Enhanced Heat-Network-source Heat Pump System for Efficient Steam Generation

To achieve decarbonization of the heating sector, heat-pump-based steam generation is crucial for the transition of industrial heating. Since the output temperature for steam generation is higher than conventional domestic heating, the temperature lift is also larger, leading to reduced COP. In this case, transporting waste heat or other heat sources through a heat network is important for improving system performance. However, temperature mismatch exists in multiple sections of such heat-network-source heat pump for steam generation. To address this issue, an enhanced heat-network-source heat pump system for efficient steam generation is proposed, with double-section heat pump and feed water preheating. Thermodynamic analysis shows that the system can generate saturated steam at 100–130°C with a maximum COP of 3.34, under 65°C heat network inlet temperature. Compared to the basic heat pump steam generation system, the COP can be improved by 34.2%. Moreover, the proposed system is more advantageous as the heat network temperature difference increases. The exergy analysis further reveals that the performance improvement is associated with reduced exergy loss in the evaporators, owing to improved matching between the heat network and the heat pump system. Besides, exergy loss in condenser is reduced by the preheating process, due to reduced temperature difference in steam generation. With a higher-quality heat source from heat network and improved COP, the proposed system provides a practical configuration for improving the efficiency of steam production.