Comparative Study of Different DC/DC Power Converter for Optimal PV System Using MPPT (P&O) Method

The objective of this work is to show when and how to choose the type of DC/DC power converter that must be introduced in a stand alone PV solar system’s optimization process, which is necessary to characterize the area’s climatic conditions of the system implementation, take into account the partial shading effect on the Photovoltaic Generator (PVG). In addition, determine the resistivity of the load that envisaged to be introduced with the help of the direct coupling responses of the PVG. Based on the MATLAB/Simulink software and the PVG data sheet choice, we could plot the current-voltage (I-V) and power-voltage (P-V) characteristic, using the manufacturer data and determining the maximum power point (MPP), as a function of the area’s weather conditions variations, at the same time observing the direct coupling response of the load adapted to the PVG. From this observation, we can specify the DC/DC power converter type to be introduced in the production optimization process of a standalone PV solar system. Thus, we must use a Boost converter type, if the direct coupling voltages responses are higher than those of MPP responses, or a Buck converter type in the opposite case, or both at the same time Buck-Boost converter type, if we need to increase and decrease the voltage.     

Comparison of numerical and experimental performance criteria of an ammonia–water bubble absorber using plate heat exchangers

A mathematical model for ammonia–water bubble absorbers was developed and compared with experimental data using a plate heat exchanger. The analysis was performed carrying out a sensitive study of selected operation parameters on the absorber thermal load and mass absorption flux. Regarding the experimental data, the values obtained for the solution heat transfer were in the range 0.51–1.21 kW m^?2 K^?1 and those of the mass absorption flux in the range 2.5–5.0 × 10^?3 kg m^?2 s^?1. The comparison between experimental and simulation results was acceptable being the maximum difference of 11.1% and 28.4% for the absorber thermal load and the mass absorption flux, respectively.     

The enhancement of creep in Al–22?wt% Ag alloy by cyclic stressing

The plastic deformation behavior of Al–22 wt% Ag alloy during phase transformation was investigated by studying the creep behavior under cyclic stress reduction of low frequencies. The cyclic creep curves obtained describe clearly the cyclic stress acceleration behavior. Increasing frequency of cyclic stress reduction enhanced the creep deformation depending upon the combination of the experimental variables as testing temperature, aging temperature and static creep rate. The irregularity in the creep parameters, n, β and ε_st with increasing aging temperatures, has been explained on the basis of structure transformations occurring in Al–Ag system and their mode of interaction with mobile dislocations.     

A combined process integration and fuel switching strategy for emissions reduction in chemical process plants

The combustion of fossil fuel to provide process heating is the major source of atmospheric pollution. Combustion products such as carbon dioxide, oxides of sulfur, oxides of nitrogen and particulates are known to be the major causes for global warming, acid rains and smog. This paper presents a combined method of fuel switching and heat exchanger network (HEN) retrofit to reduce flue gas emissions. The method is demonstrated using pre-heat train of a crude oil distillation unit as the case study. Target emissions reduction of 50% is achieved at an approximate payback period of 0.44 year on the capital investment due to the combination of the two methods.     

Preparation of new and novel wave like poly(2-anisidine) zirconium tungstate nanocomposite: Thermal,electrical and ion-selective studies

It is necessary to synthesize new material for the advancements of the technology. In this study, new and novel poly(2-anisidine)@zirconium tungstate(P2A/ZrW_2O_8) was synthesized by simple so-gel method. Physicochemical characterization of P2A/ZrW_2O_8 was done by thermogravimetric analysis(TGA), scanning electron microscopy(SEM), X-ray powder diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), ion exchange and simultaneous four probe dc conductivity studies. The conductivity study revealed its highly semiconducting nature, in the range of 10~(-1)–10~(-2) S·cm~(-1). Ion-exchange capabilities of the composite make it applicable for cation-exchange studies. The result of distribution studies(Kd) revealed its selectivity towards Cd~(2+) compared to other metal ions. This property of the composite was utilized for designing Cd~(2+) selective membrane electrode. Several important physical parameters of the ion-selective electrode were determined, such as Nernstian slope(32.32 mV·decade~(-1)), working pH range was 2.0–4.0 and response time was found ～ 17 s.The analytical utility of this wave like composite membrane electrode was as, indicator electrode in various potentiometric titrations.     

Spatial optimization of an underhood cooling module – Towards an innovative control approach

The present paper reports a numerical investigation of spatial optimization of heat-exchanger by acting on its positioning in the vehicle’s cooling module. This analysis also elucidates how to act on the different parameters influencing heat-exchanger performance in order to optimize their functioning. A two-dimensional computation code permits optimizing the performance of the cooling module by positioning different heat exchangers, in both the driving and stop phases of the vehicle. The ultimate aim is to apply new control approaches to real vehicles so as to reduce pump and compressor energy consumption and thus fuel consumption. Compared to a reference “in-series” configuration of the cooling module HXs (in which the different HXs are superposed in the airflow direction), an “in-parallel” configuration (in which the different HX surfaces are in a row with respect to the air flow direction) increases the thermal power of the HXs by 4.4% and decreases the pressure losses by 0.9%.     

Microstructure,hot oxidation resistance and damping capacity of Al- alloyed cast iron

Ductile cast iron was developed by adding Aluminium (up to16 wt%Al). Effects of aluminium on microstructure, hardness, oxidation resistance at high temperature and damping capacity of cast iron were studied. Adding Al up to 4.0 wt% raised degree of graphitisation. More than 4.0 wt% up to 13.8 wt%Al showed precipitation of hard carbides. Hardness was increased signi?cantly by increasing Al due to formation of intermetallic compounds. More than 5.8 wt%Al showed a higher oxidation resistance due to formation of complex Fe-Al oxide, acted as a protective and adherent scale. Damping capacity of 2.6 and 4.0 wt%Al was increased as the volume fraction of graphite increased as well as the change of graphite from spheroidal to compacted ones. Damping capacity of 16 wt%Al was enhanced due to high ferrite (86%) containing graphite. However, decreasing of ferrite and disappearing of graphite as well as presence of carbides highly deteriorated damping capacity of 5.8, 9, 12.8 and 13.8 wt%Al cast iron.     

Corrosion behavior of pure Mg and AZ31 magnesium alloy

Protection of Metals and Physical Chemistry of Surfaces - Purpose of this article is to study corrosion behavior of pure magnesium and AZ31 magnesium alloy in electrolyte containing different...