One of the top medical institutions in the Middle East, the King Faisal Specialist Hospital and Research Center in Riyadh, Saudi Arabia, is adding 176,515 square meters of medical space and 167,225 sq m of landscaped underground parking. A central challenge to the job is to keep the buildings cool in the hot desert climate.

Desert construction is no walk in the park. Riyadh's temperatures can range from -2° C in winter to 44° C in summer. Warm weather lasts from May 14 to September 27, with an average daily high temperature above 38° C. Within a city of seven million people, the campus is located near Riyadh's urban core.

In response to the arid desert climate, the existing campus architecture is made of rugged limestone with limited glazing that resists intense summer heat, glare and intermittent dust storms. The $240-million addition consists of four buildings, including the 300-bed, 84,000-sq-m King Abdullah Center for Cancer and Liver Diseases and the 40,000-sq-m King Faisal National Biotechnology Center. Also new to the campus are the 12,500-sq-m, six-story Royal Wing and the 19,600-sq-m, six-story EMS and Polyclinic Building. Construction began on the additions in spring 2011, with completion scheduled for midsummer 2013.

Natural light, open spaces, external views and green spaces are incorporated throughout patient and staff areas. The building envelopes are composed of high-performance light diffusers with integrated sun-control louvers. This design optimizes daylighting while minimizing heat gain. This system is pre-engineered for each façade and tailored to address sun orientation.

"Our design solution was rooted in a strong understanding of local architectural vernacular and resulted in a contemporary vocabulary while respecting traditional methods of coping with the environment," says Andre Aoun, project principal at Cannon Design, Boston.

During the project, it has been critical to find the most cost-effective way to cool the building's air. Here, open cooling towers provide energy efficiency and reduce the equipment footprint, designers say.

"We had to make this desert environment comfortable and safe for patients and health-care staff," says John Swift Jr., principal and mechanical engineer at Cannon Design. "We need to provide an increase in the cooling capacity of the central chilled-water plant by 10,000 tons."

The embodied energy of delivering reliable water to the new plant was assessed, and a life-cycle cost analysis determined the greenest and least expensive option: a chilled-water plant that uses 30 air-cooled chillers, each rated at 365 tons. The air-cooled, modular equipment was employed in lieu of a central chilled-water plant. As an added benefit, the condensation from the cooling process will be recycled for landscape irrigation.

The system includes an 18,000-sq-m powerhouse facility and 1,800 m of tunnels to house service utility systems. With convenient access to all campus buildings, underground parking provides space for 5,000 vehicles.

The distance between the North American offices and Riyadh impacted the frequency with which the team was able to visit the client and the site, making communication more challenging. However, multimedia platforms that use videoconferencing and WebEx for online meetings continues to reduce travel times significantly.