Sunlight hall: green idea, real nature technology

Imagined What it could do

Leaves are tiny solar factories: using sunlight, they turn water and carbon dioxide from the air into sugar and oxygen. Imagine a hall whose leaf-covered walls did the same, taking carbon out of the air, making its own energy and breathing out fresh oxygen for the people inside.

Leaf cells of a moss under a microscope. The green specks are chloroplasts, where photosynthesis happens. Photo: Des_Callaghan, CC BY-SA 4.0, via Wikimedia Commons

Real world A building with algae in its walls

In 2013, the BIQ House in Hamburg, Germany, was built with a facade of glass panels filled with water and living microalgae. The algae grow in sunlight and absorb carbon dioxide. Some algae are harvested to make biogas, and the panels also capture heat from the sun and provide shade.

It is a pioneering experiment. Its designers reported that the facade could supply part of the building's heat, but the system is complex and expensive, and engineers had to fix problems such as clogged pipes.

Real world Plants versus solar panels

Plants are amazing, but they are not very efficient at turning sunlight into stored energy: most crops store only one or two percent of the sunlight that falls on them, while ordinary solar panels convert around a fifth into electricity. Scientists are studying "artificial photosynthesis", which tries to copy the way leaves split water using sunlight, to make clean fuels.

Art In this artwork

This illustration shows a grand hall wrapped in trees, with flowers and waterfalls. Here we imagine it running on sunlight like a leaf.

Look closer

Find the leafy canopy over the roof.
Where does water flow around the building?

Think about it

If a building could breathe like a plant, what would change about cities?
Why might scientists copy leaves even though solar panels are more efficient?
Would you want algae in the walls of your home?

Key words

Photosynthesis: How plants use sunlight to make food from water and carbon dioxide.
Algae: Simple plant-like living things that grow in water.
Bioreactor: A container where living things are grown to make something useful.