August 15, 2023

Looking back at ACAW 2022

A year ago we participated in the Architectural Ceramic Assemblies Workshop (ACAW) and this summarizes our work as a presenting team.


The Terracotta City

Terracotta is one of New York City’s most robust, historic materials. Ribboned around the facades of buildings dating back to the late 1800s, the application of terracotta in New York is both decorative and functional. The sturdy, fire resistant material wraps exteriors in colors ranging from subdued cream to rich, earth-tone reds. Across NYC, delicate terracotta cladding details reveal floral motifs, flattened arches, column orders, and Art Deco mosaics. Today, the application of terracotta holds a similar sentiment to its historic past, but functions in a way beyond aesthetic value. At BKSK, terracotta is one of our firm’s most-used sustainable resources, applied for its visual diversity and as a lightweight, durable resource.

Image © NewYorkitecture

Charlotte of the Upper West Side © Christopher Payne | ESTO

ACAW’s Ask: Limitless Architecture

This past Summer, the BKSK team was invited to participate in the ACAW 2022 workshop. ACAW – the Architectural Ceramic Assemblies Workshop – is a hands-on research initiative for architects and façade engineers to explore the creative, productive, and aesthetic use of terracotta. Organized by Boston Valley Manufacturers, the Carnegie Melon School of Architecture, and the University at Buffalo School of Architecture and Planning the workshop invites and encourages architects to explore the vast possibilities of terracotta as a performance material. As an exercise of exploration, architects can envision their terracotta project without impact of client interest or budget. Purely to assess performance, the ACAW workshop offers the opportunity to produce and present an individualistic terracotta façade design to test as a sustainable practice in architecture.

The Power of Terracotta

In preparation for the ACAW workshop, BKSK proposed the use of architectural terracotta in to focus sunlight on a zone of high efficiency photovoltaic (PV) panels. Terracotta in baguette shapes layered into a screen would be fixed to a building to reflect sunlight toward the façade. Building Integrated Photovoltaics (BIPV) is gaining widespread acceptance as an energy harvesting surface cladding material. It represents the cutting edge of building technology.

Our goal was to use the architectural terracotta as a brise solei – a feature that would reduce heat gain within a building through sunlight deflection. Because we wanted to capture the reflected thermal energy, our terracotta application had to be met with a performance goal. Through the application of a specifically made glaze, the terracotta would reflect the sun’s rays onto the BIPV panel optimally, requiring fewer panels to achieve a desired energy output.

Like solar panels, photovoltaic panels absorb sunlight and convert the energy into electricity. We envisioned our terracotta application on a residential, south-facade building in New York, 29 degrees off north-south, per the Manhattan grid. We determined our brise solei would be applied to the building’s façade 30 feet off the existing façade, below a spandrel and above a zone of window glass. Once situated, we performed a sun analysis to ensure our terracotta paneling system would perform thermal capture without being compromised by shadows of the needed materials. The possible orientation of the terracotta as a façade screen varied. The materials could lay horizontally, vertically, or even be twisted. . Favoring the location of the terracotta in relation to the building’s spandrels—the materials which separate the stories of buildings—properly shaded the building interior while also harvesting maximum thermal energy.


When in Buffalo

When our BKSK team arrived at the University at Buffalo School of Architecture and Planning to present our design for the ACAW workshop, we were able to physically assemble and test our design in real time. Thanks to our partners at Onyx Solar and Thornton Tomasetti we received solar panels and the necessary tools to formally document the terracotta reflection and associated wattage reading. Our team conducted a reading on a cloudy day at New York orientation. The first test was with the terracotta brise soleil covered by a matte black sheet to determine the power output of the panels by themselves.  The second was with the terracotta panels uncovered to determine the total power output of the assembly and the third was with the BIPV panels shaded from the sun to determine the power output with only the reflection of the brise soleil onto the BIPV. The tests indicated an increase of 40-60% in the power output of the panels with the glazed terracotta.

Greater Importance

The results of our experimentation presented virtually and to the other teams assembled at ACAW was received with support and praise. We will continue to look for applications of our assembly in future projects.

You can watch our presentation online.