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This paper discusses the characterisation of micro-channel absorber plates for compact flat plate solar thermal collectors, which are suitable for building integration. Experimental and computational studies were carried out at typical operating conditions for flat plate solar collectors. Three-dimensional numerical analysis using commercial CFD package, ANSYS CFX, showed that heat transfer occurred on only three surfaces of the channel and there was a peripheral variation of the heat flux density. It was also observed that axial thermal conduction could modify the surface boundary at the inlet and outlet; however, the middle section of the channel could be approximated as a rectangular channel with three walls transferring heat under an H1 boundary condition. Experimental studies were used to estimate the standard parameters for predicting performance of the flat plate collectors, which indicated promising performance results. The collector flow factor F″ and the heat removal factor could be improved by increasing the collector capacitance rate; this can be achieved by increasing the mass flow rate per collector area m·/Ac as well as reducing the overall heat loss, UL. This analysis is important for optimising design and operating parameters, especially to minimise temperature gradient in the transverse and longitudinal directions.Practical application: The proposed compact micro-channel absorber plate has the potential to make flat plate collectors more efficient, cheaper and aesthetically attractive in building integration. It could therefore promote the uptake of solar thermal collectors in buildings. The analysis presented in this study would be beneficial for optimising the design and operating parameters of building integrated solar thermal collectors with micro-channels. [ABSTRACT FROM AUTHOR]

Slowing rates of global biodiversity loss requires preventing species extinctions. Here we pinpoint centers of imminent extinction, where highly threatened species are confined to single sites. Within five globally assessed taxa (i.e., mammals, birds, selected reptiles, amphibians, and conifers), we find 794 such species, three times the number recorded as having gone extinct since 1500. These species occur in 595 sites, concentrated in tropical forests, on islands, and in mountainous areas. Their taxonomic and geographical distribution differs significantly from that of historical extinctions, indicating an expansion of the current extinction episode beyond sensitive species and places toward the planet's most biodiverse mainland regions. Only one-third of the sites are legally protected, and most are surrounded by intense human development. These sites represent clear opportunities for urgent conservation action to prevent species loss.