Marine Refergerrating Systems Dynamic Analysis And Optimum Design

At first , this paper briefly introduces the application of refrigeration system on board , i.e. traditional goods and foods being transported ,life circumstances improved by air condition . Under present developing ocean economic circumstances , the refrigeration application on special ship have become more wide and more important, such as fishing vessel-special fish (Tuna) for fish processing and refrigerator transporting ,it involved in huge economic benefit ,not only it need normal refrigeration ,but also lower temperature refrigerator ,for example the natural gas vessel exploited transported must have the equipment connected with refrigerator techniques . Along with the ocean resources exploited the ocean investigation , deep ocean exploration had become more connected with refrigeration techniques . Secondly this paper also simply introduces the simply development of control techniques of refrigeration on board from manual control to semi-automatic control, from part control to complete control.On the basis of above-mentioned discuss ,the refrigeration objective function is given . To seek system optimum performance index ,then involved in the basic though of control system, compose plan and electrical principle diagrams are designed .The sensor of measured temperature and pressure is selected to control the system .The relay system plan is firstly drawn up . the PLC techniques controlling more skillfully ,more conveniently is adopted on the basis of control thinking having more clearly . refer to the rely network system ,draw up ladder-shaped diagram compiled the related program . In order to the save the energy ,the main source frequency is relevantly regulated by means of VVVF techniques to modify the rotational speed along with load vary . During the plan is been drawing up , analysis the load characteristics of compressor and the power relation between vary frequency motor and consumption electric power compressor, meanwhile the basic principle of saving energy are also covered .In order to accurately monitor system running conditions ,every state points in thermodynamic cycle is calculated, rechecked ,for the purpose of an exact keep ofchange range and related static parameters could be grasped .As mentioned above , the refrigeration is connected with more trades of national economy ,therefore , it's very important significance not only the theory , but also the control techniques to be studied . By the science techniques developing , the simulation have been applied in control techniques . In addition , in this paper model analysis and simulation study by MATLAB are also discussed based on some main system component pressure and temperature parameters ,so as to know well the complete process.