Page 105 - Zero Net Energy Case Study Buildings-Volume 1

SCIENCE & ENGINEERING BUILDING I
CASE STUDY NO. 5
of September 21, the day of the peak heat gain condition during the year, was selected for the design of the sunshade geometry relative to the solar incidence angles. The sunshade design prevents direct solar impact on the exterior southwest-facing walls.
Additional building envelope features that effectively lower the base EUI for the building are:
• Arelativelynarrowfloorplateinordertomaximizedaylightpenetrationandthepossibility of natural ventilation to spaces not requiring controlled air flow, thus reducing lighting and ventilation loads.
• Sun control provided for windows and glazing on the other elevations, reducing the cool- ing loads.
• Glazing system that is highly-transmissive of visible daylight (70%), low U-value (0.29, a low heat conduction value) and a low shading coefficient (0.44, a low fraction of solar heat gain and half that of regular double-glazing). No reflective or tinted glazing is used in order to maximize daylight collection for the reduction of lighting loads.
• Massive exterior walls to absorb heat gain during the day and shed the heat in the cool of the Valley night.
• High roof insulation levels (R-34) under a white-colored “cool roof” thermoplastic mem- brane, primarily to reduce cooling loads.
PHOTO: EHDD
Zero Net Energy Case Study Buildings: Volume 1
PHOTO: RICHARD CUMMINGS 89