PX15 Thermosyphon tests results #02

1. PX15 Thermosyphon tests results #02 Jose Botelho Direito EN/CV/PJ

2. Chiller Power • Lauda RP 3090 CWVs. Julabo WP91-SL The Julabo Chiller was providing less than half of the announced power! (sent to repair) jbotelho@cern.ch

3. Start-up time • Minimum required flow is 25g/s; • Required chiller power to run at -20°C: • P=m.dh=0.025*(309-192)=2.93 kW • dP=143W left to sub-cool the C3F8 in the tank plus the C6F14 in the chiller bath! ( 380kg of C3F8 + 25 kg of C6F14). • It means 47 minutes to cool the liquid C3F8 by one K! • With one extra kW on the chiller (like the Julabo in good conditions) it would take 6 minutes... Lowest evaporation temperature achieved with the Lauda Chiller: -5 °C jbotelho@cern.ch

4. Expansion valve Flow instabilities Before Dead band settings on the valve actuator changed from 0.8 to 0.1%. Thanks to S. Berry & F. Corbaz After 4 hours jbotelho@cern.ch

5. Leak on a pressure manometer (bottom) Valve closed to stop the leak ~40 kg Weight trend since first fill until the leak was repaired jbotelho@cern.ch

6. New Monitored Conditions and Parameters By L. Zwalinski jbotelho@cern.ch

7. TS Stop origins: Liquid line boiling Stop! Stop! dP = -0.92 bar dP = -0.92 bar jbotelho@cern.ch

8. TS Stop causes: Liquid boiling inside the Condenser Stop! dT < 0 °C dP = -0.8 bar Stop! dT < 0 °C dP = -1.32 bar jbotelho@cern.ch

9. Water hammer – pressure peak of 24 bar Pressure Tliq = 0 °C Weight Pressure decrease at the top! Dead bands to be reviewed! jbotelho@cern.ch

10. Conclusions for the FSTS • Expected “water hammer” pressure peak to be estimated case it happens on the FSTS; • FSTS “water hammer” protection: • Mechanically (ideal) – Shock absorber every x meters on the liquid line? • Control system: valve at the top of the liquid line closure when expected liquid column is bellow a certain value. • Case the liquid column is too low this valve needs to open slowly. • Start-up time and other time constants to be estimated. jbotelho@cern.ch