A High-Temperature Tri-Phase Thermochemical Heat Pump for Industrial Process Heating
Thermochemical heat pumps have attracted widespread attention due to their capability to provide flexible energy conversion and regulation in intelligent energy networks. However, conventional two-phase absorption systems, such as LiBr-H2O, are intrinsically constrained by crystallization, which fundamentally limits their achievable temperature lift and operational flexibility. To overcome these limitations, this work proposes a new tri-phase thermochemical heat pump system in which solid phase participation extends the thermochemical conversion pathway beyond conventional twophase cycles. By integrating sensible heat, latent heat, and thermochemical energy, the system enables high density energy conversion and a large temperature lift. A thermodynamic model is developed to describe the interaction principles among the three phases. A comprehensive evaluation methodology is established to analyze the effects of key parameters. Results show that the introduction of the solid phase leads to a significant improvement in system performance, with discharge temperatures exceeding 140 °C. Specifically, the energy efficiency is enhanced by up to 19.5%, and the exergy efficiency is increased by up to 34.2%. The system achieves a maximum temperature lift of 60 °C. Additionally, the heat release per unit mass of the salt has increased by 2.6 times, indicating the system capacity of largescale thermal energy regulation and conversion. Furthermore, an innovative microencapsulation design is proposed to eliminate the risks of blockage and corrosion, consequently ensuring stable tri-phase operation. Overall, the proposed system provides a significant performance breakthrough over conventional cycles, thereby supporting the transition toward industrial decarbonization.