Civil Engineering Reference
In-Depth Information
effective heat transfer taking place between the air and the structure is maximum
throughout its operation.
In the cooling mode, during night-time, the low-temperature air is allowed to
flow through the cores, which in turn releases its cold energy to the slab
component. As the ceiling slab is exposed to the indoor space, during day-load
conditions, the indoor air in contact with the surface of the slab cools down to the
designed set temperature and meets out the required cooling load demand.
Storing of heating energy is also possible with this arrangement, wherein hot air
in place of low-temperature air is allowed to flow through the hollow-core module.
The overcooling or overheating of conditioned zones imposes for having control
logic-like monitoring strategies for ensuring the effective functioning of such
system on a long run.
3.1.3 Storage with Embedded Coil Elements
The fabric structures embedded with heat exchange coil inserts play a vital role in
achieving good TES capabilities in buildings. The heat transfer fluid flowing
through the heat exchange coil element serves as both cold and hot sources of
energy. In the part-load conditions (cooling mode), the chilled water from cooling
plant is diverted to flow across the serpentine-like coil structures being embedded
with the building structure.
By this, the cool thermal energy being stored in the fabric structure during off-
peak load conditions are retrieved back by the supply air flowing over the building
structure during on-peak load conditions. Likewise, in the heating mode, hot water
supply through the coil element facilitates to store heat energy in the building
structure, which is then is utilized for providing heating in occupied zones during
daytime operation in winter seasonal conditions.
The mass flow rate, specific heat capacity, temperature difference and viscosity
of the heat transfer fluid are the influencing parameters that would determine the
overall heat transfer performance of such system, in addition to their inherent
frictional pressure losses.
3.1.4 Storage with Underfloor Slab Component
Thermal energy in the form of heat or cold can be stored and redistributed using
the underfloor slab component in buildings. The heat transfer fluid (hot water or
chilled water) pipe elements embedded into the fabric structure underneath the
floor of the room serves as the heat transport source for charging the building
fabric component. Typically, the cooling capacity that can be experienced using
this system is accounted to be in the range of 25-35 W/m
2
(Seaman et al.
2000
).
Since, the mode of heat transfer is largely by radiation means, the net heat
output delivered by this system is appreciable. The indoor air which comes into
contact with the floor surface traps off the heat or cold energy and dissipates them
