Studio Banana TV interviews Alday-Jover, authors of the river-side park on the Zaragoza Expo 08 and of the power station in the park.
Two buildings, SET and DHC, are inserted in the northern vertex of the Ranillas meander to hold energy generation and transformation-related facilities with extremely strict technical planning requirements. They form a considerable part of the frontage of the Metropolitan Waterpark, and they are also the first buildings that visitors encounter along a strategic entrance to the city. Power station buildings (DHC) are usually located on the outskirts of cities or in industrial settings or, in environments like Barcelona Forum 2004, they adopt a concealment strategy. In this case, however, we have chosen not to hide the facility: it cannot be placed below ground level on account of the flood-prone site, while at the same time, we manifest our preference for visibility and its impregnation with urbanity. We adopt two strategies: discipline within the overall volumetric order, and comprehensibility by means of potential public access and an outward expression of its purpose.
The purpose of this facility is centralised optimisation of heat and cold production using riverwater for cooling, and electricity cogeneration. There is a 20% reduction in energy consumption, the equivalent of 20,000 Tm lower greenhouse gas emission than conventional systems.
It consists of a large half-buried water tank (11,000 m3) and a building alongside for machinery. The pumps and heat exchangers are in the second basement; the transformers are on the ground floor, the engine and chillers are on the first floor and finally the monitoring equipment and boilers (five units of up to 60 tonnes each), are on the second floor.
The building is in face concrete stained dark grey inside and outside, with a 25 cm thick bearer skin structure. The outer finish is resolved using a powerful fretted texture that leaves the mark of the formwork, uneven and imperfect, in the background. This texture produces an apparently random combination of four fretted sheets with different widths and depths. The black colour nuances the contrasts of light and shadow, and makes the final texture more complex and changing. The lightweight, deconstructable roof above the boiler room is resolved with corrugated polycarbonate sheeting. A strip of RGB LEDs is set beneath each corrugation, controlled individually by a lighting control system which allows images to be generated. This large (20 x 20 m) projection screen is completed with another 4 m high by 30 m long screen at ground level with the same features.
The initial decision to make this power station visible also involved a desire for non-literal transparency of its contents and operation. It will therefore be a visitable space, for the purpose of which specific infrastructure for high-level routes has been designed, using colour criteria to highlight the types of energy, in contrast with the black colour of the machinery halls. The complex operation of the DHC, with its three types of generation (cold, heat and electricity), and the variation on the proportions between all three in the course of the day and the seasons, is explained by changes in the digital images projected outwards onto the large polycarbonate screen on the avenue frontage. The central management computer at this power station reports to the software about the output in course, which is converted into video signals. The original concrete building becomes transparent by digital, not material procedures. Its video contents are part of Eulàlia Valldosera’s EXPO artwork program. At night, the black building disappears and the images of this work of art become independent, floating amongst the trees in the Waterpark.
