Povećanje energetske efikasnosti malih hidroelektrana

Abstract

The core of the dissertation is to improve energy efficiency of small hydropower plants (SHPPs). The focus is to solve the problems of (1) decreased electricity production during low water flows and (2) inadequate functioning of multi-chamber settling basins because of an uneven flow distribution among the chambers. The latter problem has been solved by an original methodology, which is an upgrade on the traditional usage of CFD and analytical models. The methodology is among the scientific contributions that are:  a method for the iterative finding of a technical solution by the use of a CFD and an ancillary analytical model, which is a guide for a complex and slow CFD model towards an optimal geometry;  a method for the determination of local pressure drops (minor losses) for complex geometrical shapes with multi-dimensional flow patterns using: CFD simulations, regression analysis, and indirect validation;  the application of modern software for the design, optimization, modeling, and modernization of SHHPs.  a novel solution for simultaneous equalization of flows among the chambers of a multi-chamber settling basin and the dissipation of turbulent kinetic energy. These results were implemented on a case study, which includes two cascade SHPPs with a common side water intake and nominal installed capacities of 1.220 MW and 1.327 MW. The solving of both problems resulted in technical solutions for:  the determination of an optimal configuration under existing conditions (gross head, turbine types, pipeline diameters) by the use of new turbine(s) and independent or coupled operation of two run-of-the-river SHPPs;  the equalization of flows among the chambers of a multi-chamber settling basin and the dissipation of turbulent kinetic energy by the use of: (a) pillars with vanes in a common inlet zone and (b) sluice gates with tranquilizing racks. The solution of the (1) problem increased the electricity production by 4.8% and the solution of the (2) problem reduced the total loss by 8%. The results are applicable to all new and existing SHPPs with side water intakes, whereas the developed methodologies exceed the field of SHPPs.