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This paper presents a short view of the first Archimedean Screw Turbines CFD modelling results, which were carried out within the recent research entitled "Rebirth of Archimedes in Greece: contribution to the study of hydraulic mechanics and hydrodynamic behavior of Archimedean cochlear waterwheels, for recovering the hydraulic potential of Greek natural and technical watercourses". This CFD analysis, based to the Flow-3D code, concerns typical Tubular Archimedean Screw Turbines (TASTs) and shows some promising performances for such small hydropower systems harnessing the important unexploited hydraulic potential of natural and technical watercourses of Greece, of the order of several TWh / year and of a total installed capacity in the range of thousands MWs. [ABSTRACT FROM AUTHOR]

The present paper proves that the vast water supply infrastructure of Athens and the region of Attica could produce useful hydropower. The first aim of this paper is to present the unconventional small hydro philosophy of recovering the hydraulic energy wasted in the existing break pressure devices and energy dissipating structures of the Water Supply Network of Athens, the capital of Greece and of the whole Attica region. The paper discusses themes concerning the replacement, in this large drinking water infrastructure, of all the existing break pressure devices, by a series of small hydro plants and also the efficient ways by which such small unconventional hydro schemes could be realized. The second aim of the paper is to highlight some important CFD simulation features which however needs further investigations and to present preliminary some Flow-3D results concerning the hydrodynamic performances of this series of small hydro plants harnessing the important wasted hydraulic energy of the Attica Water Supply Network. [ABSTRACT FROM AUTHOR]

The present paper describes the evaluation of the Greek Archimedean Small Hydro Resources, considering the basic data for the 14 water regions of the country, adopting a holistic assessment methodology of the total theoretical hydro potential of Greece, which could be exploited by using Archimedean Screw Turbines (ASTs). The total evaluation of the theoretical Archimedean hydropower potential of Greece, which may be produced with ASTs, is of the order of several TWh / year, with a theoretical installed capacity of screw turbines in the range of thousands MW, with important values of special capacity and special capacity density, demonstrating the major existing unexploited hydropower potential for a future true sustainable development with small hydro plants in Greece based on environmentally friendly screw turbines. [ABSTRACT FROM AUTHOR]

The main aim of this paper is to prove, according to our inventory that, beyond the horizon of the era of transition and economic crisis of nowadays, Greece is a real "Archimedean Screw Hydropower Development Terra Incognita", a country generously blessed with water, having an important hydropower potential. This inventory shows that the unexploited small hydropower capacity of Greece, including Archimedean possibilities, is approximately 3.500MW. The significant untapped small hydrodynamic potential demonstrates the important role of Pindos Mountain Range, controlling the annual rainfall difference between the North-Western and the Eastern Greece. The climatic and topographic conditions in Greece favor the development of many small Archimedean screw hydropower stations, harnessing the potential of a large number of small and big watercourses crossing mainland of the country. Pleiades of very promising Archimedean small hydro screw plants, having inclined and horizontal axis hydrodynamic rotors, could be installed following two hydro development axis (spears). [ABSTRACT FROM AUTHOR]

The first aim of this paper is to present data concerning the design, construction, installation and operation of the first in the world Horizontal Axis Archimedean Screw Turbine (H.A.A.S.T.), having a length L=1m, diameters (output and input) Do=200mm and Di=100mm, a pitch S=200mm and a number of blades n=3. This horizontal screw could rotated horizontally and change direction (Δθ = 100°), forming an upstream angle of 50 ° with its initial position and a downstream angle of 50 ° with its initial position. The second aim of the paper is to present experimental results of the operation in a big hydraulic channel under various controlled conditions, simulating the operation of the physical conditions of rivers, open channels, etc. The third aim of the paper is to present a series of theoretical performance prediction results based on various S1/S2 algorithms and Linear Actuator Disk simulations. [ABSTRACT FROM AUTHOR]

This paper presents a brief history of rediscovering the old Archimedean screw pumps as a series of modern and efficient Archimedean hydropower turbines, including floating spiral screw devices, for harnessing the important and unexploited Greek small hydraulic energy potential, producing useful green electricity. The recent research concerns some Archimedean small hydropower applications, with inclined axis, in cascade and in parallel, for a series of low-head sites in small watercourses and large rivers, and for a series of horizontal floating screws, exploiting the kinetic energy of rivers, open channels and tidal currents. The inclined-axis Archimedean turbines within pipes or troughs, and the horizontal-axis Archimedean kinetic energy conversion systems, harnessing the unexploited flowing kinetic hydraulic potential of watercourses, open channels, and coastal or tidal currents seem to prove the importance of the "back to the future" rediscovering the Archimedean ideas. The two kinds of Archimedean screw hydropower plants tend to emphasize jumping between the past and future, and to find the most reliable sustainable development way for Greece through the obstacles of the actual transition period. [ABSTRACT FROM AUTHOR]

The Archimedean renewable energy systems are enjoying a renewed interest, since about one decade, and have become increasingly popular throughout Europe. It seems that this low head Archimedean technology is still a niche product. Despite the age of the Archimedean screws there is no consistent and appropriate theory for the screw hydraulic design linking the screw's geometry with their performances. This paper after giving a brief history of the Archimedean screw pumps and screw turbines presents an eagle's view of the recent NTUA and ASPETE Computational Fluid Dynamics (C.F.D.) modelling results, of the carried out within the program ARCHIMEDES III research, entitled "Rebirth of Archimedes: contribution to the study of hydraulic mechanics and hydrodynamic behavior of Archimedean cochlear waterwheels, for recovering the hydraulic potential of natural and technical watercourses, of maritime and tidal currents". [ABSTRACT FROM AUTHOR]