Search results for "Process Engineering"
showing 10 items of 931 documents
An assessment of the state of grain mixture with the use of the method of statistical reduction
1995
Abstract A new way of assessment of the state of a granular mixture is presented in this paper. It is based on the method of statistical reduction and it enables a more precise assessment to be made of the state of a grain mixture as compared with other methods, especially when the mixture represents a large population. The new method is illustrated by a computational example.
Photochemical Reactors Engineering Fundamentals
1988
For the rapidly developing area of Photochemical Reactors Engineering an assessment of some fundamentals is reported. Topics surveyed are light sources, types of photoreactors and radiation modelling approaches. Some general remarks are also reported from which the need for further development of the general research area arises.
Life Cycle Assessment of Solid Oxide Fuel Cells and Polymer Electrolyte Membrane Fuel Cells
2017
Abstract Fuel cells (FCs) are among the key technologies that Europe will have to rely on in order to comply with the most recent environmental targets inspired by decarbonization and circular economy. The assessment of the real advantages of using FCs for producing energy must include a reliable analysis of the energy and environmental impacts during the life cycle of these systems, including the raw materials supply, production, use, and disposal. In this context, the life cycle assessment (LCA) is a well-established methodology for assessing the eco-profile of products and services and for identifying the components and the life cycle steps having the largest contribution to energy and e…
A mathematical model to determine the electrical energy production in photovoltaic fields under mismatch effect
2009
Among the electrical energy production systems from renewable sources, the photovoltaic one represents today one of the most efficient and technically tested choice. In this paper the authors present a mathematical model that allows the maximization of the generated power of photovoltaic (PV) plants under unequally radiation conditions. In particular, thanks to the model of a PV plant, unequally radiated, developed in Matlab-Simulink environment, in this paper the mismatch problem of PV plants is dealt with. The simulations curried out allow to assert that by putting into action re-configuration techniques of series-parallel connections of PV plants, under unequally radiation, can allow to …
Comparing the efficiency of wastewater treatment technologies through a DEA metafrontier model
2011
Abstract The assessment of economic and technical efficiency is a useful tool to select the most appropriate technology for wastewater treatment. However, traditional models require that the units being assessed operate with the same technology. To overcome this limitation, we investigate the viability of using a non-concave metafrontier approach that is based on data envelopment analysis (DEA) to calculate the techno-economic efficiency and technological gap ratios (TGRs) of wastewater treatment plants (WWTPs) operating with non-homogeneous technologies. The model is applied to a sample of 99 Spanish WWTPs, encompassing four alternative technologies: activated sludge; aerated lagoon; trick…
On-site Experimental Study of HCFC-22 Substitution with HFCs Refrigerants
2012
Abstract The European Regulation no 2037/2000 has banned manufacturing HCFC refrigerants from January 1st 2010, although its use is allowed up to 2015 if the fluids come from a recycling process. This situation creates the need for developing new working fluids to replace the HCFC in the refrigeration plants now in operation. Among all the HCFCs the R22 is the most widely used in a wide range of applications, especially in air conditioning. This paper presents the results of an experimental analysis comparing the performance of a vapour compression refrigerating unit operating with R22, and its performance in comparison to some HFCs fluids, substituting the former. In particular, the plant …
Editorial overview: Green analytical chemistry
2019
International audience
Experimental performance evaluation of a vapour compression refrigerating plant when replacing R22 with alternative refrigerants
2011
Abstract This paper presents the results of an experimental analysis comparing the performance of a vapour compression refrigerating unit operating with R22, and its performance in comparison to a new HFC fluid, substituting the former according to Regulation No 2037/2000. In particular, the plant working efficiency was first tested with R22 and then with three new HFC fluids: R417A, R422A and R422D. The investigation verified that despite the case of substitution and the advantage of being able to continue to use mineral oil as a lubricant in the compressor, the performance with the new tested fluids did not result as efficient as when using R22.
A measurement methodology for monitoring a CHCP pilot plant for an office building
2003
Abstract In Mediterranean areas, climate conditions determine quite equal demand both for thermal and cooling energy. The possibility to convert a cooling demand in thermal one through an absorption chiller allows to extend widely the number of running hours of a cogeneration plant. A trigeneration pilot plant for two office building is described, in which an integrated lay-out includes a NG prime mover with heat exchanger, an absorption chiller and a reversible heat pump. The pilot plant is completed and pre-running test were performed. Different fluid dynamics parameters will be monitored, in order to build the actual cumulative curve for thermal power. The measurement methodology is also…
Solving underwater crimes: development of latent prints made on submerged objects.
2013
Underwater crime scenes always present a challenge for forensic researchers, as the destructive effect of water considerably complicates the chances of recovering material of evidential value. The aim of this study is to tackle the problem of developing marks that have been left on submerged objects. Fingermark deposition was randomly made on two surfaces - glass and plastic whilst the material was submerged under tap water and then left for one to fifteen days before drying and development. For their later development, various reagents - Black Powder, Silver Metallic Powder, Fluorescent Powder, Sudan Black (powder and solution) and Small Particle Reagent - were used and the effectiveness o…