One dimensional thermal analysis of silicon carbide ceramic foam used for solar air receiver

摘要

Using air as heat transfer fluid for electricity generation offers some significant advantages for the development of Concentrated Solar Power (CSP): high conversion efficiency, low environmental impact and being used in deserts or other areas scarce of water resources. Silicon carbide ceramic foams have the characteristics of light weight, high strength, large specific surface areas, high porosity and excellent thermal shock resistance performance which make them particularly fit for absorber material in CSP. In this paper, thermal performance of silicon carbide ceramic foam as solar air receiver is investigated analytically based on the one dimensional physical model. The analytical results show that the air flow resistance increases obviously with increasing air outlet temperature, the air flow resistance while the air outlet temperature is equal to 1000℃ is nearly 3 times the one while the air outlet temperature is equal to 20℃ with air velocity range is between one and six meters per second. The results of one dimensional analysis of flow and heat transfer process of ceramic foams suggest that there exists an input solar energy flux limit for the unpressurized system, which will lead to limit the power capacity and the outlet air temperature enhancement.