1. Underwater Thermoelectric Generator P14254 10/8/2013Rochester Institute of Technology

2. Agenda Background Problem Statement Customer Requirements Engineering Requirements House of Quality System Analysis Functional Decomposition Concept & Architecture Development Engineering Analysis Risk Assessment Test Plan Project Plan 10/8/2013Rochester Institute of Technology

3. Discussion Points ● Heat Sinking ● Materials ● External vs. System Electronics Power Source 10/8/2013Rochester Institute of Technology

4. Background 10/8/2013Rochester Institute of Technology

5. Background Information B OEING ’ S UUV, E CHO R ANGER ▪ Developed in 2001 for seafloor mapping for oil/gas industry ▪ Currently testing the idea for potential military applications ▪ISR ▪Harbor security ▪ Current run time ▪~28 hours 10/8/2013Rochester Institute of Technology

6. Background Information Boeing wants to extend the mission time of their submarine They are interested in thermoelectrics Our Task: Prepare a proof-of-concept underwater thermoelectric generator that charges a battery. 10/8/2013Rochester Institute of Technology

7. Project Updates Since last time... Battery voltage: 12V Battery capacity: 750mAhr Battery type: Li-ion Emphasis on thermoelectric and total system efficiency ❏ Was undecided ❏ Was Li-Poly ❏ We will not put much emphasis on specific heat source 10/8/2013Rochester Institute of Technology

8. Customer Requirements Continuously generate power Operate efficiently Charge a battery Operate underwater Heat source provides a constant source of heat System can withstand interior enclosure temperature Utilize passive safety features 10/8/2013Rochester Institute of Technology

9. Engineering Requirements Power Output: 20W Heat Source Power Input: 500W Upper Ambient Operating Temperature: 30°C Thermal Overload Protection: 10% of max T Operates Without User Input: 0 interactions Heat Source Temperature: Ideally 300°C 10/8/2013Rochester Institute of Technology

10. House of Quality 10/8/2013Rochester Institute of Technology

11. System Analysis 10/8/2013Rochester Institute of Technology

12. Functional Decomposition Generate Electrical Power Protect System Resist Operating Temperature Operate Under Water Resist Corrosion Resist Pressure Resist H20 Ingress Generate Heat Use Electric Heater Transfer Heat Spread HeatReject Heat Generate Electricity Utilize Temperature Difference Store Energy Charge Battery Transfer Electricity Monitor Systems Measure Power (Power input and output) Measure Ambient Conditions (Temperature, humidity, moisture content, pressure) Resist Operating Temperature 10/8/2013Rochester Institute of Technology

13. Mechanical System Level View 10/8/2013Rochester Institute of Technology

14. Thermal System Level View 10/8/2013Rochester Institute of Technology Red arrows are lost heat. Main heat path: Source  TEG  Sink  Water

15. Electrical System Level 0 10/8/2013Rochester Institute of Technology

16. Electrical System Level 1 10/8/2013Rochester Institute of Technology

17. v v Instrumentation System Level View 10/8/2013Rochester Institute of Technology

18. Morphological Chart *Ideas in red have proven to be not feasible 10/8/2013Rochester Institute of Technology Functions Means Generate Heat Spread Heat Monitor Systems Reject Heat Enclosure Material Enclosure Shape Thermo- electrics Seal 1 Cartridge Electric Heater Air Embedded Microcontrollers Pump Non-corrosive metal enclusure Rectangular Prism stackedVacuum 2 Film Electric Heater Oil External Computer FanCeramicSpheresingleduct tape 3 Resistor Electric Heater WaterTactile Metallic Fins PlasticCylindertop/bottom electrical tape 4BurningCopper InsulatorRubberDumbbellall sidesgasket 5Friction Wheel Aluminu m Rigid metals Hexagonal Prism o-rings 6 Steel PolycarbonateOctagon weld 7 Polycarbonate/ Metal Hybrid epoxy

19. 10/8/2013Rochester Institute of Technology CriteriaSolution 1Solution 3Solution 7Solution 8Solution 9 Allowable Enclosure Temp0+0-0 Electronics temp0+0++ Autonomous0-000 Compact0--0- Cost0---- Easy of Assembly/Disassembly0+0-- Ease of Waterproofing0-0-- Easy to Troubleshoot0---+ Efficiency of Thermoelectrics00+00 Cold Side Temperature0++00 Manufacturability0-0-- Number of Gerbils00000 Safe0+000 Weight000+0 DATUM +5222 -6365 FunctionSolution 1Solution 3Solution 7Solution 8Solution 9 Generate HeatCartridge Spread HeatCopper MonitorMicrocontrollersExt CompMicrocontrollerMicrocontrollersMicrocontroller Reject HeatFins Enclosure MaterialNon Corrosive MetalCeramicNon Corrosive Metal Polycarbonate/Met al Hybrid Non Corrosive Metal Enclosure ShapeRectangular PrismDumbbellRectangular Prism Dumbbell Thermoelectrics Electrical Configuration Series Thermoelectrics Mechanical Configuration All Sides All Sides - Double Stacked TE's All Sides Seal/ProtectGasket

20. Pugh Conclusions Shapes: The simple rectangular prism won. No External Control: We are going to have a microcontroller anyway Enclosure Material: Thermoelectric side will need non-corrosive metal, electronics side can be plastic. 10/8/2013Rochester Institute of Technology

21. Engineering Analysis Battery Capacity Leakage Heat Sinking TEM efficiency 10/8/2013Rochester Institute of Technology

22. Batteries Li-Ion instead of Li-Poly ●Li-Ion are more readily available and cost less than Li-Poly. Li-Poly’s higher energy density does not outweigh its cost, and it’s shape characteristics are not an added benefit to the project. 10/8/2013Rochester Institute of Technology

23. Batteries 10/8/2013Rochester Institute of Technology Battery Voltage: 12 V Battery Capacity: (20 W*95% efficiency )/12V = 1.58A 1.58A*0.5 hr charge time = 754mAhr

24. Leakage At 2 feet test depth: P = ρgh P = 999 kg/m^3 * 9.81m/s^2 * 0.61m P = 6 kPa or 0.87 psi Test Spec IP68 met by a number of cheap enclosures by Integra Enclosures 10/8/2013Rochester Institute of Technology

25. Thermal Circuit Analysis 10/8/2013Rochester Institute of Technology

26. Thermoelectrics ● 20% heat loss ● 95% efficient charging system ● Constant Thermoelectric Properties ● Heat Sink is flat, isothermal vertical plate. 10/8/2013Rochester Institute of Technology

27. Heat Sink 10/8/2013Rochester Institute of Technology Length (cm)Resistance (K/W) 9.70.199 5.60.500 3.81.00

28. Budget Thermoelectrics – $40/ea Enclosure – $200 Electronics (Including cabling, microcontroller, and battery) – $250 Testing – $100 Rough Total - ~$550 + 40n 10/8/2013Rochester Institute of Technology

29. Thermoelectrics Power strongly dependent on Heat Sink. 10/8/2013Rochester Institute of Technology

30. Dumbbell Enclosure If heat sink has 0.5K/W or greater resistance, the “cold” side will be very hot We need to protect our electronics from damage Dumbbell shape best mitigates risk to electronics 10/8/2013Rochester Institute of Technology

31. Risk Assessment 10/8/2013Rochester Institute of Technology CategoryRisk ItemEffectCauseLikelihoodSeverityImportanceAction to Minimize Risk Overheat Local system overheat of Thermoelectric device Component degradation or loss. Replacing component delays testing. Poor heat sinking, rapid removal from water 122 Heat sinking testing without component, follow test protocol for removing device from water Enclosure Pressure vessel breach due to failure of seals Equipment degradation, possible partial or complete system loss. This is potentially a large time draw as multiple components would require replacing before resuming testing. Deflection due to thermal or mechanical stress, improper assembly 236 Heat sinking and pressure testing without electronics, follow testing procedure for assembly Electrical Electrical failure of PCB / microcontroller Possible component failure. Possible long lead time item requires replacing, delaying testing. Short circuit133 Thorough subsystem testing and CAD simulation Project Lack of guidance / late guidance from Boeing Design criteria left open-ended, design without Boeing input, last minute changes put project behind schedule Boeing contact is busy, does not respond in a timely manner 313 Provide ultimatum proposal to Boeing, rely on benchmarking competitors where detailed technical information is needed.

32. Test Plan  Test waterproofing without heat  Test thermoelectric, sensors, charging and max power point circuits  Test waterproofing with heat 10/8/2013Rochester Institute of Technology

33. Test Plan Test heat sink Integrate and test full system. 10/8/2013Rochester Institute of Technology 1: Heat Sink 2: Thermoelectric Array 3: Heat Source 4: Instrumentation 5: Microcontroller & Charging circuit 6: Battery

34. Project Plan We only have 2 weeks This is how we do it ▪ 5 days --- integrate --- 5 days Update EDGE & Risk Assesment 10/8/2013Rochester Institute of Technology

35. Issues on the Horizon ● Thermoelectric clamping (300kPa min - recommend 1.2MPa) ● External vs system powered electronics (sensors, microcontrollers, etc) ● Heat sinking 10/8/2013Rochester Institute of Technology

36. Clamping Configurations 10/8/2013Rochester Institute of Technology

37. Questions 10/8/2013Rochester Institute of Technology

38. Problem Statement Current State ▪ Boeing’s current UUV, the Echo Ranger has a maximum mission time of 28 hours. Boeing would like to significantly extend this mission time. Desired State ▪ Boeing would like to utilize a thermoelectric system to significantly extend mission time of their UUVs. Project Goals ▪ Demonstrate proof of concept of thermoelectric system ▪ Use a temperature differential to charge a battery ▪ Achieve maximum thermoelectric efficiency over a range of temperatures ▪ Establish a UUV-based research partnership between Boeing and RIT Constraints ▪ System must operate underwater ▪ System must utilize a thermoelectric device ▪ System must operate autonomously 10/8/2013Rochester Institute of Technology

39. Customer Requirements 10/8/2013Rochester Institute of Technology

40. Engineering Requirements 10/8/2013Rochester Institute of Technology