DESIGN, DEVELOPMENT, AND TESTING OF AN AUTOMATED WINDOW SHADE CONTROLLER

An approach to the design of active window shades is developed to cont rol the direct solar gain through a window. Using simple actuation har dware and sensors, a control strategy is presented that automatically adjusts window shades to save HVAC energy by controlling direct solar radiation passing through a window. The control algorithm is based on a simple apl,roach that admits direct light in the winter and blocks t he direct light in the summer, while providing shade adjustment that a ffords maximum I visibility through the window. Cloudy skies or indire ct sun result in horizontal placement of the shades, and the shades cl ose at night. The implementation uses two thin film photovoltaic cells as sensors and a control algorithm that is independent of the window orientation latitude, or solar time, so that it operates properly in a ny installation location. Preliminary analytic and rest results show s ignificant energy savings when the automatic window shades are compare d with a window without shades, and with a window outfitted with fixed horizontal shades.