B.P. Jelle, T. Gao
SINTEF Building and Infrastructure / Norwegian University of Science and Technology (NTNU), Norway
pp. 226 - 229
Keywords: electrochromic, smart, window, energy-efficient, building
The utilization of electrochromic materials (ECM) and windows (ECW) for smart window applications in energy-efficient buildings has a large potential. The ECWs are able to regulate the solar radiation throughput by application of an external electrical voltage. Thus, ECWs may decrease heating, cooling and electricity loads in buildings by admitting the optimum level of solar energy and daylight into the buildings at any given time, e.g. cold winter climate versus warm summer climate demands. It is crucial to be able to compare the dynamic solar radiation control for different ECWs and hence require specific ECW properties. The solar radiation control for ECWs may readily be characterized by several solar radiation glazing factors like e.g. visible solar transmittance, solar transmittance and solar factor. A comparison of these solar quantities for various ECW configurations enables one to select the most appropriate ones for specific smart window applications in energy-efficient buildings, and as an example a particular ECW based on the ECMs polyaniline, prussian blue and tungsten oxide is presented. This ECW is able to regulate as much as 60 % of the visible and 59 % of the total solar radiation, whereas the solar factor regulation is as high as 44 %.