Patrick Glouannec

Energy characterisation of an aquacultural installation in closed loop

This article deals with the elaboration of a methodology for the energy characterisation of an aquacultural plant in closed circuit. A simplified dynamic model representative of the temperature response of the water volume is defined by identification. The input data are the air temperature, the insolation and the injected power. According to experimental readings, the value of parameters results from the minimisation of a quadratic error criterion between the model output and the water temperature measurements. That model enables the user to quantify the losses and to make energy consumption calculations. In the first place, the studies carried out on a pilot pond set up on the grounds of the laboratory allowed the testing of the methodology. Coherent results were first obtained for the open pond and then for the pond equipped with a transparent thermal protection. Then, a closed loop designed for the breeding of turbots was studied. From experimental readings, a model was established and validated by following the same procedure.

Off-Line Determination of the Optimal Command Policies for a Sludge Drying Application

The main objective of this work is to develop, using a predictive control method, an off-line determination of the operating parameters for a sludge drying stage. At each time step, two operating parameters are identified by simultaneously minimizing three objective functions over a finite horizon. A laboratory dryer is briefly presented and used, in order to evaluate the suitability of the direct model employed to simulate sludge drying. Surface temperature, drying kinetics, and evaporated mass flux obtained from experimental measurements are compared to numerical simulations. Afterward, the optimization procedure is carried out and the results are discussed.

Setting and Drying of Bio-Based Building Materials

Bio-based materials become successful in the field of building construction because of their sustainability and environmental benefit. In the present chapter, we focus on one of them: Hemp Concrete. This material is made out of hemp shivs mixed with a pre-formulated lime based binder and water, and can be manufactured through three classical processes: spraying, moulding or mechanical mixing and tamping. Similarly to classical concrete, setting and drying are important stages since it influences the mechanical and hygrothermal properties. Here, setting and drying stages are investigated through different experiments performed on several instrumented blocks and on a large-scale wall during the curing time. The instrumentation (thermocouples, humidity sensors, weight-scales) allows investigating the drying kinetics and apprehending the hygrothermal behaviour of the material. It is observed that manufacturing process influences the initial water content whereas the hygrothermal behaviour depends on the material formulation. In addition, a model of multi-physics knowledge taking into account the various couplings is developed to predict desorption kinetics. Particular attention is paid in the experimental determination of hygrothermal properties. A roughly good agreement was found between simulations and experiments for different conditions.