1. M. Battistin – 9 th June 2010EN/CV/DC M. Battistin (EN/CV/DC) 9 th June 2010 Detector Cooling Project - WP III Advancement Status

2. M. Battistin – 9 th June 2010EN/CV/DC2 Main streams of investigation Since the compressor refurbishment executed during spring 2009 we decided to not invest on Haug compressors any longer and study alternative solutions. Two main streams of study has been defined: 1)No compressors: thermosiphon project 2)Alternative compressors (screw, labyrinth, membrane, centrifugal): finally the centrifugal magnetic bearing oil free compressor has been identified as very good candidate (Turbocor – McQuay) Oil free gas bearing centrifugal compressor is a very new investigation line we are opening now. It is premature to give details.

3. M. Battistin – 9 th June 2010EN/CV/DC3 The thermosiphon solution PR thermal screen others 4 liquid lines 4 gas lines condenser liquid tank pneumatic valve manual valve manual valve dummy load Heater BPR pixel 6 X SCT manual valve pneumatic valve The mini-thermosiphon test bench has provided full results. The full scale test bench in PX15 is under construction and will allow the complete qualification of the solution. We need to understand if we what just replace the present compressors leaving unchanged the evaporation temperature or even decrease the evaporation temperature of 5, 10 or 13 K ????? Piping in PX15 (DN100 and DN40) will be part of the solution. Low temperature Chiller UX15 USA15 Surface

4. M. Battistin – 9 th June 2010EN/CV/DC4 The pump is not a reasonable solution PR thermal screen others 4 liquid lines 4 gas lines condenser liquid tank pneumatic valve manual valve manual valve dummy load Heater BPR pixel 6 X SCT manual valve Installing two redundant pumps on the liquid line in the cavern is possible but: -Low temperature (cryogenic) pump -Why having active machine in a system that could avoid them (maintenance, radioactive fluid, etc.) -There is no space for a low temperature chiller underground: connecting pipes shall be installed anyway. Low temperature Chiller UX15 USA15 Surface

5. M. Battistin – 9 th June 2010EN/CV/DC5 The Turbocor solution lay-out PR thermal screen others 4 liquid lines 4 gas lines condenser liquid tank pneumatic valve manual valve manual valve dummy load Heater BPR pixel 6 X SCT manual valve pneumatic valve Once the solution will be qualified and accepted the gas shall be condensed on the surface (7 bar a – 15 °C) Standard and cheaper chiller (0°C) will be sufficient. Piping in PX15 (DN100 and DN40) will be part of the solution. Standard Chiller UX15 USA15 Surface

6. M. Battistin – 9 th June 2010EN/CV/DC6 The back-up solution (Haug) PR thermal screen others 4 liquid lines 4 gas lines condenser liquid tank pneumatic valve manual valve manual valve dummy load Heater BPR pixel 6 X SCT manual valve pneumatic valve Standard Chiller Or Chilled Water UX15 USA15 Surface In the case no alternative solution is sufficiently attractive to replace the present compressors… we have to keep them. In this case we can use them at lower pressure (8 bar instead of 15 bar) and condensate again on the surface. This should increase the lifetime of the present compressors. Piping in PX15 (DN100 and DN40) will be part of the solution. The old tank of the evaporative replaced last year can be reused. 7 Haug compressors

7. M. Battistin – 9 th June 2010EN/CV/DC7 Piping between USA15 and SDX1 PR thermal screen others 4 liquid lines 4 gas lines condenser liquid tank pneumatic valve manual valve manual valve dummy load Heater BPR pixel 6 X SCT manual valve pneumatic valve UX15 USA15 Surface The three solutions: -Turbocor centrifugal compressors -Thermosiphon no compressor -Haug low pressure compressors Require the interconnecting piping between the compressor room and the surface building for the full flow-rate. EN/MME is available for the installation in the second part of the year only. In 2011 they will start the preparation works for the long shutdown. 7 Haug compressors

8. M. Battistin – 9 th June 2010EN/CV/DC8 Centrifugal oil free compressors A market survey has been launched last summer to identify alternative compressors to Haug ones: Labyrinth Membrane Oil free screw Three main lines of investigation are now active: Turbocor oil free magnetic bearings centrifugal compressor McQuay oil free magnetic bearings centrifugal compressor Ateko oil free gas bearings centrifugal compressor The three possibilities are and will be investigated. All of them give some concerns.

9. M. Battistin – 9 th June 2010EN/CV/DC The most promising alternative to HAUG compressors is centrifugal compressors: full oil free solution high power density (one single machine could make the work the ID cooling needs) High rotation speed (48 krpm) leads to an almost vibration less system The cost of one of this compressor is about half of the Haug one. Positive feed-backs form the market after about 10 years of industrial applications on fridge systems (mainly HVAC industry). “it is extremely reliable!!” Hermetic compressor system guarantee high leak- tightness of the process. Mandatory feature to manage the activated fluid we will have in some year. 9 Turbocor project

10. M. Battistin – 9 th June 2010EN/CV/DC10 The Turbocor solution on paper First calculations show that the smallest Turbocor compressor TT-300 (the one we have now) could manage 90% of the flowrate required by ATLAS ID cooling. Larger compressors are available from Turbocor (TT-400 and TT-550) and McQuay (from 1000 kW). Discharge pressure will be most probably limited to 7-8 bar a. The surface condensation will allow to gain the other 8-9 bar needed to feed the detector.

11. M. Battistin – 9 th June 2010EN/CV/DC11 Turbocor qualification process We shall qualify this compressor with our gas (R218 = C 3 F 8 ) We have bought a test bench (see picture). The system has been modified to test the compressor performances (new piping, pressure regulator and flow meter). A test area has been set-up in SMI2 (close to 298). -Test procedure -Support from Turbocor -A list of problems: Turbocor compressor has been designed to handle R134a, the standard fluid for refrigeration industry. This technology is less then 10 years old and is progressively conquering the market now. Main parameters to consider for fluid change; Compressor cooling: apparently R134a @ ≈+4°C, R218 @ ≈ - 40°C? Corrosion problems? Material compatibility problems? Control issues: shall we (you) modify the internal code? Shaft forces check; Critical components in case of fluid change; Detailed Test Procedure; The test of the compressors foresees many phases with different fluids (R134a, C3F8, blends) and will take many months to reach the full qualification. The support of the design team would be extremely important… or even fundamental: what is the guarantee of a try and error process?? Recent contact with Turbocor design team is promising!

12. M. Battistin – 9 th June 2010EN/CV/DC12 McQuay wants to collaborate McQuay Europe is qualifying this machines for the European power (50 Hz – 400 V) now. We were searching for support from the design team: Meeting with McQuay Europe in Rome on 22 nd of April 2010. T. Watson (Chief Engineer of McQuay USA) and L. Paolella (General Manager of McQuay Europe). T. Watson is verifying on paper the feasibility of this project. The “stone-wall” condition could critical and could limit the maximal performances of the machine. The control of the machine should be most probably modified: L. Sorabella (control specialist of McQuay could help on this point). McQuay compressors use the same technology of Turbocor. The design offices worked together to develop Turbocor in ‘90. McQuay launched more recently a series of larger compressors (more than 1 MW) using this technology. P m’ Stall Stone wall Meeting with Padova University on 26 th of May (two days ago). Prof Zilio and Prof. Cavallini. We are defining a three partners collaboration and identifying one resource dedicated to the compressor qualification project working in strict collaboration with CERN, McQuay (Italy and USA) and UniPadova. Phone conference to be organized soon.

13. M. Battistin – 9 th June 2010EN/CV/DC13 Gas bearing oil free compressor “It will be possible to design for above mentioned parameters as a one machine 1.2 kg/s which will be based on following components: High speed asynchronous motor 33 kW / 65 000 rpm (rotor: diameter 66.6 mm, active length 105 mm, materials: heat treated carbon steel, Cu, Ti), stator: outer diameter 160 mm, air cooled. Fully dynamic self acting radial & axial gas bearings (materials: Al alloy, heat treated carbon steel, graphite composite) One stage working stage containing blades impeller D=68 mm / 65 000 rpm (material: Al alloy, outer body of the spiral case carbon steel) Pressure body - galvanized carbon steel or Al alloy Frequency converter (FC)” “It will be possible to design for above mentioned parameters as a one machine 1.2 kg/s which will be based on following components: High speed asynchronous motor 33 kW / 65 000 rpm (rotor: diameter 66.6 mm, active length 105 mm, materials: heat treated carbon steel, Cu, Ti), stator: outer diameter 160 mm, air cooled. Fully dynamic self acting radial & axial gas bearings (materials: Al alloy, heat treated carbon steel, graphite composite) One stage working stage containing blades impeller D=68 mm / 65 000 rpm (material: Al alloy, outer body of the spiral case carbon steel) Pressure body - galvanized carbon steel or Al alloy Frequency converter (FC)” We are organizing a technical visit to the supplier in the next 2 weeks. Question marks: Is that a brand new design? Is the company solid enough (Haug II)? We will start debugging it in few years? …

14. M. Battistin – 9 th June 2010EN/CV/DC Blends studies on mini thermosiphon 200920102011 Mini thermosiphon Bdg 191 – 10 k€ Thermosiphon PX15 – 200 kCHF Market Survey + Invitation to Tender for low temperature chiller – 2 MCHF Validation Design and procurement for the final solution installation in 2012 Procurement & installation Perfluorocarbon Blends cooling test in SR1 and PX15 14 Validation TURBOCO R tests PX15 piping installation Turbocor purchase and installation phase

15. M. Battistin – 9 th June 2010EN/CV/DC Resources needed Jan Godlewki Danilo Giugni Michele Battistin Are following the all process part time Elena Perez Jose Direito Have this activity as first priority and dedicate to this at least 50% of their time. Elena Perez up to Jan 2011. Jose Direito fellowship starts Sep 2010. Stephane Berry Pierre Bonneau Pierre Feraudet Olivier Crespo Florian Corbaz Daniel Lefils They all are contributing to the projects providing technical support for mechanical, electrical, control aspects in parallel to the daily operation and maintenance activity of the section. New resources shall be dedicated to these projects (Oil free compressor + thermosiphon) Alex Bitadze Lukasz Zwalinski Delio Ramon Are following this project part time.

16. M. Battistin – 9 th June 2010EN/CV/DC16 Last events in the project 22 nd of April 2010: visit to McQuay (Rome) - T. Watson 26 th of May 2010: Visit to Padova Univiersity: Prof. Cavallini and Prof. Zilio – Collaboration CERN-UNIPA-McQuay May 2010: launch of MS-3684/EN/ATLAS for low temperature chiller installation 28 th of May 2010: III Thermosiphon workshop: ILK Dresden + Johan Bremer as reviewers 14 th of June 2010: visit to Ateko (Check Republic) 15 th of June 2010: visit to J&E Hall International (London) for low temperature chillers 28 th and 29 th of June: visit to CERN of R. Conry (father of Turbocor compressors)

17. M. Battistin – 9 th June 2010EN/CV/DC17 General Conclusions Mini-thermosiphon tests showed that the thermosiphon is a valid technology to replace the compressors in the ATLAS ID and ALICE SPD cooling systems. Fully validation will be achieved with PX15 TSP test bench. Centrifugal oil free compressors of new generation can provide a valid alternative to the present compressors or thermosiphon. The validation process of these compressors is not easy. Promising contacts with McQuay and Turbocor. We need to specify what we want as minimal evaporation temperature using pure C3F8 and with blends. By the end of the year we shall be ready to identify and finance the alternative solution to the present system. In case of failure of the validation process, the present compressors could run at lower pressure to reduce the risk of failure and increase their lifetime The piping connecting USA15 to the surface are needed anyway. New resources are needed to follow these projects. We ask ATLAS and DCP to finance them.