A numerical model for the dynamic simulation of a recirculation single-effect absorption chiller

摘要

A dynamic model for the simulation of a new single-effect water/lithium bromide absorption chiller is developed. The chiller is driven by two distinct heat sources, includes a custom integrated falling film evaporator-absorber, uses mixed recirculation and is exclusively cooled by the ambient air. Heat and mass transfer in the evaporator-absorber and in the desorber are described according to a physical model for vapour absorption based on Nusselt's film theory. The other heat exchangers are handled using a simplified approach based on the NTU-effectiveness method. The model is then used to analyze the chiller response to a step drop of the heat recovery circuit flow rate, and to a sudden reduction of the cooling need in the conditioned space. In the latter case, a basic temperature regulation system is simulated. In both simulations, the performance of the chiller is well represented and consistent with expectations.