Exhale is a chandelier that contains living algae. Designed by London-based design engineer Julian Melchiorri, it holds 70 hand-made glass-like leaf modules filled with microalgae. Under daylight and LED light the algae photosynthesise: they take in carbon dioxide and give off oxygen, so the light fitting doubles as a small biological air filter. It was shown at the Victoria and Albert Museum during the London Design Festival in September 2017, won that year's Emerging Talent Medal, and later entered the V&A's permanent collection.
It is a striking object and a clever piece of design. It is also a prototype, and it helps to separate what it shows from what it can realistically do. Below is how it works, who made it, where the idea went next, and what the honest limits are.
How the algae chandelier works
Each leaf of the chandelier is a sealed, transparent module containing green microalgae suspended in liquid. Microalgae are tiny single-celled organisms that carry out photosynthesis just like plants, and they do it very efficiently because every cell is exposed to light and nutrients.
According to descriptions of the piece, the algae are activated by a mix of natural daylight and LED light, and fed with nutrients through a slow drip. As they grow, they absorb carbon dioxide from the surrounding air and release oxygen. The leaves come in three sizes and are held on a hand-made metal frame, fabricated with the London metalwork studio Millimetre.
The design is modular. Leaf modules can be produced in different shapes and arranged in different configurations, which is why Melchiorri described the chandelier as a demonstration of a system rather than a one-off sculpture.
Seen from below, the chandelier's ribbed leaves overlap like the scales of a pine cone. The ribs moulded into each module give the leaves their plant-like veins and stiffen the thin shells.
This closer view shows how light passes through the algae, giving each leaf a yellow-green glow. The colour comes from chlorophyll, the same pigment that makes plant leaves green.
Who is Julian Melchiorri?
Melchiorri completed two master's degrees in Innovation Design Engineering in 2014, a joint programme of Imperial College London and the Royal College of Art. His work follows what he calls a biomimicry approach: copying the way nature solves problems and putting it into everyday objects.
His first well-known project, the Silk Leaf (2014), was billed as a synthetic biological leaf. It suspended chloroplasts, the parts of plant cells that carry out photosynthesis, in a material made from silk protein, which helped them stay stable. The idea was that a man-made leaf could absorb carbon dioxide and water and produce oxygen in places where plants struggle, from buildings to spacecraft. It attracted wide media interest but remained a concept rather than a product.
Melchiorri went on to become the V&A's first Engineer in Residence, received an Arts Foundation fellowship for materials innovation in 2017, and was reportedly named in Forbes's 30 Under 30 Europe list for social entrepreneurs in 2017. He founded the company Arborea to turn his photosynthesis research into commercial technology.
Viewed straight up from underneath, the leaves form a radial, flower-like pattern. The symmetry is intentional: Melchiorri describes his approach as letting function shape form, much as it does in natural structures.
From museum piece to the BioSolar Leaf
Exhale was always meant to point towards something bigger. In April 2019 Imperial College London announced it would work with Arborea on what it called the world's first BioSolar Leaf: large panels that look like solar panels but grow microalgae, diatoms and phytoplankton instead of generating electricity.
Arborea said the system could remove carbon dioxide and produce oxygen at a rate equal to about a hundred trees, measured against the ground area of a single tree. The biomass grown in the panels would also be harvested for nutritious food ingredients for plant-based products. Imperial agreed to fund an outdoor pilot on its White City Campus in west London, and Hammersmith and Fulham Council said it planned to be the first to install the panels in the borough.
Some reports at the time claimed the panels would also generate electricity for cities. Imperial's announcement did not say that, and the name refers to sunlight-driven biology rather than power generation. The “hundred trees” figure is the company's own claim and had not been independently tested when it was announced.
Hung in front of tall windows, the chandelier catches daylight from outside as well as its own LEDs. Natural light matters, because photosynthesis depends on how much light reaches the algae.
Can an algae chandelier really clean a room?
This is the question most readers want answered, and the honest answer is: not by much, on its own. A single light fitting holds only a small volume of algae compared with the volume of air in a room. Studies of houseplants have found a similar problem. A well-known 2019 review in the Journal of Exposure Science & Environmental Epidemiology concluded that you would need an impractically large number of plants to match the air cleaning that ordinary ventilation provides.
That does not make the project pointless. Exhale shows, at a human scale, that photosynthesis can be built into designed objects, and it makes a biological process visible in a way that a laboratory tank does not. The larger-scale BioSolar Leaf is where any meaningful carbon removal would have to happen, and its value depends on measured results in real conditions.
If indoor air quality is your concern, the proven steps are simpler: open windows or use mechanical ventilation, reduce indoor sources of pollution such as gas cooking and smoke, and consider a certified air purifier with a HEPA filter for particles. Anyone with asthma or other breathing problems should talk to a doctor about what is right for them.
A close-up of the leaf cluster highlights the craftsmanship: each module was hand-made and hung individually. Building a living object means planning for maintenance, from topping up nutrients to keeping the algae healthy.
Common myths about “breathing” design
- Myth: algae objects replace trees. Trees also store carbon for decades in wood and soil, cool streets with shade and support wildlife. Algae panels may complement them, not replace them.
- Myth: more oxygen is the goal. Indoor air almost never runs short of oxygen. The real problem is usually carbon dioxide build-up, particles and chemical pollutants, which ventilation handles best.
- Myth: a prototype is a product. Exhale was a museum installation. As far as public information shows, it was not sold as a household appliance.
Projects like this sit in a wider family of algae experiments, from packaging to building facades. For another example, see our look at Ari Jonsson's algae bottle.
The top tier of leaves shows the thin metal stems that connect each module to the frame. Seen together, they resemble a cluster of seed pods, a fitting image for a design that is still at the growing stage.
Sources: V&A: Exhale bionic chandelier (London Design Festival 2017); MaterialDistrict: Exhale Bionic Chandelier; The Arts Foundation: Julian Melchiorri; Imperial College London, 29 April 2019: World's first BioSolar Leaf; Design Milk: LDF17 at the V&A. Photographs of Exhale by Julian Melchiorri/Arborea.
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