The energy-water nexus: Renewable energy and water desalination

The essential connection between energy and water, also defined as the energy-water nexus, has been recognized by scientists and policy makers worldwide. Integrated solutions and policies that consider both energy and water aspects into future planning have been developing at a fast pace. In this paper, we review the state of the art of the energy-water nexus, with particular focus on the integration between renewable energy and desalination technologies. We also model the integration of reverse osmosis (RO) desalination and solar photovoltaics in an edge-of-grid coastal town in Western Australia. The current literature agrees on the sustainable use of renewable energy sources to improve the water-energy nexus in the context of water desalination. Although the integration of solar and wind energy with desalination technologies is a mature and well-proven solution at both small and large scales, the intermittency and fluctuating nature of wind and solar power still constitute the main technical challenge that has limited the diffusion of renewable energy powered desalination on a large scale. Several successful applications of renewable energy powered desalination in remote, off the grid, locations have tackled the issue of power intermittency by the use of batteries and diesel generators. Such systems often couple reverse osmosis desalination with solar photovoltaic energy. Large desalination plants have been successfully connected to wind farms and grid electricity to secure uninterrupted plant operations, thus meeting water targets in large-scale systems. Our review identifies a knowledge gap in the integration of decentralized energy systems, e.g. rooftop solar photovoltaic, with small scale RO desalination. Such configuration would benefit those regional towns that have historically suffered from weak and unreliable connections to the electricity grid, thus helping them secure both their energy and water requirements. The modelling exercise on a renewable energy powered RO plant in an edge-of-grid town in Western Australia has identified an operating strategy that maximizes the renewable energy fraction and secures the annual supply of water. The system involves operating the RO unit for six months of the year at a daily variable load and integrating solar energy with grid electricity. Careful evaluation of the RO performance under such operating conditions is necessary to ensure a safe and reliable water treatment process. A niche in the literature of the energy-water nexus has been identified in the integration of rooftop solar photovoltaic, grid electricity and desalination technologies applied in a regional context. A future study will consider the rollout of rooftop solar photovoltaic installations across the whole town, thus enabling the active engagement of the community by integrating the households’ energy demand response patterns to the operations of both rooftop photovoltaics and the desalination unit

The energy-water nexus: Renewable energy and water desalination

The essential connection between energy and water, also defined as the energy-water nexus, has been recognized by scientists and policy makers worldwide. Integrated solutions and policies that consider both energy and water aspects into future planning have been developing at a fast pace. In this paper, we review the state of the art of the energy-water nexus, with particular focus on the integration between renewable energy and desalination technologies. We also model the integration of reverse osmosis (RO) desalination and solar photovoltaics in an edge-of-grid coastal town in Western Australia. The current literature agrees on the sustainable use of renewable energy sources to improve the water-energy nexus in the context of water desalination. Although the integration of solar and wind energy with desalination technologies is a mature and well-proven solution at both small and large scales, the intermittency and fluctuating nature of wind and solar power still constitute the main technical challenge that has limited the diffusion of renewable energy powered desalination on a large scale. Several successful applications of renewable energy powered desalination in remote, off the grid, locations have tackled the issue of power intermittency by the use of batteries and diesel generators. Such systems often couple reverse osmosis desalination with solar photovoltaic energy. Large desalination plants have been successfully connected to wind farms and grid electricity to secure uninterrupted plant operations, thus meeting water targets in large-scale systems. Our review identifies a knowledge gap in the integration of decentralized energy systems, e.g. rooftop solar photovoltaic, with small scale RO desalination. Such configuration would benefit those regional towns that have historically suffered from weak and unreliable connections to the electricity grid, thus helping them secure both their energy and water requirements. The modelling exercise on a renewable energy powered RO plant in an edge-of-grid town in Western Australia has identified an operating strategy that maximizes the renewable energy fraction and secures the annual supply of water. The system involves operating the RO unit for six months of the year at a daily variable load and integrating solar energy with grid electricity. Careful evaluation of the RO performance under such operating conditions is necessary to ensure a safe and reliable water treatment process. A niche in the literature of the energy-water nexus has been identified in the integration of rooftop solar photovoltaic, grid electricity and desalination technologies applied in a regional context. A future study will consider the rollout of rooftop solar photovoltaic installations across the whole town, thus enabling the active engagement of the community by integrating the households’ energy demand response patterns to the operations of both rooftop photovoltaics and the desalination unit

MC1R gene: comparison between different farm animal species

Il gene MC1R: confronto fra diverse specie animali di interesse zootecnico. Negli animali di interesse zootecnico, il polimorfismo del gene MC1R coinvolto nella pigmentazione \ue8 stato studiato a livello molecolare soltanto nell\u2019ultimo decennio. Si sono confrontate descrizioni fenotipiche e polimorfismi del gene MC1R in alcune razze bovine (Rendena, Bruna, Cabannina, Ottonese-Varzese e Pezzata Rossa) e nel cavallo (62 animali). Tutti gli animali feomelanici sono portatori delle mutazioni recessive allo stato omozigote indipendentemente dalla tonalit\ue0 del mantello. I cavalli neri sono portatori dell\u2019allele selvatico del gene MC1R e della mutazione recessiva del gene ASIP allo stato omozigote. Nei cavalli bai e nelle altre razze bovine studiate \ue8 presente, almeno allo stato eterozigote, l\u2019allele selvatico. Nella Bruna e nella Cabannina \ue8 presente anche l\u2019allele E1. Nel gene MC1R, sequenziato in capre di razza Bionda dell\u2019Adamello e Nera di Verzasca, si \ue8 evidenziata l\u2019unica mutazione descritta in letteratura. I risultati sono stati confrontati con le informazioni disponibili nella specie murina e umana.Coat colour genes in farm animals have only been studied at molecular level over the last ten years, starting with Klungland et al. in 1995. Among the genes involved in pigmentation, MC1R, previously known as Extension locus, revealed polymorphisms related to red and black coat colour in different farm animal species. More exactly, the MelanoCortin-1 Receptor (MC1R) gene, specifically expressed in melanocytes, encodes for the homonymous G-protein coupled receptor involved in the regulation of the type of melanin synthesized. Melanocytes produce in fact two different types of melanins: the black or brown eumelanin and the yellow or red pheomelanin. The hair distribution of eu- and pheomelanins depends on the activity of MC1R, which is normally modulated by response to the melanocortin hormone, antagonized by the action of Agouti protein encoded by the ASIP gene. We previously studied the MC1R polymorphisms in some cattle reared in Italy (Crepaldi et al., 2003) and we now present the data on MC1R in other Italian cattle breeds, horses and goats. The aim of this work is to compare the pigmentary phenotypes and causative MC1R mutations in different farm animals and model species, such as mouse and human, in order to highlight differences and similarities between phenotypes and MC1R polymorphisms. The relationship between phenotypes and Agouti locus is also discussed

Parametric multi-objective optimization of an Organic Rankine Cycle with thermal energy storage for distributed generation

Abstract This paper focuses on the thermodynamic modelling and parametric optimization of an Organic Rankine Cycle (ORC) which recovers the heat stored in a thermal energy storage (TES). A TES with two molten-salt tanks (one cold and one hot) is selected since it is able to operate in the temperature range useful to recover heat from different sources such as exhaust gas of Externally Fired Gas Turbine (EFGT) or Concentrating Solar Power (CSP) plant, operating in a network for Distributed Generation (DG). The thermal storage facilitates a flexible operation of the power system operating in the network of DG, and in particular allows to compensate the energy fluctuations of heat and power demand, increase the capacity factor of the connected plants, increase the dispatchability of the renewable energy generated and potentially operate in load following mode. The selected ORC is a regenerative cycle with the adoption of a Heat Recovery Vapour Generator (HRVG) that recovers heat from molten salts flowing from the Hot Tank to the Cold Tank of the TES. By considering the properties of molten salt mixtures, a ternary mixture able to operate between 200 and 400 °C is selected. The main ORC parameters, namely the evaporating pressure/temperature and the evaporator/condenser pinch point temperature differences, are selected as variables for the thermodynamic ORC optimization. An automatic optimization procedure is set up by means of a genetic algorithm (GA) coupled with an in-house code for the ORC calculation. Firstly, a mono-objective optimization is carried out for two working fluids of interest (Toluene and R113) by maximization of the cycle thermal efficiency. Afterwards, a multi-objective optimization is carried out for the fluid with the best performance by means of a Non-dominated Sorting Genetic Algorithm (NSGA) in order to evaluate the cycle parameters which maximize the thermal efficiency and minimise the heat exchanger surface areas. Toluene results able to give the best trade-off between efficiency and heat exchanger dimensions for the present application, showing that by with respect to the best efficiency point, the heat exchange area can be reduced by 36% with only a penalty of 1% for the efficiency

Numerical simulation of a complete charging-discharging phase of a shell and tube thermal energy storage with phase change material

Abstract Numerical simulations of a shell and tube energy storage device based on a phase change material (PCM) in vertical position are performed. The heat transfer fluid (HTF) is a diathermic oil and the PCM, made by molten salts, is confined within a closed shell surrounding the tube where the HTF flows. The energy loss through the external wall is included. The test has been carried out within the experimental activity performed by ENEA. A complete cycle is considered: the initial stabilization, the charging phase and the discharging phase. Details of flow behavior within the molten PCM are described highlighting its influence on the device performance

Landscape genomics and biased FST approaches reveal single nucleotide polymorphisms under selection in goat breeds of North-East Mediterranean

<p>Abstract</p> <p>Background</p> <p>In this study we compare outlier loci detected using a <it>F<smcaps>ST </smcaps></it>based method with those identified by a recently described method based on spatial analysis (SAM). We tested a panel of single nucleotide polymorphisms (SNPs) previously genotyped in individuals of goat breeds of southern areas of the Mediterranean basin (Italy, Greece and Albania). We evaluate how the SAM method performs with SNPs, which are increasingly employed due to their high number, low cost and easy of scoring.</p> <p>Results</p> <p>The combined use of the two outlier detection approaches, never tested before using SNP polymorphisms, resulted in the identification of the same three loci involved in milk and meat quality data by using the two methods, while the <it>F<smcaps>ST </smcaps></it>based method identified 3 more loci as under selection sweep in the breeds examined.</p> <p>Conclusion</p> <p>Data appear congruent by using the two methods for <it>F<smcaps>ST </smcaps></it>values exceeding the 99% confidence limits. The methods of <it>F<smcaps>ST </smcaps></it>and SAM can independently detect signatures of selection and therefore can reduce the probability of finding false positives if employed together. The outlier loci identified in this study could indicate adaptive variation in the analysed species, characterized by a large range of climatic conditions in the rearing areas and by a history of intense trade, that implies plasticity in adapting to new environments.</p

Microsatellite diversity of the Nordic type of goats in relation to breed conservation: how relevant is pure ancestry?

In the last decades, several endangered breeds of livestock species have been re-established effectively. However, the successful revival of the Dutch and Danish Landrace goats involved crossing with exotic breeds and the ancestry of the current populations is therefore not clear. We have generated genotypes for 27 FAO-recommended microsatellites of these landraces and three phenotypically similar Nordic-type landraces and compared these breeds with central European, Mediterranean and south-west Asian goats. We found decreasing levels of genetic diversity with increasing distance from the south-west Asian domestication site with a south-east-to-north-west cline that is clearly steeper than the Mediterranean east-to-west cline. In terms of genetic diversity, the Dutch Landrace comes next to the isolated Icelandic breed, which has an extremely low diversity. The Norwegian coastal goat and the Finnish and Icelandic landraces are clearly related. It appears that by a combination of mixed origin and a population bottleneck, the Dutch and Danish Land-races are separated from the other breeds. However, the current Dutch and Danish populations with the multicoloured and long-horned appearance effectively substitute for the original breed, illustrating that for conservation of cultural heritage, the phenotype of a breed is more relevant than pure ancestry and the genetic diversity of the original breed. More in general, we propose that for conservation, the retention of genetic diversity of an original breed and of the visual phenotype by which the breed is recognized and defined needs to be considered separately

Simulazione numerica del flusso oscillante su una parete scabra

Nell’articolo è affrontato lo studio del flusso oscillante su una parete coperta da una scabrezza regolare. La scabrezza considerata è costituita da semisfere disposte su una parete piana secondo una matrice esagonale. Le equazioni che reggono il moto del fluido sono state risolte numericamente su una griglia cartesiana. Le condizioni al contorno sulla parete sono state imposte utilizzando la tecnica dei contorni immersi (Fadlun et al., 2000). Il metodo numerico è stato validato riproducendo i risultati sperimentali di Keiller &amp; Sleath, (1976). E’ analizzato l’andamento temporale delle strutture vorticose e delle forze indotte sulla parete dalle oscillazioni del fluido. Il lavoro numerico condotto contribuisce a chiarire alcuni aspetti dei lavori sperimentali presenti in letteratura (Keiller &amp; Sleath, 1976; Sleath, 1987; Jensen et al., 1989) e risulta essere un potente strumento di indagine nello studio di questo tipo di flusso