MODELING OF AN AUTOMOTIVE EXHAUST THERMOELECTRIC GENERATOR

Journal of Electronic Materials, 2018

In an internal combustion engines; efficiency of engine is around 30 %, roughly 30% of the fuel energy is wasted in exhaust gases, and 30% in cooling water and 10% are unaccountable losses. Efforts are made to catch this 30 % energy of exhaust gases. If this waste heat energy is tapped and converted into usable energy, the overall efficiency of an engine can be improved. Thermoelectric modules which are solid state devices that are used to convert thermal energy to electrical energy from a temperature gradient and it works on principle of Seebeck effect.

Energies, 2021

Nearly 70% of the energy produced from automotive engines is released to the atmosphere in the form of waste energy. The recovery of this energy represents a vital challenge to engine designers primarily when a thermoelectric generator (TEG) is used, where the availability of a continuous, steady-state temperature and heat flow is essential. The potential of semi-truck engines presents an attractive application as many coaches and trucks are roaming motorways at steady-state conditions most of the time. This study presents an analytical thermal design and an experimental validation of the TEG system for waste heat recovery from the exhaust of semi-truck engines. The TEG system parameters were optimized to achieve the maximum power output. Experimental work was conducted on a specially constructed setup to validate the analytically obtained results. Both analytical and experimental results were found to be in good agreement with a marginal deviation, indicating the excellent accuracy...

Renewable Energy and Power Quality Journal, 2017

Thermoelectric generators (TEGs) have become a promising technology for vehicle exhaust heat recovery. In this paper, a novel prototype with reduced thermal inertia, low size and capable to withstand the exhaust highest temperatures has been proposed. A small-scale prototype has been built and tested for further study. Results of experiment show the reasonability for exhaust heat recovery. The prototype can generate a maximum power output of about 111 W when operating at exhaust temperatures of 700 ºC. The vehicle speed is a significant factor affecting the TEG performance for waste heat recovery. It can be found that the higher the vehicle speed is, the better the performance of the ATEG is. Also the temperature of the cooling system strongly affects the ATEG performance. Higher water cooling temperatures reduce temperature difference between hot and cold side of TEGs and cause a reduction on ATEG efficiency.

2017

Thermoelectrictechnology has good potential for its application as automotive exhaust based thermoelectric generator (TEG). In this work, the temperature variation on the surface of the automotive exhaust thermoelectric generator (AETEG) heat exchanger has been studied.The surface of heat exchanger acts as base for applying TEG modules to recover waste heat from the exhaust. Experiments have been carried out by varying the distance of the AETEG heat exchanger from the engine exhaust side by increasing pipe’s length. In addition to it, the load on the engine was also varied to study its effects. These experimental results have been validated by simulating the same cases in CFD solver Star CCM. The experimental results show good agreement with the computed results. Simulation and experiments, both reveal that the variation in length of the pipe has very little effect on the temperature distribution on AETEG, however increasing the load increases the temperature on AETEG due to the inc...

2020

15 One of the main obstacles for the use of thermoelectric generators (TEGs) in vehicles is the highly variable 16 thermal loads typical of driving cycles. Under these conditions it will be virtually impossible for a conventional 17 heat exchanger to avoid both thermal dilution under low thermal loads and TEG overheating under high thermal 18 loads. The authors have been exploring an original heat exchanger concept able to address the 19 aforementioned problems. It uses a variable conductance thermosiphon-based phase-change buffer between 20 the heat source and the TEGs so that a nearly constant, optimized temperature is obtained regardless of 21 operating conditions. To the best of the authors’ knowledge, the thermal control feature of the system is unique 22 among existing TEG concepts. The novelty of the present work is the actual computation of operating pressure 23 and temperature and the corresponding vaporization and condensation rates inside the thermosiphon system 24 during...

Ideal heat exchangers recover as much heat as possible from an engine exhaust at the cost of an acceptable pressure drop. They provide primary heat for a thermoelectric generator (TEG), and their capacity and efficiency is dependent on the material, shape, and type of the heat exchanger. Six different exhaust heat exchangers were designed within the same shell, and their computational fluid dynamics (CFD) models were developed to compare heat transfer and pressure drop in typical driving cycles for a vehicle with a 1.2 L gasoline engine. The result showed that the serial plate structure enhanced heat transfer by 7 baffles and transferred the maximum heat of 1737 W. It also produced a maximum pressure drop of 9.7 kPa in a suburban driving cycle. The numerical results for the pipe structure and an empty cavity were verified by experiments. Under the maximum power output condition, only the inclined plate and empty cavity structure undergoes a pressure drop less than 80 kPa, and the largest pressure drop exceeds 190 kPa. In this case, a mechanism with a differential pressure switch is essential to bypass part of the exhaust.

Renewable Energy and Power Quality Journal, 2017

Because of the increasing emphasis on environmental protection, applications of thermoelectric technology are being extensively studied. Before a new car is released to the market, testing is undertaken to ensure it meets the latest emissions regulations. The regulations differ from country to country, but they are always getting more stringent. To meet these tightening regulations, car companies must reduce the fuel consumption of their cars. A waste heat recovery system has the potential to convert some of this waste heat into electricity and consequently reduce the fuel consumption of the car by reducing the load on the car alternator The present experimental and computational study investigates an exhaust gas waste heat recovery system (WHRS) for vehicles, using thermoelectric modules and a heat exchanger to produce electric power.

Energies, 2018

The need for more sustainable mobility promoted research into the use of waste heat to reduce emissions and fuel consumption. As such, thermoelectric generation is a promising technique thanks to its robustness and simplicity. Automotive thermoelectric generators (ATEGs) are installed in the tailpipe and convert heat directly into electricity. Previous works on ATEGs mainly focused on extracting the maximum amount of electrical power. However, the back pressure caused by the ATEG heavily influences fuel consumption. Here, an ATEG numerical model was first validated with experimental data and then applied to investigate the effects that modifying the main ATEG design parameters had on both fuel economy and output power. The cooling flow rate and the geometrical dimensions of the heat exchanger on the hot side and the cold side of the ATEG were varied. The design that produced the maximum output power differed from that which maximized fuel economy. Back pressure was the most limiting...

International Journal of Control and Automation, 2016

This paper gives an overview on the use of thermoelectric materials to generate electricity through the waste heat of the exhaust gases of a vehicle. Various thermoelectric modules will be attached to the end of the exhaust of the vehicle. The exhaust pipe will act as the hot end. Fins will be used to provide a cold end for the module. By using Seebeck effect of thermoelectricity, a voltage difference will be generated which will be used to charge batteries. The batteries will be automatically charged when the vehicle runs and then, that power, generated free of cost, can be utilized further.