Enhancing Thermoelectric Energy Recovery Via Modulations of Source Temperature for Cyclical Heat Loadings

2005 ◽  
Author(s):  
R. McCarty ◽  
K. P. Hallinan ◽  
B. Sanders ◽  
T. Somphone
Keyword(s):  
Energy Recovery ◽  
Waste Heat ◽  
Equivalent Model ◽  
Thermoelectric Device ◽  
Thermoelectric Efficiency ◽  
Source Temperature ◽  
Thermal Switch ◽  
Thermoelectric Energy ◽  
Recovery System ◽  
Heat Loading

Very recent thermoelectric (TE) device materials improvements have pushed this technology to the cusp of usefulness in converting waste heat to electricity in a variety of applications — from automotive to aerospace. For applications where the heat loading is cyclical or non-constant, the effect of active control to maintain the source temperature at or near the peak allowable temperature while maximizing the temperature difference across a TE temporally on the overall thermoelectric efficiency is investigated. Efficiencies for constant heat loading applications that are not at near peak allowable temperatures are also investigated. The modulation of the source temperature would be achieved through the use of a ‘thermal switch’ or ‘active thermal potentiometer’ between the heat source and the thermoelectric device. Two methods are used to model the thermoelectric energy recovery system. First, an RC equivalent model is used to define the controlling factors for efficiency on a first order basis. Second, a numerical model is created to investigate the system in more detail. Both models demonstrate that maximizing the exergy of the source by maximizing its temperature during off-peak heat loadings is capable of improving the time-averaged efficiency of a thermoelectric device. For some conditions, improved time averaged efficiencies of more than 4 times are realized. Criteria defining the operation space where efficiency improvements are realized are also developed.

Enhancing Thermoelectric Energy Recovery via Modulations of Source Temperature for Cyclical Heat Loadings

2006 ◽  
Vol 129 (6) ◽  
pp. 749-755 ◽  
Author(s):  
R. McCarty ◽  
K. P. Hallinan ◽  
B. Sanders ◽  
T. Somphone
Keyword(s):  
Heat Flow ◽  
Energy Recovery ◽  
Waste Heat ◽  
Temperature Drop ◽  
Source Temperature ◽  
Physical Conditions ◽  
Thermal Switch ◽  
Thermoelectric Energy ◽  
In Series ◽  
Flow Through

Recent improvements in thermoelectric (TE) materials have expanded the potential to use this technology to generate electricity from waste heat in a variety of applications. The performance of a TE generator improves when the temperature difference across the generator is as large as possible given the constraints associated with its application. This paper considers the use of a “thermal switch,” located physically between the heat source and the TE device, to modulate the heat flow through the TE device. A control schema is envisioned which permits heat to flow from the source to the TE device only when the source temperature is near maximum, yielding a higher time-averaged temperature drop across the TE and therefore a higher efficiency. A numerical model is used to evaluate the benefits of an active thermal switch in series with a TE generator relative to a baseline case defined by the absence of a thermal switch for both time-varying and constant heat inputs. The results demonstrate that modulating the heat flow through the TE device and maintaining the source temperature at a near constant maximal value is capable of improving the time-averaged TE device energy recovery efficiency. For some conditions, improved efficiencies of more than five times are realized. The requisite physical conditions necessary for achieving these improvements are also identified.

scholarly journals High thermoelectric performance enabled by convergence of nested conduction bands in Pb7Bi4Se13 with low thermal conductivity

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lei Hu ◽  
Yue-Wen Fang ◽  
Feiyu Qin ◽  
Xun Cao ◽  
Xiaoxu Zhao ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Waste Heat ◽  
Low Frequency ◽  
Thermoelectric Performance ◽  
Environmental Crisis ◽  
Quality Factors ◽  
Thermoelectric Efficiency ◽  
Low Thermal Conductivity ◽  
Conduction Bands ◽  
Thermoelectric Energy

AbstractThermoelectrics enable waste heat recovery, holding promises in relieving energy and environmental crisis. Lillianite materials have been long-term ignored due to low thermoelectric efficiency. Herein we report the discovery of superior thermoelectric performance in Pb7Bi4Se13 based lillianites, with a peak figure of merit, zT of 1.35 at 800 K and a high average zT of 0.92 (450–800 K). A unique quality factor is established to predict and evaluate thermoelectric performances. It considers both band nonparabolicity and band gaps, commonly negligible in conventional quality factors. Such appealing performance is attributed to the convergence of effectively nested conduction bands, providing a high number of valley degeneracy, and a low thermal conductivity, stemming from large lattice anharmonicity, low-frequency localized Einstein modes and the coexistence of high-density moiré fringes and nanoscale defects. This work rekindles the vision that Pb7Bi4Se13 based lillianites are promising candidates for highly efficient thermoelectric energy conversion.

RACER Conceptual Design

1983 ◽  
Vol 105 (3) ◽  
pp. 621-626 ◽  
Author(s):  
J. T. Halkola ◽  
A. H. Campbell ◽  
D. Jung
Keyword(s):  
Gas Turbines ◽  
Energy Recovery ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Rankine Cycle ◽  
Fuel Saving ◽  
Fuel Savings ◽  
Waste Heat Recovery System ◽  
Recovery System

The Rankine Cycle Energy Recovery (or RACER) is an unfired waste heat recovery system designed for use aboard U.S. Navy gas turbine powered ships. The system converts waste heat from the exhaust of the main propulsion gas turbines into useful shaft horsepower and is currently planned for installation aboard the new DDG-51 class of ships. The design philosophy used in determining an overall system concept to minimize manning yet maximize availability, reliability and fuel savings is discussed. The paper also describes the trade-off analyses made to size the system in relation to overall fuel saving and gives a brief summary of the test programs to verify the system prior to ship installation.

scholarly journals Design and Simulation of a Waste Heat Recovery System for a Cement Manufacturing Process

2021 ◽  
Vol 23 (06) ◽  
pp. 1092-1101
Author(s):  
Tharun Sivakumar ◽  
Keyword(s):  
Energy Efficiency ◽  
Manufacturing Process ◽  
Energy Recovery ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Successful Implementation ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Heat Recovery System

As the ever-changing world continues to desperately look for alternative energy sources in the midst of an energy crisis, new technologies to recover power are revealing themselves and being implemented all across the globe. Most power plants are looking for more sustainable sources of energy over the long term. One such technology being adopted now by a lot of enterprises are Energy Recovery Systems. These systems work to retain and reuse energy that would otherwise be lost to the atmosphere after a certain process. They are sustainable and require comparatively lower capital. The objectives of this project revolve around the modelling of a Waste Heat Recovery System (WHRS) for a heat-intensive manufacturing process. The heat, which would otherwise be lost to the atmosphere, is trapped and converted by a heat recovery unit into reusable energy. The main principle on which such a system would operate is The Rankine Cycle, an idealized thermodynamic cycle. Successful implementation of such an energy recovery system would not just boost energy efficiency but also reduce operational costs. The modeling and simulation of the heat recovery system are done on an open-source chemical process flow software known as DWSIM. An analysis of this heat recovery model shows an increase of 19.66% in the energy efficiency of the manufacturing process. Heat recovery systems also have great benefits for the environment, as they reduce the emissions of greenhouse gases by such manufacturing plants and help reduce global warming.

New Perspectives in Thermoelectric Energy Recovery System Design Optimization

2013 ◽  
Vol 42 (7) ◽  
pp. 1725-1736 ◽  
Author(s):  
Terry J. Hendricks ◽  
Naveen K. Karri ◽  
Tim P. Hogan ◽  
Charles J. Cauchy
Keyword(s):  
Design Optimization ◽  
System Design ◽  
Energy Recovery ◽  
Energy Recovery System ◽  
Thermoelectric Energy ◽  
Recovery System ◽  
System Design Optimization

scholarly journals Realizing a 14% single-leg thermoelectric efficiency in GeTe alloys

2021 ◽  
Vol 7 (19) ◽  
pp. eabf2738
Author(s):  
Zhonglin Bu ◽  
Xinyue Zhang ◽  
Bing Shan ◽  
Jing Tang ◽  
Hongxia Liu ◽  
...  
Keyword(s):  
High Performance ◽  
Figure Of Merit ◽  
High Efficiency ◽  
Phonon Scattering ◽  
Waste Heat ◽  
Chemical Diffusion ◽  
Thermoelectric Device ◽  
Thermoelectric Efficiency ◽  
Good Service ◽  
Thermoelectric Figure

GeTe alloys have recently attracted wide attention as efficient thermoelectrics. In this work, a single-leg thermoelectric device with a conversion efficiency as high as 14% under a temperature gradient of 440 K was fabricated on the basis of GeTe-Cu2Te-PbSe alloys, which show a peak thermoelectric figure of merit (zT) > 2.5 and an average zT of 1.8 within working temperatures. The high performance of the material is electronically attributed to the carrier concentration optimization and thermally due to the strengthened phonon scattering, the effects of which all originate from the defects in the alloys. A design of Ag/SnTe/GeTe contact successfully enables both a prevention of chemical diffusion and an interfacial contact resistivity of 8 microhm·cm2 for the realization of highly efficient devices with a good service stability/durability. Not only the material’s high performance but also the device’s high efficiency demonstrated the extraordinariness of GeTe alloys for efficient thermoelectric waste-heat recovery.

scholarly journals The potential of thermoelectric energy harvesting in vehicles equipped with ICE

2019 ◽  
Vol 179 (4) ◽  
pp. 70-74
Author(s):  
Ryszard BUCHALIK ◽  
Krzysztof ROGOZIŃSKI ◽  
Grzegorz NOWAK
Keyword(s):  
Internal Combustion Engine ◽  
Heat Recovery ◽  
Waste Heat ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Thermoelectric Effects ◽  
Thermoelectric Energy ◽  
Thermoelectric Energy Harvesting ◽  
Recovery System ◽  
Engine Power

The paper deals with an issue of waste heat recovery in a selected configuration of an internal combustion engine. A possibility of using thermoelectric cells (currently available on the market) for production of electricity with heat extracted from the exhaust gas was considered. The calculations were made using specialized software. Features and design assumptions of the heat recovery system were presented and their influence on parameters of the entire system was investigated (efficiency of the internal combustion engine, power, etc.). An assessment of the applicability of the energy recovery system based on thermoelectric effects and characteristic of the proposed configuration was performed. Some issues that require further research have been highlighted.

Fuel economy analysis under a WLTP cycle on a mid-size vehicle equipped with a thermoelectric energy recovery system

Energy ◽  
2019 ◽  
Vol 179 ◽  
pp. 306-314 ◽  
Author(s):  
E. Massaguer ◽  
A. Massaguer ◽  
T. Pujol ◽  
M. Comamala ◽  
L. Montoro ◽  
...  
Keyword(s):  
Fuel Economy ◽  
Energy Recovery ◽  
Energy Recovery System ◽  
Thermoelectric Energy ◽  
Recovery System ◽  
Economy Analysis
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