Power Plant and Infrastucture Buildings

The project for the Water Park – designed for the city of Zaragoza, Spain, in the context of the 2008 International Exhibition – not only had to respond to significant territorial and landscape challenges, its broader structures also had to accommodate the necessary transition between the complex urban systems of the adjacent, densely populated neighborhood of Actur and the natural features of the Ranillas meander. In order to achieve this ambitious goal, the project for the Water Park outlined a gradual progression from the city to the river that begins at Avenida de José Atarés. Before the intervention, this street marked a clear boundary between the artificial and natural spheres. The dividing line of the former Avenida Atarés, renamed Boulevard de Ranillas, comes to be understood as a wide urban strip that forms a permeable junction. A threshold on a monumental scale to enter the Water Park from the city, it is comprised of three elements: a structure of trees that anticipates the silver forest of the Water Park; a 25-meter-wide canal that is crossed by floating bridges; and a geometric urban area connected to the neighborhood, which, nonetheless, breaks away from the line of the road to incorporate buildings – such as the Power Plant and Video Art Center – with façades that face both the park and the city.

This new urban planning framework contains, from north to south, the infrastructure buildings for the park and the meander, the police station, the supermarket and the offices for the International Exhibition, as well as the United Nations Water Secretariat. Located within this new built threshold is a sequence of three buildings that provide services for the Water Park: The Power Plant and Video Art Center, the Transformer Substation (SET) and the Park Administration Building for the park’s management. These buildings are all dedicated to the generation and transformation of energy, or the catchment and management of water from the Ebro River, which supplies the park and guarantees its successful operation. The arrangement of this infrastructural triad forms most of the park’s façade, in addition to being one of the first built volumes at one of the most strategic entrances to the city.

The intense technical requirements for installations of this type would generally be associated with a peripheral site, removed from urban routes. Such infrastructures would be situated in more industrial environments, or strategies would be designed to hide them, limiting citizens’ visual and physical access to them. Instead, here they are not hidden but are given an urban quality, responding to a clear desire for visibility, having accepted that their presence is necessary and that the flood-prone nature of the site makes it impossible to hide them underground. As such, the three infrastructural facilities are organized as part of the overall layout of built volumes. At the same time, they are rendered easy to understand through the possibility of public access and the expression of their function on the exterior, in a display of non-literal transparency with regard to the function and content of each volume.

Power plant and video art center

The power plant building (district heating and cooling, DHC) is designed as a trigeneration plant that will provide cooling and heating to all the new buildings in the Ranillas Meander, in addition to cogenerating electricity that will eventually be fed back into the grid. These programmatic characteristics ultimately spell out a highly complex program with significant requirements in terms of safety and insulation. Its location between the Water Park and the neighborhood of Actur, very close to the river, defines its role as a public facility that is open to the city, without hidden back façades or service yards. The desire to make this infrastructure into a link between the workings of the park and the residents of the city is realized through two strategies: first, by generating a safe interpretive path for visitors; and, second, with the inclusion of a public video art program. The technical requirements for the power plant make construction using in situ concrete a necessity, for questions of safety, soundproofing and structural requirements.

The power plant consists of a large semi-underground water tank (11,000 m3) and an adjacent volume containing the engine room. The pumps are located in the sub-basement (-2), the electric transformers, motors and chillers are on the ground floor, and the control station and boilers (five units of up to 60 tons each) are located on the second floor. The building is made of exposed black-colored concrete both inside and outside, with a load-bearing envelope that is 30 cm thick. The exterior finish is given a noticeable corrugated texture, which draws attention away from the edges of the formwork and the imperfections. The black color adds nuance to the contrasts between light and shadow and adds complexity and variability to the final texture. The interior can be visited through public paths on a mezzanine level, defined by a color scheme that reflects the different kinds of energy, contrasting with the black of the engine room. In the lightweight roof of the boiler room – built with corrugated polycarbonate for safety reasons, due to the risk of explosion or gas leaks – a matrix of LED lights generates a sequence of images, generating a digital vision (as opposed to a literal view) of the room’s contents and operations. This large 20x20-meter video surface is complemented by another at ground level (4 meters high and 30 meters long) with the same characteristics. The Power Plant sends data to the video software detailing the type of energy being produced and its proportions throughout the day and the different seasons, controlling the video art images in an installation created by Eulalia Valldosera. At night, when the installations are closed to the public, the black building disappears and the images of the artwork on the outdoor polycarbonate panels become detached, floating among the trees of the Water Park. New videos will be added to the collection to be screened at festivals and events. Between the video art pieces, the media façade provides ongoing information about the production of energy and the facility’s performance, providing public accountability. The original concrete building thus becomes partially transparent, in a sort of experimental piece that uses digital processes (as opposed to material ones) to express and communicate the production taking place inside.