Comparative life cycle and technical-economic analysis of renewable energy technologies and numerical modelling of heat pipes for application in solar thermal plants

Nkor, John Vurebari Koko (2021) Comparative life cycle and technical-economic analysis of renewable energy technologies and numerical modelling of heat pipes for application in solar thermal plants. Doctoral thesis, Northumbria University.

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This research presents a comparison between mainstream and emerging solar-thermal renewable energy technologies (RETs) using an integrated environmental and techno- economic assessment framework and the numerical modelling of heat pipes for solar thermal applications. Using the framework, the overall sustainability potential is quantified in terms of a novel environmental and techno-economic index (ETEI), combining the Levelised Life Cycle Impact (LLCI) with the Levelised Cost of Energy (LCOE). A set of three ‘mainstream’ (Photovoltaic-PV, Wind Turbine-WT, Bioenergy) and three ‘solar- thermal’ (Parabolic Trough Steam-driven turbine, Parabolic Trough and Linear Fresnel Reflectors, the latter two with Organic Rankine Cycle, respectively PT-ORC and LFR- ORC) RETs are used. Economic and environmental evaluation of the RETs for technological innovation is relevant in making an informed decision as to the value these technologies present. Hence, this study also assesses the efficiency of technical innovations of the six RETs, using the eco-efficiency approach by integrating life cycle assessment and life costing. A demonstration case study is presented for two sites with favourable renewable resources over 25-year operational life. The results show improved overall sustainability scores for solar-thermal, attributed mainly to the additional thermal energy recovery from the ORC. PV emerges as the most preferred option when only electricity generation is considered, whereas accounting for the additional thermal energy outputs makes PT-ORC as the most preferred option during to its technological maturity and LFR-ORC the second preferred option.

The transient behaviour of a heat pipe, designed by an industrial partner of the Northumbria University team, leading Horizon 2020 R & I Activity Project on the development of a small solar thermal plant, was investigated numerically. The heat pipe is a part of the plant, and its operation was studied for different tilt angles (0 = 0°, 45°, 90°). The numerical solutions were obtained using a fully implicit Finite Difference Method that considered the motion of the liquid and a known time-varying temperature boundary condition at the liquid front. The liquid front position was found to be dependent on the applied heat flux, the initial conditions, and the thermophysical properties of the working fluid. Additionally, the distribution of power output and wall temperatures was predicted. The temperature distribution of the working fluid was consistent with experimental results from the previous literature and provided valuable insight into the room-temperature start- up phenomenon.

Item Type: Thesis (Doctoral)
Uncontrolled Keywords: Levelized Life Cycle Impact and Levelized Cost of Energy of Renewable Energy Technologies, Framework for Integrating Environmental and Techno-economic assessment for Renewable Energy Technologies, 3-D Porous Wick Heat Pipe Modelling
Subjects: H300 Mechanical Engineering
H800 Chemical, Process and Energy Engineering
Department: Faculties > Engineering and Environment > Mechanical and Construction Engineering
University Services > Graduate School > Doctor of Philosophy
Depositing User: John Coen
Date Deposited: 25 Jan 2022 09:17
Last Modified: 25 Jan 2022 09:17

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