Transient thermal performance response characteristics of porous-medium receiver heated by multi-dish concentrator

The transient thermal performance response characteristics of porous-medium receiver have a major impact on the operability of a solar thermal power plant (STPP). To investigate the transient thermal performance response characteristics of porous-medium receiver, method coupled to the Monte Carlo ray tracing (MCRT) and finite volume method (FVM) was developed to establish a 2D transient state heat-transfer model using a local thermal non-equilibrium (LTNE) calculation. The effects of the fluid thermophysical characteristics, the fluid-phase type, and the solid-phase thermal conductivity on the unsteady-state heat-transfer performance were investigated to determine the transient thermal performance response characteristics of porous-medium receiver. The numerical results indicated that the variation in the air thermophysical properties due to the high working temperature can induce a very small transient thermal performance response in porous-medium receiver (a maximum deviation of 1.9% was observed in this study). A porous-medium receiver with a high thermal conductivity can benefit from the dispersion of concentrated energy. The dimensionless solid-phase temperature eon the center point of receiver in case of λ = 40 W/(m·K) was 1.05 at t = 240 s, decreasing to 0.92 in case of λ = 120 W/(m·K).