A module for ice-based thermal energy storage (TES) systems has been developed and integrated within EnergyPlus. The TES module uses building load and system thermodynamics (BLAST) models for two direct ice systems (ice-on-coil external melt and ice harvester) and one indirect ice system (ice-on-coil internal melt). The TES systems are integrated as part of the EnergyPlus cooling plant components and are able to operate for any charge/discharge rates provided as input data. In this paper, the structure of the TES module as implemented in EnergyPlus is described. In addition, typical input-output variables from the added TES module are illustrated. Moreover, the operation of the TES systems is discussed for various conventional control strategies. (C) 2004 Published by Elsevier B.V.