Civil Engineering Reference
In-Depth Information
During the daytime (i.e. when on-peak load conditions prevail in building), by
circulating the warm air over the ceiling slab, the stored cold energy is dissipated
to the indoor spaces to meet out the cooling and thermal comfort requirements.
Factually, the temperature swings achieved inside conditioned zones using this
storage system is estimated to be 2-4 C.
The amalgamation of ceiling slab storage system with mechanically assisted fan
unit can still improve the overall heat transfer performance of the combined
system, especially when the heat exchange mechanism between the slab compo-
nent and supply air is appreciable. With the condition of outdoor air being at a
lower temperature than the indoor design set temperature, the cooling capacity of
storage component can be increased significantly (both under passive and active
modes of operation).
The free energy storage that is possible during night-time using the fresh air
(outdoor/ventilation air) can enhance the storage capability of slab component on
an average by 5-10 %. The ceiling slab can be made to expose directly to the
indoor spaces or covered with a suspended ceiling arrangement. The suspended
ceiling decouples the stratification effects of indoor air with the ceiling component
to some extent, thereby providing good thermal comfort to occupants with
enhanced energy efficiency.
Furthermore, the installation of longer ductwork air distribution systems are
less pronounced, which further enhances the energy savings potential of this type
of storage system. The floor slab storage system is much similar to the ceiling slab
configuration, but the fabric slab material is arranged in conjunction with the floor
component of the building. The operational strategy of this system is the same as
that of ceiling slab system.
The main advantage of floor slab storage arrangement is that the cold air after
transferring its energy to the slab is supplied from the floor level into the condi-
tioned space. The vertical movement of air from the floor surface to the ceiling
space can add value in effectively offsetting the heat load demand as well as
maintain the temperature stratification in indoor environment much better than the
ceiling slab configuration.
In intermediate seasonal conditions, both the storage systems are capable
enough to capture any excess heat energy produced from the conditioned zones
during daytime, thereby facilitating to compensate the additional heat losses in
buildings that occur in night-time.
3.1.2 Storage with Hollow-Core Ceiling Slab Component
The next level of storing thermal energy using the fabric component is achieved
through the implementation of hollow-core slab arrangement in buildings. The
fabric structure made up of construction materials contains a series of hollow cores
(or voids), wherein the low-temperature air flows across the slab structure through
these cores. The pitch between the cores is maintained in such a way that the
