A self-condensation supercritical carbon dioxide Rankine cycle system realized by absorption refrigeration

Abstract

A novel self-condensation supercritical carbon dioxide (sCO2) Rankine cycle system in which a lithium bromide-water absorption refrigeration cycle is used to utilize the waste heat of exhaust gas from the carbon dioxide power cycle and provides a cold source to condense the exhaust gas is proposed. The new system avoids the huge compression power consumption of the sCO2 Brayton cycle system by replacing the compressor with a more efficient pump and the requirement of an extra low-temperature cold source. The power consumption during pressurization, thermal efficiency and levelized cost of electricity (LCOE) of the new integrated system are 26.50% lower, 3.77% higher and 4.32% lower than those of the stand-alone regenerative sCO2 Brayton cycle system, respectively. Parametric analysis is carried out to study the effects of key parameters on the thermodynamic and economic performance of the integrated system. The results show that the generator temperature, maximum system pressure and maximum system temperature have a positive effect on the thermal efficiency and LCOE, while the evaporator temperature and minimum system pressure have a negative effect.