Fault-tolerant and Dependability
For remote arid areas, a fault-tolerant system is necessary because it cannot be assumed that skilled technical personnel are available at the operation site to meet the high availability requirement on the plant. Dependability of the overall system will be achieved through monitoring of critical components and specially developed fault-recovery schemes depending on the operating-point and overall cost. Redundancy in the components and its costs will also have to be studied.
Energy management system
While the electric energy production of renewable energy sources is generally fluctuating over the day and seasons showing strong dependence on the meteorological conditions, the energy and water requirements of the consumer usually show different behaviour over time. Therefore, the energy demand of the plant and thus the water and energy production will have to be adapted to characteristics of the employed energy sources. The energy management subsystem provides for an optimal energy-mix of the available energy sources and determines the desired operating point of the plant at any time instant. Weather forecast and meteorological data can be taken into consideration to enhance the performance of the energy management.
Dynamical simulation is a very important tool for system optimisation in terms of the material-flow (processes), energy-flow (consumption/production), information-flow (control, monitoring and maintenance) and monetary-flow (cost/benefit). This modelling concept called 4-Flow Dynamic Modelling (4-FDM) is meant to model the dynamic interactions between the four main flows of the system in explicit form. Simulation will be employed for the proper choice of system structure and components for the plant. A component library will facilitate the adequate design of the plant in view of the end-user requirements. Simulation is mandatory for the design of the optimal system.
Decision Support System
The Decision Support System (DSS) will be a tool for the system implementation under site conditions taking into account energy efficiency, cost effectiveness, socio-economic impact and environment protection. The criteria, on the one hand, stem from the site conditions like user requirements, natural and human resources, socio-economic boundary conditions, and on the other hand reflect the demands for energy efficiency, cost effectiveness, socio-economic compatibility and environment protection.
Real-time control, Supervision, Remote monitoring and Diagnosis of components
In order to reach the strong operation conditions imposed to the plant, it is necessary to design an optimal control system that takes into account concepts of fault-tolerant design, fault detection and remotely monitoring. Monitoring and fault-detection tasks require appropriate modelling of the plant behaviour and prediction methods (also including weather-forecast data). Moreover, the supervision also helps to reduce the maintenance and to avoid unexpected failures or at least to predict some of them. Problems to be solved are for example: high recovery ratio and a very high efficiency in order to maximise the quality and quantity of produced water with minimum energy requirement, variability of the available energy during the day, lack of skilled personnel for extended periods.
Building a testing laboratory prototype
Applying concepts and tools developed to satisfy the previous objectives a laboratory test bed will be designed and constructed in one of the participating MPC in order to complement the design with practical experience. The plant is going to be used for posterior research, teaching as well as an example for know-how transfer to the industry. Components for all subsystems should be selected and optimally integrated. Software for the real-time operation will be developed, implemented and verified.