Publication: Study on space charge suppression for thermal electronic energy conversion
| dc.contributor.author | Khalid, Kamarul Aizat Abdul | |
| dc.date.accessioned | 2024-01-23T02:27:16Z | |
| dc.date.available | 2024-01-23T02:27:16Z | |
| dc.date.issued | 2020-07-01 | |
| dc.description.abstract | Electricity may be produced in an efficient way from thermal energy sources using thermionic energy converters (TICs). Unlike conventional generators that utilize moving parts to generate electricity, TICs provide an opportunity for converting heat directly and statically by utilizing electrons as the working fluid. Despite having huge potential as an efficient direct energy conversion device, the development of TICs have been held back due to their low conversion efficiency. There are mainly two obstacles for achieving highly efficient TICs; the strict need for low emitter and collector work functions in order to achieve maximum conversion efficiency and the mutual repulsion of electrons within the inter electrode gap, known as the space charge effect. The space charge effect is the formation of electrons within the electrodes that dramatically reduces the current densities thereby disrupting the performance of the device. In this thesis, a new configuration has been proposed based on simulation of recent concepts that attempt to reduce or even eliminate the decelerating forces produced by the space charge cloud, namely the thermoelectronic energy conversion. This method uses an electrostatic field generated by a gate electrode to pull electrons away from the condensed space charge cloud. A magnetic field is also applied to guide electrons away from the gate electrode. Unlike the original scheme, this work will be focusing on improving the performance of thermoelectronic energy converters (TECs) with the intention of reducing the parasitic thermal radiation losses suffered in the current concept of TEC. This design will provide some modifications by intentionally making use of cylindrical geometric emitter coupled with rotor-like design collector to maximize the effective surface area to give more space and time for electrons to travel towards the collector and the electrodes do not have to be facing each other and the heat transfer will be minimized. Apart from that, accelerating gate electrodes will be inserted to attract electrons thus manipulating the pathways of electrons and reducing crossover between them. In this work, three dimensional (3D) simulations were generated and the electrostatic potential within the inter electrode space was calculated. Apart from that, the assessment of attainable output powers and efficiencies was accomplished in this work. An extrapolation of the system performance gives strong evidence that practically high output power densities and conversion efficiencies exceeding 10% compared to the previous system may be achieved if the requirement of low work function emitter and collector can be fulfilled. | |
| dc.identifier.uri | https://erepo.usm.my/handle/123456789/18183 | |
| dc.language.iso | en | |
| dc.title | Study on space charge suppression for thermal electronic energy conversion | |
| dc.type | Resource Types::text::thesis | |
| dspace.entity.type | Publication | |
| oairecerif.author.affiliation | Universiti Sains Malaysia |