LiBr-H₂ O 吸收式热泵的热力学分析

A theoretical model for analysis of single stage LiBr-H₂O absorption heat pump was established and computer simulation for its thermodynamic cycle performance was conducted. The effects of varying operation conditions (circulation ratio, inlet temperature of low temperature waste water, inlet temperature of hot water and inlet temperature of high temperature vapor) on the four performance criteria (COP, entransy efficiency, exergy efficiency and entropy generation) are investigated, and the consistency of the four criteria are examined. It is found that the performance is degraded with the increases circulation ratio, inlet temperature of hot water and inlet temperature of high temperature vapor. Only when the inlet temperature of waste water increases, the performance is improved. It is also found that the variation trends of the four criteria with the operation conditions are different, and some are even opposite. To be specific, the increase of hot water inlet temperature worsens the system performance according to COP and entransy efficiency while improves the system performance according to exergy efficiency and entropy generation. However, the results obtained by the COP agree well with those by the entransy efficiency, indicating that the entransy efficiency is feasible for the heat pump performance analysis.