1. CEDAR Detector Ventilation System Review
F. Dragoni, G. Nitwinko, M. Alam
EN-CV

2. Summary & Scope Locations Thermal Housing Analysis
Technical solution: PID, Integration, Controls
Planning
Budget
Risks

3. Required Air Flow: Theoretical Study
Geometry shape used as Cross-Section
SUMMER
TOUT = 30degC
Aerogel
Max Heat Gains [W]
53.3
55.6
61.9
Min Airflow [m3/h]
1695
1767
1968
WINTER
TOUT = 15degC
Max Heat Losses [W]
-37.6
-40.2
-47.5
1195
1276
1508
Selected air flow for each thermal housing: 2500 m3/h

4. Technical Solution Air flow: 2500 m3/h - 100% recirculation
Extremely long cooling coils – 30 rows
Laboratory chiller
Water temp stability under all load conditions
Simplifies controls – Can set temperature & pressure
Water IN
Temp = 23 degC
Water OUT Temp = 24 degC
Air OUT
T = 23 degC
Air IN
T = 25.5 degC

5. PID
Air Handling Unit
Precision Chiller

6. Location & Physical Constraints
Platform is preferable location for ventilation system
CEDAR
BEAM

7. Integration
Air Handling Unit
Return Ductwork
Supply Ductwork
Chiller

8. Controls Fixed fan speed to achieve 2500 m3/h
Set circulating fluid Temperature + Pressure, i.e. the chiller internal controls keep stable circulating water temperature
No active control. Monitoring only via WAGO
CEDAR air inlet/intermediate/outlet Temp
Chiller status + water supply Temp
Water Flow rate
Water Inlet/Outlet Temp
Fan status + fan speed
Filter/Strainers pressure switches
Air average temperatures before/after cooling coils

9. Limitation due to fixed point functioning
Water temperature is not adapted to seasons
AHU
CEDAR
Set T = 23.0 °C
Summer Air in Temp= °C
Winter Air in Temp= °C
Air flow rate reduces as filter clogs – Minimal impact due to 100% recirculation

10. Planning

11. Budget
Based on received estimates and framework contractor’s unit prices
Item
Estimated Cost
Possible Savings
Air Handling Unit
12,700 CHF
N/A
Duct network, fittings and air-side sensors
18,950 CHF
-1,650 CHF
Pipework, fittings and water-side sensor
19,850 CHF
-600 CHF
Cooling system (Chiller)
10,000 CHF
Electricity, ethernet and monitoring (WAGO)
10,400 CHF
Design, documentation, testing
5,150 CHF
- 250 CHF
Items supplied by CERN (drainage extension)
2,800 CHF
- 900 CHF
External Transport (air handling unit, chiller)
2,000 CHF
- 1,150 CHF
Other supplies transport (5% value of supplies)
2,300 CHF
- 150 CHF
FSU (Draftsman, Work Supervisor)
4,000 CHF
10 %  Contingency
5,700 CHF
Sub-Total
93,850 CHF
89,150 CHF
EN-EL Power Supply
2,950 CHF
Total
96,800 CHF
92,100 CHF
Assumptions
1 concrete slab can be removed
Concrete blocks can be drilled for supports
EUR/CHF = 1.18
EN-EA responsible for design, supply and install of steel frame/mountings where AHU will sit
Minor modification to handrail are allowed – cost not included
CERN Internal Transport is free
Note design costs include:
detail design of ductwork, pipework and cable runs
design of electrical cabinet

12. Possible/Potential savings
Ask CERN transport to organise transport of AHU from factory to Previssin  Possible saving 1150 CHF
Swap supply and return ducts – supply ductwork is more expensive due to thickness insulation  Possible saving 650CHF.
Only 1 set of flexible joints  Possible saving 1,000CHF.
Buy flow meter transducer/switch from SMC  Potential saving 600 CHF.
Possible saving on drainage cost  Potential saving 900 CHF.

13. Conceivable not likely
Risks #
Risk
Impact P C
Mitigation 1
EUR/CHF exchange rate – approx. 85% supplies are paid in EUR
Cost increase in CHF terms 5% increase in EUR/CHF  4k CHF more needed
Likely
20%<P<50%
Cost:
4-5 kCHF
No mitigation 2
Late delivery of AHU
Delay to project completion
Conceivable not likely
10%<P<20%
Delay
1 week
1. Place order asap
2. Put pressure on manufacturer 3
Drainage point cannot be moved
Possible delays - added cost: additional supply, pump and piping.
Delay:
3-5 kCHF
1. Start civil study asap 4
Handrail needs major modifications
Possible delays and additional cost
1. Start frame integration with platform asap

14. Q&A?

15. Challenge Design a ventilation system:
To have a sufficient air flow to maintain longitudinal temperature stability inside 2 CEDAR
Capable of supply air at a set temperature ±0.1K

16. Summer - Heat Loads Ambient Temp = 30 degC Set Temp = 23degC
Max Q = 70 W
Ambient Temp = 30 degC
Set Temp = 23degC
Total Q = 2.0 kW
23.1 C
Max Q = 68 W
25.5 C
23.0 C
23.2 C
Max Q = 20 W
Running Q = 0.6kW
Max Q = 1.5 kW
23.5 C
Max Q = 110 W
23.3 C
Max Q = 120 W
23.6 C
Max Q = 70 W

17. Winter - Heat Losses Ambient Temp = 15 degC Set Temp = 23degC
Max Q = 70 W
Ambient Temp = 15 degC
Set Temp = 23degC
Total Q excluding motor = -0.5 kW
Including motor = 0.1 kW
22.9 C
Max Q = 68 kW
23.0 C
22.8 C
Max Q = 20 W
Running Q = 0.6kW
Max Q = 1.5 kW
22.5 C
Max Q = 110 kW
22.7 C
Max Q = -140 kW
Max Q = 70 W

18. Chiller selection
Packaged precision chiller of smaller sizes do not allow to achieve required flow rate required pressure 0.3M
No Inverter on pump – less flexibility in system
5kW Chiller Pump Curve
10.5kW Chiller Pump Curve

19. Modifications to Handrail

20. Removal of concrete slab
Slab to be removed

21. Technical Solution
CEDAR #1
CEDAR #2
AHU
2500 m3/h
Chiller