World-beating eco design

Photos: VArquitectos

08/03/2016

6 | passivehouseplus.co.uk | Issue 28

INTERNATIONAL

A SELECTION OF PASSIVE & ECO BUILDS FROM AROUND THE WORLD

BOLUETA BUILDING, BILBAO, SPAIN

At 28 storeys tall and rising to a height

of 88 metres, the Bolueta building in the Spanish city of Bilbao is now the tallest building in the world certified to the passive house standard. Developed by the Basque government’s own property development firm Visesa, it will soon be accompanied by a second 21-storey passive block, with the two buildings containing 361 social housing units.

But the project had a rocky start. Back in 2012, architects VArquitectos won a competition to design the project. It was intended to be energy efficient from the get-go — but not necessarily passive house standard — and to draw heat from the local district heating network. But when the network supplier went bust, Visesa decided it needed an even more efficient building.

VArquitectos and energy consultant Energiehaus started to examine the possibility of adopting the passive house standard, and found that the optimum geometry, low surface-to-volume ratio and the warm local climate all made it ideally suited. So, the team set about beefing up the energy efficiency spec.

The finished building is constructed from steel-and-masonry, with mineral wool

insulation to both the outside (10cm) and inside (5cm). The designers swapped out the double glazing for triple glazing when re-designing the project. and introduced heat recovery ventilation. All units in the building were made individually airtight and achieved an air test result of between 0.28 and 0.35 air changes per hour — about half the maximum 0.6 allowed under the passive house standard, an exceptional achievement.

The shining external finish, meanwhile, is a ventilated aluminium cladding. “The black colour symbolises the industrial past of the city,” says architect Germán Velázquez of the practice VArquitectos. “It is a tribute to the two-and-a-half century old heavily coal-based industry.” The second tower, meanwhile will be grey in colour to allude to the steel industry once prominent in the city.

The architects estimate that all the improvements over the initial project increased the capital cost of the project by about 3%, while cutting energy bills in half and improving comfort and air quality.

“Now that Bolueta is complete, there are no excuses anymore,” says Velázquez. “It is possible to realise such a project in Bolueta, and it is just as possible to realise one almost anywhere.”

ph+ | international | 7

8 | passivehouseplus.co.uk | Issue 28

Photos: Jordan Parnass Digital Architecture

STAR GARMENT INNOVATION CENTRE, SRI LANKA

This new clothing factory in Colombo,

Sri Lanka is the first passive house project in South Asia and, located just above the equator, it posed vastly different climatic challenges than your average European passive house designer is used to — think tropical monsoons, year-round heat, and extremely high relative humidity.

Developed by the Star Garment Group — a global apparel sourcing, design and manufacturing firm — the building serves as the company’s new product development centre, a hub for design, material sourcing, pattern making and sowing. And according to its designers, Jordan Parnass Digital Architecture, it “sets a new high bar for sustainability, energy efficiency and worker comfort” in the garment industry.

Rather than build entirely from scratch, the project team opted to retrofit an old factory on the site, stripping it back down to the original steel frame and concrete slab,

thus reusing elements that would otherwise have significantly increased a new building’s carbon footprint.

The original steel frame was filled in with a new thermal envelope comprised of high performance curtain walling, externallyinsulated masonry and insulated metal roofing panels — all of it made airtight. Given its tropical location the building has zero heating load, but instead requires mechanical cooling and dehumidification. There are also strategically designed overhangs and external shading screens to help keep the sun out.

The project was recently certified to the Enerphit standard, the Passive House Institute’s benchmark for retrofit projects. “By promoting the project’s goals and inspiring the local building industry, JPDA has sought to establish a clear path to both reducing global carbon emissions and putting an end to worker ‘sweatshop’ conditions,” say the architects.

ph+ | international | 9

Low u-value insulation at roof, exterior walls, and underside of cantilevered slab

Reduce solar heat gain with roof eves and exterior shading device

Reflect solar heat

Mechanical ventilation with more than 75% heat recovery

PV panel for solar electricity and dehumidification

Thermal bridge free

Underside of cantilevered slab is insulated for continuous thermal enclosure.

Exterior columns are covered with insulation to reduce heat transfer into interior space.

Airtight thermal envelope

Insulation is extended few inches beyond the footing for thermal enclosure.

Low u-value insulation PV panels Exterior shading device

10 | passivehouseplus.co.uk | Issue 28