491 research outputs found
Integration of μ-SOFC Generator and ZEBRA Batteries for Domestic Application and Comparison with other μ-CHP Technologies
Abstract This study investigates the possibility to integrate a Solide Oxide Fuel Cell (SOFC) prime mover and ZEBRA batteries, with the aim to fulfill a domestic user energy demand and to reduce the primary energy consumption, thereby, to enhance the total efficiency in a μ-CHP (Combined Heat and Power) application on a yearly basis. A realistic operational sequence of the SOFC-ZEBRA integration has been calculated using simple logic conditions. Both electric and thermal integration have been considered, in order to exploit the SOFC residual heat for the battery stand-by feeding. The key advantage of this system architecture is that the SOFC is operated without major load variations close to constant load, resulting in longer lifetime and thus reducing total costs of operation. Eventually, a comparison with alternative μ-CHP technologies has been carried out, highlighting the SOFC-ZEBRA potential
Pump Hydro Storage and Gas Turbines Technologies Combined to Handle Wind Variability: Optimal Hydro Solution for an Italian Case Study☆
Abstract Load and wind energy profiles are totally uncorrelated, therein lies the problem of variable energy sources. Managing load with increasing wind penetration may call for operational ranges that conventional systems cannot readily access. Storage technologies could allow tolerating the unsteadiness of renewable sources with smaller fossil fuel plants capacity. Pumped Hydro Storage (PHS) is a crucial technology for balancing large steam power plants and may become increasingly important for storing renewable energies. Hence capacity ranges of PHS as well as its dynamic response to renewable power variability, will become progressively relevant. An integrated system made of a wind farm, a PHS plant and a set of gas turbines (GTs), as programmable fossil fuel devices, to handle renewable variability and maximize renewable energy exploitation, is studied in this paper. A specific case study is analyzed: a wind farm with a nameplate capacity equal to that installed in Sardinia is considered. To match the power output requested by the region with the integrated systems different configurations of PHS plant will be investigated. The impact of reversible or separate Francis machines with constant or variable speed will be analyzed in order to minimize electric power output overproduction and GTs fuel consumptions. Minimum and maximum capacity range for reversible or separate machines will be considered. The aim of the study is the optimum sizing and design of a PHS unit in a hybrid wind-hydro-gas turbine power plant to match the load request. Results in terms of PHS operation, water height behavior in upper and lower reservoirs, GT units power output, natural gas consumed and electric power output overproduction will be presented for each analyzed case
Thermal integration of a SOFC power generator and a Na-NiCl2 battery for CHP domestic application
In this study the integration of a Solid Oxide Fuel Cell (SOFC) prime mover and a high temperature electrochemical Sodium Nickel Chloride (SNC) battery as storage has been investigated. The aim is to fulfil a domestic user energy demand and to reduce the primary energy consumption in comparison with a reference conventional scenario, thereby, to enhance the total efficiency in a μ-CHP (Combined Heat and Power) application on a yearly basis. A realistic operational sequence of the SOFC-battery integration has been calculated using simple logic conditions. Both thermal and electric integration have been considered, where the innovative thermal integration has been proposed in order to exploit the SOFC residual heat for the battery stand-by feeding. The key advantage of this system architecture is that the SOFC is operated without major load variations close to constant load, resulting in longer lifetime and thus reducing total costs of operation. The thermal integration provides additional advantages, as calculated in this study. Eventually, a comparison with alternative μ-CHP technologies has been carried out, highlighting the potential of the system based on the SOFC. Benefits are mainly shown in terms of primary energy savings and admissible costs
Renewable Energy Storage System Based on a Power-to-Gas Conversion Process
Abstract The increasing penetration of renewable energy generation in the electric energy market is currently posing new critical issues, related to the generation prediction and scheduling, due to the mismatch between power production and utilization. In order to cope with these issues, the implementation of new large scale storage units on the electric network is foreseen as a key mitigation strategy. Among large scale technologies for the electric energy storage, the Power-to-Gas solution can be regarded as a long-term viable option, provided that the conversion efficiency is improved and aligned with other more conventional storage alternatives. In this study, a Power-to-Gas storage system is investigated, including as main components a high-temperature electrolyzer for hydrogen generation and a Sabatier reactor for methane production. The high-temperature Solide Oxide Electrolyser Cell (SOEC) technology, currently under development, is considered as a promising solution for hydrogen generation, due to the expected higher efficiency values, in comparison with conventional low-temperature electrolysis technologies. In order to evaluate the performance of the system and the energy efficiency, in this study a numerical model of the SOEC integrated with the Sabatier reactor has been implemented, including also the necessary additional auxiliaries, which can significantly affect the energy conversion performance. The whole energy conversion and storage system has been analyzed, taking into account different layout variants, by means of Aspen HysysTM numerical tool, based on a lumped modelling approach. The various Power-to-Gas storage configurations have been compared, with the aim to optimize both the system's efficiency and the composition of the produced gas stream
New immunological potential markers for triple negative breast cancer: IL18R1, CD53, TRIM, Jaw1, LTB, PTPRCAP
Breast cancer (BC) is the second leading cause of cancer death in women worldwide, and settings of specific prognostic
factors and efficacious therapies are made difficult by phenotypic heterogeneity of BC subtypes. Therefore, there is a
current urgent need to define novel predictive genetic predictors that may be useful for stratifying patients with distinct
prognostic outcomes. Here, we looked for novel molecular signatures for triple negative breast cancers (TNBCs). By a
bioinformatic approach, we identified a panel of genes, whose expression was positively correlated with disease-free survival
in TNBC patients, namely IL18R1, CD53, TRIM, Jaw1, LTB, and PTPRCAP, showing specific immune expression profiles
linked to survival prediction; most of these genes are indeed expressed in immune cells and are required for productive
lymphocyte activation. According to our hypothesis, these genes were not, or poorly, expressed in different TNBC cell
lines, derived from either primary breast tumours or metastatic pleural effusions. This conclusion was further supported
in vivo, as immuno-histochemical analysis on biopsies of TNBC invasive ductal carcinomas highlighted differential expression
of these six genes in cancer cells, as well as in intra- and peri-tumoral infiltrating lymphocytes. Our data open to the
possibility that inter-tumour heterogeneity of immune markers might have predictive value; further investigations are
recommended in order to establish the real power of cancer-related immune profiles as prognostic factors
Techno-Economic Analysis of ORC in Gas Compression Stations Taking Into Account Actual Operating Conditions
Abstract Gas compressor stations represent a huge potential for exhaust heat recovery, currently under-exploited. Typical installations consist of multiple gas turbine units in mechanical drive arrangement, operated, most of the time, at part-load conditions and with limited conversion efficiency. In this context, this paper investigates the energetic-economic potential of ORC application in typical gas compression facilities, as innovative contribution with respect to literature. The ORC is designed to convert the gas turbines wasted heat into useful power. Additional power output can be used either inside the compression facility, reducing the amount of consumed natural gas and, consequently, the environmental impact, or delivered to the electrical grid. Taking into account real operation of gas turbines in a natural gas compression station, located in North America, additional generated energy and CO 2 avoided, thanks to ORC operation, are quantified. Two ORC arrangements, namely with and without intermediate heat transfer fluid, are proposed and the design performance are identified. Influence of topper cycle part load operations on bottomer section are quantified through an off-design thermodynamic evaluation. The goal of the performed analysis is to obtain a detailed scenario of the integrated system operation on yearly basis. Results, for a reference 50 MW compression station, show that the direct heat exchange configuration guarantees up to 66 GWh/year of additional electrical energy, saving up to 36*10 3 tons/year of CO 2 , while ORC investment costs can be recovered within 7 years of operation. The performed comprehensive investigation assesses the ORC as a techno-economic profitable technology to recover wasted heat in natural gas compression facilities
Experimental Investigation with Steady-State Detection in a Micro-ORC Test Bench
Abstract The exploitation of low grade thermal sources is recognized as a feasible strategy in order to pursue the primary energy saving target worldwide. This concept, adaptable to a number of different applications, is aimed at exploiting low-value heat fluxes that would be wasted otherwise; additional useful electric power can be produced locally, with ORC energy systems; this is one of the most promising heat recovery solutions. In particular, the paper refers to the test bench developed in the laboratories of the University of Bologna; a prototypal micro-ORC energy system is here investigated. The micro-ORC system presents a reciprocating three-piston expander operated with refrigerant fluid. Heat is provided to the ORC from via hot water at low temperature, in order to simulate a constant low-enthalpy heat recovery process. The system rejects unused heat via a water-cooled condenser, dependent on the external ambient conditions. The test bench layout and the real-time data acquisition system, developed in the LabVIEW environment, are here described. In particular, the paper focus is on the system steady-state detection methodology. Starting from an experimental campaign, steady-state operational points are identified through an appropriate literature approach. The measured quantities and calculated performance have been post-processed in order to evaluate the influence on steady state detection, of different hot source temperature set points. Moreover, the selected steady-state detection method is suitable for real-time implementation, due to its simple formulation and the low number of variables required to be stored at time step of acquisition
A Micro-ORC Energy System: Preliminary Performance and Test Bench Development
Abstract A large market potential for small electricity and heat generators can be identified in the domestic sector. Among the under development micro-scale power generation technologies the ORC (Organic Rankine Cycle) concept is a promising solution, already proven in the MW-range of power. There is still a prospective for smaller units for domestic users, with low temperature thermal demand. A test bench for a micro-CHP unit, currently run with a prototypal prime mover, is under development at University of Bologna. In particular, the system in study in the test facility is a micro-ORC system, rated for up to 3 kW. The ORC input heat is provided from an external source, which can be an external combustion system (a 46 kW biomass boiler will be connected to the thermal cycle) or an electric heater. The heat source delivers hot water to the bottoming ORC, currently operated with R134a as working fluid, which evolves in a recuperated cycle, with a 3-piston reciprocating expander, producing mechanical/electric power. The residual low-value heat is discharged to the environment with a water cooled condenser. The hot and cold water circuits have been realized in the lab to test the ORC performance. The micro-ORC internal layout and the external hot and cold water lines have been instrumented, implementing an acquisition and control software by means of LabVIEW software. A preliminary test campaign has been performed on the micro-ORC system, obtaining information on the actual thermodynamic cycle and the real performance under different operating conditions
MicroRNAs, miR-154, miR-299-5p, miR-376a, miR-376c, miR-377, miR-381, miR-487b, miR-485-3p, miR-495 and miR-654-3p, mapped to the 14q32.31 locus, regulate proliferation, apoptosis, migration and invasion in metastatic prostate cancer cells
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Novel transglutaminase 1 mutations in patients affected by lamellar ichthyosis
Lamellar Ichthyosis (LI) is a form of congenital ichthyosis that is caused by mutations in the TGM1 gene that encodes for the transglutaminase 1 (TG1) enzyme. Functional inactivation of TG1 could be due to mutations, deletion or insertions. In this study, we have screened 16 patients affected by LI and found six new mutations: two transition/transversion (R37G, V112A), two nonsense mutations and two putative splice site both leading to a premature stop codon. The mutations are localized in exons 2 (N-terminal domain), 5, 11 (central catalytic domain), and none is located in the two beta-barrel C-terminal domains. In conclusion, this study expands the current knowledge on TGM1 mutation spectrum, increasing the characterization of mutations would provide more accurate prenatal genetic counselling for parents at-risk individuals
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