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In this paper, a fuzzy logic controller is developed in order to control the inside temperature and relative humidity inside an agricultural greenhouse. First, a thermal dynamic model was developed to describe the greenhouse environment and to predict the inside temperature and relative humidity. The agricultural greenhouse was modeled using Matlab-Simulink environment. The simulation results showed...
This paper presents a study on the use of ice to improve the energy efficiency of a domestic refrigerator by applying a pseudo bond graph model that describes the thermal transfers sustained by a quantity of ice introduced inside the cavity of refrigeration. The use of ice resulted in a global energy saving of 4.68%. The effect of ice was found to be more significant during the transitional regime...
A fractional order model that describes thermal and moisture behaviors in the greenhouse was done. In modeling the greenhouse many authors use a simple model of soil that neglect the heat / mass coupling, furthermore they use the discretization techniques for solving the heat conduction equation leading to a very high order model, this causes problems when applying a control and requires a high time...
This paper aims to prove the efficiency of using the free, abundant cold air flow stemming from the outside in high altitude to enhance the cooling inside a refrigeration cavity and to reduce the energy consumption. The cold air flow is spread out inside a cavity covering the side wall of the appliance and, which is connected to the inlet and outlet conducts. For that purpose, a Simulink model is...
A PI controller and a generalized predictive control strategy of the temperature inside a cavity of refrigeration are proposed, using Matlab/Simulink environment. The control strategies were applied to a third-order discrete state space system, which computes the internal air temperature according to the temperature at the level of the evaporator exchanger, under the influence of the ambient temperature...
The greenhouse is a complex, non-linear and high order system, it combines two fields “hydraulic and thermal”, and then it is not easy to analyze and control it. Hence, simplification is used in order to obtain model which facilitate the global analysis. In this paper we present a linear and simplifed bond graph model of a greenhouse from the model developed by Abbes [1]. The MORA method is used for...
In this paper we present a new method of reduction for large-scale switched system, which is an important class of hybrid and non linear systems. In this work, we focus on linear switched systems. This new method is based on the generation of Krylov subspace by the use of the Arnoldi algorithm, which is numerically efficient and applicable for any order, from which we solve the problem of H∞ model...
The paper presents a pseudo bond graph model of a thermo-hydraulic system which is composed by two warm and cold water pipes, a plastic tank and an evacuation pipe. This model is designed on 20sim software and it allows varying the temperature, inside the tank, by acting on the mass flows of the warm and cold water, as well as on the evacuation pipe. A simulation is done for constant and variable...
In this paper, we propose an implementation of a synthesizable VHDL program of generalized predictive control (GPC) without constraints on a map XC3S700A Xilinx Starter Kit using the Xilinx ISE 10.1 software. The control strategy was applied to a second order state system. The VHDL language was used as a programming tool. Real variables were described with the fixed-point representation to overcome...
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