24 hours of health, almost zero energy consumption | From the shooter to the city


Facade of the Health Center in Lodosa (Navarra) designed by Varquitectos.
Facade of the Health Center in Lodosa (Navarra) designed by Varquitectos.Varquitectos

This is an exercise in self-correction, learning, and growth. It was 2008 when the study VArquitectos won a competition to build a Health Center in Lodosa, Navarra. Eight years later, when it was finally possible to start construction, it was necessary to adapt that winning project to the new regulations. The architects also chose to prepare it for the future and alter in it everything that, in those years, they had learned about zero energy consumption (Passivhaus). They had studied it in European regulations, in Spain it was not yet regulated, although since 2015 there was a decree on energy self-consumption that complicated its implementation and prohibited the sale of excess energy. Let’s say that, until it was questioned in 2018, electricity monopolies were more protected by Spanish laws than consumers. Thus, updating this project required (or self-required) a radical change from the architects: bringing energy consumption close to zero without being able to change almost anything because the budget was closed, the interior distribution could hardly be altered and, while The Health Center was expanded, it should continue to function.

The architects concentrated on the openings, the facades and the roofs. And they decided to pay more attention to the microclimate of the city, which, bathed by the Ebro river, suffers from strong thermal fluctuations and has little to do with Northern Navarra.

Interior garden of the Health Center with almost zero energy consumption.
Interior garden of the Health Center with almost zero energy consumption.Varquitectos

The first change decision was spatial: a building in L would close the open lot. With half of the project finished, they moved the uses and concentrated on the other L, which closes the landscaped patio that solves views and natural lighting.

With a concrete structure, which favors hermeticism, the new building has low pre-slab slabs with 20 centimeters of insulation. The architects explain that they increased the insulation where it was cheapest (the roof and the slabs of the floors).

After triple glazing with thermal bridges, the façade is today a folded sheet of micro-perforated cortain steel that offers privacy, security, hides rainwater pipes and prevents overheating. Under this layer, 20 centimeters of double density mineral wool, perforated bricks with water-repellent exterior coating and gypsum plaster guarantee thermal control: the thermal inertia is in the facades and in the floors. Although the sheet metal unifies the facade, it is treated à la carte: with more or less ventilation depending on the area, to avoid overheating.

Detail of the corten steel enclosure.
Detail of the corten steel enclosure.Varquitectos

There is also stone wool in the sloped, ventilated expanded polystyrene roof that improves ventilation with a system similar to solar fireplaces.

The initial building was designed with large exterior openings, to take advantage of the light and the views towards the landscaped spaces, the architects corrected this opening due to the thermal losses it entailed. They also looked for sunlight in the south, setting back the building to avoid the shadows of the wall. Where privacy was solved by gardens, they eliminated the sheet that surrounds the property so that the sun could enter in the cold months. The vertical holes became horizontal to let in more light. In other words, the form was put at the service of one end: reducing energy consumption.

On the roof, the architects installed photovoltaic panels pending a reformulation of the 2015 decree on self-consumption. Even without its service, the cold energy power has been reduced by 60% and the heat power by 70% compared to the initial project. Thanks also, in part, to three high-efficiency enthalpy heat recovery units (85%). The building also offers the possibility of dehumidification in summer and humidification in winter.

“Without apparently changing too much, we have managed to change everything, going from a building with a heating demand of 118 kWh / (m2a) to another with a demand of 14 kWh / (m2a)”, concludes the architect Sara Velázquez. The funny thing about this case is that they were both designed by them. In a decade, Varquitectos have learned a lot about energy saving. And they show it rectifying.

Cost per square meter, according to the architects: 1,430 euros.


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