A joint project by America’s SERA Architects and Cutler Anderson Architects in association has earned the nation’s highest accolade for sustainability in the built environment.

The architects’ renovation of The Edith Green – Wendell Wyatt Federal Building (EGWW) in Portland, Oregon received the 2016 Top Ten Plus award from the American Institute of Architects, ahead of 10 other exemplar sustainable projects listed on the AIA’s annual ‘Top Ten’ list.

The EGWW was a Top Ten award winner back in 2014 but has since improved its ecological footprint through a process of post occupancy studies and refinement of its technologies and performance. The AIA’s Committee on the Environment (COTE), who oversee the awards, felt these improvements and commitment to ongoing refinement warranted the award upgrade.

IT'S GETTING BETTER AND BETTER

Then and now: The Edith Green – Wendell Wyatt Federal Building by SOM and the SERA renovation. Image: Nic Lehoux

Until 2013, the 47610sqm EGWW could only have been considered an energy hog, using around 1.7kwh of energy per sqm. But by 2015, after an extensive green retrofit by SERA and CAA in association, and a post-occupancy tweaking of its technologies, the building is now using less than half that figure and also 60 per cent less water than a typical building.

Central to the building’s new performance was the architect’s biggest undertaking, the replacement of the former pre-cast concrete cladding with a high-performance skin of aluminium reflecting panels and shading elements that were modelled to respond year-round variations of the sun.

On the southwest and southeast elevations, horizontal light shelves reflect light and provide shade, while west-facing vertical ‘reeds’ provide relief from the low-angle sun – all without obstructing views.

The building’s precast concrete cladding was replaced with a relatively light glass and aluminium system which lightened the structure and allowed the building to meet today’s more stringent earthquake code without requiring a major structural upgrade. Image: SERA

Key to the building’s energy efficient design was transforming the existing, un-insulated facade to a high-performance curtain wall with elevation-specific shading devices. Image: SERA

The replacement of the pre-cast concrete cladding with a high-performance skin not only made the building more energy efficient, but also allowed for a radiant heating and cooling system that freed up approximately 2,900sqm of extra net rentable space.

Another key to the building’s performance is that radiant heating and cooling system which is said to provide better for indoor air quality than conventional systems and be incredibly efficient – it’s estimated to save 10 per cent to 15 per cent of total building energy use when compared to a variable air volume mechanical system. One of the challenges of a radiant tempering system however is the lack of air movement which isn’t necessarily well received by tenants who are accustomed to noisily blown cool or warm air (as in traditional systems). To address this, the team educated their tenants on what to expect in their new environment and adjusted the range of temperature allowed to improve the balance between energy savings and occupant comfort.

The radiant panel ceiling system was also designed as as a kit of parts, reusable in future tenant improvements and designed to with disconnects that allow for the building mechanical zones to be reconfigured.

The building’s water cycle was also dramatically improved by a dual strategy of incorporating water-conserving plumbing fixtures together with a 600,000 litre tank for collecting rainwater. Created by repurposing an underground rifle range, the tank allows rainwater to be stored and used for toilet flushing, irrigation and mechanical cooling tower makeup water. It is collected from runoff from the 180 kW solar array atop the building which is channelled directly to the storage tank.

65% water savings has been achieved through a dual strategy of incorporating water conserving plumbing fixtures together with a rainwater collection system. Image: SERA

The building scored a Platinum LEED Rating and its energy performance is only expected to improve.

Photography by Nic Lehoux unless stated
Source: http://www.aiatopten.org/

Nathan Johnson

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