In this study, effects of different nanoparticles and porosity of absorber tube on the performance of a Concentrating Parabolic Solar Collector(CPSC) were investigated. A section of porous-filled absorber tube was mod...In this study, effects of different nanoparticles and porosity of absorber tube on the performance of a Concentrating Parabolic Solar Collector(CPSC) were investigated. A section of porous-filled absorber tube was modeled as a semi-circular cavity under the solar radiation which is filled by nanofluids and the governing equations were solved by FlexPDE numerical software. The effect of four physical parameters, nanoparticles type, nanoparticles volume fraction(φ), Darcy number(Da) and Rayleigh number(Ra), on the Nusselt number(Nu) was discussed. It turns out that Cu nanoparticle is the most suitable one for such solar collectors, compared to the commonly used Fe_3O_4, Al_2O_3, TiO_2.With the increased addition of Cu nanoparticles all the parameters φ, Da and Ra shows a significant increase against the Nu, indicates the enhanced heat transfer in such cases. As a result, low concentration of Cu nanoparticle suspension combined with porous matrix was supposed to be beneficial for the performance enhancement of concentrating parabolic solar collector.展开更多
Due to some serious environmental problems like global warming and greenhouse effect,studies on solar energy systems are being conducted all over the world.The studies conducted in recent years are on hybrid designs i...Due to some serious environmental problems like global warming and greenhouse effect,studies on solar energy systems are being conducted all over the world.The studies conducted in recent years are on hybrid designs in which solar energy systems can realize both electricity and heat production at the same time.In this way,both electrical energy and heat energy can be generated from the same system In this study,the design and analysis of a concentrated solar air collector with a heat storage unit were carried out.In the solar air collector,heat energy was depot in paraffin wax,and the electrical energy which was stored in the battery using the PV(photovoltaic)modules in the system enabled the operation of the system fan.The experiments which aimed at determining system performance were carried out in winter when the ambient temperature was low.The experiments were performed with or without a heat storage unit,and a comparative analysis was made.It was found that the temperature of the air released from the collector ranged from 15°C to 40°C when the exterior temperature was-5°C.The average efficiency of the concentrated system without the heat storage unit was calculated as 67%.The average efficiency of the concentrated system with the heat storage unit was calculated as 96%.展开更多
基金financial support of the National Natural Science Foundation of China (No.51422604,51776165)China Postdoctoral Science Foundation (No.2017M610638)
文摘In this study, effects of different nanoparticles and porosity of absorber tube on the performance of a Concentrating Parabolic Solar Collector(CPSC) were investigated. A section of porous-filled absorber tube was modeled as a semi-circular cavity under the solar radiation which is filled by nanofluids and the governing equations were solved by FlexPDE numerical software. The effect of four physical parameters, nanoparticles type, nanoparticles volume fraction(φ), Darcy number(Da) and Rayleigh number(Ra), on the Nusselt number(Nu) was discussed. It turns out that Cu nanoparticle is the most suitable one for such solar collectors, compared to the commonly used Fe_3O_4, Al_2O_3, TiO_2.With the increased addition of Cu nanoparticles all the parameters φ, Da and Ra shows a significant increase against the Nu, indicates the enhanced heat transfer in such cases. As a result, low concentration of Cu nanoparticle suspension combined with porous matrix was supposed to be beneficial for the performance enhancement of concentrating parabolic solar collector.
文摘Due to some serious environmental problems like global warming and greenhouse effect,studies on solar energy systems are being conducted all over the world.The studies conducted in recent years are on hybrid designs in which solar energy systems can realize both electricity and heat production at the same time.In this way,both electrical energy and heat energy can be generated from the same system In this study,the design and analysis of a concentrated solar air collector with a heat storage unit were carried out.In the solar air collector,heat energy was depot in paraffin wax,and the electrical energy which was stored in the battery using the PV(photovoltaic)modules in the system enabled the operation of the system fan.The experiments which aimed at determining system performance were carried out in winter when the ambient temperature was low.The experiments were performed with or without a heat storage unit,and a comparative analysis was made.It was found that the temperature of the air released from the collector ranged from 15°C to 40°C when the exterior temperature was-5°C.The average efficiency of the concentrated system without the heat storage unit was calculated as 67%.The average efficiency of the concentrated system with the heat storage unit was calculated as 96%.
