Numerical investigation and optimization of a proposed heat-driven compression/absorption hybrid refrigeration system combined with a power cycle

Abstract

On the basis of the energy distribution characteristic of flue gas, a heat-driven compression/absorption hybrid refrigeration (CAHR) system combined with a power cycle is proposed and designed. In the proposed system, a power cycle with NH3/H2O as working fluid is driven by the heat of flue gas to produce mechanical work for the hybrid system. On the basis of the models of the turbine and compressor, the mathematical model of the proposed CAHR system is built up by considering the conservations of mass and energy of working fluids. Then, the validation and energy conservation of the mathematical model are conducted. The total heat conductance of each component is calculated under basic condition. The influences of NH3/H2O mass fraction, turbine outlet pressure, generation temperature, and compression ratio on the operating parameters of the CAHR system are simulated and analyzed in detail. Taking COP as the optimization objective, the above four parameters are optimized. The thermal performances of CAHR system are compared with those of the heat-driven double-effect absorption refrigeration. Comparison results show that the thermal performances of the proposed CAHR system are better than those of the heat-driven double-effect absorption system.