Total Solar Transmittance Quantifying of Transparent Insulation Building Materials Based on Real Climate Outdoor Measurements

Solar transmittance belongs to the optical properties that are more frequently required in the field of buildings as those specifically related to solar energy and thermal aspects point of view. A possible method for the measurement of solar transmittance of building's systems and materials was introduced and tested. The method is based on an outdoor climate conditions and two pyranometers setup applying of comparative in-situ measurement approach. The experimental setup was contrasted by spectrophotometer method and its validity was tested by measurements comparison with different options to obtain the best solar transmittance determination in an outdoor uncontrollable condition. Although, these measurements are applicable only for the particular measurement environment, they can easily provide an information about studied parameters. A good agreement was found and the introduced method was verified for a typical building's transparent and translucent systems like simple glass pane and Plexiglas. This was also implemented for the solar transmittance determination of a particular transparent insulation material in the form of honeycomb on Poly Methyl Methacrylate basis. Coupling of the two pyranometers (or photodiodes) with the monitoring of solar intensity behind and in front the measured materials and its ratio estimation enables its applicability as an alternative, integrated and less cost consuming method towards the characterization by more sophisticated spectrophotometer or solar simulator method.