Browsing by Author "Jie, Zhu"

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Heat Transfer Enhancement of a Modularised Thermoelectric Power Generator for Passenger Vehicles
    (Applied Energy, 2017) Li, Bo; Kuo, Huang; Yuying, Yan; Yong, Li; Ssennoga, Twaha; Jie, Zhu
    Transport represents over a quarter of Europe's greenhouse gas emissions and is the leading cause of air pollution in cities. It has not seen the same gradual decline in emissions as other sectors. Recently, the thermoelectric power generation (TEG) technology emerges as an alternative solution to the emission reduction challenge in this area. In this paper, we present an innovative pathway to an improved heat supply into the concentric shape-adapted TEG modules, integrating the heat pipe technologies. It relies on a phase changing approach which enhances the heat flux through the TEG surface. In order to improve the heat transfer for higher efficiency, in our work, the heat pipes are configured in the radial direction of the exhaust streams. The analysis shows that the power output is adequate for the limited space under the chassis of the passenger car. Much effort can also be applied to obtain enhanced convective heat transfer by adjusting the heat pipes at the dual sides of the concentric TEG modules. Heat enhancement at the hot side of the TEG has an effective impact on the total power out of the TEG modules. However, such improvements can be offset by the adjustment made from the coolant side. Predictably, the whole temperature profile of TEG system is subject to the durability and operational limitations of each component. Furthermore, the results highlight the importance of heat transfer versus the TEG power generation under two possible configurations in the passenger car. The highest power output per repeat unit is achieved at 29.8 W per 0.45 Litre with a ZT value 0.87 for a Bi2Te3-based thermoelectric material in our studies. The study provides an insight into a structurally achievable heat exchanger system for other high-temperature thermoelectric materials.
  • Thumbnail Image
    Item
    Performance analysis of thermoelectric generator using dc-dc converter with incremental conductance based maximum power point tracking
    (Energy for Sustainable Development, 2017) Ssennoga, Twaha; Jie, Zhu; Yuying, Yan; Bo, Li; Kuo, Huang
    Thermoelectric (TE) devices are regarded as alternative and environmentally friendly for harvesting and recovering heat energy. Particularly, thermoelectric generators (TEGs) are used for converting heat into electricity. One of the challenges behind TEG is that the power generated is unstable and therefore needs proper power conditioning mechanism before it is supplied to the load. Moreover, it is necessary to track the maximum power point (MPP) at all times so that maximum power is always extracted from TEG devices. The objective of this work is to analyse the performance of a dc-dc converter with maximum power point tracking (MPPT) enabled by incremental conductance (IC) method. The simplified model is used as the basis for TEG design while the dc-dc boost converter is used for boosting and stabilising the power generated from TEG. The results of the IC based MPPT approach have been compared with those of perturb and observe (P&O) based MPPT from a previous researcher. The results indicate that the IC based MPPT approach is able to track the MPP but with relatively lower efficiencies than the P&O based MPPT method. The matching efficiency within a temperature range of 200oC– 300oC is in the range of 99.92% - 99.95% for P&O and 99.46% - 99.97% for IC method. However IC based MPPT method has higher voltage gain and converter efficiency than the P&O based MPPT method. Therefore, dc-dc converters are able to improve the steady state performance of TEG system as well as boosting the voltage to the desired level, hence improving the overall performance of TEG system. Although both P&O and IC are two classical algorithms that can be implemented to extract the maximum power from TEG, the comparative study has established that P&O technique outperforms the IC method.