Improving the energy efficiency of buildings with hollow core slabs: A numerical investigation

Thermal mass is the capacity of a material to store heat. Concrete or masonry has a higher heat storage capacity than air; therefore, there is significant potential in using the natural thermal mass of buildings to reduce and to shift peak load energy demands. Most residential and commercial buildings have adequate thermal mass that can be utilized to reduce and shift peak energy load. In particular, hollow core slabs that utilize air passing through the slabs to transfer heat in and out of concrete, have the potential to reduce and to shift peak load requirements. This paper presents a numerical investigation that aims to investigate design parameters of hollow core slabs for the maximum energy efficiency, particularly with respect to peak energy demand reduction and shifting. Results reveal that hollow core slab system can be actively used to improve the energy efficiency of buildings. The use of phase change materials (PCM) along with the thermal mass of hollow core slabs enhances both peak load reduction and phase shift; therefore, composite systems that combine the thermal mass of concrete with PCMs emerge as feasible design alternatives to commonly used flat slab systems.