Heat Transfer Analysis And Design Optimization Of Flat Plat Solar Collector

Due to the advantages of simple structure, good durability and highly flexibilitywhen combined with buildings, flat-plate solar collector has been widely applied inmany fields. To further improve its efficiency and competitiveness compared withconventional energy, domestic and foreign scholars have conducted huge amounts oftheoretical and experimental studies.In this paper, the energy transfer processes involved in the flat-plate solarcollector are analyzed, and the methods of calculating heat transfer coefficient inevery process are shown. Based on them, a flat-plate solar collector theoretical modelis established, and Visual Basic 6.0 software is used to program calculation of theflat-plate solar collector. Coupled with the structural parameters, entrance parameters,optical parameters and environmental parameters, the program is closely integratedwith the actual operating conditions of collector, and can be applied to simulate finefficiency, efficiency factor, heat removal factor and thermal efficiency. Takingthermal performance and material content of absorber into account, a copper absorberstructural optimization map is drawn. With the map, not only the collector thermalperformance of different specifications can be analyzed and compared quickly, butalso the design of the absorber plate can be optimized. Flat-plat solar collector isresearched by the way of experiments. Transient method and calorimetry are used totest the instantaneous efficiency of flat-plate solar collector. Comparing efficiencyequations derived from transient method and program calculation indicates thereliabilities of the flat-plate solar collector theoretical model and program.With the help of the program, the effects from different input parameters onthermal performance of flat-plat solar collector are researched. The results show:(1) It has a significant non-linear effect on thermal performance of flat-plat solarcollector, when the conductivity of absorber is greater than 100 W/(m·K), or else theeffect is gradually weakened. The collector thermal efficiency increases by 33.5%when a steel absorber plate is replaced by an aluminum one, whereas, the collectorthermal efficiency increases by only 2.7% when a copper absorber plate is replaced byan aluminum one.(2) The collector used in the experiment is optimized. It is observed that copperconsumption can be reduced 47.8% by varying width and thickness of absorber, in thecase of the same efficiency factor.