Thermodynamic analysis of a novel combined heat and power system incorporating a CO2 heat pump cycle for enhancing flexibility

•A novel combined heat and power (CHP) system integrated with a CO2 heat pump (HP) cycle.•Enhancing flexibility of CHP and diminishing the minimum power outputs under high heat loads.•The exhaust steam with a relatively high temperature is the heat source of the CO2 HP cycle.•Converting the surplus self-produced electricity into useful heat in a high efficiency.•Excellent performance on conserving fuel and further deploying renewable power.