Preliminary Exam Presented by: Yacouba Moumouni Committee members : - PowerPoint PPT Presentation

Preliminary Exam Presented by: Yacouba Moumouni Committee members : Dr. R. Jacob Baker (Advisor and Chair) Dr. Yahia Baghzouz Dr. Rama Venkat, and Dr. Robert F. Boehm

Designing, building and testing a solar thermal electric generation, STEG, for energy delivery to remote residential areas in developing regions Contents Future Work .Contributions .Contributions Background of .Summary .Summary (The remaining the research .Publications (II) work) .Publications (I) 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 2

Part I--Background TEG inside “Insulation Box” Insulation foam water boiling Data logger/Laptop 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 3

Block diagram  4/20/2015 UNLV - Prelim Exam - Electrical Engineering 4

The Seven (7) TEG Modeling Steps Identify the Components Calculate the Biot Number Calculate the thermal R and C Define and draw parasitic elements (R, L, C) Express the Electrical equivalence of thermal parameters Connect the analogy blocks in series-parallel Run the TEG in LTspice 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 5

Thermal to Electrical Equivalence  Thermal Electrical o C/Watt Ohm (Resistor) Joules/ o C Farad (Capacitor) Watt Ampere (Current Source) o C Volt (Voltage Source) Ambient Temperature GND (0V) 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 6

Some TEG properties  Material ρ[kg/m 3 ]; c [J/kg · K]; κ[W/m · K] Aluminum 2770 875 177 Alumina 3570 837 35.3 Bi 2 Te 3 Al 2 O 3 Bi 2 Te 3 7530 544 1.5 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 7

TEG Parameters Internal Extracted from parasitic components Inductances Device Material and Datasheet properties geometries Capacitances 8 4/20/2015 UNLV - Prelim Exam - Electrical Engineering

Sample parameter computations  Mass of the ceramic plate The mass of the semiconductors  𝑛 𝐶𝑗2𝑈𝑓3 = 𝑛 𝑈 − 𝑛 𝑑𝑓𝑠 [𝑙𝑕] 3570𝑙𝑕  𝑛 𝑑𝑓𝑠 = 𝜍 ∙ 𝑊 𝑙𝑕 = ∙ = 4.8 − 2.239 ∙ 10 −2 𝑙𝑕 𝑛 3 0.056𝑛 2 ∙ (0.002𝑛) = 2.561 ∙ 10 −2 𝑙𝑕 = 2.239 ∙ 10 −2 𝑙𝑕 Molar heat capacity of the plate The molar heat capacity 𝐷 𝑛𝑝𝑚  𝐷 𝐶𝑗2𝑈𝑓3 = 𝑁 ∙ 𝑛 𝐶𝑗2𝑈𝑓3 [𝐾/𝐿]  𝐷 𝑑𝑓𝑠 = 𝜍 ∙ 𝐷𝑞 ∙ 𝑊 [𝐾/𝐿] 126.16𝐾∙𝑛𝑝𝑚 = 800.76𝑕∙𝑛𝑝𝑚∙𝐿 ∙ 25.61𝑕 3570𝑙𝑕∙837𝑋∙ 6.272 ∙ 10 −6 𝑛 3 = = 4.036𝐾 𝑛 3 ∙𝑛∙𝐿 = 18.74𝐾/𝐿 𝐿 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 9

Spice Model of the TEG  4/20/2015 UNLV - Prelim Exam - Electrical Engineering 10

Experimental Results  TEC Temp Variations 60 Hot side Temp Cold side Temp Differential Temp 50 40 Temp [Deg C] 30 20 10 0 0 5 10 15 20 25 30 35 Time [Min] 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 11

Comparative Results  Temp Variation Comparison Between Experimental and LTSpice Modeling 55 Hot Temp [LAB] Cold Temp [LAB] Cold Temp [SPICE] 50 Hot Temp [SPICE] 45 Temp [Deg C] 40 X: 10 Y: 37.31 35 30 25 20 1 2 3 4 5 6 7 8 9 10 Time [Min] 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 12

My Contributions (I)   Data extraction from the manufacturer datasheet, material properties, and device geometries  Utilization of the extracted data to compute the thermal capacities and thermal resistances necessary to perform the thermal to electrical conversion required for the simulation  Through the reverse polarity method, I was able to run the TEG as a TEC ( Δ T = 13.43°C )  I was the first to summarize concisely the Thermal to Electrical conversion methods into seven (7) broad steps  I was able to accurately compute all the parameters and lay out the LTspice model of the TEM  Successfully model the real behavior of the TEM through LTspice simulator 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 13

My Publications (I) Y. Moumouni and R. Jacob Baker, "Concise Thermal to Electrical Parameters Extraction of Thermoelectric Generator for Spice Modeling," accepted for publication in MWSCAS 2015. Y. Moumouni and R. Jacob Baker, "Improved SPICE Modeling and Analysis of a Thermoelectric Module," accepted for publication in MWSCAS 2015. 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 14

State of the art of TEG   TEGs have been proposed for woodstoves  Body heat powered watches  Car seat cooling/heating for passenger comfort ( Toyota, GM, Nissan, Ford, and Range Rover )  Industrial waste heat recovery to power ancillary devices  Vehicular waste heat recovery to enhance fuel economy  Harvesting micropower for low power applications such as wireless, mobile sensors, and bio-sensors 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 15

One of the Most recent TEG applications Previous studies Recent (STEG) mentioned: Domestic Rural (lighting, electrification heating, ventilating, etc.) UNLV - Prelim Exam - Electrical Engineering 4/20/2015 16

Literature Review ( Spice ) References Study  Limitations Chen et al. SPICE model of TEG and stabilization time Idealized T h and T c to be [33] after load change occurs constant [34] Demonstrated that Seebeck coefficient is dependent on temperature Lineykin et Developed a Spice compatible equivalent No enough precision in the al. [35] circuit of a TEM results – R of Al. plates and C of the chamber neglected. [36] An improved micro energy harvesting TEG in a Spice. Mihail [37] Proposed an energy harvesting system by Systems were limited to and means of the LTspice laboratory experiment Gontean et al. [32] 17 4/20/2015 UNLV - Prelim Exam - Electrical Engineering

Part II Complete Energy Harvesting System  • Solar Tracker U • 5 TEGs • Pyrheliometer • Solar flux sensor • Two Aluminum Heat exchangers • Two thermocouples (K) • Data logger N • DC-DC converter • Battery L • Wind speed sensor • Wind direction sensor V • Relative humidity sensor 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 18

Methods   Analytical Transient Heat Transfer-- Cumbersome  Numerical electrical analogy method is proposed  LTspice software simulator to be used  A lookup table of real data ( T H and T L ) created  Built-in piecewise linear (PWL)  Simulation speed improved  Experimental and simulated curves compared  Efficiency will be computed 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 19

Energy harvested  2 𝐽 2 ∙ 𝑆 𝐽𝑜𝑢 + 𝜆 ∙ ∆𝑈 = 0 1  𝑅𝑑 − 𝛽 ∙ 𝑈 𝐷 ∙ 𝐽 + 1 2 𝐽 2 ∙ 𝑆 𝐽𝑜𝑢 + 𝜆 ∙ ∆𝑈 = 0  𝑅ℎ − 𝛽 ∙ 𝑈 𝐼 ∙ 𝐽 − Electrical power generated  𝑄 𝐹𝑚𝑓𝑑𝑢 = 𝑅ℎ − 𝑅𝑑 = 𝛽 ∙ ∆𝑈 ∙ 𝐽 + 𝑆 𝐽𝑜𝑢 ∙ 𝐽 2 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 20

Data  UNLV - Prelim Exam - Electrical 4/20/2015 21 Engineering

Results before DC-DC converter Irradiance 1.4 1.2 INSOLATION [kW/m2]  1 0.8 0.6 0.4 0.2 0 0 100 200 300 400 500 TIME [min] Output Voltage w/o conv. Temperature profile 1000 120 900 800 100 700 TEMPERATURE [Deg. C] VOLTAGE [mV] 600 80 500 Tc 60 400 Th-Tc 300 40 Th 200 100 Ambient Temp. 20 0 0 100 200 300 400 500 0 -100 0 100 200 300 400 500 TIME [min] -20 22 TIME [min] 4/20/2015 UNLV - Prelim Exam - Electrical Engineering

Results (3V) Solar Irradiance 1.2 INSOLATION [kW/m2] 1  0.8 0.6 0.4 0.2 0 0 100 200 300 400 500 600 TIME [min] Voltage profile w/ conv. Temperature Variations 3500 120 3000 TEMPERATURE [Deg. C] 100 2500 VOLTAGE [mV] 80 2000 Th 1500 60 Tc 1000 40 Th-Tc 500 20 0 0 0 100 200 300 400 500 600 0 100 200 300 400 500 600 -500 TIME [min] TIME [min] 4/20/2015 UNLV - Prelim Exam - Electrical Engineering 23

Results (5V) Voltage profile w/ conv. Irradiance 6000 1.4 5000 1.2 INSOLATION [kW/m2]  1 4000 VOLTAGE [mV] 0.8 3000 0.6 2000 0.4 1000 0.2 0 0 0 50 100 150 200 250 0 50 100 150 200 250 -1000 TIME [min] TIME [min] TEMPERATURE VARIATIONS 90 80 3.2V TEMPERATURE [Deg. C] 70 60 50 Th 40 Tc 30 Th-Tc 20 10 0 0 50 100 150 200 250 -10 TIME [min] 24 4/20/2015 UNLV - Prelim Exam - Electrical Engineering

Summary of the Work (Physics and Theory) Seebeck effects Peltier effects Joule effects Thomson effects ( Negligible ) 25 4/20/2015 UNLV - Prelim Exam - Electrical Engineering

Summary of the Work (cont.) TEG efficiency increase is challenging STEG — Energy Harvesting System-- accordance with Electrical and Mechanical standards Thermal to Electrical Analogy (LTspice) A true 30 degrees increment manual solar tracker is proposed, instead of the real tracker (Seen above) Finally, Economic Analysis be performed UNLV - Prelim Exam - Electrical Engineering 4/20/2015 26