# Presentation: 901595

## Examples of ILC Cryogenic Systems Cost Optimization  

- T. Peterson
- 28 September 2007

## Possibility for Cost Optimization

- Cryomodule / cryogenic system cost trade-off studies
- Costs of the cryomodules per meter are much larger than the costs of the cryogenic system per meter
- Optimization studies for capital and operating costs should consider tradeoffs of cryomodule complexity with heat loads
**For example, thermal shields, thermal intercepts, and MLI can perhaps be simplified for efficient production **
**At a minimum, the 5 Kelvin thermal shield bridges at cryomodule interconnects can probably be eliminated**

- 28 Sep 2007  Tom Peterson

## Two examples

- Remove the entire 5 K thermal shield
**Retain the 5 K - 8 K piping and thermal intercepts **
- Remove only the 5 K thermal shield bridge at interconnects

- 28 Sep 2007  Tom Peterson

## Type 4 cryomodule

- 28 Sep 2007  Tom Peterson

## Heat loads scaled from TESLA TDR

- 28 Sep 2007  Tom Peterson

## Module predicted heat loads -- 5K

- TESLA     ILC 9-8-9

- With removal of 5 K thermal
- shield, radiative load goes
- down to 2 K level

- Retain the 5 K - 8 K
- helium circuit for
- thermal intercepts

- 28 Sep 2007  Tom Peterson

## Module predicted heat loads -- 2K

- TESLA     ILC 9-8-9

- Additional 1.41 W
- static heat

- Note:  implied is a pessimistic assumption that view
- factor of 2 K objects is as large as 5 K thermal shield

- 28 Sep 2007  Tom Peterson

## Module predicted heat loads -- 40K

- TESLA     ILC 9-8-9

- No significant change

- 28 Sep 2007  Tom Peterson

## Cryogenic unit parameters

- With 5 K thermal shield

- 28 Sep 2007  Tom Peterson

## Cryogenic unit parameters

- No 5 K thermal shield

- 28 Sep 2007  Tom Peterson

## Cryogenic system cost

- Cost impact is calculated for cryoplants and their installation but not for distribution system
**Installed plant power increases from 4.28 to 4.49 MW for each of the large cryoplants **
**Assume capital cost increases by installed power ^0.6 **
**$7.59 M total cryogenic plants capital cost increase  **
**1815 standard 1.3 GHz cryomodules including sources (not including multi-magnet cryomodules) **
- Cryosystem additional M&S is $4200 per cryomodule
- Cryogenic plant operating power
**Increases from 3.34 MW to 3.50 MW for each of the 10 large plants**
**Total of 1.6 MW added for ILC cryogenic system **
- Added operating cost at $0.10/kW-hr is $1.38M/yr or $770 per cryomodule per year

- 28 Sep 2007  Tom Peterson

## 5 K thermal shield cost data

- LHC
**Thermal shield for dipole cryostats was $550/meter (M&S only)**
- A bit simpler than ILC cryomodule 5 K and 40 K thermal shields since not so many feedthroughs
- Input couplers are a complication for ILC
- MLI not included
**MLI cost is about $130/m  **
**So with MLI M&S is about $680/m or $8600 per cryomodule**

- 28 Sep 2007  Tom Peterson

## 5 K thermal shield cost estimates

- Industrial cost estimate
**M&S estimate for 5 K shield including MLI is $4000 **
**Installation labor is estimated at $1700 **
- Fermilab cost estimate
**M&S estimate for 5 K shield including MLI is $5900 based on US LHC costs **
- Shield cost conclusion
**Average the two estimates and LHC costs **
**Total cost is $6200 M&S + $1700 labor = $7900 per cryomodule**

- 28 Sep 2007  Tom Peterson

## Result of preliminary analysis 

- Removal of 5 K thermal shield results in M&S savings of $7900 (shield) - $4200 (cryo) = $3700 per cryomodule
- Operating costs increase by about $770 per cryomodule per year
**Payback for 5 K shield is about 5 years **
- It may end up close to “break-even” or difficult to identify a definite cost advantage
**In general, with several alternatives which satisfy system requirements and show no clear cost difference, ****the “tie-breaking” criterion should be to take the simpler approach**

- 28 Sep 2007  Tom Peterson

## Next steps -- refine analysis

- Investigate thermal shield cost
**LHC experience and estimates differ **
**Assembly labor also uncertain **
**Secondary benefits of simplification not counted **
- Investigate real addition to 2 K heat
**Assumed same view factor to 2 K system as to 5 K shield, which is pessimistic **
- Consider alternative warm thermal shield temperatures with absence of 5 K shield

- 28 Sep 2007  Tom Peterson

## 5 K thermal shield bridge removal 

- Removal of the 5 K thermal shield bridge from the cryomodule interconnects should provide net gain
**Length is ~800 mm, and thermal impact scales with shield length removed = 0.8/12.65**
**Impact on cryoplant M&S is no more than 0.063 x $4200 = $270 added cryogenic system M&S per cryomodule **
- Less since little at 2 K in interconnect
**Impact on operating costs is 0.063 x $770 = $50 per cryomodule per year **
- Shield bridge interferes with pipe interconnect bellows and is labor-intensive to install, so cost is more than the per meter shield cost
**Cost more than $500 per cryomodule**
- Result is net savings for leaving out the 5 K thermal shield bridge at interconnects even after 5 years

- 28 Sep 2007  Tom Peterson

## Cryomodule/cryogenics optimization is a Work Package

- Work package #9 in Cryogenic Systems list
**High priority **
**A joint task with cryomodules **
**Norihito Ohuchi responsible for KEK effort on this topic **
- KEK may do tests at STF regarding the 5 K thermal shield in addition to analysis
**Vittorio Parma responsible for CERN effort **
- Will consist of input from LHC experience
- One input already -- LHC eliminated their 5 K thermal shield after a similar study
**Tom Peterson will coordinate Fermilab effort for this work package**

- 28 Sep 2007  Tom Peterson