Efficient hydraulic air compression for base loaded combustion turbines
01 Jan 1991-Vol. 53
TL;DR: In this article, two kinds of air compressors and their performance and power characteristics are discussed. But they do not discuss the performance and cost analysis of the two types of compressors.
Abstract: Hydraulic air compression is a method for obtaining isothermally compressed air for combustion turbines. Air is compressed in a vertical shaft by a co-flowing water stream. After separation from the water at the bottom of the shaft the air is delivered to the combustor at variable pressures and mass flow rates needed for a range of loads. This paper describes two kinds of air compressors and discusses their flow and power characteristics. Results of preliminary performance and cost analyses are also given.
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01 Aug 1997
TL;DR: In this article, a thermodynamic analysis is presented of HAC-gas turbine energy conversion systems, which are compared with conventional hydroelectric and gas turbine power plants, making further technical and economical investigations quite interesting.
Abstract: Nowadays, the most common way to improve energy conversion efficiency is the integration of different systems, thus achieving a better exploitation of the available exergy potential (e.g. combined cycles, cogeneration, etc.). As a means of producing power in hydroelectric plants hydraulic energy is commonly considered to be almost completely exploited. The aim of this paper is to analyse the possible integration of hydraulic energy sources with conventional, fossil fuel based systems; in particular, power plants based on the combination of an hydraulic air compressor (HAC) and a gas turbine are considered. In an HAC, air is entrained in the water flow in a downcomer pipe and compressed. Once separated from the water in a 'stilling chamber' at the bottom of the downpipe, the compressed air is supplied to a combustion chamber and then to a conventional gas turbine expander. An attractive characteristic of HACs is the capability, in principle, to perform an isothermal air compression instead of an adiabatic one, as in conventional compressors. In the present work, a thermodynamic analysis is presented of HAC-gas turbine energy conversion systems, which are compared with conventional hydroelectric and gas turbine power plants. The calculated performance levels of such systems are comparable to those of combined cycle plants, making further technical and economical investigations quite interesting.
9 citations
01 May 1999
TL;DR: In this article, the combined exploitation of different kinds of primary energy sources in innovative power plants is a promising way to enhance the energy conversion efficiency, which is a possible way to improve the energy efficiency.
Abstract: The combined exploitation of different kinds of primary energy source in innovative power plants is a promising way to enhance the energy conversion efficiency. In recent years, a possible ...
8 citations
01 Mar 2009
TL;DR: In this paper, a low-head hydropower system with an intermediate air transmission stage is proposed, where water is made to flow through a siphon and at the top of the siphon the pressure is sub-atmospheric and air is entrained into the water.
Abstract: Hydropower is a proven renewable energy resource and future expansion potential exists in smaller-scale, low-head sites. A novel approach to low-head hydropower at run-of-river and tidal estuary sites is to include an intermediate air transmission stage. Water is made to flow through a siphon, rather than a conventional water turbine, and at the top of the siphon the pressure is sub-atmospheric and air is entrained into the water. The siphon forms a novel, hydraulically powered vacuum pump or 'hydraulic air pump' (HAP). Air is pumped by the HAP through a separate air turbine and generator. This arrangement offers dramatic increases in turbine-generator speed and allows better control and matching of components and lifecycle cost reductions due to reduced maintenance costs and the use of smaller rotating machines. This study builds on previous work on such systems by showing why the pumping process can be treated as isothermal. Also, initial test results with a small siphon are presented and com- pared to existing models. These show a discrepancy between predicted and measured pressure ratios and therefore an overprediction of efficiency and power output using simple mathematical models.
7 citations
TL;DR: In this article, a hydrodynamic formulation of the hydraulic air compressors (HACs) is presented, and the performance of HACs is evaluated by means of simulation.
6 citations