Power Generation Efficiency with Extremely Large Z factor Thermoelectric Material

2011 ◽  
Vol 1325 ◽  
Author(s):  
Kazuaki Yazawa ◽  
Ali Shakouri
Keyword(s):  
Power Generation ◽  
Thermoelectric Power ◽  
Output Power ◽  
Thermoelectric Material ◽  
Maximum Output Power ◽  
Maximum Output ◽  
Generation System ◽  
Thermoelectric Power Generation ◽  
Power Generation System ◽  
The Impact

ABSTRACTA recently developed generic model of a thermoelectric power generation system suggests a promising future for cost effective and scalable power generation. The model is based on co-optimizing the thermoelectric module together with the heat sink. Using this model, efficiency at maximum output power is calculated. It is shown that this approaches the Curzon-Ahlborn limit at very large Z values which is consistent with thermodynamic systems with irreversible heat engines. However, this happens only when the thermal resistances of the thermoelectric device with hot and cold heat sinks exactly match. For asymmetrical thermal resistances, the efficiency at maximum output power is different. This is consistent with the very recent results for the thermodynamic engines. Finally, we study the impact of lowering the thermal conductivity of the thermoelectric material or increasing its power factor and how these affect the performance of the thermoelectric power generation system.

Energy Payback Optimization of Thermoelectric Power Generator Systems

2010 ◽  
Author(s):  
Kazuaki Yazawa ◽  
Ali Shakouri
Keyword(s):  
Power Generation ◽  
Heat Source ◽  
Thermal Resistance ◽  
Thermoelectric Power ◽  
Output Power ◽  
Heat Sink ◽  
Generation System ◽  
Thermoelectric Power Generation ◽  
Energy Payback ◽  
Power Generation System

An analytic model for optimizing thermoelectric power generation system is developed and utilized for parametric studies. This model takes into account the external thermal resistances with hot and cold reservoirs. In addition, the spreading thermal resistance in the module substrates is considered to find the impact of designing small fraction of thermo elements per unit area. Previous studies are expanded by a full optimization of the electrical and thermal circuits. The optimum condition satisfies both electrical load resistance match with the internal resistance and the thermal resistance match with the heat source and the heat sink. Thermoelectric element aspect ratio and fill factor are found to be key parameters to optimize. The optimum leg length and the maximum output power are determined by a simple formula. The output power density per mass of the thermoelectric material has a peak when thermo elements cover a fractional area of ∼1%. The role of the substrate heat spreading for thermoelectric power generation is equally significant as thermoelement. For a given heat source, the co-optimization of the heat sink and the thermoelectric module should be performed. Active cooling and the design of the heat sink are customized to find the energy payback for the power generation system. The model includes both the air cooled heat sinks and the water cooled micro channels. We find that one can reduce the mass of thermoelement to around 3∼10% of that in commercial modules for the same output power, as long as the module and elements are designed properly. Also one notes that higher heat flux sources have significantly larger energy payback and reduced cost per output power.

Development and experimental research on circumferential impulse microturbine power generation system

2013 ◽  
Vol 228 (2) ◽  
pp. 378-387 ◽  
Author(s):  
L Zhang ◽  
GZ Tang ◽  
ZB Liao ◽  
HC Shang
Keyword(s):  
Power Generation ◽  
Output Power ◽  
Rotational Speed ◽  
Maximum Output Power ◽  
Iron Core ◽  
Maximum Output ◽  
Generation System ◽  
Coil System ◽  
Coil Structure ◽  
Power Generation System

Circumferential impulse microturbine is a key component of the micro-electro-mechanical system and provides power to the latter. An innovative concept of microturbine power generation system was presented, and prototype improved circumferential impulse microturbine power generation systems were developed, and their output performances were tested. It is validated that the system can operate at a high speed in a dynamic equilibrium state using rolling bearings, and it is found that the output power and rotational speed of a six-blade turbine hollow-cup coil structure is higher than the output power and rotational speed of a six-blade turbine iron-core coil structure. The maximum output power of the eight-blade turbine hollow-cup coil power generation system is 1.1 W, and the maximum turbine rotational speed is 55,000 r/min. The maximum output power of the eight-blade turbine hollow-cup coil system increases up to 25% when compared to the six-blade turbine hollow-cup coil system and increases up to 83% when compared to the six-blade turbine iron-core coil system.

Thermoelectric Power Generation System for Future Hybrid Vehicles Using Hot Exhaust Gas

2011 ◽  
Vol 40 (5) ◽  
pp. 778-783 ◽  
Author(s):  
Sun-Kook Kim ◽  
Byeong-Cheol Won ◽  
Seok-Ho Rhi ◽  
Shi-Ho Kim ◽  
Jeong-Ho Yoo ◽  
...  
Keyword(s):  
Power Generation ◽  
Thermoelectric Power ◽  
Hybrid Vehicles ◽  
Exhaust Gas ◽  
Generation System ◽  
Thermoelectric Power Generation ◽  
Power Generation System

Power generation performance of π-structure thermoelectric device using NaCo2O4 and Mg2Si elements

2013 ◽  
Vol 1490 ◽  
pp. 185-190 ◽  
Author(s):  
Tomoyuki Nakamura ◽  
Kazuya Hatakeyama ◽  
Masahiro Minowa ◽  
Youhiko Mito ◽  
Koya Arai ◽  
...  
Keyword(s):  
Power Generation ◽  
Thermoelectric Power ◽  
Thermoelectric Properties ◽  
Waste Heat ◽  
Maximum Output Power ◽  
Magnesium Silicide ◽  
Thermoelectric Device ◽  
Maximum Output ◽  
Thermoelectric Power Generation ◽  
P Type

ABSTRACTThermoelectric power generation has been attracting attention as a technology for waste heat utilization in which thermal energy is directly converted into electric energy. It is well known that layered cobalt oxide compounds such as NaCo2O4 and Ca3Co4O9 have high thermoelectric properties in p-type oxide semiconductors. However, in most cases, the thermoelectric properties in n-type oxide materials are not as high. Therefore, n-type magnesium silicide (Mg2Si) has been studied as an alternative due to its non-toxicity, environmental friendliness, lightweight property, and comparative abundance compared with other TE systems. In this study, we fabricated π-structure thermoelectric power generation devices using p-type NaCo2O4 elements and n-type Mg2Si elements. The p- and n-type sintering bodies were fabricated by spark plasma sintering (SPS). To reduce the resistance at the interface between elements and electrodes, we processed the surface of the elements before fabricating the devices. The end face of a Mg2Si element was covered with Ni by SPS and that of a NaCo2O4 element was coated with Ag by silver paste and soldering.The thermoelectric device consisted of 18 pairs of p-type and n-type legs connected with Ag electrodes. The cross-sectional and thickness dimensions of the p-type elements were 3.0 mm × 5.0 mm × 7.6 mm (t) and those of the n-type elements were 3.0 mm × 3.0 mm × 7.6 mm (t). The open circuit voltage was 1.9 V and the maximum output power was 1.4 W at a heat source temperature of 873 K and a cooling water temperature of 283 K in air.

Effects of Non-Uniform Hot Junction Temperature Distribution on the Outputs of Thermoelectric Power Generation System

2013 ◽  
Vol 283 ◽  
pp. 87-97 ◽  
Author(s):  
Bimrew Tamrat Admasu ◽  
Xiao Bing Luo ◽  
Jia Wei Yao ◽  
Ting Zhen Ming
Keyword(s):  
Power Generation ◽  
Finite Element ◽  
Temperature Distribution ◽  
Thermoelectric Power ◽  
Material Property ◽  
Thermoelectric Module ◽  
Element Formulation ◽  
Generation System ◽  
Thermoelectric Power Generation ◽  
Power Generation System

Abstract. Besides the material property and dimensional optimization of the thermoelectric module, temperature distribution uniformity on the hot junction of the module surface highly affects the outputs of the thermoelectric power generation system. This paper reports the findings on the effects of non-uniform input temperature distribution on the performance of thermoelectric power generation system. To assure the investigation, heat transfer model and finite element formulation of thermoelectric module having non-linear material property have been developed. In addition to the experimental data from a real thermoelectric device, thermoelectric power generation system modeling and simulation using finite element packaging ANSYS software was carried out. For the simulation, temperature dependent thermoelectric material properties such as the Seebeck coefficient, thermal and electrical conductivity have been considered. The experimental and simulation results indicate that keeping the temperature distribution uniform on the hot junction of the thermoelectric module results higher efficiency, higher power, voltage and current outputs than the non-uniform temperature distribution.

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