Electrostatically actuated window blinds

An electrostatic method for actuating window blinds was recently developed by the authors in work that is documented elsewhere. The method was developed in an experimental effort without the help of predictive tools. This paper examines that problem in more detail and formulates an electrostatic model for these systems. The complexity of the charge distribution over the slats and the glass demands a relatively large model (hundreds of thousands of degrees of freedom). This paper formulates the large-order model and then shows how to reduce the order of the model significantly. The charge distribution is represented as a linear combination of assumed modes. The charge distribution is assumed to be periodic in the vertical direction, which is tantamount to neglecting end effects. Experimental results verify the accuracy of the predictions in the presence of the order-reduction assumptions. The electrostatic model predicts the slat angles to within the accuracy of the measurement system. The conductive and convective heat transfer across the air space are also analyzed. The flow patterns explain the heat transfer (thermal efficiency) of windows with slats enclosed.