Comparative experimental study on heating and cooling energy performance of spectrally selective glazing

The study aims to evaluate thermal performance of newly developed spectrally selective coated glazing (SS) which has very low near infrared (NIR) transmittance and fairly high visible (VIS) transmittance. The performance of SS was first tested in full scale mock-up test cells and then compared with three types of conventional glazing systems (single low-e, triple low-e and clear). The comparative field test without air conditioning showed that solar gain of SS was less than or similar to the conventional glazing systems due to the low NIR transmittance, which present a potential of cooling energy saving in building application. Based on the field test, the thermal performance of SS was predicted using a building energy simulation. The simulation result showed that SS reduce 21% and 33% of total energy consumption as compared to the glazing with low-e coating and the glazing without coating respectively. The study concluded that SS can achieve lighting energy reduction with high VIS transmittance and cooling energy reduction with both high NIR transmittance and high U-value. Ultimately, SS will be highly applicable in cooling-dominated buildings or climate zone.