Highly Integrated Heat Exchangers for Automotive Thermoelectric - PowerPoint PPT Presentation

www.DLR.de • Chart 1 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 Highly Integrated Heat Exchangers for Automotive Thermoelectric Generators (TEG) Methodical functional integration and numerical analysis of TEG heat exchangers Institut of Vehicle Concepts M. Kober H. Friedrich

www.DLR.de • Chart 2 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 Outline • Introduction • Methodical concept development acc. to VDI Guideline 2221 • Module structure used for functional integration • Comparison between three heat exchanger approaches • Numerical and analytic analysis with focus on • Fin buckling • Reduction of thermomechanical stress • Homogenisation of contact pressure

www.DLR.de • Chart 3 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 Evolution of TEG at DLR

www.DLR.de • Chart 4 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 Abgas Abgas Introduction heiß heiß Why use high temperature TE-Materials? n n p p - - + + - - + + • Comparison between Bithmuth Telluride and Skutterudite kalt kalt • Exemplarily Materials with zT max = 1 Kühlmittel Kühlmittel    U S T 55% 1,1 50% 1,0 𝑨𝑈 = 𝑇 2 ∗ 𝜏 45% 0,9 ∗ 𝑈 η_ Carnot 𝜆 40% 0,8 η_ ex Bi2Te3 η_ overall Bi2Te3 Efficiency η [%] 35% 0,7 𝜃 max = 𝜃 Carnot ∗ 𝜃 ex η_ ex CoSb3 Figure of Merit zT 30% 0,6 η_ overall CoSb3 zT Bi2Te3 25% 0,5 𝜃 Carnot = 𝑈 h − 𝑈 c zT CoSb3 20% 0,4 𝑈 h 15% 0,3 1 + 𝑨𝑈 𝑛 − 1 10% 0,2 𝜃 ex = 5% 0,1 1 + 𝑨𝑈 𝑛 + 𝑈 c /𝑈 h 0% 0,0 100 200 300 400 500 Hot Side Temperature T_h [ ° C]

www.DLR.de • Chart 5 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 Abgas Abgas Introduction heiß heiß Why use high temperature TE-Materials? n n p p - - + + - - + + • Higher efficiency at high temperatures mainly through kalt kalt higher Carnot efficiency • zTmax=1 leads to an exergy efficiency 𝜃 ex ~ 17% Kühlmittel Kühlmittel    U S T 55% 1,1 50% 1,0 𝑨𝑈 = 𝑇 2 ∗ 𝜏 45% 0,9 ∗ 𝑈 η_ Carnot 𝜆 40% 0,8 η_ ex Bi2Te3 η_ max Bi2Te3 Efficiency η [%] 35% 0,7 𝜃 max = 𝜃 Carnot ∗ 𝜃 ex η_ ex CoSb3 Figure of Merit zT 30% 0,6 η_ max CoSb3 zT Bi2Te3 25% 0,5 𝜃 Carnot = 𝑈 h − 𝑈 c zT CoSb3 20% 0,4 𝑈 h 15% 0,3 1 + 𝑨𝑈 𝑛 − 1 10% 0,2 𝜃 ex = 5% 0,1 1 + 𝑨𝑈 𝑛 + 𝑈 c /𝑈 h 0% 0,0 100 200 300 400 500 Hot Side Temperature T_h [ ° C] Cold Side Temperature T_c = 100 ° C

www.DLR.de • Chart 6 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 Abgas Abgas Introduction heiß heiß Why use high temperature TE-Materials? n n p p - - + + - - + + • Higher efficiency at high temperatures mainly through kalt kalt higher Carnot efficiency • zTmax=1 leads to an exergy efficiency 𝜃 ex ~ 17% Kühlmittel Kühlmittel    U S T 55% 1,1 50% 1,0 𝑨𝑈 = 𝑇 2 ∗ 𝜏 45% 0,9 ∗ 𝑈 η_ Carnot 𝜆 40% 0,8 η_ ex Bi2Te3 η_ max Bi2Te3 Efficiency η [%] 35% 0,7 𝜃 max = 𝜃 Carnot ∗ 𝜃 ex η_ ex CoSb3 Figure of Merit zT 30% 0,6 η_ max CoSb3 zT Bi2Te3 25% 0,5 𝜃 Carnot = 𝑈 h − 𝑈 c zT CoSb3 20% 0,4 𝑈 h 15% 0,3 1 + 𝑨𝑈 𝑛 − 1 10% 0,2 𝜃 ex = 5% 0,1 1 + 𝑨𝑈 𝑛 + 𝑈 c /𝑈 h 0% 0,0 100 200 300 400 500 Hot Side Temperature T_h [ ° C] Cold Side Temperature T_c = 100 ° C

www.DLR.de • Chart 7 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 Procedural method VDI Guideline 2221

www.DLR.de • Chart 8 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 List of requirements e.g. Vehicle boundary conditions DLR – test vehicle BMW 535i 3l, 6 cylinder, spark ignition 190kW @ 6600 1/min A B C installation space length 210mm 400mm 440mm width 290mm 170mm 270mm height 190mm 150mm 170mm 1) Kober, M. ; Häfele, C. ; Friedrich, H. E. (2012) Methodical Concept Development of Automotive Thermoelectric Generators (TEG). 3. International Conference 'Thermoelecrics goes Automotive', 2012, Berlin, Deutschland. λ

www.DLR.de • Chart 9 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 List of requirements e.g. Gas temperatures along exhaust system Volllast 126 g/s 1000 Full load 126 g/s 160 km/h, 6. Gear, 55 g/s 160 km/h, 6.Gang 55 g/s 145 km/h, 6.Gang 45 g/s 145 km/h, 6. Gear, 45 g/s 900 135 km/h, 6.Gang 39 g/s 135 km/h, 6. Gear, 39 g/s 120 km/h, 6.Gang 28 g/s 120 km/h, 6. Gear, 28 g/s 800 Exhaust gas temperatures [°C] 100 km/h, 6.Gang 23 g/s 100 km/h, 6. Gear, 23 g/s 70 km/h, X. Gear, 17 g/s 70 km/h, X.Gang 17 g/s 700 50 km/h, 5. Gear, 9 g/s 50 km/h, 5.Gang 9 g/s 600 500 400 300 200 100 1) 0 Gas temperatures along exhaust system at different steady state driving conditions with replaced NO x -catalyst. 1) Kober, M. ; Häfele, C. ; Friedrich, H. E. (2012) Methodical Concept Development of Automotive Thermoelectric Generators (TEG). 3. International Conference 'Thermoelecrics goes Automotive', 2012, Berlin, Deutschland.

www.DLR.de • Chart 10 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 Interactions of TEG and vehicle system electrical TEG input power   ( ) P cooling load ( ) P in co (el. power for cooling water pump and cooling fan)  P back pressure / cooling of exhaust rolling resistance ( ) ro  ( ) P (weight increase) pr

www.DLR.de • Chart 11 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 TEG concept development – Function structure exhaust + exhaust + heat heat feed heat dissipate exhaust transfer exhaust electric energy conduct distribute heat convert dissipate heat smoothly heat electric energy provide distribute contact conduct force pressure smoothly heat coolant + heat coolant feed dissipate heat to dissipate coolant coolant coolant 1) 1) Kober, M. ; Häfele, C. ; Friedrich, H. E. (2012) Methodical Concept Development of Automotive Thermoelectric Generators (TEG). 3. International Conference 'Thermoelecrics goes Automotive', 2012, Berlin, Deutschland.

www.DLR.de • Chart 12 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 TEG concept development – Sub-solutions sub-solutions sub-functions 1 2 3 4 5 6 7 feed/dissipate exhaust heat transfer conduct heat distribute heat smoothly dissipate electric energy conduct heat feed/dissipate coolant provide force distribute contact pressure 1) smoothly A2 E1 A4 B1 A3 A1 D1 C1 B2 A4 1) Kober, M. ; Häfele, C. ; Friedrich, H. E. (2012) Methodical Concept Development of Automotive Thermoelectric Generators (TEG). 3. International Conference 'Thermoelecrics goes Automotive', 2012, Berlin, Deutschland.

www.DLR.de • Chart 13 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 Overall system simulations Results for design point 135 km/h 1,0 A4 1,0 Legend: Design A4 0,5 Change in fuel consumption Change of fuel consumption [%] 0,0 Change of shaft power [%] Streckenverbrauchsänderung [%]. additional system Wellenleistungsänderung [%]  TEG as add on % F -0,5 A B C add -0,54 optimized total -0,79 -1,0 -0,95  vehicle system % F opt -1,5 -1,44 Effect on basic shaft power -2,0 -1,92 el. TEG input  % P   in   -2,5 Δ Δ Δ Δ back pressure  % P   Δ pr  Δ  Δ Δ -3,0 cooling load -2,98  % P   Δ Δ co   -3,5 Δ Δ rolling resistance  % P 1) ro -4,0 A B C 1) Kober, M. ; Häfele, C. ; Friedrich, H. E. (2012) Methodical Concept Development of Automotive Thermoelectric Generators (TEG). 3. International Conference 'Thermoelecrics goes Automotive', 2012, Berlin, Deutschland.

www.DLR.de • Chart 14 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 How can functional integration be done to reduce the TEG weight and thermomechanical stress? ? ?

www.DLR.de • Chart 15 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 Module structure (acc. to VDI 2221) for functional integration within heat exchangers

www.DLR.de • Chart 16 > Highly Integrated Heat Exchangers for Automotive TEG > M. Kober > 03.12.2013 Module structure (acc. to VDI 2221) for functional integration within heat exchangers exhaust + exhaust + heat heat feed heat dissipate exhaust transfer exhaust electric energy conduct distribute heat convert dissipate heat smoothly heat electric energy provide distribute contact conduct force pressure smoothly heat coolant + heat coolant feed dissipate heat to dissipate coolant coolant coolant functional integration of thermal and mechanical functions within the hot gas heat exchanger