Scientists at the universities of Stuttgart and Freiburg have developed an amazing shading system for buildings that adjusts itself to the weather—just like pine cones.

The new design, called “Solar Gate,” works without electricity, using only natural materials and clever engineering.

Their findings were published in Nature Communications.

Buildings use a lot of energy to keep indoor temperatures comfortable. This means high energy bills and significant carbon emissions.

The Solar Gate offers a sustainable alternative by using a bioinspired design to control sunlight and heat. Unlike traditional systems that rely on electricity or complex machinery, this new system operates entirely on natural changes in weather.

The researchers took inspiration from pine cones, which open and close depending on the weather. This movement is due to a natural material in plants called cellulose, which expands when it absorbs moisture and contracts when it dries out.

Using 4D-printing, the team recreated this effect in the Solar Gate by layering custom-made cellulose fibers. These fibers form a smart structure that curls open in high humidity and flattens closed in dry conditions.

Professor Achim Menges from the University of Stuttgart explained, “Most systems for weather-responsive architecture need a lot of energy and technical devices. With the Solar Gate, the material itself does the work.”

The team used a standard 3D printer to create the cellulose-based components, making the system affordable and easy to produce. The result is a shading system that can adjust to daily and seasonal weather changes. During the winter, it opens to let sunlight in and warm the building. In the summer, it closes to block excess heat and keep the interior cool.

Professor Thomas Speck from the University of Freiburg added, “We’ve not only recreated the functionality of pine cones but also captured the beauty of natural movements in this system.”

The Solar Gate has already been installed on a research building in Freiburg, where it’s been tested for over a year. The system works perfectly on the building’s south-facing skylight, helping to regulate the indoor climate by responding to weather changes without using electricity.

This innovation shows how renewable materials like cellulose and accessible technologies like 3D printing can offer practical, eco-friendly solutions. By reducing the energy needed for heating, cooling, and ventilation, Solar Gate could help lower carbon emissions and pave the way for more sustainable architecture.

Source: University of Stuttgart.