Comprehensive analysis of a novel coal-fired cogeneration system with integrated dual heat pumps

The low-carbon transformation of the global energy system requires flexible energy supply technologies. This paper proposes a novel coal-fired cogeneration system with integrated dual heat pumps. The return water is cooled by the absorption heat pump, which significantly expands the range of water temperature rise and the waste heat recovery. Based on EBSILON professional, the thermodynamic, operation, and techno-economic analysis is conducted. The results show that the upper limit of the thermal capacity of the novel system is increased by 164 MW, leading to a 9.86% enhancement in gross efficiency. Additionally, at a thermal load of 400 MW, the power load regulation ratio of the novel system is boosted by 10.57%. Furthermore, as the heat load varied from 200 MW to 600 MW, the minimum power load difference between the two systems increased from 28.00 MW to 100.18 MW. Technological-economic analysis conducted elucidates that the deployment of the novel system is projected to yield a substantial reduction in coal consumption by approximately 49.27 kilotons per heating season, resulting in an annual net revenue of 49.09 million CNY and a dynamic payback period of 4.59 years. The research could provide technical references for energy saving and flexibility optimization of cogeneration systems. • A novel coal-fired cogeneration system with integrated dual heat pumps is proposed. • The maximum heat load and the gross efficiency are improved by 164 MW and 9.86%. • Operational characters under the off-design condition are analyzed. • The novel system could reduce coal consumption by 49.27t per year with a dynamic payback period of 4.59 years.