Building integrated thermal energy storage (BITES) systems specifically ventilated concrete slabs (VCS) has been discussed in this article. Additionally@ a simplified three dimensional model of the VCS was developed in SolidWorks Flow Simulation software. The model was used to better understand the charging and discharging process of the VCS as a thermal energy storage. It was tested for multiple charging and discharging scenarios such as being connected to the building integrated photovoltaic and thermal (BIPV/T) system or using an air source heat pump (ASHP) as the heat source. Preliminary results show VCS is able to store up to 30% of the generated energy by BIPV/T and charging process is even more effective with an ASHP. Moreover@ it was shown a properly charged VCS would warm up the cold outdoor air by approximately 5??(9?? to be used as an inlet for the heat pump.