2024 - Sunbrella

Rain chains are drainage equipment commonly used in East Asia dating back to 16th century, to protect houses from rainwater erosion. We are inspired by the traditional equipment, with deep cultural heritage and artistic value, abstracting its umbrella-like form, as well as utilizing the principle of water refraction to introduce light into the gaps of the buildings.

In the south coast of China, there is a huge zone in subtropical monsoon climate, where heavy rainfall and strong sunshine appear alternately during summer. Besides those modern skyscrapers there, an enormous number of people are living inside communities called “Urban village”. As the expanding of modern cities，the villagers rebuild their houses higher to gain more space for newcomers to rent，earning more profits. As a result，almost all the gaps between houses are around 0.5 to 2 metres left.

We aim to guide more sunlight into the deep alley in a very cheap and simple way. A city needs these affordable places to contain newcomers pursuing their own dreams. Through our little change，we hope sunlight will no longer be charged through higher rent fare of the top floor therefore “sunlight fairness” can be promoted.

Instead of using a solar electricity exchange panel as most ideas, we want to use the direct light itself. Generally, lenses are placed in vertical groups. Sunlight will be diffused by the concave lenses, then converged by the convex lenses and repeated several times in order to achieve the amplification of the sunlight in the overall effect, introducing the light into the narrow gaps between the buildings, thus illuminating the ground and the side walls.

The assemble of the product is as simple as the industrial umbrellas made in factories. The different order of film fabric and the shaft & ribs, decides whether the umbrella functions as concave or convex lens for the purpose of refracting light. Also, rods are used to reinforce the edges of the film, making it less likely to be overturned by the weight of water.

People can control the type, the number of umbrellas and the amount of water inside to regulate the refraction and diffusion of sunlight. Of course, you can zip the umbrella or just let the water inside evaporate.

Using the Light Tools optical simulation method and HDR image technique, a comparative study was carried out to investigate the change in illuminance before and after the placement of the device. The results are shown in the figure: the overall illuminance of the side wall has increased and shifted downwards; the ground illumination upgrades to some extent.

Our umbrella device has new design requirements from ordinary umbrellas only in the strength and position of the membrane, as well as at the cap and handle, so the cost is estimated at an average of only US$2/each based on the price of accessories in the Guangzhou area. This also makes the promotion of this device possible. Perhaps in the future, it can go into areas such as Mumbai, Rio de Janeiro, and some cities in Somalia, which also have a large number of urban villages, to bring mild sunshine during the day to people surviving in darkness.