Researchers test glass membrane roofs under real-life conditions in the rooftop greenhouse of the "Oberhausen Alte Markt Garden". (Source: Fraunhofer Umsicht)
Glass roofs and architectural elements made of glass are not only visual highlights, but also serve important functions. Best of all, they are translucent and therefore convey a fantastic sense of space while also allowing plants to grow in the greenhouse. But most heavy panes consume a lot of resources. In particular, the light-transmitting top glass in a greenhouse usually consists of several pieces of insulating glass.
Therefore, in the Light-Light-Roof project, researchers from Fraunhofer Umsicht in Germany are working together with Block Industry & Garden Manufacturing to study lightweight roofs made of fiberglass, or rather , research on a modular lightweight system. The system combines a glass membrane module system with an inner roof made of mobile, translucent and infrared reflective fabric.
This module system consists of an ETFE film covering (ETFE: ethylene-tetrafluoroethylene copolymer) and a single layer of safety glass . Today, ETFE's light transmittance is as high as 95%. These materials have favorable properties and researchers were able to overcome production-related obstacles, for example through bonding and welding.
The combination of glass and film promises weight savings of up to 75% while also improving functionality. This opens up many more possibilities in building construction beyond greenhouses: For example, architects can design thinner and lighter buildings, since the supporting structures need to bear significantly less load and snow accumulation. This makes Light-Light-Roof promising in other areas besides horticulture and the plant trade, such as functional building facades.
In the old market garden roof greenhouse in Oberhausen, Germany, researchers are testing the year-round operation of the glass membrane roof on a planned roof area of 160 square meters under real conditions and proving its suitability for practical use. If the tests are successful, the lightweight products from this research project will be used primarily in the booming urban farming market.
