Detailed heat balance analysis of the thermal load variations depending on the blind location and glazing type

Nowadays, curtain wall is the norm, due to which there is an increase in direct solar gain and heat loss through the window inside the building, causing massive thermal load. Use of blinds has been one of the best counter measures for this. In this study, EnergyPlus modeling has been used to measure the effect of reflectance of blind on heating and cooling load when the blind is located inside or outside for winter and summer condition. Modeling showed that in summer, as blind reflectance increased, cooling load decreased in case of internal blind and increased in case of external blind whereas in winter, the opposite was true for heating load. However, solar energy transmittance increased proportionately with the increase in reflectance of blind irrespective of position in either season. In addition, the heating load profiles under different window material compositions were determined mainly by the U-value variations, which were directly connected to the infrared and convective heat flows from the window into the space. SHGC also showed effect on the heating load to some extent by affecting the solar transmittance and convective and radiant heat flows from the blind into the space.