Evaluation of Improvements to Brayton Cycle Performance.
ARMY MILITARY PERSONNEL CENTER ALEXANDRIA VA
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This study addresses the problem of finding an energy conversion method to take advantage of the high maximum cycle temperatures achieved with solar central receivers. Most current practice is to use steam-based heat engines with solar receivers but these Rankine cycles cannot operate at the higher possible temperatures. Derivatives of gas-based Brayton cycles are considered to take advantage of the expected increased cycle performance of higher temperatures. Computer modelling was done to examine the effect of maximum temperature on efficiency of two Brayton cycle derivatives and a simple Brayton cycle GT. The modified Brayton cycles include a combination of intercooling, regeneration, and reheat IGT and a Brayton cycle with steam injection STIG. The turbine inlet temperature, the steam-to-air injection mass ratio for the STIG, and the compression pressure ratios were treated as parameters in the analysis. Both First Law and Second Law efficiencies were examined. Efficiencies were highest for the IGT followed by the STIG and GT, respectively. Considerable improvements in specific work output were demonstrated by the STIG over both the IGT and GT systems. First and Second law analyses show a gradual increase of efficiency with turbine inlet temperature with diminishing returns at higher temperatures. Keywords Solar power. Theses
- Electric Power Production and Distribution
- Jet and Gas Turbine Engines