Laboratory intercomparison of solar absorptance and thermal emittance measurements at room temperature

Solar thermal absorber coatings play an important role in the opto-thermal efficiency of receivers in Concentrated Solar Power (CSP). Two standard figures of merit are the solar absorptance αsol and thermal emittance εth, derived from spectral directional hemispherical reflectance measurements at room temperature. These two figures of merit allow comparing coating formulations in terms of performance and durability. In this study, a black coating and a solar selective coating are optically characterized by different laboratories to compare spectral datasets, solar absorptance αsol and thermal emittance εth calculations. The comparison includes various benchtop spectrophotometers operating in the UV-VIS-NIR and Infrared spectral ranges as well as three commercial portable reflectometers/emissometers. A good agreement is found between the nine parties participating in this intercomparison campaign. The black coating αsol value is 96.6 ± 0.2%, while the solar selective coating αsol value is 94.5 ± 0.4%. For the thermal emittance, spectral data is concatenated and integrated from 0.3 to 16 μm. The black coating εth value calculated at 650 °C is 80.8 ± 3.8%, while the solar selective coating εth value calculated at 650 °C is 25.0 ± 0.5%

Structure of anhydrous alkali-metal formates

Single-crystal X-ray diffraction has yielded new crystal structures for cesium formate (CsOOCH) and rubidium formate (RbOOCH). The cesium formate structure has the same unit cell and space group as that published from powder X-ray diffraction data ( Masuda, Y.; Yahata, A.; Ogawa, H. Inorg. Chem. 1995, 34, 3130 - 3133) but differs radically in the placement and orientation of the formate ions. The new crystal structure has been successfully modeled with an empirical force field based on pair potentials, whereas it proved impossible to develop a force field that gave an adequate description of the powder structure. For rubidium formate, the gross structure is similar to that previously published ( Masuda, Y.; Morita, W.; Yahata, A.; Yukawa, Y. Thermochim. Acta 1998, 318, 39 43), but the space group includes a mirror plane (Pbcm rather than Pbc2(1)). From this information, we have been able to analyze the effect of the cation size on the crystal structure for alkali-metal formates

Reactions of the triosmium-antimony cluster Os3(μ-SbPh2)(μ-H)(μ3,η2 -C6H4)(CO)9 with alkynes: C-C bond coupling to a cluster-bound phenylene and catalytic alkyne cyclotrimerization

10.1021/om010911xOrganometallics2161221-1226ORGN