High-performance thermoelectric devices
Lead Research Organisation:
Heriot-Watt University
Department Name: Sch of Engineering and Physical Science
Abstract
This is a PhD research project in Mechanical Engineering. The demonstrated heat-to-electricity conversion efficiency of skin-mounted thermoelectric devices is sufficient to power wearable sensors for monitoring of the wearer, powered only by their natural heat loss. However, this statement is only true if a good thermal contact exists between skin and device. Current commercially available devices are rigid and planar and provide an extremely poor thermal contact. A current EPSRC project in our group has demonstrated a flexible, thin-film thermoelectric material, which is currently undergoing conversion efficiency optimisation.
This studentship will explore the translation from material to demonstrator device. This will begin with an in-depth literature review on the field of wearable technologies, including specifically, how a good contact between the wearers skin and the device can be achieved. Devices will be fabricated from thin-film samples already processed during EPSRC project EP/N03516X/1. This will be fabricated using masking and metal deposition using dedicated metal evaporation equipment. Devices will be tested under a range of conditions, with a particular focus on electrical output (power, open circuit voltage, ... ) as a function of operational temperature and temperature difference. These tests will be carried out on a bespoke test rig and using impedance spectroscopy measurements, with the aim of demonstrating that sufficient power can be generated to power body-worn sensors. The mechanical properties of the devise will be tested using a dynamic mechanical analysis apparatus, with the objective of testing the robustness and limits of mechanical failure on said devices. Failure modes will be investigated further, by scanning electron microscopy, to enlighten on how failure might be avoided in working devices and there operational range extended. The demonstration will particularly target adoption within astronaut EVA suits for astronaut health monitoring and will involve close collaboration with the European Astronaut Centre, Cologne, particularly with respect to the likely operational conditions and requirements that such devices might face/be subjected to.
This studentship will explore the translation from material to demonstrator device. This will begin with an in-depth literature review on the field of wearable technologies, including specifically, how a good contact between the wearers skin and the device can be achieved. Devices will be fabricated from thin-film samples already processed during EPSRC project EP/N03516X/1. This will be fabricated using masking and metal deposition using dedicated metal evaporation equipment. Devices will be tested under a range of conditions, with a particular focus on electrical output (power, open circuit voltage, ... ) as a function of operational temperature and temperature difference. These tests will be carried out on a bespoke test rig and using impedance spectroscopy measurements, with the aim of demonstrating that sufficient power can be generated to power body-worn sensors. The mechanical properties of the devise will be tested using a dynamic mechanical analysis apparatus, with the objective of testing the robustness and limits of mechanical failure on said devices. Failure modes will be investigated further, by scanning electron microscopy, to enlighten on how failure might be avoided in working devices and there operational range extended. The demonstration will particularly target adoption within astronaut EVA suits for astronaut health monitoring and will involve close collaboration with the European Astronaut Centre, Cologne, particularly with respect to the likely operational conditions and requirements that such devices might face/be subjected to.
Organisations
People |
ORCID iD |
| Nick Bennett (Primary Supervisor) | |
| Joseph Gibbons (Student) |
| Description | The absorption of solar irradiance is essential for the operation of a solar cell, however, the resulting heating is undesired. Photovoltaic (PV) cells are, like other semiconductors, sensitive to temperature. Increasing operating temperature, or thermalisation, reduces cell performance, trending further away from the ideal power output, and is considered an intrinsic loss process that limits solar cell efficiency. Research into reducing cell operating temperature is a potential route to achieve high operating efficiency. Existing solar cell cooling strategies mainly focus on nonradiative approaches and either require additional energy input or increase system complexity. A radiative cooling approach was therefore investigated. An experimental set-up was designed and built for thermal characterisation and compares the solar absorption and thermal radiation properties of a range of solar absorbers with experiments both with and without the radiative approach. The use of a planar SiO2 layer on top of the bare solar absorbers shows promise in reducing operating temperature, however, emissivity at higher wavelengths needs to be determined to show that this is a result of enhanced cooling. I have contacted the studentship department at my university to inform them of this change. They are expected to make changes in Je-S so that the award title, abstract, and any other relevant details can be updated. |
| Exploitation Route | If it is proven that enhanced cooling of solar absorbers is achieved due to the use of a planar SiO2 layer to be the case, further experimental research needs to examine how this effect can be maximised. Furthermore, the research conducted considers the thermal behaviour of the solar absorbers, however, these need to be fabricated into solar cells to investigate the effect a cooling structure has on the electrical performance and efficiency. And lastly, the planar silica layer is considered suboptimal for radiative cooling, and so further investigations are to be conducted to improve on its capabilities by practically assessing multilayer dielectric photonic design structures and potential fabrication techniques. |
| Sectors | Aerospace, Defence and Marine,Communities and Social Services/Policy,Electronics,Energy,Environment,Manufacturing, including Industrial Biotechology |
| Description | Optimizing near infrared to visible upconversion quantum yield of a trivalent erbium ion doped barium yttrium fluoride in a polyvinylidene fluoride (PVDF) host-matrix for photovoltaic (PV) solar cell devices |
| Amount | £2,500 (GBP) |
| Funding ID | PECRE1920/06 |
| Organisation | Scottish Research Partnership in Engineering |
| Sector | Academic/University |
| Country | United Kingdom |
| Start | 06/2020 |
| End | 08/2020 |
| Description | Arkwright Trust: introduction to solar PV, and laboratory demsonstration |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Schools |
| Results and Impact | I provided Solar photovoltaics (PV) demonstrations throughout the day for the Arkwright Trust Engineering Scholarship programme, held at Heriot-Watt University. This demonstration introduced the topic of solar energy, how the photovoltaic effect works, and showed the effects light can have on solar panel performance. |
| Year(s) Of Engagement Activity | 2018 |
| Description | Invited Guest Lecture (Edinburgh Napier University) |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Undergraduate students |
| Results and Impact | I was invited to deliver a 3-hour guest lecture to undergraduate students (SCQF level 10) at Edinburgh Napier University. For this, I delivered a lecture on the topic of 'Energy Efficiency'. |
| Year(s) Of Engagement Activity | 2019 |
| Description | Lothian Equal Access Programme for Schools (LEAPS) Lecture |
| Form Of Engagement Activity | A talk or presentation |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Schools |
| Results and Impact | The LEPAS programme aims to promote the benefits of higher education to young people and help prepare them for the transition from school to university or college. I provided a lecture, and compiled exam assessment, on the topic of Buoyancy as part of the programme. |
| Year(s) Of Engagement Activity | 2018 |
| Description | Meet the Expert, Glasgow Science Centre |
| Form Of Engagement Activity | Participation in an open day or visit at my research institution |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Public/other audiences |
| Results and Impact | A public engagement programme organised by the Glasgow Science Centre, which invited researchers and industry professionals from all sectors to engage with the public and school visitors by delivering fun, interactive drop-in activities to introduce school children and their parents/guardians/etc. to the concepts of STEM topics (specifically, kinetic and potential energy, and gravity). To attend this event, I underwent a one-day public engagement training curse, also held by the Glasgow Science Centre as part of their Inspire and Challenge series. |
| Year(s) Of Engagement Activity | 2018 |
| URL | https://www.glasgowsciencecentre.org/ |