Design And Development Of Measuring And Controlling System For Ocean Osmotic Power Generation

There is a kind of little-known ocean energy which is called ocean salinity gradient energy existing in where the sea and the river meet. The basic principle of ocean salinity gradient energy is utilization of the chemical potential difference between the sea water and the fresh water or two kinds of different concentration sea water converts to water potential energy. Currently, there are three recognized energy methods in academia: pressure retarded osmosis method (PRO), reverse electro dialysis method (RED) and vapor pressure method (VPD). Method of osmotic semipermeable membranes is used in this salinity gradient energy prototype testing equipment, which forces the water on the low concentration side permeates to the high side through the semipermeable membranes to generate electricity by turbines rotation.The present thesis derives from Marine renewable energy special fund project "the study and experiments making of salinity energy electricity generation". Based on the analysis which includes the working principle, structural composition and function of the prototype of osmotic power system, combined with the practical requirements of the project, programmable logic controller (PLC), Kingview software and the communication between them have been applied to the design and realization of osmotic power generation measuring and controlling system.Firstly, the overall scheme of the salinity energy measuring and controlling system has been given. The electronic components have been determined through the formula calculation, system demands and parameters comparison. The researchers have done a single semipermeable membrane experiment before the design of the prototype measuring and controlling system. In this experiment, an electrical control circuit has been exploited to control the single semipermeable membrane system, measuring the pressure and flow values in main pipes and the the permeability of the semi-permeable has been evaluated, acquiring the relationship between them.Secondly, the electrical design of PLC control part and measuring and controlling system part have been introduced in detail. In the control circuit section of the measuring and controlling system, a control scheme to the prototype is given firstly, determined that the controller is PLC which used to achieve the functions. The PLC type selection has been done, choosing Siemens SL200 PLC after all with one digital value expansion module and four analog value expansion modules.In the configuration simulation system section, the program of the measuring and controlling system has been developed with kingview software version 6.55 from Beijing Wellin Tech, Inc. The program design includes:creating a new project, designing graphical interface, defining an external device, building database structure, establishing animation connections and running the debugger, etc. In the program, not only the communication between PLC and kingview software has been finished, but also the functions of real-time data acquisition and processing, data monitoring, circuit controlling, real-time alerts and report producing have been realized. The aim is to achieve a friendly interface between man and machine and to monitor and control the entire salinity gradient power generation system on industrial personal computer (IPC).Finally, all of the research in this thesis is summarized, pointing out the shortcomings of the current measuring and controlling system for osmotic power generation and discussing the design and development of the system in the future. This measuring and controlling system is based on the prototype design of osmotic power generation equipments. The design for the osmotic power generation equipment puts forward an solution and promotes a certain references for the future salinity gradient energy development and utilization.