In consideration of geometric parameters, several researches have already optimized the thermal efficiency of the cylindrical cavity receiver. However, most of the optimal results have been achieved at a fixed solar r...In consideration of geometric parameters, several researches have already optimized the thermal efficiency of the cylindrical cavity receiver. However, most of the optimal results have been achieved at a fixed solar radiation. At different direct normal irradiance (DNI), any single optimal result may not be suitable enough for different regions over the world. This study constructed a 3-D numerical model of cylindrical cavity receiver with DNI variation. In the model of a cylindrical cavity receiver containing a helical pipe, the heat losses of the cavity and heat transfer of working medium were also taken into account. The simulation results show that for a particular DNI in the range of 400 W/m2 to 800 W/m2, there exists a best design for achieving a highest thermal efficiency of the cavity receiver. Besides, for a receiver in constant geometric parameters, the total heat losses increases dramatically with the DNI increasing in that range, as well as the temperature of the working medium. The thermal efficiency presented a different variation tendency with the heat losses, which is 2.45% as a minimum decline. In summary, this paper proposed an optimization method in the form of a bunch of fitting curves which could be applied to receiver design in different DNI regions, with comparatively appropriate thermal performances.展开更多
The optical performance of a receiver has a great influence on the efficiency and stability of a solar thermal power system.Most of the literature focuses on the optical performance of receivers with different geometr...The optical performance of a receiver has a great influence on the efficiency and stability of a solar thermal power system.Most of the literature focuses on the optical performance of receivers with different geometric shapes,but less research is conducted on the effects of critical geometric parameters.In this paper,the commercial software TracePro was used to investigate the effects of some factors on a conical cavity receiver,such as the conical angle,the number of loops of the helical tube,and the distance between the focal point of the collector and the aperture.These factors affect the optical efficiency,the maximum heat flux density,and the light distribution in the conical cavity.The optical performance of the conical receiver was studied and analyzed using the Monte Carlo ray tracing method.To make a reliable simulation,the helical tube was attached to the inner wall of the cavity in the proposed model.The results showed that the amount of light rays reaching the helical tube increases with the increasing of the conical angle,while the optical efficiency decreases and the maximum heat flux density increases.The increase in the number of loops contributed to an increase in the optical efficiency and a uniform light distribution.The conical cavity receiver had an optimal optical performance when the focal point of the collector was near the aperture.展开更多
文摘In consideration of geometric parameters, several researches have already optimized the thermal efficiency of the cylindrical cavity receiver. However, most of the optimal results have been achieved at a fixed solar radiation. At different direct normal irradiance (DNI), any single optimal result may not be suitable enough for different regions over the world. This study constructed a 3-D numerical model of cylindrical cavity receiver with DNI variation. In the model of a cylindrical cavity receiver containing a helical pipe, the heat losses of the cavity and heat transfer of working medium were also taken into account. The simulation results show that for a particular DNI in the range of 400 W/m2 to 800 W/m2, there exists a best design for achieving a highest thermal efficiency of the cavity receiver. Besides, for a receiver in constant geometric parameters, the total heat losses increases dramatically with the DNI increasing in that range, as well as the temperature of the working medium. The thermal efficiency presented a different variation tendency with the heat losses, which is 2.45% as a minimum decline. In summary, this paper proposed an optimization method in the form of a bunch of fitting curves which could be applied to receiver design in different DNI regions, with comparatively appropriate thermal performances.
文摘The optical performance of a receiver has a great influence on the efficiency and stability of a solar thermal power system.Most of the literature focuses on the optical performance of receivers with different geometric shapes,but less research is conducted on the effects of critical geometric parameters.In this paper,the commercial software TracePro was used to investigate the effects of some factors on a conical cavity receiver,such as the conical angle,the number of loops of the helical tube,and the distance between the focal point of the collector and the aperture.These factors affect the optical efficiency,the maximum heat flux density,and the light distribution in the conical cavity.The optical performance of the conical receiver was studied and analyzed using the Monte Carlo ray tracing method.To make a reliable simulation,the helical tube was attached to the inner wall of the cavity in the proposed model.The results showed that the amount of light rays reaching the helical tube increases with the increasing of the conical angle,while the optical efficiency decreases and the maximum heat flux density increases.The increase in the number of loops contributed to an increase in the optical efficiency and a uniform light distribution.The conical cavity receiver had an optimal optical performance when the focal point of the collector was near the aperture.
