Introba (formerly Integral Group) provided engineering, analysis, and daylighting services to determine a baseline and recommend a high-performance retrofit of its existing office building. Introba transformed a dark 1970s tilt-up building into an open and lively office.
Working with Xilinx, the team proposed a design to replace the glazing with high-efficiency glass and install daylighting-sensitive external shades. The office is now saturated with daylight anchored by large light wells puncturing the floorplate. A concept-level analysis was provided to illustrate the transformative effect of daylight courts punched through the existing building. Spectrally-selective high-performance glass provides 70% light transmission with just a 0.30 solar heat gain coefficient and is the most optically clear Low-E glass available. BIPV (Building Integrated Photovoltaic) installed as horizontal overhangs provide additional shading. Integrating lighting and daylighting design, Introba achieved an extremely low-lighting energy use.
The concrete walls are insulated with external rigid insulation to lock in thermal mass. Daylight monitors that punch through the second floor will provide daylight into the core of the open office plan. Operable windows in those monitors will allow for a nightly flush of the building to pre-cool the mass in the warm months.
The HVAC systems were designed to reduce or eliminate the reheat energy and increase HVAC system efficiency by dividing the building into five thermodynamic areas characterized by exposure – core, north, east, south, and west. Space conditioning requirements are expected to be very similar from space to space within a thermodynamic area; thus, all spaces within one thermodynamic zone can be met with the same air conditions, and no additional conditioning is required at the zone level.
By comparison, a conventional building is typically cut into two zones, each containing multiple thermodynamic areas with different heat gain profiles. Using this zoning method, one package unit must condition the supply air to meet the most demanding of its thermodynamic areas. Reheat coils at the zone level provide additional conditioning to compensate for the overcooling of rooms with lower cooling demand than the most demanding area.
Zero Net Energy