Design Space Exploration of a 5 MWth Small Particle Solar Receiver

Performance Assessment of Fischer–Tropsch Liquid Fuels Production by Solar Hybridized Dual Fluidized Bed Gasification of Lignite

“…The value of Φ is defined to be 0 for Φ < 0, which occurs when the solar thermal input to the receiver from the heliostats is lower than the heat losses from the receiver. The effective absorptance and emittance of the solar cavity receiver are both assumed to be unity, A coll is the heliostat collector area, A aper is the aperture area of the solar receiver, I DN is the direct normal solar insolation, σ is the Stefan–Boltzmann constant (5.6705 × 10 –8 W/(m 2 K 4 )), T rec is the temperature of the solar receiver, C is the assumed concentration ratio ( C = A coll / A aper = 2000), η o,l,rec is the proportion of other heat losses including conduction and convection losses from the receiver other than reradiation (σ T rec 4 A aper ) and optical losses and was assumed to be 10%, , η stg is the thermal efficiency of the storage unit and was assumed to be 95%, and η opt is the optical efficiency of the solar system which includes the solar receiver and heliostat field, defined in eq : ,, where η ref,coll is the heliostat collector reflection efficiency, assumed to be 88%, η sb is the shadowing and blocking efficiency of the heliostat field, assumed to be 93.3%, η itc is the interception efficiency, assumed to be 99.2%, η aa is the atmospheric attenuation, assumed to be 95%, and η ref,CPC is the reflection efficiency of the compound parabolic concentrator (CPC), assumed to be 95% . In addition, η cos is the cosine efficiency of the heliostat field, which is calculated as a function of solar time for one particular position as representative of the entire field. , Because η cos depends more strongly on the time and site than on A coll , it was further assumed to be independent of A coll .…”

“…where η ref,coll is the heliostat collector reflection efficiency, assumed to be 88%, 45 η sb is the shadowing and blocking efficiency of the heliostat field, assumed to be 93.3%, 45 η itc is the interception efficiency, assumed to be 99.2%, 45 η aa is the atmospheric attenuation, assumed to be 95%, 45 and η ref,CPC is the reflection efficiency of the compound parabolic concentrator (CPC), assumed to be 95%. 46 In addition, η cos is the cosine efficiency of the heliostat field, which is calculated as a function of solar time for one particular position as representative of the entire field. 47,48 Because η cos depends more strongly on the time and site than on A coll , it was further assumed to be independent of A coll .…”