Document
Solid State Energy Harvesting and Power
Conversion in Gas Turbine Engines
NASA Aeronautics Research Institute
Jon Goldsby, Ph.D., MBA Engineer NASA Glenn Research Center
Concept Overview
o 656 C o 536 C o 929 C o 1558 C • Solid state energy harvesting using waste heat available in gas turbine engine offers potential for power generation to meet growing power needs of Thermionic aircraft + • Thermoelectric material advances offer new Thermoelectric opportunities • Weight - optimized integrated turbine engine structure incorporating energy conversion devices Calculated power available in various Parts of the gas turbine engine
Utilization Concept: Heat Exchanger
Type of heat exchanger: Counter flow TEG Design
• One hot air channel and two
cold air channels.
• Hot air channel is between
cold air channels.
Parametric Optimization of Thermoelectric Generators for Waste Heat Recovery Shouyuan Huang, Xianfan Xu Journal of Electronic Materials 45(10) · June 2016 Skutterudite based modules from Marlow Industries
o
Results – 1, cold air T = - 35 C
Integral treatment 1, Counter flow, 𝑚 = 0 . 09𝑘𝑔 / 𝑠 ; 𝑇 = 604℃ ; ℎ ℎ𝑜𝑡 , 𝑖𝑛 Cold inlet: 𝑇 = − 35℃ , 𝑚 = 0 . 18𝑘𝑔 / 𝑠 𝑐𝑜𝑙𝑑 𝑐𝑜𝑙𝑑 , 𝑡𝑜𝑡𝑎𝑙 TEG hot inlet: 𝑇 = 377℃ ℎ𝑜𝑡 , 𝑖𝑛𝑙𝑒𝑡 , 𝑇𝐸𝐺 𝒎 (kg) 𝒎 𝑻 𝑷 𝑷 𝑷 𝑸 𝑩 𝒊 𝑻 𝒆 𝒓𝒆𝒄𝒚𝒄𝒍𝒆 𝒄𝒐𝒍𝒅 , 𝒐𝒖𝒕 , 𝑻𝑬𝑮 𝒕𝒐𝒕𝒂𝒍 𝟏 𝟐 𝒕𝒐𝒕𝒂𝒍 𝟐 𝟑 (kW) (kW) (kW) (kW) (C) (kg/s) 1.73 0.175 256 0.88 1.75 40.45
2.64
Design of TEG 𝐴 0.016 m 𝑝𝑟𝑒𝑐𝑜𝑜𝑙 𝑊 0.17 m 𝑇𝐸 𝐺 𝐿 0.75 m 𝑇𝐸 𝐺 𝑊 0.33 m 𝑇𝐸 𝐺 𝐿 0.75 m 𝑇𝐸 𝐺 ℎ 1.3 mm 𝑙𝑒𝑔
Thermoelectric generator Module Bi Te
2 3
Test Setup
Measurements Bi 2 Te 3 module • Module is kept in the package for electrical insulation and mechanical contact reasons.
• TCs mounted on copper surfaces ( T_TEMH1 - 3, T_TEMC1 - 3) , thus Δ 𝑇 measured includes metal bulk and interface resistance of metal and ceramic.
• Unable to put TCs inside, at edge of TEM (T_TEMH4, T_TEMC4 ) instead to estimate thermal resistance between copper surfaces and TEM surfaces
Test Results
Bi 2 Te 3 module IV sweep were taken (left figure below) and the maximum power was obtained at each D T.
Heat Exchangers - TEGs cause significant gains in weight and size due to thermal resistance Surfaces - LPC – Miniscule opportunity (ΔT small) - HPC – Small opportunity - Diffuser – Single kW, but do not want to create hot spots or remove heat from cycle - HPT and LPT – 10 kW contingent on avoidance of hot spots, TEG material robustness.
- Distributed, small scale power generation for wireless sensors on aircraft appear promising. A TEG measuring approximately 1 in 2 generates 50 mW to power sensing and transmission circuits.
Characteristics for a desirable thermoelectric material
• Seebeck Coefficient ~ 100uV/K
- 2
• Electrical Resistivity 10 Ohm*cm
• Thermal Conductivity ~ 10 W/m*K
• Electronic Band Gap - must be greater than zero
• High Temperature Capability
Computational Methods
BoltzTraP. A code for calculating band - structure dependent quantities ✩ Georg K.H. Madsen a , ∗ , David J. Singh b Computer Physics Communications 175 (2006) 67 – 71 Vienna Ab - initio Simulation Package Computing Platform: The Vienna Ab - initio Simulation Package, better known Hewlett - Packard Z840 Workstation as VASP , is a package for performing ab initio quantum Dual 18 - core intel Xeon processors mechanical molecular dynamics using either Vanderbilt Widows 10 pro 64 - bit pseudopotentials, or the projector augmented wave 128 GB ram method, and a plane wave basis set HEWLETT PACKARD HP Z820 WORKSTATION 2 INTEL XENON PROCESSORS ALLOWING 32 CORES FOR CALCULATION WITH 192 GB OF RANDOM ACCESS MEMORY Complex Skutterudites Thermoelectric (Mackey, Dynys) Nd0.6Fe2Co2Sb11.85Ge0.15
A Recommendation Engine for Suggesting
Unexpected Thermoelectric Chemistries
Michael W. Gaultois , Anton O. Oliynyk , Arthur Mar ,
Taylor D. Sparks , Gregory J. Mulholland , Bryce Meredig
(27 Feb 2015)
Complex Oxide – based Pyrochlores
3+ ~ 5+
mixed cation at B - site A (B , B ) O
2 7
Gd RuTaO
2 7
Provisional utility patent application was filed NASA Docket No.: LEW 19688 - 1
Calculated Cell Parameters
Parameter Original change Final % ---------- ------------ ---------- ------------ ----- a 10.091900 0.158505 10.250405 1.6 b 10.091900 0.137867 10.229767 1.4 c 10.091900 0.156757 10.248657 1.6 alpha 90.000000 - 0.361354 89.638646 - 0.4 beta 90.000000 0.392175 90.392175 0.4 gamma 90.000000 0.047839 90.047839 0.1 Volume 1027.824144 46.795542 1074.619686 4.6 Modulus Voigt Reuss Hill Density: 8.759 Mg/m^3 ------------ --------- --------- --------- Bulk 184.90 183.56 184.23 GPa Shear 90.75 89.78 90.27 Young's 233.98 231.59 232.78 Longitudinal 304.59 Elastic constant matrix (GPa): | 1 2 3 4 5 6 Velocity of sound ----- | ------------------------------------------------------------ 1 | 303.99 122.74 112.40 0.00 0.00 0.00 Calculated from Hill moduli: 2 | 122.74 342.62 128.66 0.00 0.00 0.00 transverse waves: 3271 m/s 3 | 112.40 128.66 289.89 0.00 0.00 0.00 longitudinal waves: 6009 m/s 4 | 0.00 0.00 0.00 98.03 0.00 0.00 mean: 3649 m/s 5 | 0.00 0.00 0.00 0.00 76.22 0.00 6 | 0.00 0.00 0.00 0.00 0.00 88.62 Debye temperature: 465.9 K - 6 the thermal coefficient of linear expansion at 600K = 7.60 x 10
Calculated Electronic Band Structure
Heyd – Scuseria - Ernzerhof (HSE06) Perdew – Ernzerhof – Burke (PBE) Cut off energy of 575 eV k - spacing 0.199/ A and 4x4x4 k mesh using DFT PBE the bandgap is 0.07 eV
Electrical Conductivity
-1 1.6x10 Chemical Potential, eV u = -0.032 u = 0.008 1.4x10 u = 0.89 1.2x10 1.0x10 Electrical Conductivity, (Ohm*m) 8.0x10 0 200 400 600 800 1000 1200 Temperature, K
Temperature dependent Seebeck coefficient
Chemical Potential, eV u = -0.032 u = 0.008 u= 0.089 V/K Seebeck Coeff, 400 600 800 1000 1200 Temperature, K Molecular Dynamic Computational Results:
Large - scale Atomic/Molecular Massively Parallel Simulator ( LAMMPS)
2.0 1.8 1.6 1.4 LAMMPS Pressure = 1 atm 1.2 Time Step = 1 fs 1.0 0.8 0.6 Buckingham force field: • Gd - Ru - O force field parameters came from Minervini, RW Grimes, KE Sickafus J Am Ceram 0.4 Soc 83 (2000), • Ta - O parameters came from S.M.Woodley, P.D.Battle, J.D.Gale and C.R.A.Catlow Phys.
0.2 Chem. Chem. Phys., 1, 2535 - 2542 (1999).
0.0 Thermal Conductivity, W/m*K 400 500 600 700 800
Temperature, K
2Gd O + Ta O + 2RuO 2Gd (Ta, Ru)O + ½ O
2 3 2 5 2 2 7 2 Solid state reaction, mechanical mixing, sintering in air, hot pressing
CONCLUSIONS
• Potential exist to harvest electrical power from excess enthalpy from
gas turbine engines.
• Computational methods have enabled some fundamental parameters
to be predicted in the development of thermoelectric materials.
• Some descriptions (band structure) are very sensitive to such things as
mesh density.
• Oxide pyrochlores have potential as a thermoelectric materials.