Postdoctoral research associates
Dr James Young
“Materials for ultra–high temperature in energy storage and energy recovery”
Thermal energy storage has been limited, until now, to temperatures around 800 K. If this storage temperature can be raised without incurring unacceptable thermal losses, energy density and conversion efficiency to electricity could reach a point where grid-scale thermal storage becomes technically and economically attractive. At ultra-high temperatures (1800 K) radiative losses dominate. Although these emissions can be reduced, there is a limit beyond which energy losses can only be recovered through a heat pump. For a heat pump to survive these challenging temperatures, new materials and approaches are required to produce the critical components such as compressors, turbines and heat exchangers. To achieve high efficiency, compressors and turbines have highly stressed blades operating at elevated temperatures. For heat exchangers to achieve maximum surface area and therefore energy transfer within a compact volume, they must have a thin-walled honeycomb structure. The most important failure modes that must be considered at ultra-high temperatures include creep, oxidation, thermal shock, and fracture. These have been investigated in this project along with microstructural changes, wear and erosion, vibration, fouling and fatigue.
“Ultra-high temperature heat transfer analysis and thermal insulation design”
With the advent of ultra-high temperature technologies (e.g. thermal energy storage), novel insulation designs are needed to prevent energy losses which can occur through convection, conduction or radiation. While a vacuum is an efficient solution against the former two, the latter proves more challenging. Within this framework, my work focuses on the theoretical, numerical and experimental modelling and analysis of mixed ultra-high temperature heat transfers in non-grey, semi-transparent and evacuated composite structures with temperature-dependent thermal conductivities. Specific geometries are studied that would provide both efficient high-temperature thermal insulation and sufficient mechanical support to sustain their surrounding structures
“Modelling and optimisation of gas-solid heat exchangers”.
A modified Brayton cycle is employed to extract energy from the UHTS system. This cycle has been modified such that its source of heat is the high temperature core instead of a typical combustion chamber. Gas-solid heat exchangers are used to transfer heat from the solid core to the working fluid in the cycle. In order to optimise these heat exchangers, I am producing a numerical design tool that will predict the heat transfer rates and working fluid pressure losses for a specified heat exchanger design.
"Feasibility study of integration of UHTS with electrical grids "
This project aims to develop a numerical time-domain energy system model for optimization of ultra-high temperature thermal energy storage operated within national electrical grids. The performance evaluation is based on various relevant elements such as heat and electricity demand profiles, share of renewable energies in the system, charging/discharging cycle behavior, UHTS plant sizing and layout, operational reliability and cost competitiveness. This will lead to a deeper understanding of all relevant parameters, variables and constraints which contribute to optimum operation and design of ultra-high temperature thermal storage system at grid level.
“Ultra-High Temperature Thermal Energy Storage for Concentrated Solar Power”
This project investigates the potential of integrating a novel Ultra-High Temperature (>1500 K) thermal energy Storage (UHTS) system with concentrated solar power (CSP) technologies. This involves tackling technical challenges that restrain current CSP technologies from operating at temperatures higher than 1000 K. This integration will not only improve the economic feasibility of UHTS through sharing infrastructure and storing heat directly at point of generation but should also enable CSP power cycles to operate at a much higher temperature, which can have substantial thermodynamic benefits (theoretically estimated to enhance the thermal efficiency of power generation by 50%).
“Integration of an Ultra-High Temperature Energy Storage System into Conventional thermal Power Generation Sites.”
Description: This project investigates implementation of an Ultra-High Temperature Thermal Energy Store (UHTS) at existing power generation sites. The store may be discharged through the heating of an air stream which may provide an alternate heat source to power a turbine, reducing the fuel requirement. The benefits are to be quantified by the effect on the flue gas composition, investigated with the use of Computation Fluid Dynamics and validated with experimental data. The required alterations to existing turbines to allow the system to successfully operate are also to be outlined and designed.
As second supervisor:
William Jamieson “Materials & Manufacturing Optimisation for Curved Wave Energy Device”