Effects of heat enhancement for exhaust heat exchanger on the performance of thermoelectric generator

Lu, Chi; Wang, Shixue; Chen, Chen; Li, Yanzhe

doi:10.1016/j.applthermaleng.2015.05.086

Cited by 75 publications

(18 citation statements)

References 26 publications

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“…Variation of surface temperature (from 242°C to 208°C) and decrease in pressure drop (from 4.59 kPa to 0.98 Pa) are observed upon optimization. Introducing rectangular offset‐strip fins and metal foams, the heat transfer enhancement of exhaust heat exchanger is investigated by using simulations by Lu et al Metal foams with low porosity and small pore density showed better heat transfer enhancement with increased total power and TEG efficiency. To obtain high interface temperature and thermal uniformity for TEG modules, Liu et al examined 2 heat exchangers with different internal structures (fishbone‐shaped and chaos‐shaped) and thickness as shown in Figure .…”

Section: Technical Issues Faced In Eteg and Possible Solutionsmentioning

confidence: 99%

Thermoelectric conversion of waste heat from IC engine-driven vehicles: A review of its application, issues, and solutions

Patowary

Baruah

2018

Int J Energy Res

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Summary Thermoelectric generator (TEG) is a promising thermoelectric (TE) conversion technology to effectively recover and convert waste heat from vehicle exhaust into useful energy, ie, electricity. Exhaust TEG (ETEG) is a system that is incorporated into the exhaust manifold of a vehicle. Exhaust TEG comprises of a heat exchanger, TEG modules, heat sink, and power conditioning unit. The present work reviews different vehicular ETEGs based on engine type, engine‐rated power, type and number of TEG module, efficiency of ETEG and TEG, exhaust and coolant temperature, and power output of ETEG. In addition to these, the technical issues faced in these ETEGs are addressed under 2 categories, viz., primary (TEG with low ZT TE material and inefficient heat exchanger and heat sink) and secondary issues (low operating temperature TEG modules and installation position of ETEG). In addition to it, effects of vibration and thermal cycling of exhaust system on TEG modules that may arise in ETEG are also discussed. A review of preventive solutions to the issues is also presented. Finally, the economic aspects of an ETEG are also discussed. The review highlights the need of commercialization of TE materials with ZT > 2, high‐temperature operating range, and segmented TEG modules in large volumes so that their practice can be extended in vehicular applications. Heat exchanger modeling using computational fluid dynamics and interfacing with heat transfer theory is essential to maintain temperature uniformity across the TEG modules. Installation of ETEG in the exhaust pipe should be such that it does not affect the performance of the engine. It is also realized that sturdy TEG modules should be developed for long‐term operation to prevent degradation due to mechanical vibration and thermal cycling of the vehicle. Further, ETEG is economically beneficial in vehicles such as trucks owing to availability of high thermal energy in their exhaust stream.

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Section: Technical Issues Faced In Eteg and Possible Solutionsmentioning

confidence: 99%

Thermoelectric conversion of waste heat from IC engine-driven vehicles: A review of its application, issues, and solutions

Patowary

Baruah

2018

Int J Energy Res

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“…The effective temperature difference between the hot and cold sides of the TEG module was greatly affected by the heat transfer process when the heat source and heat sink were fixed. The temperature difference can be improved by applying proper heat transfer technologies and, thus, the efficiency of the TEG module can also be improved [17][18][19][20][21][22]. Zhao et al proposed an intermediate fluid thermoelectric generator system.…”

Section: Introductionmentioning

confidence: 99%

“…Results showed that there existed optimal fin transverse spacing and fin thickness for the maximum net power output. The total power output and efficiency of the TEG can be greatly improved by the metal foams [19]. Wang et al introduced dimpled surfaces to replace the inserts fins in the conventional hot heat exchanger.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study on the Effect of Interfacial Heat Transfer on Performance of Thermoelectric Generators

Wang

et al. 2019

Energies

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The application of thermoelectric generator (TEG) systems in waste heat recovery has attracted more and more attention. In this work, the effect of interfacial heat transfer on the performance of TEG module was experimentally and numerically investigated. Three kinds of thermal greases with thermal conductivities of 2.0, 2.5, and 3.0 W/(m∙K) were used as thermal interface materials (TIMs) to improve interfacial heat transfer at different external pressures ranging from 0.1 to 0.4 MPa. The open-circuit voltage, output power, and thermal interfacial resistance were measured at different experimental conditions. It was found that the performance of the TEG module can be greatly improved by using thermal greases as TIMs. The open-circuit voltages increased from 1.73 to either 3.07, 3.4, or 3.57 V with k = 2.0, 2.5, and 3.0 W/(m∙K) thermal greases respectively used as TIMs when the temperature difference was 60 °C and external pressure was 0.1 MPa. However, the performance of the TEG was slightly affected by external pressure when thermal greases used as TIMs. The open-circuit voltages were 3.07, 3.13, 3.17, and 3.20 V at external pressures of 0.1, 0.2, 0.3, and 0.4 MPa when the temperature difference ΔT = 60 °C and k = 2.0 W/(m∙K) thermal greases were used as TIMs.

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“…Due to their heat transfer coefficients their thermal resistances are good, however extra power consumption is needed since a pump is required to make the refrigerant circulate along the circuit. Thus, to optimize the net generation (the thermoelectric generation minus the consumption of the auxiliary equipment), the increase on thermoelectric generation and the increment of the auxiliary consumption have to be born in mind [6,7].…”

Section: Introductionmentioning

confidence: 99%

“…The effect of longitudinal vortex generators and the introduction of inserts or metal foams enhance heat transfer, but they provoke higher pressure drops, and hence the consumption of the pumps greatly increases [6,[8][9][10]. The increase in thermoelectric generation could not be as noticeable as the growth in the auxiliary consumption, obtaining lower net generations [6,11,12], a totally non-desirable scenario.…”

Section: Introductionmentioning

confidence: 99%

Auxiliary consumption: A necessary energy that affects thermoelectric generation

Aranguren

Araiz

Astrain

2018

Applied Thermal Engineering

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Waste heat recovery can apply to a wide range of applications, from transportation, or industries to domestic applications. The attempts to increase the efficiency of thermoelectric generators to make this technology appealing for waste heat harvesting include the study of novel heat exchangers to be located at the generators. A liquid cooling fluid presents high heat transfer coefficients. However, it needs a pump to make it circulate through the system. Besides, to have a constant input of fresh refrigerant, the dissipation systems need secondary heat exchangers to cool down the refrigerant, so as it can be reused again. A computational methodology, which simulates the behavior of thermoelectric generators has been used to determine the potential of waste heat harvesting. The optimal thermoelectric energy obtained using heat dissipation systems with liquid as the heat-carrier is 119 MWh/year, while the maximum net energy, the usable energy, is 73 MWh/year due to the consumption of the auxiliary equipment. The latest value does represent not only a 40 % reduction from the optimal thermoelectric

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Effects of heat enhancement for exhaust heat exchanger on the performance of thermoelectric generator

Cited by 75 publications

References 26 publications

Thermoelectric conversion of waste heat from IC engine-driven vehicles: A review of its application, issues, and solutions

Thermoelectric conversion of waste heat from IC engine-driven vehicles: A review of its application, issues, and solutions

Experimental and Numerical Study on the Effect of Interfacial Heat Transfer on Performance of Thermoelectric Generators

Auxiliary consumption: A necessary energy that affects thermoelectric generation

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