fcpowered rbs data analysis and system optimization

Abstract The previous works on the use of PEM Fuel Cell based power supply system for the operation of off-grid RBS (Radio Base Stations) sites showed a strong influence of system design parameters on the energy conversion performance. In this paper a perturbation of system design is performed through validated models to understand better the variability of performance over a full year operation. Results show that a ratio of energy produced by fossil over energy produced by renewables sources of 0.2 can be reached slightly increasing the photovoltaic plant size without affecting drastically the renewable exploitation. Moreover a positive Net Present Value can be achieved in comparison with the traditional diesel genset solution (from 260k€ to 350k€). The NPV value increases with the PV size and with a reduction of the battery size that leads to a steep reduction in the RES exploitation. Therefore, an optimum has to be sought as a compromise between the two aspects

Defatted spent coffee grounds fast pyrolysis polygeneration system: Lipid extraction effect on energy yield and products characteristics

Spent coffee Grounds (SCG), residues after coffee brewing, are a biowaste diffused on a global scale rich of valuable extractives. Pyrolysis is an efficient process to valorize SCG energy content into biofuels. This study aims to experimentally investigate the impact of lipid extraction and conversion to biodiesel on energy yield of py-rolysis products. Microwave-assisted lipid extraction method was employed, and a two-step transesterification process was considered for conversion into biodiesel. Fast pyrolysis of defatted spent coffee grounds (DSCG) was performed with a 300 g/h screw reactor at the temperatures 400 degrees C and 550 degrees C. The results show an important impact of pyrolysis temperature on energy distribution of the pyrolysis products. The energy content of the organics from DSCG pyrolysis is very high (up to 32 MJ/kg) and the oxygen content is significatively reduced to 26%. Non-condensable gas composition is enriched of hydrogen and methane with temperature rise. Biodiesel energy contribution significantly improve the energy yield of the pyrolysis system, leading to a more than 10% increase of the energy efficiency at a 550 degrees C, while a limited increase of 4% in the case of 400 degrees C. This study outlines how lipids extraction significantly increases the economic potential of SCG pyrolysis-based poly-generation energy system

An Analysis of 3D Simulation of SI Combustion with an Improved Version of the Kiva 3V Code: Numerical Formulation and Experimental Validation

The correct simulation of combustion process allows to better face several SI engines design problems, not only for innovative mixture formation concepts (stratified or ultra-lean charge), but for traditional homogeneous mixture as well. Even though many commercial codes are able to describe the complex 3-D non reacting fluid dynamics in ICE, the simulation of high turbulent flame propagation does not seem to be a completely solved problem yet. In this work a comparison between two different turbulent combustion models (a characteristic time based one by Abraham and Reitz [2, 15, 16] and a flamelet based one by Cant and AbuOrf [4, 20]) has been performed using KIVA-3V code to assess simulation reliability. Models predictive capabilities have been tested with reference to specific data acquired at the engine test bench of Tor Vergata Mechanical Engineering Department on a Fiat Punto 1242 cc 8 valves SI engine over a wide range of operating conditions. A generally good agreement has been observed between experimental and numerical results obtained by using both the combustion models. In addition it can be noticed that, thanks to a more physical description of the local turbulent flame characteristics, Cant model seems to exhibit more predicting reliability in the whole engine operating field

Appendix to "Torque setpoint tracking for parallel hybrid electric vehicles using dynamic input allocation", published on IEEE Transactions on Control Systems Technology

A dynamic allocator is proposed in order to generalize a previously introduced strategy for input redundant plants, which applies to linear plants with multiple and redundant inputs. The theory is extended here to the case of multiple linear actuators, each of them with its own dynamics, acting on a nonlinear plant with strong input redundancy. In the HEV case the two redundant inputs are the ICE and EM torques and the two actuators with different dynamics are the two propulsion systems

Mathematical models of innovation diffusion with stage structure

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Grid-connected Microgrids to Support Renewable Energy Sources Penetration

Abstract Distributed generation systems and microgrids are instrumental for a greater penetration of renewables to achieve a substantial reduction on carbon emissions. However, microgrids performances and reliability strongly depend on the continuous interaction between power generation, storage and load requirements, highlighting the importance in developing a proper energy management strategy and the relative control system. In this work a Model predictive Control (MPC) strategy, based on a Mixed Linear Integer Programming framework, has been applied to a residential microgrid case. Theoretical results obtained confirm that grid connected microgrids have potential capabilities in grid balancing allowing for a larger penetration of fluctuating renewable energy sources and thus producing economic benefits for both end-user and grid operators. A microgrid test bench to reproduce previous microgrid model is also presented in the paper. The experimental setup has been used to validate results obtained from simulation. Results obtained confirm the potential of this solution and its real applicability

Natural Gas Fueling: A LES Based Injection and Combustion Modeling for Partially Stratified Engines☆

Abstract The Partially Stratified Charge Spark Ignition (PSC-SI) combustion strategy is envisaged as a way of reducing fuel consumption and therefore polluting emissions; the improved fuel economy is mainly due to lean, stratified combustion, and to the reduction of pumping losses at partial load conditions. The aim of this work is to explore the potential capabilities of the PSC-SI combustion strategy over a wide flammability air-to-fuel ratio range with a CFD-based computational approach. A validated LES solver has been used to represent the main occurring phenomena into an experimentally implemented Constant Volume Combustion Chamber (CVCC). For different air fuel ratios, both homogeneous and non-homogeneous combustion processes have been simulated in order to compare and emphasize the benefits of the PSC-SI and the impact of the choice of operating conditions

An Integrated Approach for Structural Health Monitoring and Damage Detection of Bridges: An Experimental Assessment

The issue of monitoring the structural condition of bridges is becoming a top priority worldwide. As is well known, any infrastructure undergoes a progressive deterioration of its structural conditions due to aging by normal service loads and environmental conditions. At the same time, it may suffer serious damages or collapse due to natural phenomena such as earthquakes or strong winds. For this reason, it is essential to rely on efficient and widespread monitoring techniques applied throughout the entire road network. This paper aims to introduce an integrated procedure for structural and material monitoring. With regard to structural monitoring, an innovative approach for monitoring based on Vehicle by Bridge Interaction (VBI) will be proposed. Furthermore, with regard to material monitoring, to evaluate concrete degradation, a non-invasive method based on the continuous monitoring of the pH, as well as chloride and sulfate ions concentration in the concrete, is presented

renewable sources integration through the optimization of the load for residential applications

Abstract This work presents the implementation of two different control strategies for the control of Microgrids a Model Predictive Control (MPC) technique coupled with a Mixed-Integer Linear Program (MILP) structure and a Rule Based Control (RBC) strategy both applied to a residential MicroGrid. The validation of the models has been performed with an experimental setup laid out in the laboratory of University of Rome - Tor Vergata. Results obtained show that MicroGrids connected to the main network have enough potential to support grid balancing actions, thus allowing for a greater penetration of renewable sources into the mix, and giving economic benefits for both end users and providers. In particular, using a MPC strategy major benefits can be obtained in terms of reduction of the unbalanced energy exchange with the main grid and a more efficient use of the micro-grid components