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Automotive exhaust-based thermoelectric generators are currently a hot topic in energy recovery. The waste heat of automotive exhaust gas can be converted into electricity by means of thermoelectric modules. Generally, inserting fins into the cooling unit contributes to enhancing the heat transfer for a higher power output. However, the introduction of fins will result in a pressure drop in the cooling system. In current research, in order to enhance the heat transfer and avoid a large pressure drop, a cooling unit with cylindrical grooves on the interior surface was proposed. To evaluate the performance of the cylindrical grooves, different inner topologies, including a smooth interior surface,a smooth interior surface with inserted fins and an interior surface with cylindrical grooves, were compared. The results revealed that compared with the smooth interior surface, the smooth interior surface with inserted fins and the interior surface with cylindrical grooves both enhanced the heat transfer, but the interior surface with cylindrical grooves obtained a lower pressure drop. To improve the performance of the cylindrical grooves, different groove-depth ratios were tried, and the results showed that a groove-depth ratio of 0.081 could provide the best overall performance.

The exhaust thermoelectric generator (TEG) can generate electric power from a car engine's waste heat. It is important to maintain a sufficient temperature difference across the thermoelectric modules. The radiator is connected to the cooling units of the thermoelectric modules and used to take away the heat from the TEG system. This paper focuses on the research for the integration of a TEG radiator and the flow field of the car chassis, aiming to cool the radiator by the high speed flow around the chassis. What is more, the TEG radiator is designed as a spoiler to optimize the flow field around the car chassis and even reduce the aerodynamic drag. Concentrating on the flow pressure of the radiator and the aerodynamic drag force, a sedan model with eight different schemes of radiator configurations are studied by computational fluid dynamics simulation. Finally, the simulation results indicate that a reasonable radiator configuration can not only generate high flow pressure to improve the cooling performance, which provides a better support for the TEG system, but also acts as a spoiler to reduce the aerodynamic drag force.

Recent advances in thermoelectric technology have made exhaust-based thermoelectric generators (TEGs) promising for recovery of waste heat. Utilization of exhaust-based TEGs in heavy-duty vehicles was studied in this work. Given that the generated power is limited, the alternator is still indispensable. To improve the fuel economy, the generated electricity must be integrated into the automotive electrical system and consumed by electrical loads. Therefore, two feasible ways of integrating the generated electricity into the automotive electrical system are discussed: one in which the original alternator works only under certain conditions, i.e., the “thermostat” strategy, and another in which a smaller alternator is adopted and works together with the TEG, i.e., the “cooperative work” strategy. The overall performance and efficiency are obtained through simulation analysis. The simulation results show that both methods can improve the fuel economy, but the former provides better results. Moreover, if the electrical loads can be properly modified, the fuel economy is further improved. These simulation results lay a solid foundation for application of TEGs in vehicles in the future.

Currently, automotive exhaust-based thermoelectric generators (AETEGs) are a hot topic in energy recovery. In order to investigate the influence of coolant flow rate, coolant flow direction and cooling unit arrangement in the AETEG, a thermoelectric generator (TEG) model and a related test bench are constructed. Water cooling is adopted in this study. Due to the non-uniformity of the surface temperature of the heat source, the coolant flow direction would affect the output performance of the TEG. Changing the volumetric flow rate of coolant can increase the output power of multi-modules connected in series or/and parallel as it can improve the temperature uniformity of the cooling unit. Since the temperature uniformity of the cooling unit has a strong influence on the output power, two cooling units are connected in series or parallel to research the effect of cooling unit arrangements on the maximum output power of the TEG. Experimental and theoretical analyses reveal that the net output power is generally higher with cooling units connected in parallel than cooling units connected in series in the cooling system with two cooling units.

In automotive exhaust-based thermoelectric generators (AETEGs), a certain number of thermoelectric modules are connected in series and/or parallel to recover energy from exhaust gas, which provides a way to improve fuel efficiency of the vehicle. Because of the temperature distribution on the surfaces of heat exchanger, several types of modules are planned for use in an AETEG; however, property disparities among modules exist and wire resistance cannot be neglected in practical application, so experiments have been carried out to research effects of the two factors on the maximum output power of series and parallel connection. The performance of series and parallel connections have been characterized, and mathematic models have been built to analyze and predict the performance of each connection. Experiments and theoretical analysis reveal that parallel connection shows a better performance than series connection when large differences of Seebeck coefficient and resistivity exist. However, wire resistance will cause more significant power dissipation in parallel connection. The authors believe the research presented in this paper is the first to carry out an examination of the impact of module property disparity and wire resistance on the output power of an array of thermoelectric modules connected in series and parallel, which provides a reference for choosing module connection in AETEGs.

To improve the riding comfort and rational utilization of the electrical energy captured by an automotive thermoelectric generator (ATEG), a temperature-controlled car seat was constructed to adjust the temperature of the car seat surface. Powered by the ATEG and the battery, the seat-embedded air conditioner can improve the riding comfort using a thermoelectric device to adjust the surface temperature of the seat, with an air duct to regulate the cold side and hot side of the thermoelectric device. The performance of the thermoelectric cooler (TEC) and theoretical analysis on the optimum state of the TEC device are put forward. To verify the rationality of the air duct design and to ensure sufficient air supply, the velocity field of the air duct system was obtained by means of the finite element method. To validate the reliability of the numerical simulation, the air velocity around the thermoelectric device was measured by a wind speed transmitter. The performance of the temperature-controlled car seat has been validated and is in good agreement with bench tests and real vehicle tests.

The thermoelectric generators recover useful energy by the function of thermoelectric modules which can convert waste heat energy into electricity from automotive exhaust. In the actual operation, the electrical connected thermoelectric modules are operated under temperature mismatch conditions and then the problem of decreased power output causes due to the inhomogeneous temperature gradient distribution on heat exchanger surface. In this case study, an individual module test system and a test bench have been carried out to test and analyze the impact of thermal imbalance on the output electrical power at module and system level. Variability of the temperature difference and clamping pressure are also tested in the individual module measurement. The system level experimental results clearly describe the phenomenon of thermoelectric generator's decreased power output under mismatched temperature condition and limited working temperature. This situation is improved with thermal insulation on the modules and proved to be effective.

Integrating a thermoelectric cooler (TEC) into the engine cooling system has various advantages including reducing additional mechanical parts, and saving energy and space for automotive applications. Based on performance parameters of the engine and thermoelectric modules, three different TEC configurations called plate-shape, stripe-shape, and diamond-shape are constructed with development of simulations of the different TECs and the performance of the circulating coolant. Based on these simulations, the velocity, pressure, and temperature fields of the coolant are obtained for further research. Besides, the temperature of the TEC and the output power of the thermoelectric generator (TEG) are acquired experimentally. Comparing the working performance of the different TECs, the simulation and experimental results show that the TEG using the diamond-shaped TEC achieves a relatively ideal performance. Finally, some measures are proposed to improve the cooling system, providing guidelines for future research.

Thermoelectric power generators are one of the promising green energy sources. In this case study, an energy-harvesting system which extracts heat from an automotive exhaust pipe and turns the heat into electricity by using thermoelectric power generators (TEGs) has been constructed. The test bench is developed to analysis the performance of TEG system characteristics, which are undertaken to assess the feasibility of automotive applications. Based on the test bench, a new system called “four-TEGs” system is designed and assembled into prototype vehicle called “Warrior”, through the road test and revolving drum test table, characteristics of the system such as hot-side temperature, cold-side temperature, open circuit voltage and power output are studied, and a maximum power of 944 W was obtained, which completely meets the automotive application. The present study shows the promising potential of using this kind of thermoelectric generator for low-temperature waste heat recovery vehicle.

In this study, a numerical model has been employed to analyze the internal flow field distribution in a heat exchanger applied for an automotive thermoelectric generator based on computational fluid dynamics. The model simulates the influence of factors relevant to the heat exchanger, including the automotive waste heat mass flow velocity, temperature, internal fins, and back pressure. The result is in good agreement with experimental test data. Sensitivity analysis of the inlet parameters shows that increase of the exhaust velocity, compared with the inlet temperature, makes little contribution (0.1 versus 0.19) to the heat transfer but results in a detrimental back pressure increase (0.69 versus 0.21). A configuration equipped with internal fins is proved to offer better thermal performance compared with that without fins. Finally, based on an attempt to improve the internal flow field, a more rational structure is obtained, offering a more homogeneous temperature distribution, higher average heat transfer coefficient, and lower back pressure.

A key research topic related to thermoelectric generators (TEGs) for automotive applications is to improve their compatibility with the original vehicle exhaust system, which determines the quality of the exhaust gas treatment and the realization of energy conservation and emission reduction. A new TEG integrated with a three-way catalytic converter (CTEG) by reshaping the converter as the heat exchanger is proposed. A heat-flux coupling simulation model of the integrated TEG is established at the light-off stage of the original three-way catalytic converter (TWC). Temperature distribution maps of the integrated heat exchanger, thermoelectric modules, and cooling-water tank are obtained to present the process of energy flow among the parts of the CTEG. Based on the simulation results, the output power of the CTEG is calculated by a mathematical model. A minimum output power of 31.93 W can be obtained by conversion when the TWC starts working at steady conditions. Theoretically, this case study demonstrates the great potential for use of CTEGs in vehicles.

In this case study, an energy harvesting system using a thermoelectric power generator (TEG) has been constructed. Experimental investigation of the hot and cold sides of the thermoelectric modules (TMs) in this system has been undertaken to assess the feasibility for automotive applications. Two test benches have been developed to analyze the TM performance and the TEG system characteristics, especially the temperature difference, open-circuit voltage, and maximum power output of the TM and TEG system. As the performance of a TM is most influenced by the applied pressure and the temperature difference, a thermostatic heater, thermostatic water tank, and clamping devices are used in our experimental apparatus, increasing the output power of the TEG system. Based on the test bench, a new system called the “four-TEGs” system was designed and assembled into a prototype vehicle called “Warrior,” and the characteristics of the system such as the maximum power output have been studied in road tests. The results show great potential for application of this technology in future vehicles.

In this work, an energy-harvesting system which extracts heat from an automotive exhaust pipe and turns the heat into electricity by using thermoelectric power generators (TEGs) was built. Experiments show that the temperature difference in automotive system is not constant, especially the heat exchanger, which cannot provide the thermoelectric modules (TMs) large amount of heat. The thermal performance of different heat exchangers in exhaust-based TEGs is studied in this work, and the thermal characteristics of heat exchangers with different internal structures and thickness are discussed, to obtain higher interface temperature and thermal uniformity. Following computational fluid dynamics simulations, infrared experiments and output power testing system are carried out on a high-performance production engine with a dynamometer. Results show that a plate-shaped heat exchanger with chaos-shaped internal structure and thickness of 5 mm achieves a relatively ideal thermal performance, which is practically useful to enhance the thermal performance of the TEG, and larger total output power can be thus obtained.

Many problems can arise in power transformers, beginning from the moment they arrive at the sites where they are to be installed [1], [2]. Sweep frequency response analysis (SFRA) is used by many industries and manufacturers to assess the mechanical integrity of the core, winding, and clamping structure of power transformers. It usually involves the application of low-voltage (LV) signal (2 to 15 V) at one terminal of the transformer, over the frequency range 20 Hz to 2 MHz, and measurement of the response at another terminal, as shown in Figure 1 [1]. The amplitude and phase transfer function are then determined.

This paper presents a new partial discharge (PD) location technique for power cables. Unlike commonly used time-domain reflectometry (TDR) methods, this technique is based on the analysis of phase difference between the direct and reflected waves of a PD pulse measured at the cable end. The phase difference at various frequencies can be obtained from the cross Fourier spectral density function. After implementing a phase unwrapping algorithm, the defect is located. This technique has been tested using the Electromagnetic Transient Program (EMTP) on the model of a 20 kV, 1-km underground cable. The simulation takes into account the frequency-dependent parameters of the cable and the measurement accuracy of the A/D converter (8-bit). The signal-to-noise ratio (SNR) varies from 10 dB to -5 dB for all computer simulations. The statistical results are given to demonstrate the performance of the proposed technique.

In this paper, heat conduction problems are analyzed from the view of information entropy. The variation law of temperature with time in the lumped-heat-capacity system can be expressed in the form of exponential distribution. It is proved that exponential distribution is the solution of a conditional extreme value problem with information entropy as an objective function. The general analysis procedure of heat conduction problems from the view of information entropy is proposed. Fundamental solution of heat conduction equation can be written in the form of normal distribution, and normal distribution can be derived from the maximum entropy principle.

Telomerase reverse transcriptase (hTERT) is the key determinant of telomerase activity and plays a crucial role in cellular immortalization and oncogenesis. It will be a promising target for cancer gene therapy. We constructed a novel replicative adenovirus CNHK300 in which hTERT promoter with three extra E-boxes downstream of the promoter was introduced and used to regulate adenoviral E1a gene, and studied its properties of selective replication in cancer cells and antitumoral activity. Luciferase assay was used to detect hTERT promoter activity. The selective replication of CNHK300 in cancer cells was investigated by E1a Western blot and green fluorescent protein (GFP) reporter gene assay. The antitumoral activity of CNHK300 and its toxicity were measured on animal models. Luciferase assay showed that introducing extra E-boxes downstream of hTERT promoter is beneficial to decreasing the promoter activity in normal cells without affecting its strong activity in cancer cells. Experiments in vitro and in vivo demonstrated that CNHK300 can selectively target to hTERT-positive cancer cells and replicate in them, resulting in oncolytic or antitumoral effect. CNHK300 is superior to ONYX-015 in terms of selective replication and oncolytic or antitumoral effect. The toxicity assay showed no signs of toxicity to liver cells even at the higher dosage of CNHK300 in vivo. The hTERT promoter-controlled, replication-competent adenovirus CNHK300 is a promising system for targeted cancer gene therapy.

In order to clarify the frequency of p16INK4 gene inactivation and its relationship with retinoblastoma (Rb) gene expression in non-small cell lung cancer, in situ double hybridization was established with Bio-labelled Rb cDNA probe and Dig-lablled p16INK4 cDNA probe, and immunohistochemistry was carried out with polyclone rabbit antibodies to human p16INK4 and Rb protein. The results showed that positive hybridization of p16INK4 mRNA showed blue with the detecting system of alkiline phosphatase NBT/BCIP, positive hybridization of Rb mRNA showed red with the detecting system of HPR-AEC. The negative ratios of p16INK4 and Rb gene transcription were 22.6%(7/31) and 16.1%(5/31). The results of immunohistochemistry showed that the negative ratio of p16INK4 protein was 42%(13/31) with p16INK4 polyclone antibody, the negative ratio of pRb was 19.4%(6/31) with polyclone antibody. The data indicated that p16INK4 gene and Rb gene are synergistic in the progression of lung cancer, p16INK4 gene plays a significant role in the development of non-small cell lung cancer.

A newly designed surgical procedure of ligation of the thoracic duct without thoracotomy for the treatment of postoperative chylothorax is presented. A case of chylothorax following resection of carcinoma of the oesophagus was treated successfully with ligation of the thoracic duct without thoracotomy. Its advantages were very prominent consisting of maintenance of the integrity of the thorax, less traumatization, no need of a drainage tube and shorter hospitalization, much easier to expose the thoracic duct than the conventional transthoracic approach. We can find no similar report in any published literature.

Thermoelectric technology has revealed the potential for automotive exhaust-based thermoelectric generator (TEG), which contributes to the improvement of the fuel economy of the engine-powered vehicle. As a major factor, thermal capacity and heat transfer of the heat exchanger affect the performance of TEG effectively. With the thermal energy of exhaust gas harvested by thermoelectric modules, a temperature gradient appears on the heat exchanger surface, so as the interior flow distribution of the heat exchanger. In order to achieve uniform temperature distribution and higher interface temperature, the thermal characteristics of heat exchangers with various heat transfer enhancement features are studied, such as internal structure, material and surface area. Combining the computational fluid dynamics simulations and infrared test on a high-performance engine with a dynamometer, the thermal performance of the heat exchanger is evaluated. Simulation and experiment results show that a plate-shaped heat exchanger made of brass with accordion-shaped internal structure achieves a relatively ideal performance, which can practically improve overall thermal performance of the TEG.