Thermodynamic, energy consumption and economic analyses of the novel cogeneration heating system based on condensed waste heat recovery

•A novel cogeneration heating system with full waste heat recovery is proposed.•Optimization direction of integration is revealed for waste heat recovery system.•Thermodynamic perfection, energy consumption and economy are analyzed intensively.•Total exergy efficiency of the novel system increases by 6.1–14.1%•Both the heating energy consumption and the unit heating cost are evidently reduced.