Green: Smart and Innovative Facade Systems
Written by Judhajit Chakraborty, Assoc. AIA, LEED, AP, WSP Built Ecology
We all know how important façade design is and how much of a vital role it plays in building design. In my previous articles (Early 2013), I have mentioned about how an intelligent façade design along with an optimized HVAC system can lead to substantial energy savings. We also know the role of glazing in façade design especially in office and commercial buildings. Glazed façade systems, since the last two decades, have undergone a sea change in their designs mainly in their ability to adapt to the outside conditions and user requirements. In this article I will write about some of the newer innovations in façade systems:
1: SOLAR ACTIVE FACADE SYSTEMS: These systems use solar radiation to store and release heat thereby controlling space comfort.
A: GAP solution façade system
This consists of a stable honeycomb structure made of natural materials which lets the low winter sun to penetrate deep into the honeycomb and increase their temperature. This autonomous zone reduces the heat loss from the facade or the actual building mass to almost zero and it also reduces thermal bridging. During summer months, the solar radiation is reflected due to the honeycomb structure itself. These systems can improve the U-value of an external wall by 90% depending on the orientation.
B: Thermocollect systems
These are similar systems, the only difference being, instead of the honeycomb structure, they are panel systems which open and close based on solar radiation. They open up on winter days and summer nights and close down on summer days and winter nights to prevent heat loss when heating is needed and initiate heat loss when the space needs to be cooled down. These systems have control logic embedded within them for the panel movements based on the local weather and under any condition; they can give the best U-values.
C: GlassX Crystal Phase Change Materials (PCM)
This translucent triple insulating glazing unit provides an excellent U-Value – 0.084 Btu/hr.ft².°F for a glazing unit. A layer of salt crystals (PCM) stores heat from the sun and releases to the interior space as required. An outer prismatic glass allows for the solar radiation to pass through only during winter to take advantage of the low sun heat and protects the space from overheating during summer. The PCM (salt crystals) which is stored in a polycarbonate box, stores the solar radiation by melting. During night time and the following days this stored radiation is delivered to the interior space through recrystallization (conversion to solid state). The visible light transmission is 0-28% when the PCM is solid and 4-45% in liquid state.
2: ENERGY FACADE SYSTEMS: These systems have optimized HVAC systems or renewable energy systems integrated within them.
A: i-Module Façade
This is an innovative façade system that is being used at the Capricorn Institution in Dusseldorf, Germany. The i-module system is a specially designed decentralized unit for heating, cooling ventilation and heat exchange. The lower part of the system has the outdoor air and exhaust air dampers with a function box above for heat recovery. These units have an option to either be centrally controlled or manually controlled. This system was conceptualized by Gatermann + Schossig Architects and partnered by Schueco and TROX for its development and installation.