Takeshi Yasunaga

A Simulation Model of Spray Flash Desalination System

In this paper, a simulation model of a spray flash desalination system is proposed. In the spray flash desalination system, the freshwater is made from the evaporation-condensation process, i.e., evaporation of warm surface seawater in a flash chamber and condensation of the generated vapor by deep cool seawater. A simulation model of the spray flash desalination system is constructed by using physical relations such as the energy conservation law and the mass conservation law. Simulation results of the proposed simulation model are compared with the experimental results of an experimental plant of the splay flash desalination system, and it shows the effectiveness of the proposed simulation model.

An improvement on LQG controller for liquid level control of separator in an OTEC experimental plant using Uehara cycle

This research proposes an improved controller design methodology for liquid level control of separator in an ocean thermal energy conversion (OTEC) plant using Uehara cycle. In the previous research, the control system design for liquid level control of separator was conducted based on the LQG control theory with state estimation via stationary Kalman Filter. However, it is verified by the simulation of this research that an assumption on an integral degrades the estimation accuracy of a state variable. To cope with this problem, in this research, the reset of integration is introduced to the control system. The usefulness of the proposed method is confirmed through simulation.

Evaluation of a liquid level model of separator in an OTEC experimental plant using Uehara cycle via different experimental data

This research is concerned with the evaluation of a liquid level model of separator in an ocean thermal energy conversion (OTEC) plant using Uehara cycle. The liquid level model is described by the polynomial of valve opening and white Gaussian process. The mean and the variance of white Gaussian process are determined by two kinds of experimental data. The behavior of the liquid level model is evaluated by numerical simulations based on two kinds of experimental data. The simulation results indicate that the model construction of liquid level can ben successfully conducted even if the experimental data to be used are different.