ETFE Membrane Facade Double Skin Solar Collector by Petr Franta

Bronze Architecture, Building and Structure Design · 2022

ETFE Membrane Facade Double Skin Solar Collector

by Petr Franta

A' Design Award 2022 Bronze Winner in Architecture, Building and Structure Design
Awarded April 15, 2022
CLIENT: Ctu
Estimated Number of Design Views: 16,365
Verification code E139D73D26 · Verify this award

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About ETFE Membrane Facade Double Skin Solar Collector

ETFE Membrane Facade is a double skin facade designed for a research and teaching building. The outer skin is formed by welded transparent cushions of ethylene tetrafluoroethylene, three metres wide and up to sixty-two metres long, kept under constant air pressure and installed diagonally on a secondary steel structure with aluminium clamps. The facade cavity acts as a solar collector, and warm air is drawn into the ventilation units, reducing energy use by up to 30 percent. The membrane is cleaned by rainwater and adds acoustic protection from street traffic.

Press Kit

Unique Properties: Applying Double Skin Facade with ETFE Ethylen Tetrafluor Ethylen transparent membrane assembly for energy saving up to 30 percent. Acting as solar collector with recuperation of hot air on the top floors in winter season.
Additional acoustic protection on busy traffic streetscape.
Aesthetics, added value as large span between structural members.
Self cleaning exterior of the facade ETFE membrane with additive chemical component rejecting dirt as automatic cleaning of the facade with rain water.
Dimensions & Packaging: Pneumatic ETFE membrane cushions are 3 m wide and up to 62 m long, installed diagonally and kept under constant air pressure 300 Pa.
Cushions are anchored on secondary structural steel system with aluminium extrusion clamps structurally designed for wind load.
Acoustical properties in combination with triple glazing system 47 dB adds 10 dB to 57 dB in composite calculation.
Area of ETFE membrane facade is divided in two parts 1294 m2 and 570 m2.
Height of facade 20 m. Length of facade is 68 and 30 m.
Tags: ETFE, Ethylen TetraFluor Ethylen membrane, Double skin pneumatic facade,
Production Technology: 3 m wide ETFE Ethylen Tetrafluor Ethylen cushions in south and west facade with seam in aluminium profiles on the secondary steel structure are welded cushions and kept under constant air pressure 300 Pa.
Weight is 1% of glass installation of outer skin.
Recuperation of hot air from facade as solar collector, energy saving up to 30%.
Self cleaning exterior ETFE membrane with additive chemical component rejecting dirt cleaning of the facade with rain water.
ETFE 50-years lifespan of the material.
Design Challenge: Turning of the corner of diagonally placed pneumatic cushion of ETFE membrane detail in double skin facade.
Special aluminium extrusion detail was developed (with live size models) especially for this project to allow the twisting diagonal clamp with 1000 mm radius, placed on secondary steel tubing. We had to comply with European standards DIN different for aluminium and steel. Large mock-ups, samples and models were part of the design process to make sure that the membrane does not wrinkle.
Project Duration: Project design started in 2008 in Prague with presentation to Technical university scientists committee.
Realized in years from 2015 to 2017 on Czech Technical University in Prague campus for Czech Institute of Informatics, Robotics and Cybernetics of the CTU in Prague.
Operation Flow: Applying double skin facade with ETFE membrane assembly for energy saving with recuperation of hot air on the top floors, saves 30 percent of an energy consumption.
From double facade acting as solar collector hot outside air is sucked into the ventilation HVAC units on each floor from two places - from south facade for the winter and transition period and from the north facade in the summer. (Solar collector - double facade between the glass facade and the outer facade of the ETFE facing south).
Research: Design research was very complex with scientists, structure engineers in applications ETFE membrane around the world (London, Munich, New York) - design datas with manufacturers, designers.
We searched design and structural properties of Ethylen TetraFluor Ethylen transparent membrane facades for building types use, duration in life span, wind load on pneumatic cushions, aluminium clamps detailing, secondary steel structure detailing, transparency properties, weight, width versus span dimensions.
Inspiration: Presentation of 8 x 6 m sample of ETFE membrane cushion with pneumatic equipment for Allianz Arena in Munich by Herzog De Meuron Architects. It was used for football stadium, in England for museum in Leicester by Nicolas Grimshaw and other non transparent use. After researching those study cases around the world, later came to me the idea to use transparent double skin membrane for office type building for scientists, using transparent film membrane in double skin facade instead of glass.
Image Credits: Image #1 Photographer Jiří Ryzsavy
Image #2 Photographer Jiří Ryzsavy
Image #3 Photographer Jiří Ryzsavy
Image #4 Photographer Jiří Ryzsavy
Image #5 Photographer Jiří Ryzsavy
Patents: Design of pneumatic cushions fasade with ETFE Ethylen TetraFluor Ethylen trademark Taiyo Europe.