Study and Application of the Automation System Based on Labview. for Domestic Solar Water Heating Test System
Xing Li1,2, Zhifeng Wang1 , Xiao Han2
1 Institute of Electrical Engineering, Chinese Academy of Sciences Beijing 100080, P. R.CHINA
2 Himin Solar Energy Group Co.,Ltd, Dezhou, Shangdong 253090, P. R.CHINA
Corresponding Author, lixing2002@126.com
Abstract
In the present paper, the automatic control system based on Labview for domestic solar water heating test system according ISO 9459-2 is investigated. It is a measurement and automation system composed of PXI (PCI extensions for instrumentation), control panel and all kinds of devices including temperature sensors, flow meters, magnetic valves, pumps and motors etc. Considering the outdoor test methods for system performance characterization of solar-only systems, in order to accurately measure the daily system performance, the coefficient of storage tank heat loss and the degree of mixing in the storage vessel during draw-off in sequence, it is essential to clarify the whole testing contents and design a set of logical control flow. In this study the program based on Labview is finished and adjusted successfully for selected configurations under the different measuring situations. The automation system is in good conditions and the accurate data is exactly attained according to the ISO standard. Besides, visualization of monitoring and evaluation of the test system is performed, giving insight into details of the measurement and control fields, which are valuable in the friendly interface between operator and test system.
Keywords: Automation, Labview, test system, solar water heating system
As the environmental impacts of energy, solar thermal utilization attracted the extensive attention of the international community. China has become an annual output value of 6 billion industrial-scale solar water heater industries, and the possession of water heater stands on the leading position in the world. With the rapid development of solar thermal industry in China, 11 national standards with relevant to solar water heating systems have developed. But there is a big difference in the test procedures and test conditions between national standards and ISO standards. So test results of thermal performance according to the current GB standards can not be directly compare with the test results of ISO standards. Because the ISO standards are promulgated in the broad range of region and extensive applicability, our national standard system should be as far as possible with the convergence of the ISO standards in future, especially in the test conditions and test procedures. Otherwise no benchmark can be obeyed in the process of comparison between the test results of national standards and ISO
standards. In this paper, test method for domestic solar water heating system will be carried out according to ISO9459-2.
In order to improve the productivity and efficiency, it is necessary to develop a set of automatic control system to measure and auto-operate the test system. In the control system it will make use of PXI - based data collection system provided by National Instruments Company and design the control and data acquisition system based on Labview platform. Test data would be automatically measured and recorded; meanwhile control system could realize the corresponding control movements according to feedback of all kinds of sensors. In this paper, design principles, hardware structure, and software of the test system based on Labview will be presented and implemented.
