Performance of Coupled High-Temperature Heat Pump with Steam Supply Through Long-Distance Hot-Water Pipeline

To achieve efficient steam generation at the end of long-distance hot-water transmission in cogeneration systems， this study combines an absorption heat exchanger with a high-temperature steam heat pump and proposes a novel absorption-compression-coupled high-temperature heat-pump cycle system. A thermodynamic model of the system is established， and the effects of parameters， such as the supply-water temperature of the primary network， the micro-pressure steam temperature， and the steam-supply temperature， on the performance of the coupled high-temperature heat pump are analyzed. The results show that the higher the supply-water temperature of the primary network， the greater is the temperature-increasing capacity of the absorption heat exchanger， the larger is the COP （coefficient of performance） of the coupled system， and the smaller is the unit steam consumption. As the temperature of the micro-pressure steam increases from 75 ℃ to 100 ℃， the COP of the coupled system first increases and then decreases， whereas the unit steam consumption first decreases and then increases. When the temperature of the micro-pressure steam is 80 ℃， the COP of the coupled system reaches a maximum value of 2.6， and the unit steam consumption records a minimum value of 285.3 kW∙h/（t/h）. As the steam-supply temperature increases， the COP of the coupled system decreases monotonically， while the unit steam consumption increases monotonically. When the steam-supply temperature increases from 100 ℃ to 200 ℃， the COP of the coupled system decreases from 4.3 to 2.3 while the unit steam consumption increases from 166.2 to 316.0 kW∙h/（t/h）.