Experimental Investigation of Heat Transfer Across a Thermoelectric Generator for Waste Heat Recovery From Automobile Exhaust

2013 ◽  
Author(s):  
Jaideep Pandit ◽  
Megan Thompson ◽  
Srinath V. Ekkad ◽  
Scott Huxtable
Keyword(s):  
Heat Transfer ◽  
Thermoelectric Generator ◽  
Waste Heat ◽  
Reynolds Numbers ◽  
System Level ◽  
Total Power ◽  
Exhaust Gases ◽  
The Past ◽  
Metal 3D Printing ◽  
Total Power Output

The study investigates the temperature gradients achieved across a thermoelectric generator by using the exhaust gases from a vehicle as a heat source and the radiator coolant as the cold sink. Various heat transfer enhancement features are employed in order to achieve as high a temperature gradient as possible. Effect of flow Reynolds numbers and inlet temperatures are examined to create a body of data predicting total power output from the TEG. Data is normalized against results from baseline heat exchanger designs investigated in the past. The experiments are carried out at 1/5th scale of the previously examined geometry. Impingement geometry is employed on the coolant side to enhance heat transfer. The experimental test sections are fabricated using metal 3D printing. Water is used instead of radiator coolant and heated air is used for exhaust gases. The results from the experiments provide valuable data which can be used for system level optimization.

Common Currency for System Integration of High Intensity Energy Subsystems

2011 ◽  
Author(s):  
David M. Pratt ◽  
David J. Moorhouse
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
High Intensity ◽  
Waste Heat ◽  
Integrated Approach ◽  
High Energy ◽  
Heat Fluxes ◽  
System Level ◽  
Level Energy ◽  
Common Currency

Aerospace vehicle design has progressed in an evolutionary manner, with certain discrete changes such as turbine engines replacing propellers for higher speeds. The evolution has worked very well for commercial aircraft because the major components can be optimized independently. This is not true for many military configurations which require a more integrated approach. In addition, the introduction of aspects for which there is no pre-existing database requires special attention. Examples of subsystem that have no pre-existing data base include directed energy weapons (DEW) such as high power microwaves (HPM) and high energy lasers (HEL). These devices are inefficient, therefore a large portion of the energy required to operate the device is converted to waste heat and must be transferred to a suitable heat sink. For HPM, the average heat load during one ‘shot’ is on the same order as traditional subsystems and thus designing a thermal management system is possible. The challenge is transferring the heat from the HPM device to a heat sink. The power density of each shot could be hundreds of megawatts. This heat must be transferred from the HPM beam dump to a sink. The heat transfer must occur at a rate that will support shots in the 10–100Hz range. For HEL systems, in addition to the high intensity, there are substantial system level thermal loads required to provide an ‘infinite magazine.’ Present models are inadequate to analyze these problems, current systems are unable to sustain the energy dissipation required and the high intensity heat fluxes applied over a very short duration phenomenon is not well understood. These are examples of potential future vehicle integration challenges. This paper addresses these and other subsystems integration challenges using a common currency for vehicle optimization. Exergy, entropy generation minimization, and energy optimization are examples of methodologies that can enable the creation of energy optimized systems. These approaches allow the manipulation of fundamental equations governing thermodynamics, heat transfer, and fluid mechanics to produce minimized irreversibilities at the vehicle, subsystem and device levels using a common currency. Applying these techniques to design for aircraft system-level energy efficiency would identify not only which subsystems are inefficient but also those that are close to their maximum theoretical efficiency while addressing diverse system interaction and optimal subsystem integration. Such analyses would obviously guide researchers and designers to the areas having the highest payoff and enable departures from the evolutionary process and create a breakthrough design.

Conjugate Heat Transfer Analysis of Internally Cooled Configurations

2001 ◽  
Author(s):  
David L. Rigby ◽  
Jan Lepicovsky
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Energy Equation ◽  
Reynolds Numbers ◽  
Heat Transfer Analysis ◽  
Navier Stokes ◽  
The Past ◽  
Flow And Heat Transfer ◽  
Internally Cooled ◽  
Solid Region

This paper describes the addition of conjugate capability to an existing Navier-Stokes code. Also, results are presented for an internally cooled configuration. The code is currently referred to as the Glenn-HT code, because of its origin at the NASA Glenn Research center and its proven ability to predict flow and Heat Transfer. In the past, the code had been called traf3d.mb. The addition of the conjugate capability to the code was accomplished with a minimum amount of changes to the code, with the understanding that if more advanced techniques were required they could be added at a later date. In the solid region, the density is constant and the velocities are of course zero which leaves only a simplified form of the energy equation to be solved. This simplified energy equation is solved using the same method as in the gas regions with only minor changes to the numerical parameters. At the interface between the gas and solid the wall temperature is set so as to produce the same heat flux in each region. Results are presented for a pipe flow to validate the implementation. Numerical and experimental results are then presented for flow over a flat plate that is cooled internally. Flat plate Reynolds numbers in the range 180,000 to 950,000, and coolant channel Reynolds numbers in the range 30,000 to 60,000 are presented.

Furnace Design for Improved Exhaust Gas Circulation and Heat Transfer Efficiency

2020 ◽  
Author(s):  
Ayoola T. Brimmo ◽  
Mohamed I. Hassan Ali
Keyword(s):  
Heat Transfer ◽  
Metal Surface ◽  
Flue Gas ◽  
Waste Heat ◽  
Operating Conditions ◽  
Aluminum Production ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Exhaust Gases ◽  
Gas Circulation

Abstract In the aluminum production industry, metal furnaces are operated by diffusion flame over the metal surface to maintain the aluminum metal at the set point temperature for alloying and casting. Heat is transferred from the flame and its exhaust gases to the metal surface via radiation and convection. The exhaust gases leaves through the furnace’s chimney carrying a significant amount of waste heat to the atmosphere. Furnace efficiency could be improved by enhancing the heat transfer inside the furnace. In this study, a validated full-scale 3-D CFD model of a natural gas fired aluminum furnace is developed to investigate the effect of flue gas ventilation configurations and burner operating conditions on the heat transfer inside the furnace. Onsite measurements are carried out for the fuel and airflow rates as well as flue gas temperature. Four flue ventilation configurations are considered with eight furnace’s operation modes. The flue-gas’s waste-heat varies from 49–58%, with the highest value occurring at the high-fire operating mode. This indicates a significant room for improvement in the furnace performance. Results suggest that a symmetrical positioning of the exhaust duct favors effective exhaust gas circulation within the furnace and hence, increases hot-gases’ heat-transfer effectiveness inside the furnace. These results provide some guidelines for optimal aluminum reverberatory furnace designs and operation.

Efficient Heat Transfer Methods in a Hybrid Solar Thermal Power System for the FSPOT-X Project

2015 ◽  
Author(s):  
David E. Lee ◽  
Bill Nesmith ◽  
Terry Hendricks ◽  
Juan Cepeda-Rizo ◽  
Michael Petach ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Power System ◽  
Waste Heat ◽  
Thermal Power ◽  
Electrical Power ◽  
System Level ◽  
System Efficiency ◽  
Hybrid Power System ◽  
Thermal Transfer ◽  
Hybrid Power

The FSPOT-X Project, focused on maximizing exergy generated from AM1.5 sunlight, targets an overall system efficiency of >35%. The objective hybrid power system will deliver grid-ready AC power while simultaneously providing thermal energy storage for dispatchable electrical power generation in post sunset conditions. The challenging system-level requirements flow-down critical temperature differential and thermal transport requirements to multiple system components and their interfaces. By integrating and demonstrating multiple technologies, the FSPOT-X hybrid power system seeks to efficiently convert photons to electrons maximizing heat transfer efficiency across system element interfaces. These include: I1) capturing all incident sunlight from the solar concentrator in a receiver cavity to maximize energy generation from the CPV cells, I2) extracting PV thermalization heat from the receiver and into the reflux chamber, I3) moving heat from the reflux chamber through the thermal transfer interface, I4) using the thermal transfer interface to shift heat into the TAPC’s hot heat exchanger, I5) storing excess unused heat in phase change material, and I6) disposal of waste heat at the system level. For each of these thermal interfaces, effective and efficient technical means are being used and applied in order to maximize overall system efficiency for delivery of a next generation cost-effective and market-ready solar power system.

Effect of Convection Heat Transfer on Performance of Waste Heat Thermoelectric Generator

2015 ◽  
Vol 36 (17) ◽  
pp. 1458-1471 ◽  
Author(s):  
Ronil Rabari ◽  
Shohel Mahmud ◽  
Animesh Dutta ◽  
Mohammad Biglarbegian
Keyword(s):  
Heat Transfer ◽  
Thermoelectric Generator ◽  
Waste Heat ◽  
Convection Heat Transfer ◽  
Convection Heat

scholarly journals Heat Transfer Characteristics of Thermoelectric Generator System for Waste Heat Recovery from a Billet Casting Process: Experimental and Numerical Analysis

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 601
Author(s):  
Saurabh Yadav ◽  
Jie Liu ◽  
Man Sik Kong ◽  
Young Gyoon Yoon ◽  
Sung Chul Kim
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Thermoelectric Generator ◽  
Cold Water ◽  
Waste Heat ◽  
Experimental Results ◽  
Inlet Temperature ◽  
Heat Transfer Characteristics ◽  
One Dimensional ◽  
Transfer Characteristics

In this study, experiments were performed to use the waste heat in a billet casting industry utilizing bismuth telluride thermoelectric generators (TEGs). Four d-type absorber plates made of copper were installed above the manufactured billet during the cooling process. Three sides of each absorber plate were attached to thermoelectric units. Therefore, a total of 12 units of the thermoelectric system were found to generate a power of 339 W. The power density of the TEG system was found to be 981 W/m2 while running the system at the operating voltage of the battery energy storage system (58 V). A one-dimensional numerical simulation was carried out using FloMASTERTM v9.1 (Mentor Graphics Corporation, Siemens, Dallas, TX, USA) to verify the experimental results, and the numerical results were found to exhibit good agreement with the experimental results. Furthermore, a one-dimensional numerical simulation was carried out to obtain the heat transfer characteristics at varying flow rates of cold water (Reynolds number = 2540–16,943) and at different inlet temperatures (10–25 °C) for the cold side of the TEG. The results indicate that the performance of the thermoelectric generator increases with an increase in the cold-water flow rate and a decrease in the inlet temperature of the cold water.

A Study of Heat Transfer Augmentation for Recuperative Heat Exchangers: Comparison Between Three Dimple Geometries

2012 ◽  
Vol 134 (7) ◽  
Author(s):  
Michelle I. Valentino ◽  
Lucky V. Tran ◽  
Mark Ricklick ◽  
J. S. Kapat
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Waste Heat ◽  
Rectangular Channel ◽  
Reynolds Numbers ◽  
Secondary Flows ◽  
Low Reynolds Numbers ◽  
Heat Transfer Augmentation ◽  
Flow Disturbances ◽  
Side Walls

This study presents an investigation of the heat transfer augmentation for the purpose of obtaining high effectiveness recuperative heat exchangers for waste heat recovery. The focus of the present work is in the fully developed portion of a 2:1 aspect ratio rectangular channel characterized by dimples applied to one wall at channel Reynolds numbers of 10,000, 18,000, 28,000, and 36,000. The dimples are applied in a staggered-row, racetrack configuration. In this study, a segmented copper test section was embedded with insulated dimples in order to isolate the heat transfer within the dimpled feature. The insulated material used to create a dimpled geometry isolates the heat transfer within the dimple cavity from the heat transfer augmentation on the surrounding smooth walls promoted by the flow disturbances induced by the dimple. Results for three different geometries are presented, a small dimple feature, a large dimple, and a double dimple. The results of this study indicate that there is significant heat transfer augmentation even on the nonfeatured portion of the channel wall resulting from the secondary flows created by the features. Overall heat transfer augmentations for the small dimples are between 13–27%, large dimples between 33–54%, and double dimples between 22–39%, with the highest heat transfer augmentation at the lowest Reynolds number for all three dimple geometries tested. Heat transfer within the dimple was shown to be less than that of the surrounding flat regions at low Reynolds numbers. Results for each dimple geometry show that dimples are capable of promoting heat transfer over the entire bottom wall surface as well as the side walls; thus the effects are not confined to within the dimple cavity.

scholarly journals Coupled simulation of a thermoelectric generator applied in diesel engine exhaust waste heat recovery

2020 ◽  
Vol 24 (1 Part A) ◽  
pp. 281-292 ◽  
Author(s):  
Guo-Quan Xiao ◽  
Zheng Zhang
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Diesel Engine ◽  
Thermoelectric Generator ◽  
Waste Heat ◽  
Cooling Water ◽  
Transfer Model ◽  
Outlet Temperature ◽  
Engine Exhaust ◽  
Diesel Engine Exhaust

This work develops a heat transfer model of a thermoelectric generator to explore the coupled relationship between high temperature exhaust flows, structure, and the external cooling air. The coupled heat transfer results showed that the fins reached a uniform high temperature, for the rated speed, the average temperature is 474 K. The coupled design scheme of the thermoelectric generator tested by installing it in a 4-cylinder turbocharged Diesel engine exhaust system. Comparison of the test and simulation results showed that as engine speed in-creased, the inlet and outlet exhaust temperatures of the thermoelectric generator exhibited a parabolic trend increase. The cooling water outlet temperature and the top, middle, and bottom fin temperatures increased linearly, and the coupled model was verified. From idle speed to rated speed, the top, middle, and bottom fin temperatures increased from 458 K to 476 K, 417 K to 463 K, and 406 K to 449 K, respectively; the cooling water outlet temperature increased from 293.6 K to approximately 303 K. Hence, the thermoelectric components installed in fins can experience temperature differences of over 100 K, the heat transfer efficiency can increase which ensures consistent output performance of the thermoelectric generator based on coupled design between the heat exchanger and thermoelectric modules array column.

scholarly journals Waste Heat Recovery from Exhaust Gases through I C Engine Using Thermoelectric Generator

2011 ◽  
Vol 3 (7) ◽  
pp. 270-271 ◽  
Author(s):  
Ajay Chandravanshi ◽  
◽  
Dr. J. G. Suryawanshi Dr. J. G. Suryawanshi
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Thermoelectric Generator ◽  
Waste Heat ◽  
Exhaust Gases
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