Thermodynamic performance study on solar-assisted absorption heat pump cogeneration system in the coal-fired power plant

A new cogeneration system which integrates a solar-assisted absorption heat pump (SAAHP) into a coal-fired power plant for waste heat recovery of exhausted steam from a steam turbine is presented to improve utilization efficiency of fossil fuels. This study compares the performances of three cogeneration systems which differ in their driving heat source of AHP in the heating system. The following cogeneration systems are considered: conventional cogeneration system (CCS), cogeneration system with AHP driven by extracted steam (CSAES) and cogeneration system with AHP driven by solar (CSAS). Compared with the CCS and CSAES, output power respectively increases by about 11.43 and 6.48 MW; coal consumption rate reduces by 26.27 and 14.29 g/kWh in the CSAS with 11529 kJ heating capacity at 100% THA (Turbine heat acceptance) condition. The integral thermal and exergy efficiency of the CSAS are 58.32% and 36.26%. Meanwhile, reduced coal consumption rate and increased power both increase with increasing heating capacity. It is found that thermal efficiency and exergy efficiency for solar energy utilization both increase with the increasing load.