Absorption refrigeration systems gained considerable attention recently for their environmental friendly behavior and for activation using thermal energy sources. In LiBr-H2O absorption chillers, solution crystallization represents a severe problem. The crystallization of the solution blocks the chiller internal piping and stop the chiller operation. In this paper a crystallization detection function is developed and embedded into a dynamic simulation model to detect solution crystallization due to abnormal operation. The crystallization detection function is developed by introducing critical concentration equation that was generated from linearization of the crystallization line in Equilibrium chart for aqueous lithium bromide solutions. The model successfully depicted the solution concentration when the solution concentration is approaching the crystallization line. © 2015 The Authors. Published by Elsevier Ltd.