Numerical Simulation of the Accidental Transient of an Industrial Steam Boiler

Numerical simulation allows a better understanding of thermal-hydraulic phenomena that can take place in thermal installations. It is a capital contribution, especially in accident situations. The code RELAP5/Mod3.2 makes it possible to predict the thermal-hydraulic behavior of these installations during the normal and accidental operations. The present chapter focuses on accidental transient modeling and simulation of an industrial steam boiler by the code RELAP5/Mod3.2. This steam boiler is radiant type, high power, natural circulation, and a single drum. The model of the boiler developed for the RELAP5/Mod3.2 code encompasses the entire installation. The control loop of the water level in the steam drum and the superheated steam temperature are also included in the model. The qualification process of the steam boiler model is based on the steam boiler operation data under steady-state operating conditions. The comparative study shows that the theoretical results of the code RELAP5 are in good agreement with the operating data of the installation. To evaluate the behavior and response of the boiler in accident situations, the loss of feedwater following pump power loss, with and without protective operations, was simulated

Effect of spherical geometry on the heat and mass transfer in a solar still

In solar still, transparent cover plays a decisive role in the process of evaporation and condensation of water. Also receiving the solar radiation strongly depends on the geometry and orientation of the glass. In order to determine the impact of changing glass cover geometry on conventional solar still heat balance, we elaborate a theoretical model for a spherical solar still. The obtained equations are solved by using 4th order Runge–Kutta method. The numerical results allowed us to evaluate the water temperatures and the yield of still. Theoretical results are validated by the experimental tests in different climatic conditions. We observed that the spherical geometry of the transparent cover has the advantage of a large surface of condensation and does not have a preferred direction to capture maximum of solar energy

Thermo-mechanical characterization of construction material lightened by olive pomace

Abstract The development of porous materials requires a thorough knowledge of their physical properties. When used as thermal insulation, the properties that govern their insulating capacity are thermal conductivity, thermal diffusivity and specific heat. The presence of moisture, some of its origin, in buildings causes damage to walls that extend from the formation of mold in complete impregnation through the degradation of the thermal and mechanical performance. The major objective of this study is to determine the physical properties of a building material lightened by vegetable fiber (concrete pomace olive), used as an insulation bearer. Our goal is to develop and expand the field of use of these materials in construction. A judicious choice of additions proportions and implementation techniques will be considered. A particular interest is the thermal characteristics and mechanical strength, which is a decisive criterion for selecting a material in the construction. We determine the thermal conductivity of the materials studied with experimental equipment that allows us to make measurements of the thermal properties under actual use conditions (temperature and humidity) and also the study of the mechanical compressive strength of the materials studied and the interest in these materials is highlighted

Analytical and experimental investigation of a novel cooling system, biomass boiler-powered adsorption chiller

International audienceIn this study, a completely new adsorption refrigeration system powered by biomass boiler, under condition of lower than 85°C driving hot water temperature was proposed. A numerical model of the whole system including the model of silica gel-water adsorption chiller, water tank, which reveals the transient operation process of the adsorption cooling system, is developed and verified by experiments. Parametric studies were performed using the model to determine the effect of parameters matching of components configuration and operation process on the cold generation capacity, the performance and the cyclic characteristics of the system, such as the chiller startup temperature, cooling and chilled temperatures, not only in the conventional cycle mode but also in direct cycle mode. The fluctuation of temperature in conventional cycle mode was significantly smoother than that in the direct cycle mode at heat source temperatures below 65°C. The cold delivered in the direct cycle mode was a little more fluctuating of the former but doesn't significantly reduce the performance of the machine. It was also found that the adsorption chiller could work efficiently on direct cycle mode under the conditions of heating temperatures of 60-65°C, with the COP of 0.33-0.4 and the cooling power of 3.8-4.15 kW while producing 10°C chilled water

Analytical and experimental investigation of a novel cooling system, biomass boiler-powered adsorption chiller

International audienceIn this study, a completely new adsorption refrigeration system powered by biomass boiler, under condition of lower than 85°C driving hot water temperature was proposed. A numerical model of the whole system including the model of silica gel-water adsorption chiller, water tank, which reveals the transient operation process of the adsorption cooling system, is developed and verified by experiments. Parametric studies were performed using the model to determine the effect of parameters matching of components configuration and operation process on the cold generation capacity, the performance and the cyclic characteristics of the system, such as the chiller startup temperature, cooling and chilled temperatures, not only in the conventional cycle mode but also in direct cycle mode. The fluctuation of temperature in conventional cycle mode was significantly smoother than that in the direct cycle mode at heat source temperatures below 65°C. The cold delivered in the direct cycle mode was a little more fluctuating of the former but doesn't significantly reduce the performance of the machine. It was also found that the adsorption chiller could work efficiently on direct cycle mode under the conditions of heating temperatures of 60-65°C, with the COP of 0.33-0.4 and the cooling power of 3.8-4.15 kW while producing 10°C chilled water

Modernizing Training on Renewable Energies in the Maghreb Transfer of experience (MOMATE)

Le projet vise à développer une formation de type DUT (Diplôme Universitaire de Technologie) en ingénierie des Energies Renouvelables et à soutenir l'émergence de technopoles spécialisées dans les Energies Renouvelables. L'objectif est de développer des compétences permettant d'acquérir des connaissances de base sur la production d'électricité à partir d'énergies renouvelables (éolienne, solaire, photovoltaïque, etc.). El proyecto pretende desarrollar un programa de formación como el DUT (Diplôme Universitaire de Technologie) en ingeniería de Energías Renovables y apoyar la aparición de tecnopolos especializados en Energías Renovables. Para ello se pretende desarrollar competencias que permitan adquirir conocimientos básicos sobre la producción de energía eléctrica a partir de energías renovables (eólica, solar, fotovoltaica, etc.)The project aims to develop a DUT (University Diploma of Technology) type training in Renewable Energies engineering and to support the emergence of technology parks specializing in Renewable Energies. The objective is to develop skills allowing to acquire basic knowledge on the production of electricity from renewable energies (wind, solar, photovoltaic, etc.). The project intends to launch a training program such as the DUT (University Diploma of Technology) in Renewable Energy Engineering and to support the appearance of engineers specializing in Renewable Energy. Para ello claims to desarrollar competences that allow to acquire basic knowledge sober the production of electrical energy from renewable energies (electrical, solar, photovoltaic, etc.)MOMAT