| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系 === 104 === This study investigates the performance of the fin flat-plate solar collectors constituted of single tube and single fin. There are two different types of flat-plate collector (FPC) in this study. The first one, the FPC tube is mounted on the sunny side. The second one, the FPC tube is mounted on the back of the sunny side. ISO 9806:2013 performed a quasi-dynamic test (QDT) on FPC performance under variable and real weather conditions. Based on the QDT, two types of FPCs were tested with different inlet flow rates in Tainan, Taiwan for finishing the performance analysis.
The tube of the first FPC module was irradiated by the solar radiation directly, so the energy transferring path was comparetively shorter. At a small inlet flow rate, the optimal efficiency without heat loss (η0) of the FPC was almost 0.66. η0 decreased gradually as the inlet flow rate was increasing. In the second FPC module, solar radiation irradiates to the absorber plate of the FPC. The heat was transferred to the tube of the FPC via thermal conduction. At a small inlet flow rate, η0 of the second FPC was at most 0.60. As the flow rate was increasing, η0 increased gradually. There was a peak value of η0 when the inlet flow rate was increased to almost 1.0 of the standard flow rate stated in ISO 9806:2013. After the standard flow rate, η0 decreased as the flow rate was increasing. In the first FPC module, the tube of the FPC contacted the air layer inside the FPC system directly, so the mean temperature of the FPC was higher in the process of energy absorption. Therefore, the degree of heat loss of the first FPC is higher than the second FPC.
Under most actual weather, there is an obvious temperature difference between the FPC system and the surroundings. Performance and collection efficiency of the first FPC module is worse than the second one. The only advantages are appeared under the conditions of the small inlet flow rate and the small temperature difference between the system and environment.
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