Autori: R. D. Rugescu, D. Tsahalis, C. Tulita

Editorial: 2nd IC-SCCE-2006, July 5-8, 2006, Arthens, Greece, 2006.

Rezumat:

The SEATTLER solar power plant, consisting of a tall tower where the atmospheric air is heated by a heliostat array through a solar receiver and drives an air turbine by the new mechanism of cold air gravity draught, is modeled into a mathematical integral equivalent. The all-air working fluid principle is proposed as the result of an encouraging previous, small scale research sponsored by the CNCSIS Grant No. 27642 of 14 March 2005 in Romania. The presented numerical investigation on the model is targeted towards demonstrating the feasibility and efficiency of the all-air system at full scale. The natural peculiarities of the solar tower systems are connected to their small working pressures and, in the present case, to the medium working temperatures in particular. At the same time, air enthalpy capture efficiencies between 65% and 80% are known within the SOLAIR project in Spain, while the SEATTLER efficiency could go much further. The alternative here evoked is focused on preliminary temperature ranges of 100-300C and over 1300C. In either case simple and high efficiency solar radiation solid-air heat exchangers are to be yet developed. Due to the small pressure variations along the gasdynamic channel, the mathematical model here presented proves a high instability in regard to the assumptions introduced and to the limit conditions of the flow at entrance and exit of the tower. The quasi-resonance behavior is demonstrated through several independent paths. The characteristic of the turbine tower proves markedly different from the simple, warm air thermal draught in high stacks.

Cuvinte cheie: Thermal draught, Convective flow, Gravitational draught, Thermal air acceleration