Architects such as Le Corbusier or Alvar Aalto thought about it a few decades ago. With the concept of "Mur Neutralisant", where a fluid (in Le Corbusier's designs, air) passes through two glass panels along a building's facade, thermal regulation comes naturally. Cool air is used in summer to prevent external heat to diffuse inside the building, and warm air in winter provides protection against external cold.
More recently, vegetal facades, also referred to as Green Walls, have gathered interest in urban environment, where they contribute to reducing the overall temperature of the buildings. Unlike concrete, asphalt or other inert surfaces, plants' temperature seldom rises more than 4 or 5°C over ambient temperature. Green Walls remain cool in summer, and are good insulators in winter.
Phytoplankton-loaded photobioreactors placed on buildings' facade and roof combine the advantage of both concepts, while providing for the energy source needed for this building and its surroundings. In this case, water, well known and widely used for its heat transfer properties, replaces air as the cooling fluid and circulates inside the photobioreactor, whose material has been adequately chosen for resistance, thermal and light specter management properties. In the meantime, the phytoplankton inside provides the same water clarification functions as a Green Wall, while also absorbing considerably more CO₂.
The heat captured by the system is transformed into energy, either to be used by the building's facilities, or by the system itself. Should the need arise, heat transfer can also be reversed to evacuate excess heat. The whole device is used as a global thermal regulator.
Ennesys is currently working with industry experts to refine system and components design that will achieve the efficiency and reliability that are required for commercial use on currently projected Eco-buildings.