Performance simulations of heat and mass transfer of a novel compound absorber

The miniaturization of absorption heat pump is mainly restricted by the conventional shell-and-tube absorber which requires large heat and mass transfer area. This paper proposed a novel type of plate-fin flat heat pipe absorber (PFFHPA) with compact structure and low metal consumption. In this paper, by building the mass balance equations, energy balance equations, phase equilibrium equations of ammonia-water and heat and mass transfer characteristic equations, a two-dimensional numerical model is developed to simulate the heat and mass transfer process of the absorber. The model takes account of the distribution of liquid-phase temperature and concentration, heat transfer coefficient and absorption rate. A parametric analysis is also conducted to assess the effect of inlet conditions and pressures on the absorption performance. As expected, the novel structure is conducive to a great volume reduction of the absorber by 70% and thereby the entire volume of absorption heat pump system can be greatly reduced in comparison with the conventional heat pump with shell-and-tube absorber.