Abstract: “In this numerical simulation the Building Dynamic Software is used in an application of underground thermal energy storage in a university building with complex topology. The numerical simulation is made in summer conditions with mediterranean environment. In this numerical simulation, the passive and active solar strategies are considered. Building Dynamic Software calculates the air temperature of the spaces, the surface temperature of opaque bodies, transparent bodies and internal bodies, the mass of contaminants and water inside the spaces and in the surfaces, the thermal comfort and air quality and the energy transport and consumption. The university building is divided into 319 spaces, distributed by four floors, and is composed by 329 transparent surfaces (windows) and 3585 opaque surfaces (internal and external walls, doors, and others). Below the ground floor is considered, numerically, an underground floor, with the same area of the building and with a typical floor height, u”

Keywords: Building Dymamic Software; Undeground Space; Thermal Energy Storage; Thermal Comfort, Indoor air quality.