Almudena Rueda. EcosimPro Applications Team The scarcity of fresh water has been decried in forums and organizations all over the world. It therefore comes as little surprise that considerable efforts are being made to improve water management. One such endeavor is desalination. Desalination is a process by which salt and other minerals are removed from water to obtain a product apt for human consumption and for irrigation. Because this type of process requires high energy consumption, one of the objectives of designing and operating desalination plants is to minimize energy costs and make the processes for obtaining fresh water profitable.   There are currently more than 12,000 desalination plants worldwide, and production of fresh water is expected to rise to 100 million m3/day by 2015.     In this context the usefulness of the new Reverse Osmosis Simulation (ROSIM) library in EcosimPro becomes clear. Developed for EcosimPro by the University of Valladolid, it can be used to simulate desalination processes for studies for optimizing the design and operation of desalination plants. The library started with the need to simulate reverse osmosis processes, so it has a large number of membranes (simple, with various discharges, discretized, etc.) as well as including components needed for the processes associated with reverse osmosis, the pre- and post- treatment (chemical or pH additives, filtration, pumping, etc.). But the scope of this library is not limited to processes of reverse osmosis. Rather, it also includes components for simulating thermal desalination processes (Multi Stage Flash (MSF) and Multi Effect Desalination (MED)) as well as energy recovery systems (Dual Work Exchange Energy Recovery (DWEER), Energy Recovery Device (ERD), etc.) and analog components for setting the desired control logic in the process. Consequently, ROSIM can be used to develop models of complete desalination plants, and by combining their components, hybrid plants, which combine membrane and thermal processes to optimize desalination efficiency. Some of the most important components are: This makes ROSIM a professional library for handling high-level industrial problems. Thanks to its design and implementation, end-users can solve highly complex problems without having to concern themselves over low-level tasks. The following figure shows the model of a reverse osmosis plant in which ROSIM components are used to portray the complete process. The saltwater stream must first go through a pre-treatment process involving chemical additives and filtration of the homogenized mixture. The pressure of the stream is then raised using a positive displacement pump whose discharge goes directly to the membrane in which the reverse osmosis occurs. The permeated stream than undergoes post-treatment with chemical additives before it reaches the storage tanks. There are various control loops for controlling some of the process variables, such as the pre-treatment loop in which the pH additive varies according to the reading on the pH sensor located after the homogenizer. EcosimPro Model of an Inverse Osmosis plant: pre-treatment, pressurization, RO membrane and post-treatment.

Victor Pordomingo. EcosimPro Applications Team The new Electric Machines library developed for EcosimPro in 2012 integrates a wide range of electrical components such as machines, transformers, power converters, control algorithms, etc, which makes it very useful for modelling multi-disciplinary systems that involve electrical components. The new library is closely related to the ELECTRICAL library already included in EcosimPro and has been specially designed for joint use with the CONTROL library and with another new library, still being developed, for renewable energy. The new Electric Machines library includes the following components: The figure below shows the Electric Machines library palette of over 80 components: The new library, apart from allowing the inclusion of electrical systems in other EcosimPro models, offers the possibility of carrying out simulations of generation systems, responses of drive systems, supply and consumption control, etc. The use of object orientated programming and the possibilities provided by the EcosimPro simulation monitor constitute a very suitable environment for developing electrical models in a simple and intuitive way. By joint modelling with the CONTROL and ELECTRICAL libraries, the user can analyze, for example, the current control on an induction motor (see figure below). The asynchronous three-phase motor is powered by means of an active inverter controlled under current. This is achieved using Relays from the CONTROL library which maintain the current consumed by the motor around a reference value and commutes the poles of the inverter when said current reaches the limits of the hysteresis band. Thus, as can be seen in the graphs below, the machine accelerates up to its stationary speed without the consumption current peaking during startup as would happen if no control were imposed on the system.          Current control model on an induction motor It also allows the implementation of complex control algorithms that take into account different variables of the model in order to take the right decisions at each instant. The library includes control techniques such as Space Vector modulation and PWM for different types of converters. The figure below shows this technique being applied to a 3×3 AC/AC conversion matrix. This control technique allows the generation of an output voltage whose value is easily controlled, and in addition the consumed current can also be controlled, and therefore so can the power of the system. To do this, two rotating vectors are generated in the Park space. One of them is the voltage reference, while the other is the current reference. Once they have been generated, their rotations are followed and the status of the conversion matrix is decided, as is its application time as a function of the position of both vectors at each instant on the basis of a high frequency carrier signal. Model of a conversion matrix

Antonio Rivero. EcosimPro Applications Team OPC (OLE for Process Control) is a communications standard developed jointly by large industrial groups of industrial software, instrumentation and control via the OPC Foundation consortium. Thanks to its client-server architecture based on Microsoft’s OLE, COM and DCOM technologies, OPC lets different hardware and software be connected easily and without “fighting” with each device driver. The final aim of OPC is to build systems with servers (usually data-generating hardware) and clients (software to control and monitor the data generated). Fig. 1: OPC Communications Network EcosimPro uses the standard OPC in its simulations by means of a new software tool called “OPC Toolbox” that integrates in the normal environment as a new plug-in. The main features of this new tool are: On each screen of the wizard, the user can set up general characteristics of the simulation, such as: public variables, initializations, simulation times, type of execution vs time (real time), etc.    Wizard to generate an OPC sever based on a DECK The end result of the process is a new OPC server capable of running a simulation autonomously and independently from the EcosimPro environment. Steps for generating an OPC server based on a DECK On each screen in the wizard, the user can: configure which servers to connect, which variables to communicate, what types of communication to send, etc.    Wizard to generate an OPC client that connects two servers The end result is an OPC client that can exchange data between two servers. Communication client generated with EcosimPro to connect two OPC servers With its new “OPC toolbox” plug-in, EcosimPro’s capabilities for use in simulations are myriad, with it being the platform on which are based products such as: For more information contact with Antonio Rivero (aiw@ecosimpro.com)

Fernando Carbonero. EcosimPro Development Team EcosimPro provides source code control for ASCII files used inside the tool (additional files, ASCIIs or binaries, could be added by using a “miscellaneous files window”). This feature will be supported both functionally and graphically. It is assumed that the user has installed a SubVersion (SVN) repository to connect to, that is to say, EcosimPro cannot create or administer the repository. A source code control is a system for controlling changes in files and for arbitrating how those files are to be shared. It is generally meant for ASCII files, since it can be used to control and compare the differences between the various different versions. This does not mean that it cannot be used with binary files, but it does mean that it can only identify if the file has been changed or not, but not the differences between the versions. Each user works with an independent local copy. When changes must be shared (or simply stored for control purposes) they will be uploaded to a repository. A repository is a data base that stores files with all their modifications throughout the project. Text files are not stored as such in the repository, but rather, they are stored in compressed form. Furthermore, if a file is modified, the new file is not stored as a whole, but rather, only the changed part is stored. This way, the repository can house a large amount of information by optimising the available storage space. This optimisation is not possible with binary files, since binary files do require the entire file to be stored after each modification. Each time a change is uploaded to the repository, it is marked with a number. Each change is called a revision. A revision is comparable to a snapshot of the entire project at a given time. In other words, a revision is a global number that belongs to all the files, not only to the one(s) on which the change was made. In principle, only the files created by the user should be uploaded to the repository, and not the ones generated by EcosimPro, i.e., the ASCII files of source code, setup files, input data files, partitions, experiments, schematics, etc. as well as binary files such as .lib files for external libraries, etc. The files generated as .elb, .unt, .dll, etc. should not be uploaded. The ASCII files are not only for finding differences, but also, when two users modify the same code at the same time, mechanisms are set to detect and correct any conflicts. This is not possible in binary files. The uploaded elements should be as needed to generate the rest of the files again. EcosimPro will only handle these source files, although there is an option for uploading other file types. Thus, when a library is uploaded to a repository, it is advisable to do so using EcosimPro rather than an outside tool to prevent uploading files that may cause problems. Integration in current widgets The configuration manager integrates into EcosimPro using an extension of current icons with an area in which the file status will be presented. This status represents the relationship between the local file or path and the one in the repository. Colour icons have been designed to show the different statuses. Local file status related to repository SVN has a great number of statuses available, but only the ones considered as relevant to EcosimPro have been implemented. The proposed status set, with icons associated to each status is as follows: Source Code Control actions As in the case of status, SVN has a great number of actions available. Again, only the ones considered relevant to EcosimPro have been implemented. The actions available for each file will depend on its status. Only the actions that are available will be shown in the menus, so as to simplify the way that SCC actions are presented to the user. These actions will be divided into two groups: the most common actions will be shown in the context menu of the file, while the less common actions will be in an SCC submenu. The set of available actions is as follows:

Pearson-Prentice Hall has just released a new book on EcosimPro entitled Introduction to Modelling and Simulation with EcosimPro, authored by F. Vázquez, J. Jiménez, J. Garrido and A. Belmonte of the University of Córdoba in Spain. The book contains good introductory material for new users of EcosimPro in the areas of dynamic systems modelling with equations and reuse of existing libraries in the control, mechanical, electrical and thermal libraries. It also provides a good overview of the algorithms used internally to produce robust mathematical models. The final chapter is devoted to using EcosimPro models from other environments such as Excel, Matlab and C++. This new introductory book on EcosimPro has 260 pages and is structured in 6 chapters: EcosimPro and the Object Oriented Languages, First Steps with EcosimPro, Construction of Libraries, Reuse of Existing Libraries, Mathematical Algorithms and Connection with Other Software.