Surface Of Thermoelectric Generator Research Articles

Titanium foil-sealed thermoelectric generator for seafloor hydrothermal vent

The seafloor hydrothermal activity observation equipment needs a stable electric power supply; this study explored the thermoelectric generator (TEG) as the in-situ power supply method. The TEG can utilize the considerable temperature difference of the hydrothermal vent to supply electricity for the observation system. We use the titanium foil combined with the O-ring as the sealing component, thus can decrease the cold side thermal resistance and obtain a compact structure. The pressure test result shows the TEG can withstand pressure up to 20 MPa without leakage. Furthermore, a simulation is conducted to evaluate the temperature distribution of the TEG. To reduce heat loss, Polyetheretherketone (PEEK) material is used as the heat insulation layer at the surface of TEG. The simulation shows that adding the heat insulation layer can increase the hot side temperature by 4.9–7 K. The pool power generation results show that the novel structure TEG can realize 22 W output at the hot fluid temperature of 467 K. This study provides a novel sealing method for seafloor equipment with corrosion-resisting and low thermal resistance features.

The Representative Thermal Conductivity of Wickless Heat Pipes in a Thermoelectric Generator Module Design via Computational Numerical Analysis

Thermoelectric generator (TEG) cells are capable of producing electricity from the flow of heat through semiconductor materials via the Seebeck effect. A TEG module (TEM) was developed through the integration of TEG cells, heat pipes, and heat sinks with the function to recover low-temperature waste heat for combined heat and power outputs. The mechanics of heat transport through the components have a distinctive impact on overall performance. Wickless heat pipes were used in the design, and it is difficult to directly evaluate the convection heat transfer coefficient within the heat pipes. Computational numerical analysis usually simplifies the heat pipe by modelling it as a solid copper pipe, where the thermal conductivity of the pipe replaces the actual value of heat transfer coefficient. To determine the representative thermal conductivity of the wickless heat pipe, a computational numerical model of the TEM was developed. Experiment data of the TEM operation, where the cold-side air inlet temperature inlet was at 20.7°C while the hot-side waste heat inlet temperature was at 70.0°C, was used to validate the computational model. The representative thermal conductivity value for the wickless heat pipe was found to be 500 W/m.K, at which the percentage difference for the hot-side and cold-side TEG surface temperatures, and the TEG surface temperature differences were below 5%. The approach has been proven suitable to analyse the representative heat pipe thermal conductivity for simplified thermoelectric generator modules.

Integrated Heat Regenerator (IHR) Designs with Hydrogen Preheater and Thermoelectric Generator for Power Enhancement of a 2 kW Fuel Cell Vehicle

The power train efficiency of fuel cell vehicles (FCV) can be enhanced by improving the hydrogen energy utilization. Based on a mini FCV running on a 2 kW open-cathode Polymer Electrolyte Membrane (PEM) fuel cell, a waste heat recovery system design needs to be developed as an approach towards higher energy efficiency. The novelty of the system is on the integration of thermoelectric generator technology with hydrogen preheating process for a combined heat and power output. This manuscript presents the proposed integrated heat regenerator (IHR) designs, analysed using numerical computational modelling. Three IHR designs were proposed where the main design criteria are (i) a minimum of 10oC hydrogen preheating degree, and (ii) non-parasitic active cooling for the Thermoelectric generator (TEG) cells. Three design concepts were studied to identify its design and performance limitations. The numerical results were validated with theoretical modelling analysis for hydrogen exit temperatures and TEG surface temperatures. The analysis on predicted fuel cell power enhancement, TEG power generation and waste heat utilization were performed by relating the temperature profiles of the hydrogen reactant and TEG surfaces to fuel cell reaction models and TEG power relationships. A compact IHR design that produced 7.7 to 8 % total power enhancement and suitable in size for a mini FCV was identified for future development works

Atmospheric Hygroscopic Ionogels with Dynamically Stable Cooling Interfaces Enable a Durable Thermoelectric Performance Enhancement.

In thermoelectric generator (TEG) systems, heat dissipation from their cold sides is an accessible, low-cost, and effective way to increase the temperature gap for their thermoelectric performance enhancement. Although significant efforts have been dedicated mediated by hygroscopic hydrogel coolers as self-sustained alternatives for effective heat removal, it still remains a challenge for overcoming instabilities in their cooling process. The inevitable mechanical deformation of these conventional hydrogels induced by excessive water desorption may cause a detached cooling interface with the targeted substrates, leading to undesirable cooling failure. Herein, a self-sustained and durable evaporative cooling approach for TEG enabled by atmospheric hygroscopic ionogels (RIGs) with stable interfaces to efficiently improve its thermoelectric performance is proposed. Owing to its superior hygroscopicity, the RIGs can achieve higher heat dissipation for TEG through water evaporation than that of common commercial metal heat sinks. Moreover, its favorable adhesion enables the RIG closely interact with the TEG surface either in static or dynamic conditions for a durable thermoelectric performance enhancement. It is believed that such a self-sustained evaporative cooling strategy based on the RIG will have great implications for the enhancement of TEG's efficiency, demonstrating a great promise in intermittent thermal-energy utilizations.

Design of Power Conditioning Circuit for Thermal Energy Harvester in Powering a Wireless Sensor Node

Wireless Sensor Network (WSN) comprises of huge quantity of miniature sensor nodes (SNs) with certain limitation of computer resources which capable for sensing, gathering, data processing and wireless communication. Since most of the SNs are powered by traditional batteries, it can be inconvenient due to their limited lifespan. In this paper, a thermoelectric generator (TEG) is used as thermal energy harvester with the intention to extend the SN lifespan. Since the output voltage generated by this TEG is insufficient to power up the node, a DC-DC step-up converter circuit based on MAX757 integrated circuit is designed to step up the output voltage produced from TEG up to 3V. The SN required an average power which is about 25mW in the active mode and 60µW when it is in sleeping mode. This node can transmit data whenever there is at least a temperature gradient of 15℃ between the hot and cold surface of TEG.

Research, development of the design and calculation of thermal and electrical parameters of the TEG for the ship M/V NSU Keystone

This article is devoted to the issues of increasing the efficiency of thermoelectric generator (TEG) due to the intensification of heat transfer. The analysis of TEG structures and methods for increasing their efficiency are carried out. Based on the analysis, the basic design of the TEG and the method for increasing its efficiency have been selected. The thermal and electrical parameters for the base TEG are calculated using the example of the ship M/V NSU Keystone. A TEG design with changed heat exchanger surfaces from the exhaust gas side of the internal combustion engine has been proposed and changes have been made in the calculation of the thermal and electrical parameters of the TEG taking into account the specific heat exchange processes in the intensified TEG surface.

Experimental Study of Heat Energy Absorber with Porous Medium for Thermoelectric Conversion System

The thermoelectric conversion system usually consists of the heat absorber, the thermoelectric generator (TEG) and the heat sink, while the heat absorber collects the heat to increase the temperature on the hot surface of TEG and enhances the generating electricity. This study experimentally investigated the performance of the brass-beads packed-bed heat absorber for the thermoelectric conversion system. The packed-bed heat absorber is installed in a square channel with the various flow orientation systems and the small ratio of channel width to bead diameter. The flow orientation systems included the straight flow and jet flow systems. This study showed the local and average heat transfer characteristics for various parameters. The experimental results can be the base of designs for the novel porous heat absorber of the thermoelectric conversion system.

Geometric effect on cooling power and performance of an integrated thermoelectric generation-cooling system

Geometric design of an integrated thermoelectric generation-cooling system is performed numerically using a finite element method. In the system, a thermoelectric cooler (TEC) is powered directly by a thermoelectric generator (TEG). Two different boundary conditions in association with the effects of contact resistance and heat convection on system performance are taken into account. The results suggest that the characteristics of system performance under varying TEG length are significantly different from those under altering TEC length. When the TEG length is changed, the entire behavior of system performance depends highly on the boundary conditions. On the other hand, the maximum distributions of cooling power and coefficient of performance (COP) are exhibited when the TEC length is altered, whether the hot surface of TEG is given by a fixed temperature or heat transfer rate. The system performance will be reduced once the contact resistance and heat convection are considered. When the lengths of TEG and TEC vary, the maximum reduction percentages of system performance are 12.45% and 18.67%, respectively. The numerical predictions have provided a useful insight into the design of integrated TEG–TEC systems.

Experimental Study of Heat Energy Absorber with Porous Medium for Thermoelectric Conversion System

The thermoelectric conversion system usually consists of the heat absorber, the thermoelectric generator (TEG) and the heat sink, while the heat absorber collects the heat to increase the temperature on the hot surface of TEG and enhances the generating electricity. This study experimentally investigated the performance of the brass-beads packed-bed heat absorber for the thermoelectric conversion system. The packed-bed heat absorber is installed in a square channel with the various flow orientation systems and the small ratio of channel width to bead diameter. The flow orientation systems included the straight flow and jet flow systems. This study showed the local and average heat transfer characteristics for various parameters. The experimental results can be the base of designs for the novel porous heat absorber of the thermoelectric conversion system.

Evaluation and Analysis of Temperature Uniformity for Planar Automotive Waste Heat Thermoelectric Generator

The present paper discusses temperature distribution of Thermoelectric Generator (TEG) using automotive waste heat , an index to evaluate the temperature uniformity of hot end box surface of TEG is proposed. Three-dimensional heat transfer model is established to simulate the temperature distribution on hot end box surface of TEG with computational fluid dynamic program FLUENT. The simulation result indicates that under the same topology of thermoelectric modules , the internal structure inside the hot end box could effectively improve the heat transfer between waste gas and hot end box, raising the hot end box surface average temperature by 7.2 percent from 534.2K of to 572.6K ; raising the temperature uniformity coefficient by 4.8 percent from 0.83 to 0.87, the result shows that the waste gas could be utilized more efficiently and generate more output.

Integration of CuO thin films and dye-sensitized solar cells for thermoelectric generators

This study investigates a solar-thermoelectric module for power generation from solar energy. The proposed method uses recycled external exhaust heat to generate electric power, further enhancing the thermoelectric conversion efficiency of the thermoelectric generator (TEG). Using electrophoresis deposition, self-prepared CuO nanofluid is deposited onto a Cu plate and then adheres to the surface of a thermoelectric generator (TEG). Experimental results show that the CuO thin film coating on the TEG surface can elevate the temperature by around 2 °C and the voltage by around 14.8%, thus enhancing the thermoelectric conversion efficiency of the thermoelectric generator by 10% and increasing the overall power output by 2.35%. It was found that this solar-thermoelectric module can generate about 4.95 mW/cm 2 under solar radiation intensity of about 100 mW/cm 2.