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. © 2004 Published by Elsevier B.V.