Publications (6) View all
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Chapter: A New Method to Calculate Indoor Natural Lighting by Improving “Lumen Models”
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ABSTRACT: Many researches were undertaken in order to set up models which enable to calculate indoor daylighting [1-3]. There are three of type’s method to calculate the daylight luminance through windows and large openings inside the building. Among others, ’simplified methods’ (Lumen method, Split Flux System method, etc…), ’numerical simulation method’ (Radiosity, Ray Tracing, etc…) and finally ’experimental method’ (scale model, building experimental, etc…) are described in literature. We put some specific interest in the ’simplified methods’ because they are easy to use and don’t need a lot of inputs for simulation. The big disadvantage for most of these models is these models depend on restricted conditions. For example, if we considered ‘’Split Flux System method”, we see that the models can be used only to overcast conditions. Another example, the ‘’lumen method” applied for any skies, but the models gives only five values in the space. Therefore they can only work under precise and limited circumstances. In this present paper, we purpose to see how we can circumvent these difficulties by improving the ‘’Lumen Model”. Indeed, we will to introduce the notion of ‘’Equivalent Deep” (ED) into the ‘’Lumen method”. This ‘’Equivalent Deep” will calculate any values and any types of skies instead of the original “Lumen method”; that only calculate five values.12/2008: pages 456-460; -
Article: A combined approach for determining the thermal performance of radiant barriers under field conditions
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ABSTRACT: This paper deals with a combined approach for assessing the thermal performance of radiant barriers under field conditions, based both on dynamic simulations and field measurements. The methodology involves the combination of model predictions and experimental results of a complex roof including a radiant barrier installed on a dedicated test cell. During the empirical validation of the building thermal model and more particularly thanks to the results of sensitivity analysis, simplifications of the model were made. These considerations lead to successive simplified versions of the model and finally a very simplified one, which is used to determine the thermal resistance of the complex roof. We first present the detailed thermal model, elaborated with a prototype of building simulation code. We then describe the experimental test cell and put the emphasis on the details of the roof. The simplification of the detailed model is then explained and the results presented. A value of the thermal resistance is finally obtained and confirms the potential of radiant barriers for a tropical climate.Solar Energy. -
Article: Hybrid modelling of the sucrose crystal growth rate
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ABSTRACT: Cited By (since 1996): 4, Export Date: 10 April 2012, Source: ScopusInternational Journal of Modelling and Simulation. 21(1):23-29. -
Article: Hybrid modelling of a sugar boiling process
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ABSTRACT: Cited By (since 1996): 8, Export Date: 10 April 2012, Source: ScopusControl Engineering Practice. 8(3):299-310. -
Article: Hybrid modelling of a sugar boiling process
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ABSTRACT: The first and maybe the most important step in designing a model-based predictive controller is to develop a model that is as accurate as possible and that is valid under a wide range of operating conditions. The sugar boiling process is a strongly nonlinear and nonstationary process. The main process nonlinearities are represented by the crystal growth rate. This paper addresses the development of the crystal growth rate model according to two approaches. The first approach is classical and consists of determining the parameters of the empirical expressions of the growth rate through the use of a nonlinear programming optimization technique. The second is a novel modeling strategy that combines an artificial neural network (ANN) as an approximator of the growth rate with prior knowledge represented by the mass balance of sucrose crystals. The first results show that the first type of model performs local fitting while the second offers a greater flexibility. The two models were developed with industrial data collected from a 60 m3 batch evaporative crystallizer.Control Engineering Practice.
