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Underwater Thermoelectric Generator P14254. 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.
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Underwater Thermoelectric GeneratorP14254 Rochester Institute of Technology
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 Rochester Institute of Technology
Discussion Points • Heat Sinking • Materials • External vs. System Electronics Power Source Rochester Institute of Technology
Background Rochester Institute of Technology
Background Information Boeing’s UUV, Echo Ranger • 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 Rochester Institute of Technology
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. Rochester Institute of Technology
Project Updates Since last time... Was undecided Was undecided Was Li-Poly We will not put much emphasis on specific heat source • Battery voltage:12V • Battery capacity: 750mAhr • Battery type: Li-ion • Emphasis on thermoelectric and total system efficiency Rochester Institute of Technology
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 Rochester Institute of Technology
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 Rochester Institute of Technology
House of Quality Rochester Institute of Technology
System Analysis Rochester Institute of Technology
Functional Decomposition Rochester Institute of Technology
Mechanical System Level View Rochester Institute of Technology
Thermal System Level View Red arrows are lost heat. Main heat path: Source TEG Sink Water Rochester Institute of Technology
Electrical System Level 0 Rochester Institute of Technology
Electrical System Level 1 Rochester Institute of Technology
Instrumentation System Level View v v Rochester Institute of Technology
Morphological Chart *Ideas in red have proven to be not feasible Rochester Institute of Technology
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. Rochester Institute of Technology
Engineering Analysis • Battery Capacity • Leakage • Heat Sinking • TEM efficiency Rochester Institute of Technology
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. Rochester Institute of Technology
Batteries Battery Voltage: 12 V Battery Capacity: (20 W*95% efficiency )/12V = 1.58A 1.58A*0.5 hr charge time = 754mAhr Rochester Institute of Technology
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 Rochester Institute of Technology
Thermal Circuit Analysis Rochester Institute of Technology
Thermoelectrics • 20% heat loss • 95% efficient charging system • Constant Thermoelectric Properties • Heat Sink is flat, isothermal vertical plate. Rochester Institute of Technology
Heat Sink Rochester Institute of Technology
Budget • Thermoelectrics – $40/ea • Enclosure – $200 • Electronics (Including cabling, microcontroller, and battery) – $250 • Testing – $100 Rough Total - ~$550 + 40n Rochester Institute of Technology
Thermoelectrics • Power strongly dependent on Heat Sink. Rochester Institute of Technology
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 Rochester Institute of Technology
Risk Assessment Rochester Institute of Technology
Test Plan • Test waterproofing without heat • Test thermoelectric, sensors, charging and max power point circuits • Test waterproofing with heat Rochester Institute of Technology
Test Plan • Test heat sink • Integrate and test full system. 1: Heat Sink 2: Thermoelectric Array 3: Heat Source 4: Instrumentation 5: Microcontroller & Charging circuit 6: Battery Rochester Institute of Technology
Project Plan • We only have 2 weeks • This is how we do it • 5 days --- integrate --- 5 days • Update EDGE & Risk Assesment Rochester Institute of Technology
Issues on the Horizon • Thermoelectric clamping (300kPa min - recommend 1.2MPa) • External vs system powered electronics (sensors, microcontrollers, etc) • Heat sinking Rochester Institute of Technology
Clamping Configurations Rochester Institute of Technology
Questions Rochester Institute of Technology
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 Rochester Institute of Technology
Customer Requirements Rochester Institute of Technology
Engineering Requirements Rochester Institute of Technology