Smart Curtain : An Innovative System for Energy Conservation

Sammanfattning: The goal of the thesis was constructing a control system for a curtain that would regulate its position between up- and down states depending on out/indoor temperature and incoming solar radiation in order to be more energy efficient. A curtain hanging in front of a window creates a pocket of air, which in tandem with the curtain insulates the window and decreases heat loss, but at the same time it vastly decreases how much solar energy enters the room. A considerable part of a households total heat energy loss occurs through its windows. In order to lower this outflow and maximize the inflow of solar energy, it was decided upon to build a system that regulates the state of a window’s curtain. A scaled down prototype was constructed, consisting of a Styrofoam box with a window on one side, and a curtain in front of it. It was used to measure actual energy savings and also compare theoretical coefficients with experimentally procured ones, and extrapolate the results unto a larger scale. Heat transfer rates both with and without the curtain were experimentally tested. This data was then used to implement a computer program, which was developed specifically for the project. It took input arguments needed for the calculations and output whichever curtain state would be most beneficial at any given moment. The program input was partially collected from two temperature sensors and one light sensor. The output was then used to control an actuator in the form of a stepper motor to change the curtain state. Finally, wireless controlling and monitoring of the system utilizing a dashboard accessible via the internet was implemented to permit tracking of data and overriding of the control system’s decisions, should the user desire. It was found that a system of this type could deliver energy savings on the magnitude of tenths of a kilowatt-hour per day during the winter in central Sweden.