Leonard Of Vinci Pole University
Leonard Of Vinci Pole University
Oignet J.,IRSTEA |
Delahaye A.,IRSTEA |
Torre J.-P.,CNRS Laboratory of Thermodynamics and Energetics of Complex Fluids |
Dicharry C.,CNRS Laboratory of Thermodynamics and Energetics of Complex Fluids |
And 5 more authors.
Chemical Engineering Science | Year: 2017
Secondary refrigeration and thermal energy storage are promising solutions to enhance the performance of refrigeration systems and reduce the impact of refrigerants on the environment. To improve the energy efficiency of secondary refrigeration loops, phase change material (PCM) slurries with a high energy density, such as CO2 hydrate slurries, can be used as a secondary refrigerant. In addition, hydrate-based processes could be an innovative option to capture CO2 from flue gas. In both applications, the rheological properties of the CO2 hydrate slurry have to be controlled. In the present study, CO2 hydrate slurry in the presence of Sodium Dodecyl Sulfate (SDS) was studied in a dynamic flow loop. The results show that SDS used at concentrations of 1500–2000 ppm significantly decreases agglomeration and improves the flow properties of the slurry. Moreover, SDS helps decrease the viscosity of the CO2-hydrate slurry at high fraction (>10 vol%) and therefore could be suitable for use in industrial applications such as secondary refrigeration, in which hydrate slurries must be easy to handle. © 2016 Elsevier Ltd
Dufour T.,IRSTEA |
Hoang H.M.,IRSTEA |
Oignet J.,IRSTEA |
Osswald V.,IRSTEA |
And 4 more authors.
Applied Energy | Year: 2017
Phase change material (PCM) slurries are considered as high-performance fluids for secondary refrigeration and cold thermal energy storage (CTES) systems thanks to their high energy density. Nevertheless, the efficiency of such system is limited by storage dynamic. In fact, PCM charging or discharging rate is governed by system design (storage tank, heat exchanger), heat transfer fluid temperature and flow rate (cold or hot source), and PCM temperature. However, with classical PCM (ice, paraffin…), phase change temperature depends only on material/fluid nature and composition. In the case of gas hydrates, phase change temperature is also controlled by pressure. In the current work, the influence of pressure on cold storage with gas hydrates was studied experimentally using a stirred tank reactor equipped with a cooling jacket. A tank reactor model was also developed to assess the efficiency of this storage process. The results showed that pressure can be used to adjust phase change temperature of CO2 hydrates, and consequently charging/discharging time. For the same operating conditions and during the same charging time, the amount of stored energy using CO2 hydrates can be three times higher than that using water. By increasing the initial pressure from 2.45 to 3.2 MPa (at 282.15 K), it is also possible to decrease the charging time by a factor of 3. Finally, it appears that the capacity of pressure to increase CO2-hydrate phase-change temperature can also improve system efficiency by decreasing thermal losses. © 2017 Elsevier Ltd
Guerard G.,Leonard Of Vinci Pole University |
Pichon B.,Leonard Of Vinci Pole University |
Nehai Z.,Leonard Of Vinci Pole University
SMARTGREENS 2017 - Proceedings of the 6th International Conference on Smart Cities and Green ICT Systems | Year: 2017
The hierarchical, centrally controlled energy grid is ill-suited to the third digital revolution. The electric power industry is undergoing rapid change. The energy transition move from the current energy system using nonrenewable resources to a smart grid, including distributed resources and home automation. Now, the demand is flexible and can be managed, it is called Demand-Side-Management (DSM). It encompasses different domains of reducing consumption, it can be both a physical standpoint than digital. In this paper, after a quick state of an art on DSM, we will focus on the digital way. The main idea is to create consumption's schemes, thanks to home automation in order to find the best way to consume. © 2017 by SCITEPRESS Science and Technology Publications, Lda. All Rights Reserved.
Fakhoury R.,United Nations Development Programme Office |
Aubert B.,Leonard Of Vinci Pole University
International Journal of Information Management | Year: 2015
Active citizenship and trustworthiness may affect behavioural intentions to use e-government services. Such uses of information and communication technologies may improve public administration, yet adoption of e-government systems by end users has remained far below expectations, despite continued efforts in many countries. The low adoption and use of e-government services by end users thus remain major barriers to successful e-government implementation that might be addressed by greater trust in government, the Internet, and technology, as well as increased citizenship beliefs and actions. Active citizenship implies empowered, engaged, participatory citizens. The results of this quantitative study, conducted in the unique setting of Lebanon, show that by developing trustworthiness and active citizenship, citizens will increase their behavioural intention to use of e-government services. Thus, intentions to use public e-services grow stronger when the government foster trustworthiness and empowers average, passive citizens. © 2015 Elsevier Ltd. All rights reserved.
Da Fonseca J.,Auckland University of Technology |
Gnoatto A.,Ludwig Maximilians University of Munich |
Grasselli M.,University of Padua |
Grasselli M.,Leonard Of Vinci Pole University |
Grasselli M.,Quanta Finanza S.r.l.
Operations Research Letters | Year: 2015
This paper provides the pricing for a new class of derivatives with different affine stochastic volatility models. These products are characterized by payoffs depending on both stock and its volatility. We provide closed-form solutions for different products and two multivariate Wishart-based stochastic volatility models. The methodology is independent of the dimension of the problem. Overall, our results highlight the great flexibility and tractability of Wishart-based stochastic volatility models to develop multivariate extensions of the Heston model. © 2015 Elsevier B.V. All rights reserved.