Analysis of two heat storage integrations for an Organic Rankine Cycle Parabolic trough solar power plant

Among the concentrated solar power technologies, those based on Organic Rankine Cycles have a very low market presence. However they have favorable characteristics for applications with low temperature and small/medium size (<10 MW), such as off-grid applications or distributed power generation. In this paper is analyzed a 5MW parabolic trough plant integrated with an Organic Rankine cycle power block and thermal storage. On this purpose, two different thermal storage integrations are analyzed. They are based on two different heat storage layouts: direct system using Hitec XL both as Heat Transfer Fluid and as storage medium; indirect system using Therminol VP-1 as Heat Transfer Fluid and Hitec XL as storage medium. Full system performance at rated and off-design conditions is presented operating with different organic working fluids. Its potential application and main challenges for its development are discussed in terms of performance and costs. Among the analyzed working fluids, the best results were obtained for the cycle working with Toluene with an efficiency at the power block of 31.5% and an estimated power block cost of 825 €/kW. The indirect storage layout was the most interesting from the point of view of Levelized Electricity Cost (16.19 c€/kW) and productivity (28.2 GW h/y for a 5 MWel plant) for 10 h of storage However, it results in a storage tanks volume 26% greater than the obtained for the equivalent direct storage layout. The results show the competitiveness and the potential of the proposed integrated small size parabolic trough designs for isolated applications as mines or for some distributed generation uses where grid capacity is limited

Data informed physical models for district heating grids with distributed heat sources to understand thermal and hydraulic aspects

The aim of the study was to develop data informed physical models for simulation of district heating (DH) grids for better presentation of hydraulic and thermal aspects in the DH grids integrating heat prosumers. A DH grid organized as a ring and integrating a heat prosumer from a data center was analyzed. In this study, an extensive analysis for thermal and hydraulic aspects of theDH grid considering different configurations of distributed sources was performed. Different configurations for the prosumer connection, the return to return and the return to supply, together with the pressure and temperature control, were investigated. The results showed that increasing the share of renewable heat from the prosumer to the DH grid caused a pressure imbalance in substations close to it. Variable speed pump control was the solution for these issues and it gave up to 34% electricity savings. Lowering temperature levels in the DH network led to a decrease in DH heat losses of up to 14%. The return to supply configuration showed advantages in integrating the prosumer, as regards lower return temperatures and better waste heat utilization. The results indicated the main hydraulic and thermal features of integrating the prosumer in the DH grid

Multiscale analysis of tunnel ventilation flows and fires

Presentazione a 11èmes journées du GDR Incendie, CSTB - Champs sur Marne, Paris (Fr), 17th -18th June 201

A Prevention through Design Approach for the Environmental S&H Conditions and the Ventilation System at an Italian Underground Quarry

Even if the number of the Italian quarrying operations in underground is steadily growing, in many cases the safety criticalities are somehow underestimated, in spite of the regulations D.Lgs. 81/08 and D.Lgs. 624/96, Italian enforcements of the European Directives. Ventilation system is conceived to face very simplified requirements, whilst critical pollutants or emergency situations are not taken in due considerations. Asides, the ventilation system fault and availability analysis is seldom included in the project. The paper deals with the results of a research work started some years ago at an underground quarry exploited through drift sublevel based on drill and blast technique, to identify criteria suitable to grant effective safety and health -S&H- conditions for the workers operating in the underground in the Prevention through Design approach. Taken into account that the phases for an effective approach to the S&H problems in underground must follow a hierarchic method in which the risk management should be faced from an effective hazard reduction to a minimum at the sources, and the ventilation should be considered only as a 4th level solution, the possibilities of control at the main pollution sources, i.e. the emission of pollutants due to the rock winning and mucking operations, have been examined. The residual risk was then faced with both the original underground and airways layout definition for a new exploitation development, based on technical and efficiency considerations, and on fire emergency computer simulations. Finally, the paper summarizes the results of an availability analysis of the ventilation system for the normal operating conditions and the emergencies management, on the basis of the results of Hazard Evaluation techniques, in particular Hazard and Operability Analysis and Fault Tree Analysis

The energy center initiative at politecnico di torino: practical experiences on energy efficiency measures in the municipality of torino

Urban districts should evolve towards a more sustainable infrastructure and greener energy carriers. The utmost challenge is the smart integration and control, within the existing infrastructure, of new information and energy technologies (such as sensors, appliances, electric and thermal power and storage devices) that are able to provide multi-services based on multi-actors and multi and interchangeable energy carriers. In recent years, the Municipality of Torino represents an experimental scenario, in which practical experiences in the below-areas have taken place through a number of projects: 1. energy efficiency in building; 2. smart energy grids management and smart metering; 3. biowaste-to-energy: mixed urban/industrial waste management with enhanced energy recovery from biogas. This work provides an overview and update on the most interesting initiatives of smart energy management in the urban context of Torino, with an analysis and quantification of the advantages gained in terms of energy and environmental efficiency

The role of P2 receptors in controlling infections by intracellular pathogens

A growing number of studies have demonstrated the importance of ATPe-signalling via P2 receptors as an important component of the inflammatory response to infection. More recent studies have shown that ATPe can also have a direct effect on infection by intracellular pathogens, by modulating membrane trafficking in cells that contain vacuoles that harbour intracellular pathogens, such as mycobacteria and chlamydiae. A conserved mechanism appears to be involved in controlling infection by both of these pathogens, as a role for phospholipase D in inducing fusion between lysosomes and the vacuoles has been demonstrated. Other P2-dependent mechanisms are most likely operative in the cases of pathogens, such as Leishmania, which survive in an acidic phagolysosomal-like compartment. ATPe may function as a ‘danger signal–that alerts the immune system to the presence of intracellular pathogens that damage the host cell, while different intracellular pathogens have evolved enzymes or other mechanisms to inhibit ATPe-mediated signalling, which should, thus, be viewed as virulence factors for these pathogens

Nitric oxide synthases and tubal ectopic pregnancies induced by Chlamydia infection: basic and clinical insights

Human ectopic pregnancy (EP) remains a common cause of pregnancy-related first trimester death. Nitric oxide (NO) is synthesized from L-arginine by three NO synthases (NOS) in different tissues, including the Fallopian tube. Studies of knockout mouse models have improved our understanding of the function of NOS isoforms in reproduction, but their roles and specific mechanisms in infection-induced tubal dysfunction have not been fully elucidated. Here, we provide an overview of the expression, regulation and possible function of NOS isoforms in the Fallopian tube, highlighting the effects of infection-induced changes in the tubal cellular microenvironment (imbalance of NO production) on tubal dysfunction and the potential involvement of NOS isoforms in tubal EP after Chlamydia trachomatis genital infection. The non-equivalent regulation of tubal NOS isoforms during the menstrual cycle suggests that endogenous ovarian steroid hormones regulate NOS in an isoform-specific manner. The current literature suggests that infection with C. trachomatis induces an inflammatory response that eventually leads to tubal epithelial destruction and functional impairment, caused by a high NO output mediated by inducible NOS (iNOS). Therefore, tissue-specific therapeutic approaches to suppress iNOS expression may help to prevent ectopic implantation in patients with prior C. trachomatis infection of the Fallopian tube

Hematopoietic stem cell transplantation for multiple sclerosis

Hematopoietic stem cell transplantation (HSCT) was proposed as a treatment for multiple sclerosis (MS) in 1995 based on favorable results in animal models including experimental autoimmune encephalomyelitis. These initial or first-generation trials were developed by medical oncology subspecialists, used malignancy-specific myeloablative transplantation regimens, and selected patients with secondary progressive MS with rapid progression of disability. In general, these trials suffered from higher than anticipated toxic reactions including treatment-related and disease-related mortality, continued loss of brain volume as seen on magnetic resonance imaging (MRI), and, at least in some patients, continued progressive disability despite marked attenuation or absence of gadolinium-enhancing lesions on MRI. Learning from these experiences, second-generation transplantation trials for MS are using MS-specific nonmyeloablative transplantation regimens and selecting for active relapses despite the use of interferon treatment in patients with less accumulated disability. While still preliminary, results using second-generation nonmyeloablati