High Performing Buildings - Fall 2010 - (Page 47)

F C g u l F F R e e W a y o F F I C e B u I l d I n g T he Gulf Freeway Office Building in Houston is the fourth of four buildings designed for the same owner. The two-story, core and shell office building has 24,084 conditioned ft2 on 1.68 acres. It was completed in May 2010 and was 40% occupied as of July. Occupancy is expected to increase to 60% soon. tons because the designers did not yet understand the impact of having a vegetative roof. This was the impetus for the designers to create the evaluation methodology for the roofs. To date, the Cheyenne One system has only used 100 tons of capacity at most. B u I l d I n g at a g l a n C e name fC gulf freeway office Building location Houston owner fC gulf freeway Principal use office includes drive-through banking facility for future bank tenant employees/occupants Approx. 48 (potential for 120) gross square footage 26,703 including balconies Conditioned space 24,084 Total Cost $3,775,000 Cost Per square foot $141.36 substantial Completion/occupancy June 2010 occupancy 40% as of July 2010 Cooling Benefits Cheyenne III benefited from what the designers learned from Cheyenne One. It incorporates a 140 ton, air-cooled, rotary scroll chiller. This building has an area for specialty medical device manufacturing that requires strict temperature, air quality and humidity controls. The existing building systems easily handled these requirements. No system modifications were necessary. At Cheyenne One, monitors that have been in place since the building’s activation feed data into the building management system. Temperature sensors are located in the air above the roof, buried mid-depth in the soil mixture, and at the bottom of the soil mixture immediately above the drainage/ filter media. The air temperature in the summer is usually in the low- to mid-90s or higher. The mid-depth sensor typically reads temperatures in the mid80s, and the base sensor typically reads in the low 80s or upper 70s. Moisture content directly impacts these ranges. As a result, the HVAC systems only have to address a temperature differential of 10 to 15 degrees at the underside of the roof. Vegetative Roof Integral to the building is a 15,781 ft2 intensive vegetative roof that is a minimum of 10 in. deep. The roof retains 73% of all rainfall that strikes the surface and provides an R-value of 66. Additionally, it removes approximately 650 pounds of airborne particles annually and produces enough oxygen per day for 975 people. Based on their experience with vegetative roofs, the designers have developed a methodology to evaluate the evaporative cooling capacity of the roofs on a monthly basis along with solar radiation mitigation. The Gulf Freeway roof at its peak performance provides the equivalent of 65 tons of HVAC capacity offset because of the evaporative cooling, and 79 tons due to solar radiation mitigation. The decision to incorporate a vegetative roof, especially an intensive vegetative roof in all four buildings, has been affirmed by the performance. Intensive green roofs are typically deeper and designed to create more of a natural landscape than extensive green roofs, which are shallower with shorter plants. Cheyenne One (see Building on Experience, p 52) incorporated a multistage, air-cooled chiller of 250 Above This image of Cheyenne One’s vegetative roof was taken six days after Hurricane Ike hit Houston in 2008. Although a neighboring building lost part of its façade and roof, the 120 mph winds and 11 in. of rain did not damage Cheyenne One’s roof. Opposite The roof overhang and balcony on the eastern, western and southern faces of the Gulf Freeway Office Building prevent glare and heat gain. Stone and plaster are used in the building’s exterior design. fa l l 2 0 1 0 HigH Performing Buildings 47

Table of Contents for the Digital Edition of High Performing Buildings - Fall 2010

High Performing Buildings - Fall 2010
Table of Contents
IDeAs Z2 Design Facility
Lighting Design Alliance
Manassas Park Elementary School and Prekindergarten
FC Gulf Freeway Office Building
Capturing Condensate
National Australian Built Environment Rating System
Tyson Living Learning Center

High Performing Buildings - Fall 2010