Comparisons of different working pairs and cycles on the performance of absorption heat pump for heating and domestic hot water in cold regions

In order to explore the suitable working pair and cycle style for heating and domestic hot water in cold region, single-stage and double-stage air source absorption heat pump (ASAHP) and ground source absorption heat pump (GSAHP) are modeled in this paper. Based on these models, the performance of absorption heat pump (AHP) at different generating temperatures, evaporating temperatures and condensing temperatures is simulated respectively when using NH₃-H₂O, NH₃-LiNO₃ and NH₃-NaSCN as working fluid. The results indicate that NH₃-LiNO₃ requires lower generating temperature, and at the same time can work at lower evaporating temperature and higher condensing temperature than other solutions for the same heat pump cycle. Besides, the double-stage AHP is advantageous over single-stage AHP in utilizing low temperature driving source, operating in very cold climate and producing higher temperature hot water. Finally, combining the simulated performance with required hot water temperature and climate conditions, the applicability of different AHP cycles (single-stage or double-stage), heat sources (air source or ground source) and working pairs (NH₃-H₂O, NH₃-LiNO₃ or NH₃-NaSCN) is analyzed in different regions respectively.