Thermodynamic analysis for CAES-HAT system combined power and heat generation

A combined heat and power system (CAES-HAT) based on humid air turbine cycle is proposed to improve turbine power and efficiency of the conventional CAES system, where water serves as the heat storage medium in charge process to utilize compression heat and exhaust air heat properly for generating electricity and heat with humid air and water as working media, respectively. The changing trends of combustor fuel flow rate, turbine power, electricity supply, heat supply and system efficiency are analyzed with respect to several key parameters. The trend of working medium temperature of discharge progress inlet is discussed by changing the above parameters. Compared with the conventional CAES system, the proposed CAES-HAT system produces more electricity power and operates more efficiently. The electricity power of the proposed system increases by 19.17% under the design condition and reaches 354.75 MW. The heat power reaches 66.36 MW and the system saves 18.17% of fuel with the same power generation, and its total efficiency reaches 58.14%. The parameters of discharge units affect electricity power obviously. Power and heat supply are more sensitive to liquid-to-gas ratio.