Development of sustainable ORC applications in the tertiary sector: a case study in the Mediterranean climate

In recent decades, climate change strong advancement has led many countries, especially the most developed ones, to a greater sense of environmental responsibility. On a global, European and national level, adaptation/mitigation strategies and actions aimed at improving energy-environmental sustainability and resilience in the tertiary sectors have been increasingly intensified. In this sector, therefore, plays a fundamental role the integration/introduction of technologies able to operate an efficient conversion of energy, such as indeed Organic Rankine Cycle (ORC) plant, other than renewable energy sources, in order to reduce both energy consumption and pollutant emissions. Within this scenario, the aim of this work is to investigate the potential application of a cogeneration ORC system powered by solar collector and geothermal sources, by evaluating its energy, environmental and economic advantages and limitations. To this purpose a case study involving the coverage of the energy needs of a hotel located in Catania (Southern Italy) has been simulated and analyzed. The outcomes put in evidence the importance of the operative conditions in optimizing the productivity of an ORC plant, especially when associated with renewable energy sources, although at the moment investment and supply costs are still quite high

A Solar Pond for Feeding a Thermoelectric Generator or an Organic Rankine Cycle System

The world energy demand is continuously growing, which means an increase in consumption for all modern fuels or stronger effort on the development and improvement of renewable technologies. Moreover, Developing Countries claims more energy and they have often wide unutilized or unusable lands. The solar energy represents a useful opportunity for these Countries. The Solar Pond is both a solar collector and a thermal storage for long period and is suitable to use in wide sunny areas. Solar pond technology is able to supply heat for several applications requiring low-grade thermal energy or for electrical power production. In order to produce electrical energy from solar ponds it is necessary to use systems fed by low enthalpy sources, such Thermoelectric Generator (TEG) and Organic Rankine Cycle (ORC). In this paper, a model of a Solar Pond for power generation is analyzed in conjunction with an Organic Rankine Cycle. The model has been validated using climate data of an area near to Palermo city (Italy) and exactly the Test Reference Year developed by the Authors

Thermodynamic-based method for supporting design and operation of thermal grids in presence of distributed energy producers

District heating networks are well-established technologies to efficiently cover the thermal demand of buildings. Recent research has been devoting large efforts to improve the design and management of these systems for integrating low-temperature heat coming from distributed sources such as industrial processes and renewable energy plants. Passing from a centralized to a decentralized approach in the heat supply, it is important to develop indicators that allow an assessment of the rational use of the available heat sources in supplying heating networks, and a quantification of the effect of inefficiencies on the unit cost of heat. To answer these questions, Exergy Cost Theory is here proposed. Thanks to the unit exergetic cost of heat, energy managers can (i) quantify the effects of thermodynamic inefficiencies occurring in the production and distribution on the final cost of heat, (ii) compare alternative systems for heat production, and (iii) monitor the performance of buildings’ substation over time. To show the capabilities of the method, some operating scenarios are compared for a cluster of five buildings in the tertiary sector interconnected by a thermal grid, where heat is produced by a cogeneration unit, an industrial process, and distributed heat pumps. Results suggest that moving from the centralized production of heat based on fossil fuels to a decentralized production with air-to-water heat pumps, the unit cost of heat can be decreased by almost 30% thanks to the improvement of thermodynamic efficiency. In addition, the analysis reveals a great sensitivity of unit exergetic cost to the maintenance in substations. The developed tool can provide thermodynamic-sound support for the design, operation, and monitoring of innovative district heating networks

Systematic review of fatty acid composition of human milk from mothers of preterm compared to full-term infants

Background: Fatty acid composition of human milk serves as guidance for the composition of infant formulae. The aim of the study was to systematically review data on the fatty acid composition of human milk of mothers of preterm compared to full-term infants. Methods: An electronic literature search was performed in English (Medline and Medscape) and German (SpringerLink) databases and via the Google utility. Fatty acid compositional data for preterm and fullterm human milk were converted to differences between means and 95% confidence intervals. Results: We identified five relevant studies publishing direct comparison of fatty acid composition of preterm versus full-term human milk. There were no significant differences between the values of the principal saturated and monounsaturated fatty acids. In three independent studies covering three different time points of lactation, however, docosahexaenoic acid (DHA) values were significantly higher in milk of mothers of preterm as compared to those of full-term infants, with an extent of difference considered nutritionally relevant. Conclusion: Higher DHA values in preterm than in full-term human milk underlines the importance of using own mother's milk for feeding preterm babies and raises the question whether DHA contents in preterm formulae should be higher than in formulae for full-term infants. Copyright (c) 2008 S. Karger AG, Basel

A Marfan syndrome gene expression phenotype in cultured skin fibroblasts

<p>Abstract</p> <p>Background</p> <p>Marfan syndrome (MFS) is a heritable connective tissue disorder caused by mutations in the fibrillin-1 gene. This syndrome constitutes a significant identifiable subtype of aortic aneurysmal disease, accounting for over 5% of ascending and thoracic aortic aneurysms.</p> <p>Results</p> <p>We used spotted membrane DNA macroarrays to identify genes whose altered expression levels may contribute to the phenotype of the disease. Our analysis of 4132 genes identified a subset with significant expression differences between skin fibroblast cultures from unaffected controls versus cultures from affected individuals with known fibrillin-1 mutations. Subsequently, 10 genes were chosen for validation by quantitative RT-PCR.</p> <p>Conclusion</p> <p>Differential expression of many of the validated genes was associated with MFS samples when an additional group of unaffected and MFS affected subjects were analyzed (p-value < 3 × 10^-6under the null hypothesis that expression levels in cultured fibroblasts are unaffected by MFS status). An unexpected observation was the range of individual gene expression. In unaffected control subjects, expression ranges exceeding 10 fold were seen in many of the genes selected for qRT-PCR validation. The variation in expression in the MFS affected subjects was even greater.</p

Metal-directed columnar phase formation in tetrahedral zinc(II) and manganese(II) metallomesogens

New, non-discoid M(II) complexes [MCl2(L)] {M = Mn, Zn; L = 2,6-diformyl-4- methylphenolbis[3’,4’,5’-tris(hexadecyloxy)phenylimine]} have been prepared and shown to exhibit columnar mesophases, the nature of which was found to be metal-dependent. As analysed by DSC and small-angle X-ray diffraction experiments, the complex [ZnCl2(L)] exhibits a single mesophase with rectangular symmetry (Colr) between 46 and 145 °C, whereas the Mn(II) analogue [MnCl2(L)] displays a purely hexagonal mesophase (Colh) phase between 55 and 285 °C. By combining these results with those obtained from dilatometry, a model for the molecular organisation within the columnar mesophases is proposed. The single-crystal X-ray structure of the related complex [Zn(NO3)(L’)2]NO3.3MeOH {L’ = 2,6-diformyl-4-methylphenolbis[3’,4’,5’-tris(methoxy)phenylimine]} has been determined and supports the proposed mode of binding of the ligand to the metal via only one imine and a phenol

Multimodal imaging and diagnosis of myopic choroidal neovascularization in Caucasians

To investigate myopic choroidal neovascularization (mCNV) by fluorescein angiography (FA), spectral-domain optical coherence tomography (SD-OCT), near-infrared (NIR) reflectance, and autofluorescence (AF)

Ensayo bajo norma IRAM de colectores solares planos y de tubos evacuados : Comparación de características

Los colectores solares están en permanente equilibrio con el ambiente. La eficiencia de conversión del mismo depende de la radiación solar, la temperatura ambiente, la temperatura del agua de entrada y salida, la velocidad del viento y el caudal de circulación. De esta manera, no es posible asignar un solo valor de eficiencia a los colectores solares sino que es necesario determinar su curva de rendimiento. Esta curva representa el funcionamiento de los colectores solares bajo distintas situaciones ambientales y es necesaria para dimensionar cualquier sistema. La curva de rendimiento se determina experimentalmente bajo condiciones controladas de los parámetros mencionados y conforme a la norma IRAM 210002. En el banco de ensayos del LESES (Laboratorio de Estudios sobre energía Solar) se realizaron ensayos de diferentes colectores bajo la norma IRAM 210002. Este trabajo presenta una comparación de varios colectores ensayados y relaciona sus características constructivas con los parámetros determinados. Los resultados de este trabajo servirán para ser utilizados en el dimensionamiento de sistemas que utilicen los colectores ensayados. Asimismo, el LESES se encuentra transitando la adaptación del banco para cumplir con los requerimientos de la nueva versión de la Norma que entró en vigencia el corriente año y es objetivo del mismo, difundir la existencia de estas instalaciones para que sean consideradas a la hora de implementar una política de promoción de la energía solar térmica y para divulgar las actividades de investigación que allí se realizan.Asociación Argentina de Energías Renovables y Medio Ambiente (ASADES