 0 C). Acceptable if margin is guaranteed at the cooling level: Evaporating T @ detector outlet (with margin) = -35 0 C T @ Accumulator? = to be calculated with respect to transfer line sizing (*1 – next slides) POWER Power @ 15 C = FE + cables= 84 kW Power @ -35 C = FE + Si chip + cables = 88 kW Missing power to be added: environmental contribution for thermal screen functions (if no independent TS): = about 3 kW OPERATION 1.Minimize the time between failure & system restart: if possible design for “no stop” in case of CO2 component failure 2.Need to maintain all TK volume cold (<0 0 C) for most of the time – warm time allowed is few weeks/year (total detector budget), but only few hours/year shall be due to cooling issues 3.T ramp down XX C/min (Check Pix operation as for inlet heaters) 4.During ramp up in T of Tk volume the CO2 system shall not continue cooling (no active heating is possible) The TB2S Total n of cooling loops124 Loop max power [W]195.5 Loop min power [W]190.9 Loop avg power [W]192.9 Total max power [kW]23.9 Total min power [kW]22.6 The TBPS Total n of cooling loops112 Loop max power [W]286.9 Loop min power [W]126.0 Loop avg power [W]201.4 Total power [kW]23.9 Total min power [kW]22.8 The TEDD (both ends) Total n of cooling loops280 Loop max power [W]178.8 Loop min power [W]110.2 Loop avg power [W]145.1 Total power [kW]40.6 Total min power [kW]38.2 Summary Total n of cooling loops516 Loop max power [W]286.9 Loop min power [W]110.2 Loop avg power [W]171.3 Total power [kW]88.4 Total power @ 15 C (min power) [kW]83.7 13/06/16P. Tropea

5. Transfer lines - data Transfer lines TB2S Number of transfer lines12 Max power/transfer line [kW]2.48 Min power/transfer line [kW]1.56 TBPS Number of transfer lines12 Max power/transfer line [kW]2.31 Min power/transfer line [kW]1.86 TEDD Number of transfer lines20 Max power/transfer line [kW] 2.131 9153 36 Min power/transfer line [kW] 1.948 9578 73 Summary Number of transfer lines44 Max power/transfer line [kW]2.48 Min power/transfer line [kW]1.56 Typical lengths PP1/manifold = 30-40 m (40 m = sector -15 Pix Phase I) Manifold/plants? Consider plants in underground control room & manifolds on both sides… ***(integration office) 13/06/16P. Tropea

6. The redundancy during operation FUNCTION Ensure data taking is not interrupted for more than XX hours because of CO2 failure The system shall be operational in these scenarios Failure of one CO2 plant Failure of the primary systems (one pump/compressor out) POSSIBLE APPROACH N+1 redundancy on: CO2 plants: one plant = to the others stays on at the T set point, functioning in by-pass, thus allowing quick swap in case of one plant failure Primary system main components: compressor + 1 or brine pumps + 1… 13/06/16P. Tropea

7. The needs to stay cold & how to achieve it FUNCTION Maintain operation T (WHICH ONE?) when TK off (no load but environment) to guarantee a total “warm” time < XX days/year The system shall be operational in these scenarios Power cuts water tower maintenance (3w/year) main chiller(s) maintenance (2w/year) Primary chiller major failure Open points - How quick shall the system react to any of these events? POSSIBLE APPROACHES 1)A dedicated CO2 plant serves a Thermal Screen and all “backup + redundancy” systems apply to that one - One additional object to design + only this CO2 plant need full redundancy/backup (see next slide) 2)One plant of the operation chain serves a partition of the TK that is enough to keep the full volume cold -The partition shall be accurately chosen in order to guarantee a uniform T (detector level) -The plant redundancy can be complex: 1.the plant is one of the many: all plants need a backup chiller and need to be operated on Diesel 2. the plant is a dedicated one: can be the only one with backup chiller, but in this case if the plant itself fails or the backup fails during non-availability of primary (3-4 weeks/year) than the TK goes warm Layout on next page for these two options 13/06/16P. Tropea

8. Controls CO2 plant 1 CO2 plant 2 Pneumatics GN DieselUPS Primary chiller Backup chiller CO2 plant 3 H2O Dry airN2 AIR AC C TS1 AC C 3 AC C 2 AC C 1 CO2 plant TS1 MAN TS1 MAN 3 MAN 2 MAN 1 Redundancy at system level in P5 Pneumatic air considered always available Controls on UPS (always up for monitoring and piloting valves if needed) Backup system on diesel * Water availability depends on CV & general maintenance plans – power cut would interrupt it * Put on diesel & backup chiller: one backup chiller + 1 plant (serving as TS) + all accus (to maintain cold) ONE POSSIBLE LAYOUT 13/06/16P. Tropea

9. The testing needs Small lab units (TRACI style) Several institutes will need to test “small parts” of TkII – How many? When? Segmentation to be tested looks like 1 detector cooling loops, i.e. a max power of 287 W Operating T shall be the one of the TKII, i.e. -30 C Few kW lab units (Lucasz style) Are they needed? Typical use a good partition (several CL) One request from Louvain received by Paolo TIF in 2025 15 kW @ - 30 C With present plant: 15 kW @ -20 is ok Plan: move outside & replace chiller? 13/06/16P. Tropea