Design Of A Vehicular Test System For The Thermal Performance Of Solar Collectors

In this thesis, a vehicular test system for the thermal performance of solarcollectors based on virtual instrument has been designed, which providing reference toimprove quality of solar collectors. Some rapid and accurate methods of flow rate andtemperature control in this system have been researched.The major research work include pipe system design, methods of temperaturecontrol and flow rate control, software design, and system debugging of the workingcondition and data analyses.1. The pipe subsystem of a test system for the thermal performance of solarcollectors has been designed to meet test requirements listed in GB/T4271-2007.2. Some plans of temperature control and flow rate control have been studied onthe basis of virtual instrument technology. For the whole test system, its control strategyof temperature and flow rate under single condition, and control scheme under thecondition of mode conversion have been analyzed. Typical combined control strategy inthe comprehensive test system has been presented. All hardware of temperature controland flow rate control have been choosed. Temperature control under each workingcondition has been simulated. Moreover, by adding orthogonal experiment to classicPID control, the three parameters of PID controller under different conditions for thistest system have been found.3. The module software of measurement and control system have been developedon the basis of LabVIEW. The software can finish the some functions including dataacquisition, display, control, storage and so on during instantaneous efficiency test,pressure drop test, incident angle modified coefficient test and time constant test. Withthe control strategy and the use of the state machine, program diagrams of themeasurement and control system have been written, and programs of the sub-VI ofseveral important parameters have been done.4. One flat plate collector was selected as the test object. The performance andstability of the measurement and control system have been debugged on the spot. On thebasic of analysis and research of the data collected, results show that the collector inlettemperature can be stabilized in the set value of±0.1℃and stable time in more than 40minutes, the fluctuations of the flow would not exceed the range of set value plus orminus1%. This control system has good performance, strong robustness, etc.