ADVANCED FAÇADE SYSTEMS
SESSION 21
DATE // START TIME // ROOM NUMBER:
Thursday, September 30, 2010 – 9::00am – Altman B
ABSTRACT:
Panel will discuss the technical and energy efficient aspects of the Liquid Wall as an architecturally versatile, systems-integrated, high-performance, unitized building envelope of a type never seen before. Winner of the American Institute of Architects’ Open Call for Innovative Curtain Wall Design, the Liquid Wall is currently in full-scale prototype production.
MODERATOR:
Peter Arbour, Project Manager, RFR Consulting Engineers
SPEAKERS:
Robert Del Vento, Jr., Architectural Project Manager, Coreslab Structures
Mitsu Edwards, Structural Engineer, Project Director, RFR Consulting Engineers
Kelly Henry, Architectural Project Manager, Lafarge North America
Kevin D. Schaefer, Principal, CSArch
DESCRIPTION:
The Liquid Wall derives its name from the three aspects of its innovative design. The first is its fabrication method of concrete casting; the liquid state of poured concrete provides an architectural freedom unprecedented in glazed, unitized curtain wall design. The second is its inherent capacity for form-finding; the initial design, arising from a strict adherence to the structural criteria of a building’s envelope, results in undulating profiles and an aesthetic of “frozen flow.” The third and most important liquid aspect is the actual flow of liquids through the spandrel cassette, which captures solar energy transmitting it to systems for use as radiant heat, domestic hot water production, and dehumidification of ventilation systems.
Each Liquid Wall unit consists of two concrete frames cast in Ductal®, an ultra-high-performance concrete (20,000psi), and martensitic stainless steel tension bars. The panels are assembled using a cast-in, structural, thermal break technology of pultruded glass fiber. Vision panels are of clear triple glazing, maintaining an excellent u-value with a 70% glazed exterior wall.
The panel’s spandrel cassette is similar to an inserted shadowbox. It is a glazed assembly containing a system of tubes set against an energy-absorbing backpan. A non-freezing liquid mixture flows into the system from inside the building. The heated fluid is then recovered from the panels and transferred to one of several possible uses. This simple, passive harvesting of solar radiation energy significantly reduces a building’s fossil fuel energy consumption. The integration of the envelope with the MEP systems provides an economy of means and of construction without additional cost and without compromising the efficiency of the envelope installation process.
The use of ultra-high performance concrete reduces the required material by 90% relative to other precast concrete wall products. The post-fixing of reinforcing armature eliminates the need to extract steel rebar for concrete recycling. The Liquid Wall aims to be a 100% recyclable system, and is expressly designed to avoid the extensive use of typical high-carbon-footprint materials such as aluminium.
Panelists will also discuss the Liquid Wall Prototype, which is being constructed using the direct transfer of 3D computer modelling to CNC milling of pieces that are used to create state-of-the-art flexible molds. The fabrication of molds and of the panels is a repeatable process that can streamline the production of facades covering large surface areas of multiple designs that precisely address the needs of various orientations and solar exposures. All sunshading devices and decorative grillwork can be cast of-a-piece with the structural framing, allowing reduction of the costs and risks of on-site assembly procedures. In addition, the smooth, highly detailable finish of the cast concrete provides endless design possibilities for architects and façade designers, possibilities not seen since the use of cast iron and cast terra cotta, with an integral structure and environmental performance that exceeds the ever more stringent criteria of today’s building envelope.
The functions required by building envelopes remain the same throughout the process of technical innovation. All facades must insulate without thermal bridging; they must provide water and air seals and secondary drainage channels; they must resist the vertical spread of fire; they must be constructed efficiently at an industrial scale; and they must operate reliably without excessive maintenance costs or systemic failure. The Liquid Wall is a system that achieves all of this while tapping into our most universal and dependable source of free energy.
