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Automobile exhaust thermoelectric generation technology is an effective way to recover the waste heat from exhaust gas. In order to minimize electricity cost in commercial vehicles (CVs), a hybrid energy system consisting of a thermoelectric generator (TEG), lithium iron phosphate (LiFePO4) battery pack, lead-acid battery pack, and thermoelectric c...
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... this study, the TEG/LiFePO 4 battery pack/lead-acid battery pack/ TECs system was installed in a Tianlong CV. The proposed system is shown in Fig. 1, which consists of a TEG and a 51.2 V, 45Ah LiFePO 4 battery pack connected in parallel by a full-bridge DC/DC converter in the MPPT or current mode, and a 24 V, 330Ah lead-acid battery pack and TECs connected to the DC/DC buck converter output bus. In the proposed system, TEG and LiFePO 4 battery pack work as the primary source while ...
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... SOC of the lead-acid battery pack is set as 80%, and the initial SOC of the LiFePO 4 battery pack is determined to be 25%, 60%, and 85%, respectively. Therefore, the specific setup of boundary conditions is listed in Table 9, and the simulation work is carried out under three initial SOCs of the LiFePO 4 battery pack. The results are shown in Figs. ...
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... 10-12 show the results of modified HWFET driving cycle, in- cluding the instantaneous power of TEG, battery storage system, TECs, and SOCs of battery storage system, which can reflect the control per- formance of the proposed EMS under three initial SOCs of the LiFePO 4 battery pack. As shown in Fig. 10, the LiFePO 4 battery pack is charged as high as possible to reach the normal level, and the SOC of the lead- acid battery pack maintains stable; the TEG is controlled to provide power to the LiFePO 4 battery pack and TECs. Fig. 11 shows that the LiFePO 4 and lead-acid battery packs are prevented from huge power fluctuations to keep ...
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... the control per- formance of the proposed EMS under three initial SOCs of the LiFePO 4 battery pack. As shown in Fig. 10, the LiFePO 4 battery pack is charged as high as possible to reach the normal level, and the SOC of the lead- acid battery pack maintains stable; the TEG is controlled to provide power to the LiFePO 4 battery pack and TECs. Fig. 11 shows that the LiFePO 4 and lead-acid battery packs are prevented from huge power fluctuations to keep their SOCs in the normal level; the TEG and LiFePO 4 battery pack are discharged by the proposed EMS to supply TECs power demand. From Fig. 12, the battery storage system is dis- charged as much as possible to decrease the SOCs of the ...
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... 11 shows that the LiFePO 4 and lead-acid battery packs are prevented from huge power fluctuations to keep their SOCs in the normal level; the TEG and LiFePO 4 battery pack are discharged by the proposed EMS to supply TECs power demand. From Fig. 12, the battery storage system is dis- charged as much as possible to decrease the SOCs of the LiFePO 4 and lead-acid battery packs to the normal level, and the TEG works at current mode to reduce power absorbed by the battery storage system, as the SOC level turns to (High, High) after 3762 s. Meanwhile, the LiFePO 4 battery pack works at the optimal discharging point P Li_opt as long as possible to enhance the battery life. ...
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... performance, a real vehicle road test is designed to investigate the performance of the TEG/ LiFePO 4 battery pack/lead-acid battery pack/TECs system based on the proposed EMS. The road test system includes the TEG, 51.2 V LiFePO 4 battery pack, 24 V lead-acid battery pack, TECs, DC power meter, temperature sensors and recorder, as shown in Fig. 13. The details of the proposed system are shown in Table 2. Six Pt100 temperature sensors are arranged on one mannequin, and the cab temperature is also measured. Meanwhile, the power of four TECs is measured using APN1100AH-R DC power meter, which is powered by 24 V. The TEG output power, voltage, and the SOCs of the LiFePO 4 and ...
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... carried out at Wuhan on 25 June 2017. Before the road test, the LiFePO 4 and lead-acid battery packs were charged/dis- charged to reach their initial SOCs of 90% and 80%, respectively. The engine was pre-heated for 15 min. However, the TEG power and voltage are lower than in the simulation results, which is a result of the actual speed and loads. Fig. 14(b) shows the SOC variations of the LiFePO 4 and lead-acid battery packs. From 0 to 900 s, the SOC of the LiFePO 4 battery pack decreases rapidly from 90% to 70%, whereas the SOC of the lead-acid battery stays at ap- proximately 80%. It can be concluded that the proposed EMS helps enhance the lives of LiFePO 4 and lead-acid battery ...
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... results of the temperature measurement test are shown in Fig. 15, where the passenger's head, arm, upper body, foot, leg, haunch temperatures and the temperature in the cab are plotted. It can be observed that the temperature on the passenger's head drops from 32.1 °C to 26.2 °C, while the temperature on the passenger's upper body decreases from 31.2 °C to 26.8 °C. The passenger's arm shows a lesser ...
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... the Tianlong CV is driven at a speed of 10-40 km/h in the campus as shown in Fig. 13, the experimental results and theoretical analysis show that 1300 W TECs can replace a 2.4 kW traditional air conditioner to achieve the same equivalent temperature of one pas- senger. Therefore, the power consumption of TECs is reduced by 45.8% compared with the traditional air conditioner. It can be concluded that the proposed system ...
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... In a test room of 25.6 m 3 with Malaysia's tropical climate, as shown in Fig. 6b, the system had an optimized COP of 1.27, with a maximum temperature drop of 4.9 ºC, and a cooling capacity of 571 W. When compared to a traditional split air conditioner, the system also demonstrated a 67% energy conservation and a 76% reduction in CO 2 emission. In addition, other TEAC-specific work has emerged, such as high-precision predictions for TEAC in zero-carbon buildings [63], thermal management of limited spaces in cars [64], and automotive waste heat recovery-air conditioning systems [65], etc. ...
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... Miniaturization, low noise, and no moving parts are among the benefits of TEGs. Recovering thermal energy from exhaust gas based on thermoelectric effects can also enhance fuel efficiency while meeting the industry standards on exhaust emissions [10]. Several pilot TEG projects for vehicle applications have been reported in recent years [11,12]. ...
The conventional methods to improve the performance of annular thermoelectric generators (ATEGs) heavily rely on optimizing the thermal design of individual annular thermoelectric couples (ATECs). However, since a practical ATEG consists of many ATECs, the optimal structure of the ATEG can differ from the ATEC-based design. On the other hand, optimization by simply considering all ATECs can lead to a heavy computation burden. This work first proposes a high-fidelity, fluid-thermal-electric multiphysical ATEG model, solved by a computationally-efficient dual-finite-element method to cope with the challenge. This model explores the effects of ATEC microstructure and heat exchanger structure on ATEG performance under various operating conditions. Comparative multi-objective optimization studies were performed at three levels, i.e., for a single ATEC, a single ring of ATEG, and the entire ATEG. The results reveal that the optimized structural parameters of ATECs have some new features when considering the entire ATEG as the optimization objective. The optimal height, angle, and thickness of ATECs are 12 mm, 2.35°, and 10 mm, respectively. The corresponding net power, efficiency, and power density of ATEG are 321.6 W, 6.58%, and 634.15 W/m3, respectively. Compared to the traditional design method based on a single ATEC and a single ring, the net power of the ATEG designed with the proposed method can be enhanced by 168% and 197%, respectively, at the expense of only a 20% reduction in the power density.
... In this study, a distributed thermoelectric energy recovery system is proposed and its schematic diagram is shown in Fig. 1. The example system consists of a TEG and a 51.2-V 60-Ah lithium-iron-phosphate (LiFePO 4 ) battery pack, designed for a heavy-duty commercial vehicle (Li et al., 2018). The TEG and the battery pack are connected via a three-string parallel-connected multi-input single-output (MISO) dc/dc converter consisting of three SEPIC structures. ...
... Denote i the index of the row (i ∈ 1, 2, . . . , 17), the OCV U OC−H , the internal resistances R TEG−H , and the maximum output power P MAX−H of high-temperature region of the AETEG are expressed as (Li et al., 2018): ...
... where N is the number of PN junctions in each TEM, ∆T i is the temperature difference between the hot sides and the cold sides of TEMs, L is the length of the thermoelements, and S is the cross section area of one pair of PN junctions. Here, the Seebeck coefficient α PNi and the electrical resistivity ρ PNi of thermoelectric material of the TEMs are given by Li et al. (2018): ...
The inevitable non-uniform temperature distribution across a large number of thermoelectric modules can cause reduced output power of the automotive exhaust thermoelectric generator (AETEG). In order to achieve accurate tracking of maximum power point for an AETEG, a distributed thermo-electric energy recovery system is proposed consisting of several parallel thermoelectric generators and a lithium-ion battery pack. And then, a two-level energy harvesting strategy is developed to efficiently recover exhaust energy under dynamic driving cycles. The simulated results based on an experimentally validated system model under the modified Highway Fuel Economy Test (HWFET) for a commercial heavy-duty vehicle demonstrate that the proposed strategy enables the system to run at the efficient working point of DC/DC converters. It shows that the charging energy can be increased by 174013 J and the efficiency of system-control level can be raised by 2.4% compared to the conventional feedback control under the modified HWFET driving cycle, when the initial State of Charge (SOC) of the battery pack is 10%. Meanwhile, the proposed strategy can avoid the overcharging events for the battery pack since it can be effectively controlled along its pre-defined optimal working trajectory, which is verified by the campus road test.
... Unfortunately, due to their low energy conversion efficiency, the applications of TEGs are limited, most in the fields such as aerospace [1,2], wearable devices, and vehiclemounted TEGs [3][4][5]. ...
Highly variable automobile operating conditions and the ever-fluctuating exhaust parameters pose fundamental challenges to optimizing the design of automobile annular thermoelectric generators (ATEGs). This paper establishes an advanced non-isothermal mathematical model of ATEGs using the finite element method for solving this problem. First, the effects of different vehicle operating conditions on the optimal thermoelectric semiconductor volume are investigated. Based on the results, the optimal range for selecting the thermocouple volume is determined. Aiming to maintain a high net power of ATEG under variable operating conditions, two new schemes are proposed to optimize the system configuration, including 1) a weighted power deviation method and 2) a multi-objective intelligent optimization algorithm. Then, a new method for assessing the power generation cost is proposed for the ATEG. Combined with the characteristics of vehicle exhaust fluctuation in the New European Driving Cycle, the economics of the above two schemes are calculated and compared, and the optimal design is obtained. The results show that the optimal ATEG system configuration is: the PN couple volume in a single ring is 5.062510 −6 m 3 , the total PN couple volume is 2.83510 −4 m 3 , and the net power and the efficiency can reach 20.85 W and 3.9%, 2 respectively. The proposed model and method contribute to optimize the structural configuration of the on-board ATEGs, and can be further extended for other application scenarios of the thermoelectric generator system.
... Next, Attar and Lee [32] designed the cooler system with TCM, and the results validated the analytical analysis. Li et al. [33] considered the energy management system of TCM. Irshad et al. [34] presented a sizing and cost of an air duct with solar cell calculations. ...
This work presents the COP and EER of the combined air conditioning and thermoelectric cooling systems. The small-scale air conditioning (8000 BTU/hr) with thermoelectric cooling systems is set up in the closed room (2.0*2.0*2.0 m), and free energy from the photovoltaic cell is used for the thermoelectric cooling module. The COP and EER with the thermoelectric cooling module are higher than those without the thermoelectric cooling module. It is observed that the COP and EER increase as the axial fan speeds increase. In addition, there is good agreement from the comparison, giving an average error of 3.77%. The highest COP and EER for the system with the thermoelectric cooling module are 1.71 and 5.85 for an airflow rate of 4.7 m3/s, respectively. The results can be used as guidelines for developing the thermal performance of air conditioning by combining it with the thermoelectric cooling module.
... The majority of the energy produced by fossil fuels is wasted as heat in internal combustion engine vehicles, with only about 30% of the energy converted to usable work. Thermoelectric generators (TEGs) are believed to have the potential and possibility of being used in an automobile's thermal energy recovery system due to their unique advantages, such as no moving parts, no pollution, and the ability to immediately convert thermal energy into electric energy [1,2]. TEG can not only reduce pollution, but also improve fuel efficiency and save energy. ...
To ensure effective heat recovery of thermoelectric generators, a cooling system is necessary to maintain the working temperature difference of the thermoelectric couples, which decreases continuously due to thermal diffusion. In order to evaluate and improve the thermoelectric performance of a concentric annular thermoelectric generator under various cooling methods, a comprehensive numerical model of the thermo-fluid-electric multi-physics field for an annular thermoelectric generator with a concentric annular heat exchanger was developed using the finite-element method. The effects of four cooling methods and different exhaust parameters on the thermoelectric performance were investigated. The results show that, in comparison to the cocurrent cooling pattern,
the countercurrent cooling pattern effectively reduces temperature distribution non-uniformity and hence increases the maximum output power; however, it requires more thermoelectric semiconductor materials. Furthermore, when using the cocurrent air-cooling method, high exhaust temperatures may result in lower output power; high exhaust mass flow rates result in high exhaust resistance and reduce system net power. The maximum net power output Pnet = 432.42 W was obtained using the countercurrent water-cooling, corresponding to an optimal thermoelectric semiconductor volume of
9.06 × 10−4 m3; when compared to cocurrent water-cooling, the maximum net power increased by 8.9%, but the optimal thermoelectric semiconductor volume increased by 21.4%.
... Ebrahimi and Derakhshan [22] investigated a combined fuel cell and thermoelectric cooler. Li et al. [23] developed the air conditioning system's hybrid model with a thermoelectric cooling system. Muralidhar et al. [24] applied thermoelectric generators to an electric vehicle. ...
We investigated the results of the cooling performance of the pulsating water/nanofluids flowing in the thermoelectric cooling module for cooling electric vehicle battery systems. The experimental system was designed and constructed to consider the effects of the water block configuration, hot and cold side flow rates, supplied power input, and coolant types on the cooling performance of the thermoelectric module. The measured results from the present study with the Peltier module are verified against those without the thermoelectric module. Before entering the electric vehicle battering system with a Peltier module, the inlet coolant temperatures were 2.5-3.5℃ lower than those without the thermoelectric system. On the hot side, the maximum COP of the thermoelectric cooling module was 1.10 and 1.30 for water and nanofluids as coolant, respectively. The results obtained from the present approach can be used to optimize the battery cooling technique to operate in an appropriate temperature range for getting higher energy storage, durability, lifecycles, and efficiency.
... Environmental concerns such as air pollution and depletion of fossil fuels have driven the research of more environmentally friendly energy conversion technologies [1][2][3]. A thermoelectric generator (TEG) is a device that can convert thermal energy into electricity directly, and it has attracted much research attention in recent years due to its advantages of high reliability and long service life [4][5][6]. ...
The annular thermoelectric generator (ATEG) has received growing research interest due to its improved energy conversion efficiency compared to conventional flat-plate thermoelectric generators (FTEG). In this study, considering the influence of ceramic substrate and copper contact layer, a numerical model of the annular thermoelectric module (ATEM) was established for the studies of the influence of geometrical parameters on output performance under three typical application scenarios with different boundary conditions. It is found that when the heat flow on hot side is constant, the shape factors of the optimal performance are slightly different either if the convection coefficient or the temperature is considered constant on cold side. In both cases, the output power and the conversion efficiency decrease with the increase of the thickness of the thermocouple, and increase with the increase of the angle, length, and number of the thermocouples. When the temperatures are considered constant on both sides of the thermocouples, a conflicting relationship between the optimal output power and the efficiency exists. In this case, to obtain the best ATEG performance, multi-optimization problem is formulated and solved by the non-dominant sorting genetic algorithm with elite strategy method (NSGA-II).
... Continuously improving the energy conversion efficiency of automobiles is one of the major pathways to conserve precious fossil energy sources and to reduce greenhouse gas emissions. In general, only 25% of fuel energy in the internal combustion engine vehicles is utilized for vehicle mobility and other necessary use, while about 30e40% is wasted as exhaust gas [1,2]. The wasted energy in the exhaust gas can be potentially recovered using a thermoelectric generator (TEG) by converting the heat into electric energy directly through thermoelectric effects. ...
In order to increase the energy conversion efficiency of thermoelectric generators for automobile systems where the heat sources are commonly cylindrical, a novel concentric annular thermoelectric generator (CATEG) consisting of annular thermocouples and a concentric annular heat exchanger is proposed. A numerical model of the CATEG is first established using a finite-element method, based on which the thermoelectric performances of the proposed CATEG and the conventional annular thermoelectric generator (ATEG) with a cylindrical heat exchanger are compared. The relationship between the size of the heat exchanger, heat transfer characteristics, and heat flow resistances are comprehensively studied. Furthermore, to balance the relationship between heat transmission and fluid flow resistances, and to extract the maximum net power, the optimal design of the concentric annular exchanger is obtained and analyzed. Simulation results show that the optimized ratio of the inner and outer diameters of the heat exchanger is 0.94, and the new ATEG with the proposed concentric annular heat exchanger can significantly increase the total heat transfer coefficient as well as the pressure drop, leading to a maximum net power of 65% higher than the conventional ATEG. 2
... Wei et al. [21] claimed that using Bi dopants in Ge 1−x Bi x Te, the Seebeck coefficient increased, and the thermal conductivity decreased, which subsequently enhanced the electrical output of the TEG. To minimize the electricity consumption in commercial vehicles, a hybrid energy system was proposed [22]. The system was composed of a thermoelectric generator (TEG), a lithium iron phosphate battery pack, and thermoelectric coolers (TECs). ...
A wireless earphone requires a portable power source to keep it operational for long time. Currently, small batteries are integrated with the earphones that are used until the stored energy is completely diminished. When a user uses an earphone, its front side temperature remains near 305 K, and the rear side experiences ambient temperature. A route can be designed to dissipate the heat from the front side to the rear side using thermoelectric materials. The deposition of an organized thermoelectric material inside an earphone can help produce some electrical energy to enhance the durability of the battery. Thermoelectric generators (TEGs) are used to convert heat into electrical energy. In this paper, we present a numerical analysis of a thermoelectric generator in conjunction with an earphone. The TEG model consists of p-type and n-type Bismuth Telluride (Bi2Te3) semiconductor legs connected thermally in parallel and electrically in series. COMSOL Multiphysics 5.4 was used to simulate and predict the power output by the TEG. Three different temperature conditions (ΔT = 10.5, 7.5, and 4.5 K) were analyzed to investigate the performance of the TEG. Finally, the outputs at two additional temperature differences ((ΔT = 3, and 20 K) were examined by considering situations where the earphone wearer is exposed to summer and winter environments, respectively.
