Environmental Conditions in the LHC Experimental Caverns

1
Environmental Conditions in the LHC Experimental
Caverns

• JCOV Thursday 18th March

2
ATLAS

• UX15 Cavern conditions specified in Technical
  Specification IT-2659/ST/LHC (summary in
  Engineering Specification LHC-UA15-ES-001, EDMS
  No. 313039)
• Heat Load 180 kW
• Air flow rate 60,000 m3/h
• Supply temperature 17 C
• Supply air humidity 10 C dew point temperature
• Temp. range in cavern 18 C (floor) 28 C
  (vault)
• Air displacement principle
• cool air supplied at the bottom of the cavern
  (highest relative humidity)
• warm air at the extraction point at the vault

3
ATLAS

• Detailed simulations performed to study overall
  temperature gradients and local hot spots
  (Thermal analysis of the airflow around the
  ATLAS muon barrel). No simulation available for
  humidity distribution.
• Simulation made by ILK (on basis of 100 kW heat
  load) useful to illustrate humidity
  stratification.
• Requirement on relative humidity (lt 70 )
  respected.

4
CMS

• UXC55 Cavern conditions in same Technical
  Specification, IT-2659/ST/LHC.
• Heat Load 100 kW
• Air flow rate 45,000 m3/h
• Supply temperature 17 C
• Supply air humidity 10 C dew point temperature
• Temp. range in cavern 18 C (floor) 26 C
  (vault)
• Air displacement principle
• cool air supplied at the bottom of the cavern
  (highest relative humidity)
• warm air at the extraction point at the vault

5
ALICE

• UX25 Cavern conditions in Engineering
  Specification LHC-UA-ES-0004 (EDMS No. 386351).
• Heat Load 100 kW
• Air flow rate 45,000 m3/h
• Supply temperature 17 C
• Supply air humidity 10 C dew point temperature
• Temp. range in cavern 17 C (floor) 24 C
  (vault)
• Air displacement principle
• cool air supplied at the bottom of the cavern
  (highest relative humidity)
• warm air at the extraction point at the vault

6
ALICE

• UX25 Detector conditions in Engineering
  Specification LHC-UA-ES-0004 (EDMS No. 386351).
• Air flow rate 6,000 m3/h
• Pressure head 22,500 Pa
• Supply temperature 17 C
• Supply air humidity 10 C dew point temperature

7
LHCb

• UX85 Cavern conditions (UXD, detector area) in
  Engineering Specification, EDMS No. 351740 (not
  released).
• Heat Load 50 kW
• Air flow rate 22,500 m3/h
• Supply temperature 17 C
• Supply air humidity 10 C dew point temperature
• Temp. range in cavern 17 C (bottom) 24 C
  (vault)
• Air mixing principle
• cool air supplied via grilles at 2 m from the
  bottom of the cavern
• warm air extracted via duct under cavern vault
• lower stratification, much more entrained air and
  secondary flow pattern

8
LHCb

• UX85 Cavern conditions (UXC, protected area) in
  Engineering Specification, EDMS No. 351740 (not
  released).
• Heat Load 50 kW
• Air flow rate 22,500 m3/h
• Supply temperature 17 C
• Supply air humidity 10 C dew point temperature
• Temp. range in cavern 17 C (bottom) 24 C
  (vault)
• Air mixing principle
• cool air supplied via grilles at 2 m from the
  bottom of the cavern
• warm air extracted via duct under cavern vault
• lower stratification, much more entrained air and
  secondary flow pattern

9
All Experimental Caverns

• Supply air humidity 10 C dew point temperature
• Maximum humidity (extraction) 12 C dew point
  temperature (high humidity alarm)
• No internal latent loads, humidity rise may come
  from water leaks or through-wall infiltrations,
  air infiltrations from annex spaces, etc.
• Drying capacity (20,000 m3/h, between 10 12 C
  dpt )max 23 kg/h