Thermoelectric Analysis for Optimized Waste Heat Power Generation in Marine Applications

1. Thermoelectric Analysisfor Optimized Waste Heat Power Generation in Marine Applications Tucker Doane Angela Fouquette Philep Levesque

2. Summary • Potential benefits of thermoelectrics • Objectives for this year • How thermoelectric materials work • Background on previously done work • This year’s progress and development • Future work

3. Potential Benefits Thermoelectric Generators Applied to Marine Diesel Exhausts • Increase efficiency and plant performance • Decrease in fuel consumption • Decrease in operating costs • Decrease environmental impact

4. Objectives • Understand the fundamental properties of thermoelectric generators • Provide the lab with devices to characterize these properties and model various applications • Model material properties of thermoelectric modules and elements • Compare heat transfer with flow rates and pressure drops for the most efficient performance values • Comparing results to industry standard tests and modules

5. Thermoelectric Introduction Seebeck Effect: A voltage is created in the presence of a temperature difference between two dissimilar metals Z = Figure of Merit S = Seebeck Coefficient σ = Electrical Conductivity κ = Thermal Conductivity

6. Thermoelectric Introduction Seebeck Coefficient: used to characterize the sensitivity of different materials V = Voltage T = Temperature

7. Background • Previous work at Maine Maritime Academy focused on improvement and implementation on existing systems • R/V Friendship and Gas Micro-Turbine (2009) • Hybrid lifeboat test platform development and implementation (2010) • Improved heat exchanger development (2013)

8. Seebeck Coefficient Measurement Apparatus (SCMA) • Device to measure temperature and voltage output of manufactured modules, elemental samples, wires, etc. • Used to understand fundamental properties of existing and newly generated materials • Testing initially done with several types of Hi-Z modules

9. Design and Development • Copper chosen due to its excellent heat transfer characteristics • Each copper block measures 2 x 2 x 5/8 inches • Capable of accepting existing modules, new samples, wires, etc.

10. Control Schematic

15. SCMA Uses and Future Work • Can be used to test and characterize newly made samples and materials, as well as other unknown devices • Stabilize temperature differential: • Automate temperature control • Establish a better way of cooling

16. Test Bed Development • Provide the ability to test different modules, materials, and scenarios in a controlled and designated environment • Designed to accept newly made thermoelectric devices • Will be designed to utilize gas as the heating medium • Will have an associated cooling system to promote a greater temperature differential

17. System Overview

18. Heat Exchanger Design • Heat provided to simulate pressure and air flow through the exhaust of a diesel engine, boiler, or gas turbine • Designed to replicate existing marine applications

19. Preliminary Design • The test bed needs to have the largest possible range of fluid flow characteristics to better simulate a number of known exhaust systems • Initial calculations and visualization done in Microsoft Excel • The basic parameters of flow and temperature were sized based on Hatz Single Cylinder Diesel to Caterpillar 2.2 L

20. Basic Flow and Heat Modeling

21. Heat Load Requirements Enthalpy Rate Equation

22. Heat Exchanger Fluid Flow Analysis • How varying flow area, temperature, and length effect velocity and flow regime (turbulent vs laminar) for simple rectangular slot • Turbulent preferred for fluid mixing

23. Heat Exchanger Basic Arrangement

24. Advanced Modeling using MATLAB • To understand the tradeoff of pressure to convective heat transfer, in addition to other effects • An attempt to predict the conditions within the designed heat exchanger during operation and testing

25. Illustrating the Tradeoff

26. Important Dimensionless Groups • Reynolds Number • Ratio of flow momentum rate to viscous force • Nusselt Number (Pr,Re) • Ratio of convective conductance to molecular conductance over hydraulic diameter

27. Important Non-typical Equations & Estimators • Prandtl Number • Nusselt Number • NuL = 0.664*Pr^(1/3)*Re^0.8 • NuT = 0.036*Pr^(1/3)*Re^0.8 • Fluid Boundary Layer • = • BLT =

28. MATLAB Model Each element generates an array based upon the input parameters.

29. Heating System Electric Heat Fossil Fuel Heater Watlow Finned Strip Heaters 1kW Metro Services Ratiomatic 147 kW Metro Services Thermair Burner 44 kW Centrifugal Blower

30. Final Design

31. Sizing

32. Restriction & Cooling Plate

33. Instrumentation

34. Construction

37. Future Work • Complete construction of heat exchanger • Order or build Heating System • Utilize the R/V Quickwater

38. Acknowledgments • Travis Wallace • Richard Kimball • Paul Wlodkowski • Lynn Darnell • Joshua Henry • Timothy Allen • Alan Trundy • Stephen Collins • James Stefanski

39. Questions