Analysis of a developed Brayton cycled CHP system using ORC and CAES based on first and second law of thermodynamics

In recent years, studying on energy production processes has been more popular by the sharp increasing trend of energy consumption and loss. One of the effective ways considered for energy loss avoidance in power generation system is using heat loss of power cycles to provide demanded heat for industrial units. Employing auxiliary cycles and compressed air energy system alongside main power production cycle improves the produced power and performance of combined heat and power systems. In this study, a novel combined heat and power system with Brayton cycle as the main power production unit using wind renewable energy, compressed air energy system, and Rankine and organic Rankine cycles is proposed and simulated for residential approaches. All parts of model are validated via the previous published researches and the performance of proposed system in different operating conditions is investigated in detail energetically and exergetically. Results show the acceptable performance of proposed system in peak times as well as low load hours. The increase of gas turbine expansion ratio brings more first and second law efficiencies, while more irreversibility is created by compressor compression ratio increase. In addition, produced power and irreversibility have linear trend by inlet air mass flow rate beside no change in the first and second law efficiencies. Demanded mass flow rate of fuel, Rankine, organic Rankine cycle, and heating system are directly affected by inlet air mass flow rate and overall thermal efficiency can be increased by simultaneous turbine and compressor pressure ratio increase.