Experimental characterization of glazing with glass prisms

The principles of design for two types of prismatic elements have been studied. The theoretical approach has been used for design of the glass prisms to optimize their function for given application and geographic location. The two manufactured prismatic glass elements have been applied in triple glazed window samples with a low emissivity coating and experimentally tested to determine the realistic angular selective optical properties. A specific test stand for glass prism transmittance measurement has been developed and applied. The results have been compared with conventional triple glazing with clear glass panes and triple glazing with solar control pane applied, both alternatives with the identical low emissivity coating. Significant advantages of transmittance selectivity (low transmittance for high solar altitude - summer condition, high transmittance for low solar altitude - winter condition) have been proved especially for triple glazing with reverse symmetrical prism. The results open the possible application of the prismatic structures in modern façade envelopes, e.g. curtain walling facades or greenhouse walls as low-cost alternative to other types of shading devices.