An experimental investigation has been carried out with aa point focusing dish reflector of 12 square meters aperture area, exposed to the average direct normal irradiations of 810 W/m^2. This work focuses on enhancin...An experimental investigation has been carried out with aa point focusing dish reflector of 12 square meters aperture area, exposed to the average direct normal irradiations of 810 W/m^2. This work focuses on enhancinge the energy and exergy efficiencies of the cavity receiver by minimizing the temperature difference between the wall and heat transfer fluids. Two heat transfer fluids Water and SiC + water nano fluid have been prepared from 50 nm particle size and 1% of volume fraction, and experimented separately for the flow rates of 0.2 lpm to 0.6 lpm with an interval of 0.1 lpm. The enhanced thermal conductivity of nano fluid is 0.800115 W/mK with the k_(eff)/k_b ratio of 1.1759 determined by using the Koo and Kleinstreuer correlation. The maximum attained energy and exergy efficiencies are 29.14% and 24.82% for water, and 32.91% and 39.83% for SiC+water nano fluid. The nano fluid exhibits enhanced energy and exergy efficiency of 12.94% and 60.48% than that of water at the flow rate of 0.5 lpm. The result shows that the system with SiC+Water produces higher exergy efficiency as compared to energy efficiency; in the case of water alone, the energy efficiency is higher than exergy efficiency.展开更多
Concentrating solar power(CSP)is considered as a comparatively economical,more efficient,and large capacity type of renewable energy technology.However,CSP generation is found restricted only to high solar radiation b...Concentrating solar power(CSP)is considered as a comparatively economical,more efficient,and large capacity type of renewable energy technology.However,CSP generation is found restricted only to high solar radiation belt and installed where high direct normal irradiance is available.This paper examines the viability of the adoption of the CSP system in a low sun belt region with a lower direct normal irradiance(DNI).Various critical analyses and plant economics have been evaluated with a lesser DNI state.The obtained results out of the designed system,subjected to low DNI are not found below par,but comparable to some extent with the performance results of such CSP plants at a higher DNI.The analysis indicates that incorporation of the thermal energy storage reduces the levelized cost of energy(LCOE)and augments the plant capacity factor.The capacity factor,the plant efficiency,and the LCOE are found to be 32.50%,17.56%,and 0.1952$/kWh,respectively.展开更多
Solar radiation influences many and diverse fields like energy generation, agriculture and building operation.Hence, simulation models in these fields often rely on precise information about solar radiation. Measureme...Solar radiation influences many and diverse fields like energy generation, agriculture and building operation.Hence, simulation models in these fields often rely on precise information about solar radiation. Measurementsare often restricted to global irradiance, whereby measurements of its single components, direct and diffuseirradiance, are sparse. However, information on both, the direct and diffuse irradiance, is necessary forsimulation models to work reliably. In this study, solar separation models are developed using 10-min trainingdata from two different locations in Austria. Direct horizontal irradiance is predicted via regressing the directfraction using several objective functions. The models are first trained on a data set including data from bothlocations, and evaluated regarding root mean squared deviation (RMSD), mean bias deviation (MBD), andcoefficient of determination (R2) on measured and estimated direct normal irradiance. The two best performing models are then selected for further analysis. This analysis comprises of an evaluation of the models per season,transferability of trained modes between two locations in Austria, a transferability and generalisability studyconducted for four more locations in Central Europe, and a comparison with the trusted Engerer model. Thesolar separation model with polynomial terms up to order three and Ridge regularisation outperforms thesecond model based a logistic term in combination with mixed quadratic terms as well as the Engerer model.展开更多
文摘An experimental investigation has been carried out with aa point focusing dish reflector of 12 square meters aperture area, exposed to the average direct normal irradiations of 810 W/m^2. This work focuses on enhancinge the energy and exergy efficiencies of the cavity receiver by minimizing the temperature difference between the wall and heat transfer fluids. Two heat transfer fluids Water and SiC + water nano fluid have been prepared from 50 nm particle size and 1% of volume fraction, and experimented separately for the flow rates of 0.2 lpm to 0.6 lpm with an interval of 0.1 lpm. The enhanced thermal conductivity of nano fluid is 0.800115 W/mK with the k_(eff)/k_b ratio of 1.1759 determined by using the Koo and Kleinstreuer correlation. The maximum attained energy and exergy efficiencies are 29.14% and 24.82% for water, and 32.91% and 39.83% for SiC+water nano fluid. The nano fluid exhibits enhanced energy and exergy efficiency of 12.94% and 60.48% than that of water at the flow rate of 0.5 lpm. The result shows that the system with SiC+Water produces higher exergy efficiency as compared to energy efficiency; in the case of water alone, the energy efficiency is higher than exergy efficiency.
文摘Concentrating solar power(CSP)is considered as a comparatively economical,more efficient,and large capacity type of renewable energy technology.However,CSP generation is found restricted only to high solar radiation belt and installed where high direct normal irradiance is available.This paper examines the viability of the adoption of the CSP system in a low sun belt region with a lower direct normal irradiance(DNI).Various critical analyses and plant economics have been evaluated with a lesser DNI state.The obtained results out of the designed system,subjected to low DNI are not found below par,but comparable to some extent with the performance results of such CSP plants at a higher DNI.The analysis indicates that incorporation of the thermal energy storage reduces the levelized cost of energy(LCOE)and augments the plant capacity factor.The capacity factor,the plant efficiency,and the LCOE are found to be 32.50%,17.56%,and 0.1952$/kWh,respectively.
文摘Solar radiation influences many and diverse fields like energy generation, agriculture and building operation.Hence, simulation models in these fields often rely on precise information about solar radiation. Measurementsare often restricted to global irradiance, whereby measurements of its single components, direct and diffuseirradiance, are sparse. However, information on both, the direct and diffuse irradiance, is necessary forsimulation models to work reliably. In this study, solar separation models are developed using 10-min trainingdata from two different locations in Austria. Direct horizontal irradiance is predicted via regressing the directfraction using several objective functions. The models are first trained on a data set including data from bothlocations, and evaluated regarding root mean squared deviation (RMSD), mean bias deviation (MBD), andcoefficient of determination (R2) on measured and estimated direct normal irradiance. The two best performing models are then selected for further analysis. This analysis comprises of an evaluation of the models per season,transferability of trained modes between two locations in Austria, a transferability and generalisability studyconducted for four more locations in Central Europe, and a comparison with the trusted Engerer model. Thesolar separation model with polynomial terms up to order three and Ridge regularisation outperforms thesecond model based a logistic term in combination with mixed quadratic terms as well as the Engerer model.
