EFFECTIVENESS OF SOLAR SHADING FOR AN OFFICE BUILDING.

The impact of solar shading of windows on building energy consumption, energy costs and occupant comfort is examined for a typical office building. Measurements of the solar and thermal performance characteristics of three solar screens are reported. Using the DOE-2 computer program, annual building energy simulations were performed for seven climatic locations in the United States. Thirteen combinations of window thermal transmittance and shading coefficient are examined for each location. A life-cycle cost analysis is used to determine payback periods and savings-to-investment ratios for three combinations of shading device first cost and expected life. The evaluation assumes that any shading devices are fixed, and that daylighting is not used to offset interior lighting requirements. The results indicate that solar shading can reduce building energy consumption and improve comfort conditions in buildings with significant cooling loads. The optimum shading device characteristics vary with climatic location. Solar shading is more beneficial to buildings which are cooled all year, than buildings with summer-only cooling.