This paper presents a heat storage and cooling concept that utilizes a phase change material (PCM) and a thermally activated building system (TABS) implemented in a hollow core concrete deck. Numerical calculations of the dynamic heat storage capacity of the hollow core concrete deck element with and without microencapsulated PCM are presented. The new concrete deck with microencapsulated PCM is the standard deck on which an additional layer of the PCM concrete was added and, at the same time, the latent heat storage was introduced to the construction. The challenge of numerically simulating the performance of the new deck with PCM concrete is the thermal properties of such a new material, as the PCM concrete is yet to be well defined. The results presented in the paper include models in which the PCM concrete material properties, such as thermal conductivity, and specific heat capacity were first calculated theoretically and subsequently the models were updated with the experimentally determined thermal properties of the PCM concrete. Then, the heat storage of the decks with theoretically and experimentally determined thermal properties were compared with each other. Finally, the results presented in the article highlight the potential of using TABS and PCM in a prefabricated concrete deck element. (C) 2012 Elsevier B.V. All rights reserved.