Thermodynamic assessment of an integrated molten carbonate fuel cell and absorption refrigerator hybrid system for combined power and cooling applications

A hybrid system is proposed to harvest the waste heat released in MCFC through integrating an absorption refrigerator as a bottoming cycle. A thermo-electrochemical model is used to describe the main irreversible losses in the system. The operating current density interval of the MCFC that enables the bottoming absorption refrigerator to effectively cool is determined. Numerical expressions for the equivalent power output and efficiency are derived to evaluate the performance of the hybrid system under different operating conditions. Compared to the stand-alone MCFC, the maximum power density and the corresponding efficiency of the hybrid system are found to have increased by 3.2% and 3.8%, respectively. The general performance characteristics and optimum operating regions for the hybrid system are revealed. Comprehensive parametric analyses are conducted to investigate how the hybrid system performance depends on various physical properties and working conditions such as working fluid internal irreversibility inside the absorption refrigerator, heat transfer coefficients, some thermodynamic losses related parameters, and the operating current density, temperature and pressure of the MCFC.