Phoenix, Arizona, USA (2015)
This project proposes that the most critical aspect of the question of place making in Phoenix is not a matter of where, but of when. By the year 2065, average daily temperatures in the Valley will have risen over ten degrees by conservative estimates. Urban island effect will continue to raise ambient temperatures after dark to match those of current summer afternoons. What will it mean to make a habitable space in Phoenix of near-tomorrow? How might architects address effects of climate such as frequent dust storms? What about the need for shade and cooling where the city's urban mass absorbs radiated heat during the day and releases it to the environment at night, inhibiting natural cooling? Geothermal cooling technology exists in an efficient form, but commonly at small scales. This proposal scales up this technology to encompass the entire site - a geothermal cycle the size of two urban city blocks. This capacity offers the potential to affect the microclimate of the immediate site, as well as generating a stratified cooling effect within the immediately surrounding areas. In response to the identified challenges, the proposal utilizes the following:
1. BRING PEOPLE TO THE SITE - the proposal includes incorporating a new light rail stop. This platform is below grade and corresponds with the Central Avenue underpass. Combining several downtown stations to this central location serves to aggregate pedestrian gathering.
2. PROVIDE GATHERING SPACES - the site is developed with green spaces, sheltering earth berms and park areas, and two public monuments. The monuments make use of 20,000 cubic feet of shattered asphalt reclaimed from the present parking surfaces. A dense bundle of geothermal conduits cools one monument while the other is left exposed to overheat.
3. SHADE THE SITE - a forest of vertical geothermal cooling columns, up to 235 ft, and a roof assembly with a dense array of suspended rods (the cilia) shades the public gathering spaces. Desert plantings offer additional shading at ground level.
4. PROVIDE GEOTHERMAL COOLING - 672 closed-loop circulation, fluid-filled columns act as a thermal flywheel, harvesting ambient heat from the air and surrounding building mass and transferring it to the ground below.
5. MITIGATE HEAT ISLAND - remove asphalt and concrete mass from the ground and reuse the broken up components into stacked monument forms. The stacked (repositioned) mass removes the heat sink from the public gathering areas.
The site, located just south of Phoenix's urban core, serves as a gateway from the historic Warehouse District and beyond to the residential areas extending to the south. The cooling properties of the geothermal columns draw heat from the body and surrounding air. The temperature differential between the hottest point (highest in the air) and the coolest (at ground surface) produces convection current and generates a heat-lensing (mirage) phenomena over the entire site. During the cooler evenings, filtered lighting incorporated in the canopy high overhead provides a soft moonlit quality across the public gathering areas to promote nighttime occupation.
Client: AIA Phoenix Metro
Status: Open competition complete – First Place Awarded - 2015
Architect: Matthew Trzebiatowski
Project Team: Alexander Ford, Samuel Martin, Anja Trtic