CAMREG Keystone Projects - Theme 2



Theme 2: Materials for energy conversion and storage

KP5 - Manipulating light for enhanced PV generation. - Prof. Neil Robertson UoE Chemistry & Prof. Ian Underwood UoE Engineering

This project will build off the processing/device expertise in Edinburgh Engineering/Chemistry along with the research capacity into luminescent materials for spectral shifting and light concentration in Chemistry. Lightweight, flexible or semi-transparent photovoltaic systems with attractive colours could extend architectural opportunities and develop new possibilities such as portable or wearable PV, opening up new horizons and markets beyond those that can be addressed with current mature technologies. This KP aims to develop: luminescent downshifting polymeric films with embedded emissive molecules, to enhance the quantum yield of Silicon, CIGS and CdTe solar cells at short wavelength; printing of luminescent polymer/dye layers onto PV modules, allowing a post-manufacturing process to enhance appearance and performance of the device, consistent with stability requirements of outdoor use.

KP6- Increased power density in electrical generators using carbon nanotube technology. - Prof. Eleanor Campbell UoE Chemistry & Prof. Markus Mueller UoE Engineering

The capacity and power density of generators are limited by the magnetic and electrical loading limits, with the former a function of the magnetic characteristics of the materials used and the latter a function of temperature rise in the copper and the ability to remove heat. The conventional materials such as electrical steels and copper that have been used for the last 100 years limit increases in power density and increase cost/kW. Improved magnetic performance has been investigated using soft magnetic composites (SMC). The use of SMC has until now been limited to small machines due to mechanical and manufacturing constraints. Forced cooling allows increased electrical loading but requires ancillary equipment, adds weight and cost and reduces reliability.

This KP will investigate the use of carbon nanotube (CNT) technology to enhance electro-magnetic and thermal performance. Specifically, CAMREG would begin by investigating the applicability of using CNT in all aspects of electrical, magnetic and structural design, with the aim of understanding how to integrate CNT with existing design techniques for conventional and superconducting generators. This will lead to opportunities in developing advanced generator technology by increasing power density; completely new machine topologies; scalability of application of CNT and their manufacturability for MW scale generators.

KP7- Materials for ultra–high temperature in energy storage energy and recovery.- Dr. Adam Robinson UoE Engineering & and Prof. Feargal Brennan University of Strathclyde

Thermal energy storage has been limited, until now, to a temperature of around 800 K. If the storage temperature can be significantly 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 (1900 K) radiative losses dominate and although these emissions can be reduced there is a limit beyond which the only option to lower energy loss is through recovery with 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. In both cases creep deformation is the limiting factor on component life after chemical degradation is removed by the use of an inert working fluid within a closed cycle.

This would begin by bringing together experts from academia and industry to discuss how the technologies used to achieve high working temperature in air breathing gas turbines could be pushed further in a less hostile environment. It is hoped that in this environment, materials that have higher creep resistance and more aggressive cooling can be applied and a test program to increase the technological readiness of these materials and methods in heat pumps can be planned and begun. Work would begin with the creation of a numerical model or approach to track the time-dependant geometry changes in a ceramic honeycomb at ultra-high temperature. The modelling would be validated by accelerated creep tests on simplified geometries. The work described here for turbomachinery blades and heat exchangers would grow to become a much more significant collaborative research proposition. Success in either of these areas will not only push the temperature limit in thermal energy storage through ultra-high temperature heat recovery but will have equally significant implications for the energy efficiency of thermally-driven processes including electricity generation, chemical processing and extractive metallurgy.

KP8- Transformative Thermal Energy Storage Using Molten Salts. - UoE (Chemistry/Engineering -IMNS)

Thermal systems are potentially able to provide a significant contribution to efficient renewable energy storage. One exciting approach is to utilise salts which store and controllably release energy through changes in strong ionic bonding and/or phase change to maximise heat capacity and storage density. This includes such applications as solar thermal storage and heat batteries for domestic hot water and heating. Near ambient melting salt systems are of particular interest for this application, as they minimise thermal loss and maximise efficiency. This KP will explore transformative thermal energy storage/release systems through combining and exploiting key expertise and facilities in room temperature salt-based thermal storage and release systems, and high purity/high fidelity molten salt production and characterisation. Key challenges to be addressed include: identification of key molten salt phase change systems; detailed characterisation of molten salt heat capacity and phase change properties with composition to optimise and control thermal storage and release properties; the development of appropriate on-line sensor systems to enable smart regulated thermal systems, with inbuilt diagnosis of system performance and precision control and monitoring of energy storage and release properties. Specifically, partners will first identify candidate molten salt thermal storage systems at ambient and high temperature and determine their enhanced thermal storage and thermal transmission characteristics. CAMREG will exploit UoE/Strathclyde links, expertise and facilities through CMAC (the EPRSC National Centre for Innovative Manufacturing in Continuous Manufacturing and Crystallisation) to develop control of their nucleation and crystallisation/solidification process, important in controlling thermal release properties. We will investigate system materials challenges (e.g. corrosion) to enable development of thermal systems with integrated sensing for integrated monitoring and control. This activity builds upon expertise at Edinburgh, while developing the only reported microelectrodes able to survive such hazardous environments and provides the potential capability for monitoring of such thermal energy storage systems using molten salts.