Control of Energy Storage

Energy storage can provide numerous beneficial services and cost savings within the electricity grid, especially when facing future challenges like renewable and electric vehicle (EV) integration. Public bodies, private companies and individuals are deploying storage facilities for several purposes, including arbitrage, grid support, renewable generation, and demand-side management. Storage deployment can therefore yield benefits like reduced frequency fluctuation, better asset utilisation and more predictable power profiles. Such uses of energy storage can reduce the cost of energy, reduce the strain on the grid, reduce the environmental impact of energy use, and prepare the network for future challenges. This Special Issue of Energies explore the latest developments in the control of energy storage in support of the wider energy network, and focus on the control of storage rather than the storage technology itself

Semantic discovery and reuse of business process patterns

Patterns currently play an important role in modern information systems (IS) development and their use has mainly been restricted to the design and implementation phases of the development lifecycle. Given the increasing significance of business modelling in IS development, patterns have the potential of providing a viable solution for promoting reusability of recurrent generalized models in the very early stages of development. As a statement of research-in-progress this paper focuses on business process patterns and proposes an initial methodological framework for the discovery and reuse of business process patterns within the IS development lifecycle. The framework borrows ideas from the domain engineering literature and proposes the use of semantics to drive both the discovery of patterns as well as their reuse

Space mission applications of high area-to-mass-ratio orbital dynamics

High area-to-mass-ratio spacecraft experience a signifcant perturbation due to surface forces, such as solar radiation pressure and aerodynamic drag. Hence, their orbits do not evolve in the manner of traditional satellites. They undergo strong changes in eccentricity and argument of pericentre due to solar radiation pressure, and in semi-major axis due to aerodynamic drag. These effects can be exploited for a number of applications, providing solutions to existing problems for space mission design. In this thesis an analytical Hamiltonian model of the orbital evolution of high area-to-massratio objects is used to identify potential mission applications on decreasing length-scale. These applications are then investigated using numerical methods and validated against high-precision orbit propagations. On the metre-scale, applications for small satellites, of 100 kg mass or less, are developed. Firstly, a passive orbit manoeuvre from geostationary transfer orbit to low Earth orbit is investigated. This method has the potential to enable a new range of piggy-back launches for small satellites. Using the same insights, the strategy of solar radiation pressure augmented deorbiting is presented. The deorbiting method can enable passive end-of-life removal from very high altitude orbits. On the millimetre-scale, an orbit control method for so-called SpaceChips is developed. The method uses electrochromic coatings to allow the SpaceChip to alter its optical properties and thus modulate the perturbation due to solar radiation pressure. Different control algorithms are discussed and evaluated. Finally, on the micrometre-scale, a dispersion strategy for a planetary dust ring extracted from a captured asteroid is presented. The long-lived dust ring is designed to reduce the solar input to the global climate system and mitigate global warming. Heliotropic orbits are used as a means of passively controlling the ring.High area-to-mass-ratio spacecraft experience a signifcant perturbation due to surface forces, such as solar radiation pressure and aerodynamic drag. Hence, their orbits do not evolve in the manner of traditional satellites. They undergo strong changes in eccentricity and argument of pericentre due to solar radiation pressure, and in semi-major axis due to aerodynamic drag. These effects can be exploited for a number of applications, providing solutions to existing problems for space mission design. In this thesis an analytical Hamiltonian model of the orbital evolution of high area-to-massratio objects is used to identify potential mission applications on decreasing length-scale. These applications are then investigated using numerical methods and validated against high-precision orbit propagations. On the metre-scale, applications for small satellites, of 100 kg mass or less, are developed. Firstly, a passive orbit manoeuvre from geostationary transfer orbit to low Earth orbit is investigated. This method has the potential to enable a new range of piggy-back launches for small satellites. Using the same insights, the strategy of solar radiation pressure augmented deorbiting is presented. The deorbiting method can enable passive end-of-life removal from very high altitude orbits. On the millimetre-scale, an orbit control method for so-called SpaceChips is developed. The method uses electrochromic coatings to allow the SpaceChip to alter its optical properties and thus modulate the perturbation due to solar radiation pressure. Different control algorithms are discussed and evaluated. Finally, on the micrometre-scale, a dispersion strategy for a planetary dust ring extracted from a captured asteroid is presented. The long-lived dust ring is designed to reduce the solar input to the global climate system and mitigate global warming. Heliotropic orbits are used as a means of passively controlling the ring