A solar cavity-receiver packed with an array of thermoelectric converter modules

► A solar cavity-receiver was packed with thermoelectric converters. ► The system was experimentally demonstrated with concentrated solar radiation. ► A heat transfer simulation model was formulated and experimentally validated. ► 71% of incoming solar power input was conducted as useful energy through the legs. ► Re-radiation losses were reduced to 4%, versus 60% for irradiated single modules. We report on the design of a solar cavity-receiver packed with an array of thermoelectric converter (TEC) modules, which enables efficient capture of concentrated solar radiation entering through a small aperture. A 1 kW demonstrator (proof-of-concept) containing 18 TEC modules, each consisting of Al 2O 3 absorber/cooler plates, and p-type La 1.98Sr 0.02CuO 4 and n-type CaMn 0.98Nb 0.02O 3 thermoelements, was subjected to peak solar concentration ratios exceeding 600 suns over its aperture. The TEC modules were operated at 900 K on the hot side and 300 K on the cold side. The measured solar-to-electrical energy conversion efficiency was twice that of a directly irradiated TEC module. A heat transfer model was formulated to simulate the solar cavity-receiver system and experimentally validated in terms of open-circuit voltages measured as a function of the mean solar concentration ratio. Vis-à-vis a directly irradiated TEC module, the cavity configuration enabled a reduction of the re-radiation losses from 60% to 4% of the solar radiative power input. Theoretical considerations for TEC with figure-of-merit higher than 1 indicate the potential of reaching solar-to-electrical energy conversion efficiencies exceeding 11%.