Bond graph modelling of exergy in integrated energy systems

Ph. D. Thesis.Integrated municipal or district energy systems are one facet of the effort to support sustainable energy systems that work towards reducing anthropogenic climate change emissions. Current energy systems — including electricity, heat, and cooling — operate mostly independently, under the control of domain-distinct industries and regulatory bodies. Operating these separate systems in a cooperative or integrated manner promises improvements in efficiency, the ability of networks to absorb renewable energy sources and storage, emissions reductions and community-based benefits. The nature of district energy systems is that they cannot easily be modified or built upon without severe disruption to the communities they serve, so assessments of their behaviour and performance caused by potential changes must be modelled. This thesis investigates what methods can model integrated energy systems and develops a bond graph-based approach to constructing a fully-integrated system model. Although energy based methods for integrated energy system modelling exist, this thesis demonstrates that exergy can form the basis of integrated energy system models. Exergy being a measure of the usefulness of energy allows the equivalence of energy domains in a single model form, permitting development of a genuine, physically-founded integrated energy system model. An integrated model of a residential district supplied by heat and electrical networks, based on a real UK urban area, is demonstrated in OpenModelica using the developed modelling approach. The concept of an exergy storage device is introduced to provide a mechanism for mediating energy flows between the networks. The model is used to evaluate the performance of the test network, using trial cases to investigate how transferring exergy between energy domains through the mediating storage affects the overall system energy and exergy efficiencies. Operational regimes that transfer energy from the electrical to the thermal sub-system using the mediating storage are found to improve the exergy efficiency of the system.Newcastle University, Siemen

Levelised Cost of Storage for Pumped Heat Energy Storage in comparison with other energy storage technologies

Future electricity systems which plan to use large proportions of intermittent (e.g. wind, solar or tidal generation) or inflexible (e.g. nuclear, coal, etc.) electricity generation sources require an increasing scale-up of energy storage to match the supply with hourly, daily and seasonal electricity demand profiles. Evaluation of how to meet this scale of energy storage has predominantly been based on the deployment of a handful of technologies including batteries, Pumped Hydroelectricity Storage, Compressed Air Energy Storage and Power-to-Gas. However, for technical, confidentiality and data availability reasons the majority of such analyses have been unable to properly consider and have therefore neglected the potential of Pumped Heat Energy Storage, which has thus not been benchmarked or considered in a much detail relative to competitive solutions. This paper presents an economic analysis of a Pumped Heat Energy Storage system using data obtained during the development of the world’s first grid-scale demonstrator project. A Pumped Heat Energy Storage system stores electricity in the form of thermal energy using a proprietary reversible heat pump (engine) by compressing and expanding gas. Two thermal storage tanks are used to store heat at the temperature of the hot and cold gas. Using the Levelised Cost of Storage method, the cost of stored electricity of a demonstration plant proved to be between 2.7 and 5.0 €ct/kW h, depending on the assumptions considered. The Levelised Cost of Storage of Pumped Heat Energy Storage was then compared to other energy storage technologies at 100 MW and 400 MW h scales. The results show that Pumped Heat Energy Storage is cost-competitive with Compressed Air Energy Storage systems and may be even cost-competitive with Pumped Hydroelectricity Storage with the additional advantage of full flexibility for location. As with all other technologies, the Levelised Cost of Storage proved strongly dependent on the number of storage cycles per year. The low specific cost per storage capacity of Pumped Heat Energy Storage indicated that the technology could also be a valid option for long-term storage, even though it was designed for short-term operation. Based on the resulting Levelised Cost of Storage, Pumped Heat Energy Storage should be considered a cost-effective solution for electricity storage. However, the analysis did highlight that the Levelised Cost of Storage of a Pumped Heat Energy Storage system is sensitive to assumptions on capital expenditure and round trip efficiencies, emphasising a need for further empirical evidence at grid-scale and detailed cost analysis

Enhanced Cellular Immunity in Shrimp (Litopenaeus vannamei) after ‘Vaccination’

It has long been viewed that invertebrates rely exclusively upon a wide variety of innate mechanisms for protection from disease and parasite invasion and lack any specific acquired immune mechanisms comparable to those of vertebrates. Recent findings, however, suggest certain invertebrates may be able to mount some form of specific immunity, termed ‘specific immune priming’, although the mechanism of this is not fully understood (see Textbox S1). In our initial experiments, either formalin-inactivated Vibrio harveyi or sterile saline were injected into the main body cavity (haemocoel) of juvenile shrimp (Litopenaeus vannamei). Haemocytes (blood cells) from V. harveyi-injected shrimp were collected 7 days later and incubated with a 1∶1 mix of V. harveyi and an unrelated Gram positive bacterium, Bacillus subtilis. Haemocytes from ‘vaccinated’ shrimp showed elevated levels of phagocytosis of V. harveyi, but not B. subtilis, compared with those from saline-injected (non-immunised) animals. The increased phagocytic activity was characterised by a significant increase in the percentage of phagocytic cells. When shrimp were injected with B. subtilis rather than vibrio, there was no significant increase in the phagocytic activity of haemocytes from these animals in comparison to the non-immunised (saline injected) controls. Whole haemolymph (blood) from either ‘immunised’ or non-immunised’ shrimp was shown to display innate humoral antibacterial activity against V. harveyi that was absent against B. subtilis. However, there was no difference in the potency of antibacterial activity between V. harveyi-injected shrimp and control (saline injected) animals showing that ‘vaccination’ has no effect on this component of the shrimp's immune system. These results imply that the cellular immune system of shrimp, particularly phagocytosis, is capable of a degree of specificity and shows the phenomenon of ‘immune priming’ reported by other workers. However, in agreement with other studies, this phenomenon is not universal to all potential pathogens

Fostering active network management through SMEs’practises

Managing the electricity network through ‘smart grid’ systems is a key strategy to address challenges of energy security, low carbon transitions and the replacement of ageing infrastructure networks in the UK. Small and medium enterprises (SMEs) have a significant role in shaping patterns of energy consumption. Understanding how their activities interrelate with changes in electricity systems is critical for active network management. A significant challenge for the transformation of electricity systems involves comprehending the complexity that stems from the variety of commercial activities and diversity of social and organizational practises among SMEs that interact with material infrastructures. We engage with SMEs to consider how smart grid interventions ‘fit’ into everyday operational activities. Drawing on analysis of empirical data on electricity use, smart metre data, surveys, interviews and ‘energy tours’ with SMEs to understand lighting, space heating and cooling, refrigeration and IT use, this paper argues for experimenting with the use of practise theory as a framework for bringing together technical and social aspects of energy use in SMEs. This approach reveals that material circumstances and temporal factors shape current energy demand among SMEs, with ‘connectedness’ an emergent factor

Shirt sponsorship by gambling companies in the English and Scottish Premier Leagues: global reach and public health concerns

While the nature of gambling practices is contested, a strong evidence base demonstrates that gambling can become a serious disorder and have a range of detrimental effects for individuals, communities and societies. Over the last decade, football in the UK has become visibly entwined with gambling marketing. To explore this apparent trend, we tracked shirt sponsors in both the English and Scottish Premier Leagues since 1992 and found a pronounced increase in the presence of sponsorship by gambling companies. This increase occurred at the same time the Gambling Act 2005, which liberalized rules, was introduced. We argue that current levels of gambling sponsorship in UK football, and the global visibility it provides to gambling brands, is a public health concern that needs to be debated and addressed. We recommend that legislators revisit the relationship between football in the UK and the sponsorship it receives from the gambling industry

Mellow yellow: An experiment in amber

Amber natron glasses were produced from at least the Hellenistic period and continued to be produced into the early second century CE. However, as with other strong colours used for Roman vessel production, this colour gradually declined in popularity as colourless and blue-green glass came to dominate. Whilst the colouring mechanisms for blue-green glasses are relatively well understood, the cause of the distinctive amber colour is more complex and can be attributed to the iron sulphur chromophore. This paper demonstrates, using analytical data and model glasses, that the amber colour develops during primary production, and that the sulphate-rich natron is key. The analytical data show that most natron amber glass was probably produced in the Levant alongside the more common blue-green glasses, however, its composition is different. Whilst many glass colours were made in a secondary stage, by adding colourants and opacifiers to a blue-green or colourless glass base, amber glass was not made this way since it required a slightly different set of raw materials and melting technologies. These findings suggest that the production of the glass required specialist knowledge, and particularly skilled furnace operation, in order to produce repeatable results. Skilled specialists would also be required to work amber glass whilst retaining the same clear amber hue, especially for complex wares, such as mosaic vessels, where the glass would be reheated more than once

Fear filter: Visualising the UK terror threat level

Fear Filter is a digital artwork comprising of a mobile phone photo filters application for Android / iOS platforms and a digital photo stream. The photo filters are created by gathering current and historical information about the UK Threat Level from a live feed from MI5, the UK security service. Photographs taken with the mobile application are transformed by the photo filters, each of which correspond to a different moment in time and the related Threat Level from that period. The filters cover the period 1 August 2006 until the present moment. Photos shared from the mobile application are automatically posted to a public photo stream.Fear Filter exploits the confluence of mobile digital photography, platforms, networks and the online security theatre of the UK Threat Level to reformulate the relationship between photography and terrorism

Effective Caspase Inhibition Blocks Neutrophil Apoptosis and Reveals Mcl-1 as Both a Regulator and a Target of Neutrophil Caspase Activation

Human tissue inflammation is terminated, at least in part, by the death of inflammatory neutrophils by apoptosis. The regulation of this process is therefore key to understanding and manipulating inflammation resolution. Previous data have suggested that the short-lived pro-survival Bcl-2 family protein, Mcl-1, is instrumental in determining neutrophil lifespan. However, Mcl-1 can be cleaved following caspase activity, and the possibility therefore remains that the observed fall in Mcl-1 levels is due to caspase activity downstream of caspase activation, rather than being a key event initiating apoptosis in human neutrophils

A multi-scale modelling framework to guide management of plant invasions in a transboundary context

Background Attention has recently been drawn to the issue of transboundary invasions, where species introduced and naturalized in one country cross international borders and become problematic in neighbouring countries. Robust modelling frameworks, able to identify the environmental drivers of invasion and forecast the current and future potential distribution of invasive species, are needed to study and manage invasions. Limitations due to the lack of species distribution and environmental data, or assumptions of modelling tools, often constrain the reliability of model predictions. Methods We present a multiscale spatial modelling framework for transboundary invasions, incorporating robust modelling frameworks (Multimodel Inference and Ensemble Modelling) to overcome some of the limitations. The framework is illustrated using Hakea sericea Schrad. (Proteaceae), a shrub or small tree native to Australia and invasive in several regions of the world, including the Iberian Peninsula. Two study scales were considered: regional scale (western Iberia, including mainland Portugal and Galicia) and local scale (northwest Portugal). At the regional scale, the relative importance of environmental predictors sets was evaluated and ranked to determine the main general drivers for the species distribution, while the importance of each environmental predictor was assessed at the local scale. The potential distribution of H. sericea was spatially projected for both scale areas. Results Model projections for western Iberia suggest that a large area is environmentally suitable in both Portugal and Spain. Climate and landscape composition sets were the most important determinants of this regional distribution of the species. Conversely, a geological predictor (schist lithology) was more important in explaining its local-scale distribution. Conclusions After being introduced to Portugal, H. sericea has become a transboundary invader by expanding in parts of Galicia (Spain). The fact that a larger area is predicted as environmentally suitable in Spain raises concerns regarding its potential continued expansion. This highlights the importance of transboundary cooperation in the early management of invasions. By reliably identifying drivers and providing spatial projections of invasion at multiple scales, this framework provides insights for the study and management of biological invasions, including the assessment of transboundary invasion risk.This work was funded by FEDER funds through the Operational Programme for Competitiveness Factors - COMPETE and by National Funds through FCT - Foundation for Science and Technology under the project PTDC/AAGMAA/4539/2012 / FCOMP-01-0124-FEDER-027863 (IND_CHANGE). J. Vicente is supported by POPH/FSE funds and by National Funds through FCT - Foundation for Science and Technology through Post-doctoral grant SFRH/BPD/84044/2012. D.M. Richardson acknowledges support from the DST-NRF Centre of Excellence for Invasion Biology and the National Research Foundation (grant 85417).info:eu-repo/semantics/publishedVersio

Association between birthweight and later body mass index : an individual-based pooled analysis of 27 twin cohorts participating in the CODATwins project

Background: There is evidence that birthweight is positively associated with body mass index (BMI) in later life, but it remains unclear whether this is explained by genetic factors or the intrauterine environment. We analysed the association between birthweight and BMI from infancy to adulthood within twin pairs, which provides insights into the role of genetic and environmental individual-specific factors. Methods: This study is based on the data from 27 twin cohorts in 17 countries. The pooled data included 78 642 twin individuals (20 635 monozygotic and 18 686 same-sex dizygotic twin pairs) with information on birthweight and a total of 214 930 BMI measurements at ages ranging from 1 to 49 years. The association between birthweight and BMI was analysed at both the individual and within-pair levels using linear regression analyses. Results: At the individual level, a 1-kg increase in birthweight was linearly associated with up to 0.9 kg/m(2) higher BMI (P <0.001). Within twin pairs, regression coefficients were generally greater (up to 1.2 kg/m(2) per kg birthweight, P <0.001) than those from the individual-level analyses. Intra-pair associations between birthweight and later BMI were similar in both zygosity groups and sexes and were lower in adulthood. Conclusions: These findings indicate that environmental factors unique to each individual have an important role in the positive association between birthweight and later BMI, at least until young adulthood.Peer reviewe