Control Strategy Influence on the Efficiency of a Hybrid Photovoltaic-Battery-Fuel Cell System Distributed Generation System for Domestic Applications☆

AbstractThe full exploitation of locally available renewable resources together with the reduction of system installation and management costs are key issues of diffused Distributed Generation (DG). In the given context, hybrid systems are already at an advanced stage of development which typically integrate several sub-systems. In such hybrid systems, Renewable Energy Sources generation systems (e.g. photovoltaic panels) are coupled to energy storage devices (electric batteries) and with programmable generators (a diesel generator or, more recently, with a sub-system based on fuel cells) allowing stable operations under a wide range of conditions. In this paper a solution which uses hydrogen and fuel cells as a programmable source is presented and is studied by means of a mixed experimental and numerical: a Hardware-In-Loop test bench designed and realized at the Department lab, able to reproduce the behavior of a hybrid system for domestic applications. The system is controlled by means of a rule-based control strategy acting on the common DC-bus whose optimization has a significant influence both on system design and on its overall system energy performances. Results show that Rule-Based strategy have a great potential towards cost reduction and components lifetime increase, while energy efficiency mainly depends on correct system sizing

Effects of Waste Cooking Oil Biodiesel Use on Engine Fuel Consumption and Emissions: a Study on the Impact on Oxidation Catalyst and Particulate Filter

Abstract The wide use of biodiesel has been driven by its reduction potential on greenhouse emissions from diesel engines without significant technological modifications. In this study a diesel engine for non-road applications has been fuelled with Waste Cooking Oil biodiesel blended with commercial fossil fuel at 6% and 30% v/v. In line with literature trends, experimental results indicate a significant reduction of PM emissions and only a slight increase in NOx emissions. This study has been focused on diesel emissions and in particular on the analysis of PM/NO2 ratio in presence of the Diesel Oxidation Catalyst (DOC). In fact, although the NO2/NOx ratio on raw exhaust is almost unaffected, the use of biodiesel shows a slight reduction of the NO-NO2 light-off temperature. This reduction can ensure more favorable operating conditions for the Diesel Particulate Filter (DPF), and has a positive effect on fuel consumption reduction. In order to deeply analyze these issues, a numerical model of an Aftertreatment system (AS) representing the a DOC and a DPF has been developed and validated with experimental data

Cereal foods fortified with by-products from the olive oil industry

Abstract The oil industry produces large volume of waste, olive mill waste water (OMWW) and olive paste (OP), which represents a disposal and a potential environmental pollution problem. They are also promising sources of valuable compounds that can be recovered and used. The effects of OMWW and OP addition to bread and pasta, separately and combined, were studied. Both sensory and chemical properties as related to phenols content and antioxidant activity of raw materials, and fortified bread and pasta were evaluated. Results suggested that the enrichment of bread and pasta with OMWW slightly improved the chemical quality without compromising the sensory properties. While, foods enrichment with OP had considerably improved chemical quality, the sensory acceptability was worse due to the bitter and spicy taste of OP. To choose the best cereal food between bread and pasta to be enriched, a mathematical model, the whole quality index (WQI), was used. Bread was better than pasta for re-using olive oil by-products. Between OMWW and OP, the latter was more suitable for food fortification, despite the sensory problems of the enriched product. Also, when the two by-products were combined, the best product continued to be the bread

MATHICSE Technical Report : Time accurate partitioned\ algorithms for the solution of fluid-structure\ interaction problems in haemodynamics

In this work we deal with the numerical solution of the fluid-structure interaction problem arising in the haemodynamic environment. In particular, we consider BDF and Newmark time discretization schemes, and we study different methods for the treatment of the fluid-structure interface position, focusing on partitioned algorithms for the prescription of the continuity conditions at the fluid-structure interface. We consider explicit and implicit algorithms, and new hybrid methods. We study numerically the performances and the accuracy of these schemes, highlighting the best solutions for haemodynamic applications. We also study numerically their convergence properties with respect to time discretization, by introducing an analytical test case

Volatile organic compound data of ready-to-cook tuna fish-burgers: Time evolution in function of different and/or combined mild preservation technologies and relevant statistical analysis

Volatile organic compound (VOC) composition from ready-to-cook tuna fish-burgers, prepared with and without a protective microbial strain (Lactobacillus paracasei) and/or stored with modified atmosphere packaging (MAP, 5% O2 and 95% CO2), were extracted by headspace solid-phase microextraction and analyzed by gas chromatography-mass spectrometry (HS-SPME-GC-MS) during the burger shelf-life. The collected data showed volatile composition profiles in function of the mild preservation technologies employed and the storage time. Furthermore, statistical data treatment (principal component analysis and Pearson's coefficients) highlighted differences among samples and positive/negative correlations during the storage time. This paper is related to an article already published in LWT (Investigating the effects of mild preservation technology on perishable foods by volatolomics: The case study of ready-to-cook tuna-burgers” https://doi.org/10.1016/j.lwt.2019.108425)

Inexact accurate partitioned algorithms for fluid-structure interaction problems with finite elasticity in haemodynamics

In this paper we consider the numerical solution of the three-dimensional fluid–structure interaction problem in haemodynamics, in the case of real geometries, physiological data and finite elasticity vessel deformations. We study some new inexact schemes, obtained from semi-implicit approximations, which treat exactly the physical interface conditions while performing just one or few iterations for the management of the interface position and of the fluid and structure non-linearities. We show that such schemes allow to improve the efficiency while preserving the accuracy of the related exact (implicit) scheme. To do this we consider both a simple analytical test case and two real cases of clinical interest in haemodynamics. We also provide an error analysis for a simple differential model problem when a BDF method is considered for the time discretization and only few Newton iterations are performed at each temporal instant

Combined effect of active coating and modified atmosphere packaging on prolonging the shelf life of low-moisture Mozzarella cheese

Abstract In this work, the effect of active coating on the shelf life of low-moisture Mozzarella cheese packaged in air and modified atmosphere (MAP) was studied. The active coating was based on sodium alginate (2%, wt/vol) and potassium sorbate (1%, wt/vol). The MAP was made up of 75% CO 2 and 25% N 2 (MAP1), 25% CO 2 and 75% N 2 (MAP2), or 50% CO 2 and 50% N 2 (MAP3). The product quality decay was assessed by monitoring microbiological and sensory changes during storage at 4, 8, and 14°C. Results showed that the combination of active coating and MAP was able to improve the preservation of low-moisture Mozzarella cheese. Specifically, the shelf life increased up to 160 d for samples stored at 4°C, and 40 and 11 d for those at 8 and 14°C, respectively. A faster quality decay for untreated samples packaged in air was observed. In particular, the Pseudomonas spp. growth and the appearance of molds were responsible for product unacceptability. The combination of active coating and MAP represents a strategic solution to prolong the shelf life of low-moisture Mozzarella cheese and to ensure the safety of the product under thermal abuse conditions