Thermal and hydraulic characteristics of packed bed solar energy storage system having spheres as packing element with pores. (August 2020)

• Record Type: Journal Article
• Authors: Gautam, Abhishek; Saini, R.P.
• Is Part Of: Journal of energy storage. Volume 30(2020)
• Publication Date: 2020-08
• Subjects: Solar thermal energy -- Nusselt number -- Friction factor -- Thermo-hydraulic parameter -- Flow separation -- Heat transfer enhancement; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2020.101414
• Languages: English
• ISSNs: 2352-152X

Abstract

Highlights: Influence of pores over surface of spheres is investigated on thermo-hydraulic performance for solar thermal systems. Pore to sphere diameter ratio, pore depth to sphere diameter ratio, perforation index and Re are investigated parameters. The results are analysed in terms of Nusselt number, friction factor and thermo-hydraulic parameter. The maximum enhancement of 8.2% is observed in thermo-hydraulic parameter of PBSS as compared spheres as packing elements. Abstract: The thermal performance of packed bed storage system can be improved by increasing the heat transfer coefficient between the packing element and heat transfer fluid. The shape of the packing element is one of the factors that influences the heat transfer coefficient. The present experimental investigation is carried out to obtain the influence of spheres having pores as packing element in packed bed storage system. The effects of pore diameter, pore depth, number of pores and mass flow rate is discussed and presented in the present paper. In order to investigate the performance, non-dimensional parameters such as pore to sphere diameter ratio ( d/D ), pore depth to sphere diameter ratio ( t/D ), perforation index ( PI ) and Reynolds number ( Re ) are considered. The experimentations are carried out for d/D, t/D, PI and Re for the range of 0.066 to 0.20, 0.05 to 0.20, 0.06 to 0.22 and 200 to 800, respectively. The maximum value of thermo-hydraulic parameter is obtained as 0.245 correspond to d/D of 0.20, t/D of 0.06, PI of 0.18 and Re of 800 within the considered range of the investigated parameters. On the basis of the experimental investigation, it is found that the use of sphere with pores as packing element improves the thermal and hydraulic performance of the packed bed storage system.