The document discusses materials selection for a household-scale compressed air energy storage system. It considers materials for the pressure vessel shell and thermal insulation. For the shell, 304 stainless steel is recommended over other options like carbon steel due to its higher maximum operating temperature, allowing insulation to be placed outside. For insulation, ceramic fiber blanket is selected because it has the lowest thermal conductivity to minimize heat losses. The system is designed to store 7.2 kWh of energy at 675°C over 12 hours for a household.
1. December 12th, 2016
MEEN 475 – 502
Team
Gus Gremillion
Ryan Gautier
Nick Albert
Jacob Walter
Serdar Ozguc
Cory Lusk
Zach Gregory
Section Instructor
Dr. Tanil Ozkan
Compressed Air Energy Storage
2. Introduction - Compressed Air Energy Storage (CAES)
• CAES is an alternative form of energy storage to
fossil fuels and chemical batteries
• Up to 30 year lifespan with minimal
environmental impact
• Current implementations – Storage in large
underground salt caverns
• No small-scale systems currently in use
• Issue: Diabatic compression produces low
efficiency values
• Solution: Improve storage efficiency by
reducing thermal losses
• Objective: Perform materials selection for a
household-scale adiabatic CAES system
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3. System Specifications
• Energy capacity: 7.2 kWh
• 12 hour household consumption
• 2 components
• Load-bearing pressure vessel shell
• Yield Failure SF = 4 (typical of pressure vessels)
• Thermal insulation
Storage
Tank
Compressor
(Adiabatic Compression)
Electric
Power
Valve
Outlet to turbine
(electric power)
or drive shaft
(mech. power)
Thermal energy loss
through tank shell
4. Temperature Requirements
• Internal temperature = 675°C
• Adiabatic compression
• Yield Failure SF = 4
• Minimum Insulation Service
Temperature = 675°C
• Minimum Shell Service
Temperature = 300°C
• Permits consideration of
most steels
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5. Shell Material Selection
Function ● Pressure Containment
Constraints ● Ensure leak before yield failure
or fracture failure
● Radius-Thickness Ratio = 10
● Operating Temperature ≥ 300°C
Objective ● Maximize Safe Internal Pressure
● Minimize Shell Thickness
Free
Variables
● Material
● Wall Thickness
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6. Thermal Insulation Material Selection
Function ● Thermal Insulation
Constraints ● Operating Temperature = 675°C
Objective ● Minimize Thermal Energy Losses
Free
Variables
● Material
● Wall Thickness
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8. AHP Results
Shell Material:
• SA516-70 Steel has the highest score, however 304 Stainless
Steel is close and have higher operating temperature. With
Stainless Steel, insulation can be placed outside the vessel.
Insulation Material:
• Fiberfrax S Durablanket wins, mainly due to low thermal
conductivity.
Material properties from: [4, 5, 6, 7, 8, 9, 10, 11, 12]
9. Shell Manufacturing Process Selection
Process
Shape
Flat Sheet
Dished Sheet
Mass
500-1200 kg
Section
Thickness
20-50mm
Economic Batch
Size
~1000 Units
Sand Casting X ✔ ✔ ✔
Die Casting X X X X
Investment Casting X X X ✔
Forging X ✔ ✔ ✔
Sheet Forming ✔ X X X
Powder Methods X X X X
Electro- Machining X X X X
Conventional Machining ✔ ✔ ✔ ✔
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13. Shell Material Index Derivation
Stress Intensity of a crack:
Fracture stress limit:
Yield before break:
Max stress in thin-walled
pressure vessel:
Ductile failure
prevented if:
Allowable pressure:
14. Thermal Insulation Material Index Derivation
Heat
conduction:
Heat
stored:
Total heat
loss:
Total heat
loss:
Editor's Notes
Presenter - Wade
Presenter – Zach
Mention that with SF = 4 we are neglecting fatigue.
Presenter - Gus
Presenter – Ryan
Presenter – Cory
Presenter - Serdar
Need to add all tables and provide rationale for selecting stainless steel and the ceramic fiber blanket. In particular, note that with stainless steel the insulation can be placed on the exterior of the vessel; this simplifies manufacturing, maximizes the volume of air under compression, and reduces safety risks of people being burned by touching the exterior of the vessel.
Presenter - Serdar
![Introduction - Compressed Air Energy Storage (CAES)
• CAES is an alternative form of energy storage to
fossil fuels and chemical batteries
• Up to 30 year lifespan with minimal
environmental impact
• Current implementations – Storage in large
underground salt caverns
• No small-scale systems currently in use
• Issue: Diabatic compression produces low
efficiency values
• Solution: Improve storage efficiency by
reducing thermal losses
• Objective: Perform materials selection for a
household-scale adiabatic CAES system
[2]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)