Author: Kasper Verfaillie
Institution: TU Delft
Site location: EWI Building Campus TU Delft, Deflt, the Netherlands
Year : 2014-2015
A major problem of the EWI-building is the turbulence created by its shape. I began looking for a more aerodynamic shape, that resolves this problem. Not only did I reduce the turbulence majorly, I also reduced the wind load on the building by 50 %. The new shape gave possibilities to improve the EWI. Next, I studied aerodynamic shapes of some high-rise buildings. In specific I’ve studied the “30 St Mary Axe” by Norman Foster + Partners. The building is a paradox, even with more advanced techniques and simulations; the building is not energy sufficient and struggles with a lot of problems. Critics say that the building is like a Ferrari, but the users only use it in second gear.
My first approach is to make the double facade of the building as light possible, also in material efficiency, for example by working with ETFE-Foil instead of glass and reducing the mass of the bearing structure.
My second approach is to use natural ventilation in the whole building. The existing double facade and his HVAC-system is failing and users want to open a window when this is necessary. In my design I will use 2 solar chimneys. These chimneys will cool down the building in the summer and heat it up in the winter. The facade will consist of panels that use Shape Memory Alloy (SMA) wire. At a certain temperature the panels will open and fresh air will cool down the building. In the winter the panels stay closed and the solar chimney + the greenhouse effect will heat the building up. On top of the solar chimneys there are turbines that produce clean energy.
The main advantage of a double-skin facade is the greater control it provides over the thermal/fluid exchange between the perimeter zone and the outside environment.
In the summer, the cavity between the inner and outer skin could be vented out of the building through the automatic response to rising temperatures – mitigating solar gain and decreasing the cooling load of the building. In the winter, a double-skin facade can act as a passive solar heater by using the panels to seal the cavity and using the absorbed radiation to minimize the facade heat loss.
The Solar Chimney uses solar heat to reinforce natural air convection. The chimney gets hot during the day, the air inside heats, expands, and rises, in turn pulling interior air up and out. The hotter the day, the hotter the chimney and the faster the air movement will be.
By integrating thermal storage mass behind the glazing the chimney will store daytime heat and continue to exhaust air after the sun has set, thus acting as a night ventilator.
In the winter, the solar chimney is closed. The air movement is reversed: fresh air will be sucked into the chimney and warm up the hallway. Used air will be naturally pushed out the facade through the ventilation units.