Performance investigation of a new hybrid high-temperature heat PUMP with natural water medium

This study introduces a new hybrid high-temperature heat pump system, which effectively recycles and utilizes waste heat by thermally coupling an H₂O/LiBr absorption heat transformer with a water vapor compression heat pump. The system not only achieves significant temperature elevation (up to 110 °C) but also provides ultra-high temperature heating (up to 180 °C). To address the mismatch in the quantity and quality of heat and work, this paper introduces a coefficient of performance (COP) calculation method based on an equivalent Carnot cycle, and computes the system's second law efficiency accordingly. Additionally, this research considers factors such as exergy efficiency, solution concentration, and equipment heat loads to comprehensively analyze system performance. Parametric studies on waste heat temperature and coupling temperature reveal that COP varies between 3.0 and 2.5, second law efficiency between 0.64 and 0.43, and exergy efficiency between 0.72 and 0.55, demonstrating the system's superior overall performance. The investigation into solution concentration shows definite constraints between waste heat temperature and coupling temperature: a lower limit for waste heat temperature and an upper limit for coupling temperature. Notably, maximum performance parameters typically occur near these temperature limits, with coupling temperature having a significant impact on system performance. Studies on equipment heat loads indicate that the system can adapt to varying thermal load demands. However, there exists an inverse relationship between heat loads and performance parameters, necessitating precise operational conditions based on specific demands. This research provides a feasible and efficient approach for the application of ultra-high temperature heat pumps in industrial settings.