Grosu L.,Paris West University Nanterre La Défense |
Dobrovicescu A.,University Polytechnique Of Bucarest |
Untea A.,University Polytechnique Of Bucarest
International Journal of Exergy | Year: 2014
In this paper, energy and exergy analyses of an absorption cooling system using H2O/LiBr and solar energy as heat source are conducted. A simple schematic of a chiller and an improved one, are compared using Thermoptim and EES software. An increase in the coefficient of performance (COP) from 0.69 to 0.8 was noticed. Numerical simulations are performed for six values of the condensing/absorption temperatures, which vary in the interval 31-36° C. The increase in these temperatures implies a decrease in the COP from 0.8 to 0.56. The exergy analysis of the overall system and of each component shows a decrease in the exergetic efficiency of the system from 0.27 to 0.18. A detailed exergy analysis of the absorber reveals the real causes of exergy destruction. A new exergy destruction indicator was introduced, which shows the importance of the irreversibility of each component, relative to the starting potential. Copyright © 2014 Inderscience Enterprises Ltd.
Radu O.,University Polytechnique Of Bucarest |
Carpen C.,University Polytechnique Of Bucarest
UPB Scientific Bulletin, Series C: Electrical Engineering | Year: 2010
This article proposes a study on the Bang-Bang command or step by step command of a Variable Linear Reluctance Motor. This type of command offers the possibility to determin the circuit inductance. By simulations and experimental tests were obtained improved characteristics of the motor studied.
Researches on the resolution of the problems and the management of the risks in the process of conceiving products [Recherches sur la résolution des problemès et la gestion des risques dans le processus de conception des produits]
Tilina D.,University Polytechnique Of Bucarest |
Ispas C.,University Polytechnique Of Bucarest
UPB Scientific Bulletin, Series D: Mechanical Engineering | Year: 2010
The study presented aims to optimize the design in two directions. The first direction aims to consider the concept as a set of activities to solve problems and then establish a general model for solving them. The second direction of research has sought to implement a process of risk assessment in the design stages, considering the risk a parameter of the process design and positioning it in relation to a reference on the success of a product on the market: a new quality product, obtained with a reduced cost, in time and launched on the market.
Bisu C.-F.,University Polytechnique Of Bucarest |
Ghinea M.,University Polytechnique Of Bucarest |
Gerard A.,French National Center for Scientific Research |
Zapciu M.,University Polytechnique Of Bucarest |
Anica M.,Digitline Company
Mecanique et Industries | Year: 2011
Vibrations appearance, either unstability system, is the result of the dynamic interaction of the cutting process with the elastic system of machine tools in various working conditions. The objective of this work is to develop a dynamic model applied to process of milling and to monitor this one, to analyze and to optimize the cutting conditions. To set up this protocol and reach the detailed knowledge of the dynamic phenomena we divide our study into two parts: the machine and the cutting process. A detailed dynamic analysis of the machine is compulsory before modelling the present vibratory phenomena during the cutting. © AFM, EDP Sciences 2011.